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Clatter
Samba Member
Joined: September 24, 2003
Posts: 7546
Location: Santa Cruz
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 Posted: Fri Mar 16, 2018 12:21 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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Oh, lordy... You have the two most anal retentive bus engine pontificators on earth splitting hairs and making us all confused...! 
This ain't the space shuttle we're building here, guys, it's a 40-year-old bus motor that a guy wants to take camping with his kids. 
You can spend the rest of your life micro-finishing every crack and crevice on the thing if you really think that is fun.
Our OP is a busy new father, who likely even has a job,
So his goals are going to be different than yours..
Yeah, a real hone is great.
In the hands of a competent machinist, it can make even brand-new cylinders better.
I'll even say that I'm so anal I take any new sets in to be honed before use.
However,
Most people (who actually run these motors in real life),
Think I'm out of my mind, and they are probably right.
TONS of people have good luck with hones of all kinds around the world for 100+ years.
Could all of these millions of cylinders who had a light "glaze breaking" done be strewn in carnage all over the planet?
Of course not..
To or OP:
Measure the end-gap on your rings. IIRC, around .020" would be nice to see. If they are in this ballpark, you likely don't even need new rings.
You do this by sticking the ring in, and squaring it up with a piston top.
(I'll add the procedure to get this measurement in my how-to here later..)
https://www.thesamba.com/vw/forum/posting.php?mode=reply&t=695322
Measure the piston-to-cylinder clearance, you can do this with a feeler gauge.
Specs are in the Bentley.
Chances are, if they are nice and tight,
A light pass with a dingle-ball might be in order if you really want to get anal,
After you have that top damage that your machinist pointed out fixed up..
If you get new rings, the grit of dingle-ball you want will be specified by the ring vendor.
If you are good to re-use your existing rings, We can have a several-page ,1000+ word argument on here about correct grit later.
You'll need your cylinder tops fixed and your measurements first.
There's a great post about cylinders in the Performance/Engines/Racing forum right now, the only difference is that they are cutting the other end of the cylinder, so different fixturing might be required of your cylinder damage is not sand-out-able.. 
Did you ever post a pic of this damage?
I'd like to see it.
At this point, we are arguing about something we don't even know is true or not.
Your old cylinders might be at .007".. And you'll be getting new ones anyway.
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RalphWiggam
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Joined: February 02, 2018
Posts: 906
Location: SouthEast
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| Posted: Fri Mar 16, 2018 12:46 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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Just picked up everything from the machinist. I will check for the "spread center main" tonight with a flashlight. I dont know if I have any paper thin enough so the flashlight trick will have to do.
I also ordered the correct size threaded gallery plugs in steel from McMaster. I think the total was less than $3. Cheap insurance I guess. |
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raygreenwood
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Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Fri Mar 16, 2018 12:53 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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| RalphWiggam wrote: |
OK I understand what both of you are saying, but I am thoroughly confused as to how to proceed. Don't use a 3 bar hone no matter what. Got that. It doesn't seem like I will find a shop around here that will have a machine to hone standalone cylinders. I think that is out of the picture. So now I will do the next best option....
I do have a drill press.
Earlier I thought it was recommended not to use a flex hone at all. Now I should use a flex hone but make sure it is the correct grit and do it very lightly?
Do nothing to the cylinders and reuse the rings if they measure correctly in the cylinders?
Use the old rings if they measure correctly but still flex hone the cylinders very lightly?
Always use new rings you gd noob and lightly flex hone?
Did I miss any options? |
As I noted.....and as Clatter is pointing out in that last post.....measure the cylinders first or pay to have them measured. You are looking to see if they are straight in the vertical ....which is called taper......and round with no significant high or low spots.
This only takes a few minutes with a dial bore gauge.
Or....for taper at least as Clatter was getting at.....you can do a respectable job or checking for taper by taking a top or middle piston ring and inserting it into the bore near the top. Take an upside down piston and push it into the bore pushing the ring down about 3/4". This makes it sqaure to the bore.
Then use feeler gauges to measure the gap in the ring.
Push the ring down to the middle of the bore and repeat. Then down to the last half inch of the bore where the rings previously travelled....and repeat. Compare these numbers.
Clatter.....yes....I agree. Its not rocket science. And....that was my whole point. Millions of people on older style engines not using modern sophisticated ultra thin ring packages with special coatings on special liner material like modern factory engines.....can get perfectly acceptable if not spot on factory tolerance for a re-hone......and honing is NOT the same as "cutting" a cylinder to a larger size......with the careful application of a simple well made honing tool.
I have seen people with eons of experience do factory level hand honing with a simple but well made 3 stone spring hone. We know it was factory level because they had the measuring tools to check their work.
This is not saying that you need to own that tool.
I have seen many, many people using a 3 stone hone, a flexhone (ball style) or a Wiseco brush style spiral abrasive hone.....do superb work.
And.....I included that podcast because a good amount of what they noted is spot on. For general thick cast iron rings like most that we use.....the rings are not all that picky. The surface tooth only needs to be large enough.....but not too large. The angle needs to be close....but does not have to be perfect.
They will work.
My whole point to this diatribe ahout surface profiles and honing.....as happens so often here these days....is not to tell people they need $20k worth of tools.....but for damn sure do not try to tell me or other people....that the use of a less than ideal tool ....cannot produce perfectly acceptable...and even EXCELLENT results when use carefully and properly......if the person telling me this does not even own the tools to measure how well the IDEAL tool is supposedly working. See the point here?
Here is my whole point in a nutshell:
RalphWiggam..... you can do just fine for putting a new cross hatch pattern on your cylinders for new rings....with either the three stone hone or a Flexhone.
The three stone/three leg hone takes more practice. All of these hand hones take SOME practice so I suggest if you have never done this:
1. Find an old cylinder to practice on an break in the hone
Or.....
2. Have them honed for you by a shop with a proper honing machine....so that you do jot run into the exact problem that SGKent pointed out.....of the shop just using any old flexhone they have laying around.
ANY of the hand hones you buy....Flexhone or 3 leg spring hone MUST have the correct TYPE of abrasive for cast iron...which is silicon carbide.....and MUST be the correct grit as recommended by your piston ring manufacturer. You dont just by a generic hone.
MOST MOST MOST importantly....you first need to do the taper check we described. If the cylinders have too much taper.....a hand hone will not fix that.
And....just as importantly....a honing machine WILL fix taper....but then the cylinder will now be OVERSIZED....making your pistons worthless to reuse....which defeats the whole purpose of honing and reusing your cylinders.
Some "slight" low spots are not a huge issue depending on how big they are
So check the taper first.
Ray |
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Clatter
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Joined: September 24, 2003
Posts: 7546
Location: Santa Cruz
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| Posted: Fri Mar 16, 2018 1:46 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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The last set of AA P&L I have right here were almost .002" taper top-to-bottom,
The pistons varied in size over .0015,
And the fit was accordingly all over the place.
Some were even a slight interference fit to the cylinder...
So,
You are more likely to have good luck with the ones you got, even if they are used.
What's those measurements, again??
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RalphWiggam
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Joined: February 02, 2018
Posts: 906
Location: SouthEast
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| Posted: Fri Mar 16, 2018 2:47 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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| Clatter wrote: |
The last set of AA P&L I have right here were almost .002" taper top-to-bottom,
The pistons varied in size over .0015,
And the fit was accordingly all over the place.
Some were even a slight interference fit to the cylinder...
So,
You are more likely to have good luck with the ones you got, even if they are used.
What's those measurements, again?? |
Ill try and get the taper measurements tonight after the kids/wife go to bed. |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Fri Mar 16, 2018 3:05 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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| RalphWiggam wrote: |
| Clatter wrote: |
The last set of AA P&L I have right here were almost .002" taper top-to-bottom,
The pistons varied in size over .0015,
And the fit was accordingly all over the place.
Some were even a slight interference fit to the cylinder...
So,
You are more likely to have good luck with the ones you got, even if they are used.
What's those measurements, again?? |
Ill try and get the taper measurements tonight after the kids/wife go to bed. |
So you have to wait until the wife is asleep to fondel the inner parts of your metal girlfriend?.....  .....Ray |
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RalphWiggam
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Joined: February 02, 2018
Posts: 906
Location: SouthEast
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| Posted: Sat Mar 17, 2018 7:47 am Post subject: Re: Sealing rings at top/bottom of cylinders |
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Drank too many beers last night to trust myself with these kind of measurements but I've got everything that was requested.
I do not see any center main gap with an extremely bright flashlight directly behind the seam and I cannot get my .04mm feeler in there (thinnest I have).
Pistons/Cylinders/Ring Measurements (using an old ring):
The diameter of the skirt at the bottom of every piston is slightly larger than the diameters measured at the pin. I don't think there is any skirt collapse anywhere that I can measure.
Ring gap
#1 top - .4mm
middle - .4mm
bottom - .4mm
skirt gap at bottom of cylinder - .05mm
#2 top - .4mm
middle - .4mm
bottom - .4mm
skirt gap - .06mm
#3 top - .4mm
middle - .4mm
bottom - .45mm tight
skirt gap - .09mm
#4 top - .45mm tight
middle - .45mm tight
bottom - .45mm tight
skirt gap - .09mm
Cylinder distance between both sealing surfaces:
#1 - 3.603"
#2 - 3.602"
#3 - 3.603"
#4 - 3.603"
These measurement's were taken after lapping the top sealing surface on glass plates and 400 grit. I was also able to lap the bottom sealing surfaces to the case today.
Looking good or not?
I did a dry fit with the crank in the case to get a new deck measurement from #4. My deck is now .014. This is with no spacer under the cylinder, 6 case bolts torqued to about 10ftlb or so. Cylinder was lightly torqued to the case. Ive ordered .030 cylinder shims to bring the deck up to .044. A .025 shim wouldve been ok i think but i cant find any of those. I pulled out 10 oil gallery plugs as well. I left the one in that is right behind the fuel pump rod bore. I will thread those early this week and then hopefully get my case cleaned again somewhere.
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RalphWiggam
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Joined: February 02, 2018
Posts: 906
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| Posted: Sun Mar 18, 2018 5:12 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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Trying to order piston rings now. Was going to get the deves ones from acn. Does anyone know what this marking is on the tops of the pistons?
Are these oversize or standard pistons? |
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Sun Mar 18, 2018 7:23 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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89.97 would be a standard "90mm" piston.
Standard oversize increments are 0.5mm or .020". The arrow mark points toward the flywheel.
If memory serves that "+" mark denotes a weight class. According to the "without guesswork" book.....for a type 2 1700, a " - " mark weight (brown paint code when new) is 496 to 504 grams or 456 to 464 grams depending on piston type. The "+" weight code is a gray paint mark and is 504 to 512 grams or 464 to 472 grams depending on piston type.
I am not sure what the 0,4 mark means. Those look like standard pistons.
The other mark on the other side.....looks a lot like a "Cofap" brand mark. In those days....late 90s....Cofap was TRW of Brazil. They were castong their own high quality cylinders or using CIMA/Mahle cylinders paired with Kolbenschmidt German pistons. Very high quality parts
So far those look quite good. Ray |
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Clatter
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Joined: September 24, 2003
Posts: 7546
Location: Santa Cruz
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| Posted: Mon Mar 19, 2018 12:51 am Post subject: Re: Sealing rings at top/bottom of cylinders |
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OK, back to our motor build here..
Hopefully we're done with that nonsense for a while.
Way more fun doing motors than troll control..
Nice work with the measurements! 
The case parting line looks good from the pics.
It's obviously the view in real life that matters..
Jake always had what he called the 'carbon paper trick', where he used some old carbon paper,
that was a lot thinner than regular paper,
And if it can be pulled free of a torqued case without tearing,
the case was junk.
This being right next to the main bearing holes; directly adjacent.
If your case had decent oil pressure before being torn down, it's likely good as well.
Use old fashioned inches, m'self.. And they have them in the Bentley,
So pardon my translation.
The measurements made at the piston skirt to cylinder wall is .9mm (biggest)
That translates to .035. A very good sign.
Have done a re-ring on cylinders that were honed to the wear limit of .006,
And they have lasted for years and years, still together and running.
(Not that this is the best idea, just FYI).
Perhaps the machinist that did your other parts would be interested in honing them, just lightly to 'break the glaze'?
If you explained to him the situation with cylinders being 'China Only' now,
He might be receptive to the idea?
Even after the whole rigamarole here, a 'real' automotive (Almost always a Sunnen) hone is the best way to go.
Most typical auto machinists do a lot of iron bores.
Maybe make sure the grit and recommended procedures specified by the ring manufacturer can be followed?
Not all professional automotive machinists are idiots, contrary to what some on this site would have you believe.
Looking at your overall cylinder base-to-head distance..
Hoping that #2 (the short one) is the one you were lapping the mark out of?
WRT cylinder length, the closer you can get them to same the better.
Any variation in cylinder length reduces your heads' ability to seal.
Are there any local machine shops that might be willing to look at your cylinders?
A good 'prototype' machine shop (vs. Automotive) will have good inspection tools; a granite surface plate and height gauge.
If a good machinist can measure a difference, they can likely correct it.
Your damaged area seems to be coming out nicely, so this extreme step of finding (and especially trusting) a prototype shop to clean up the damage,
Then cut the rest to the same length as the fixed one,
Would be hopefully avoided..
Just sayin'.. If it ends up being a fairly big job to clean up the damaged cylinder, it will be an even bigger job to get the rest lapped down to the same size.
Then, how are you going to get them all exactly the same length?
And also, keep them square..
So,
If those marks are cleaning up easily enough,
then no big deal,
But if it takes a whole lotta humpin' to get it clean,
Some professional help might be in order.
Know that people who really care about these things will measure even new cylinders with precision equipment,
Then true as needed to get them better than new spec.
As quality has gone down, this is done more and more.
Just because yours are good quality, doesn't mean they are 100%.
(actually nothing is, right? just how good your measuring tools are, right?)
Central limit theorem again..
They can me conical inside, not square to the bore, mounting surfaces not parallel, etc. etc.
Bet you there is an old-timer machinist in your area who would enjoy the job.
Question is, if you can find him..
JMHO, FWIW, etc.
If you are building the best engine you can..
If you just want to get it going again, not neeeded at all.
Can you describe the lapping it took to get where you are now?
Looks like the pistons were balanced.
Check to make sure there is one that wasn't touched - the light one.
Do you have a small postal scale?
Would be good to check the rods too, for over-all weight, just to verify.
Anyhow, Nice job.
Thanks for sharing.
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Clatter
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| Posted: Mon Mar 19, 2018 1:08 am Post subject: Re: Sealing rings at top/bottom of cylinders |
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Looking again at your cylinder pictures..
Just based upon what they look like,
94 3/4% of builders would slap them in,
And run em' for years,
Just like they are.
It's a thing for people on forums like this to go micro-ANALyzing and splitting hairs for no reason..
Very much guilty of this as well here.
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Abscate
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| Posted: Mon Mar 19, 2018 3:50 am Post subject: Re: Sealing rings at top/bottom of cylinders |
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I've learned how to measure the taper on my pud on this thread. Now I need some oversized rings.
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RalphWiggam
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| Posted: Mon Mar 19, 2018 5:17 am Post subject: Re: Sealing rings at top/bottom of cylinders |
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My measurements for the distance between cylinder sealing surfaces was done as best as I could. It is an awkward measurement to take with a caliper gauge and I'm sure there was some margin of error.
Perhaps I can lay a straight edge across the tops of both of them while in the case to see if they are level? I did lap the tops of all of the cylinders at least some. I will also lap them to the heads when I get those.
Can I just order any standard 2mm,2mm,5mm ring package for these cylinders? My old rings all measured slightly thinner than that. |
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raygreenwood
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Posts: 21520
Location: Oklahoma City
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| Posted: Mon Mar 19, 2018 7:34 am Post subject: Re: Sealing rings at top/bottom of cylinders |
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| RalphWiggam wrote: |
My measurements for the distance between cylinder sealing surfaces was done as best as I could. It is an awkward measurement to take with a caliper gauge and I'm sure there was some margin of error.
Perhaps I can lay a straight edge across the tops of both of them while in the case to see if they are level? I did lap the tops of all of the cylinders at least some. I will also lap them to the heads when I get those.
Can I just order any standard 2mm,2mm,5mm ring package for these cylinders? My old rings all measured slightly thinner than that. |
Ok....a couple of things.
What clatter said about your pistons and cylinders....I agree they look bery good and 90% would just slap them back in and have for decades. Technically its probably fine.
However I no longer believe in doing it that way.....because.....
A. I have the tools to measure
B. Its the correct way to do it
C. I work on versions of this engine where original pistons are are nearly unobtanium. The last NOS set I saw for sale on line in December were $900.
Parts are not getting any less scarce and the bus is following the same trajectory. Conserve while you can.
That being said.....the primary reason I am suggesting you should measure as much as possible.....is that you have not been able to point to how many miles that engine has in your records. There is no way it has 250k miles. There is no way it is new either.....but it damn sure looks like it could have 30k or less.
And most importantly.....you will not find a set of small dish NOS, high quality pistons like those...almost anywhere right now. So I am trying....through measurements..... to get you to point to the fact that those pistons and cylinders are spot on. As good of condition as they "look" to be.....it would be sad to put them in and have the rest of the engine destroyed by something that was missed.
Yes....you can lap the cylinders slightly into the case....and then put a straight edge across the top of the two. Make sure its a good machine straight edge. Not just an office depot stainless ruler. Having a couple thousandths of gap here is not a problem. More than about .003" and you need to have it fixed.
You need to measure the rings with a micrometer. Post what you have. Also measure the grooves. They "should" be standard....but you will noyy know until you measure.
Tell us about the lapping on the cylinders. What are you lapping them to....lapping them with....and are you staining the edge before lapping with a sharpy marker or dye?
The case looks great so far. You need to pull and tap the galley plugs if it has not been done. Ray |
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RalphWiggam
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| Posted: Mon Mar 19, 2018 10:39 am Post subject: Re: Sealing rings at top/bottom of cylinders |
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| raygreenwood wrote: |
| RalphWiggam wrote: |
My measurements for the distance between cylinder sealing surfaces was done as best as I could. It is an awkward measurement to take with a caliper gauge and I'm sure there was some margin of error.
Perhaps I can lay a straight edge across the tops of both of them while in the case to see if they are level? I did lap the tops of all of the cylinders at least some. I will also lap them to the heads when I get those.
Can I just order any standard 2mm,2mm,5mm ring package for these cylinders? My old rings all measured slightly thinner than that. |
Ok....a couple of things.
What clatter said about your pistons and cylinders....I agree they look bery good and 90% would just slap them back in and have for decades. Technically its probably fine.
However I no longer believe in doing it that way.....because.....
A. I have the tools to measure
B. Its the correct way to do it
C. I work on versions of this engine where original pistons are are nearly unobtanium. The last NOS set I saw for sale on line in December were $900.
Parts are not getting any less scarce and the bus is following the same trajectory. Conserve while you can.
That being said.....the primary reason I am suggesting you should measure as much as possible.....is that you have not been able to point to how many miles that engine has in your records. There is no way it has 250k miles. There is no way it is new either.....but it damn sure looks like it could have 30k or less.
And most importantly.....you will not find a set of small dish NOS, high quality pistons like those...almost anywhere right now. So I am trying....through measurements..... to get you to point to the fact that those pistons and cylinders are spot on. As good of condition as they "look" to be.....it would be sad to put them in and have the rest of the engine destroyed by something that was missed.
Yes....you can lap the cylinders slightly into the case....and then put a straight edge across the top of the two. Make sure its a good machine straight edge. Not just an office depot stainless ruler. Having a couple thousandths of gap here is not a problem. More than about .003" and you need to have it fixed.
You need to measure the rings with a micrometer. Post what you have. Also measure the grooves. They "should" be standard....but you will noyy know until you measure.
Tell us about the lapping on the cylinders. What are you lapping them to....lapping them with....and are you staining the edge before lapping with a sharpy marker or dye?
The case looks great so far. You need to pull and tap the galley plugs if it has not been done. Ray |
I pulled 10 galley plugs last night. They did not come out easy, so I dont know if they really needed to be done. I left the one behind the fuel pump pushrod. Will try and get them tapped in the next few days and then the case recleaned.
For the cylinders I bought 4 sheets of 12x16 glass and stacked two together with a piece of 400 grit on top. Started working (making sure to stay perfectly flat) until I could see a perfectly shiny uniform edge. There are 2 cylinder tops that look to have a slight downward angle on the outside edge. It is shown in one of the pics I posted.
I dont think there is anyway to get rid of that without taking a lot of material off. I was kind of hoping the softer head material would deform to those spots. Is this a problem? |
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raygreenwood
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Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Mon Mar 19, 2018 11:58 am Post subject: Re: Sealing rings at top/bottom of cylinders |
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| RalphWiggam wrote: |
| raygreenwood wrote: |
| RalphWiggam wrote: |
My measurements for the distance between cylinder sealing surfaces was done as best as I could. It is an awkward measurement to take with a caliper gauge and I'm sure there was some margin of error.
Perhaps I can lay a straight edge across the tops of both of them while in the case to see if they are level? I did lap the tops of all of the cylinders at least some. I will also lap them to the heads when I get those.
Can I just order any standard 2mm,2mm,5mm ring package for these cylinders? My old rings all measured slightly thinner than that. |
Ok....a couple of things.
What clatter said about your pistons and cylinders....I agree they look bery good and 90% would just slap them back in and have for decades. Technically its probably fine.
However I no longer believe in doing it that way.....because.....
A. I have the tools to measure
B. Its the correct way to do it
C. I work on versions of this engine where original pistons are are nearly unobtanium. The last NOS set I saw for sale on line in December were $900.
Parts are not getting any less scarce and the bus is following the same trajectory. Conserve while you can.
That being said.....the primary reason I am suggesting you should measure as much as possible.....is that you have not been able to point to how many miles that engine has in your records. There is no way it has 250k miles. There is no way it is new either.....but it damn sure looks like it could have 30k or less.
And most importantly.....you will not find a set of small dish NOS, high quality pistons like those...almost anywhere right now. So I am trying....through measurements..... to get you to point to the fact that those pistons and cylinders are spot on. As good of condition as they "look" to be.....it would be sad to put them in and have the rest of the engine destroyed by something that was missed.
Yes....you can lap the cylinders slightly into the case....and then put a straight edge across the top of the two. Make sure its a good machine straight edge. Not just an office depot stainless ruler. Having a couple thousandths of gap here is not a problem. More than about .003" and you need to have it fixed.
You need to measure the rings with a micrometer. Post what you have. Also measure the grooves. They "should" be standard....but you will noyy know until you measure.
Tell us about the lapping on the cylinders. What are you lapping them to....lapping them with....and are you staining the edge before lapping with a sharpy marker or dye?
The case looks great so far. You need to pull and tap the galley plugs if it has not been done. Ray |
I pulled 10 galley plugs last night. They did not come out easy, so I dont know if they really needed to be done. I left the one behind the fuel pump pushrod. Will try and get them tapped in the next few days and then the case recleaned.
For the cylinders I bought 4 sheets of 12x16 glass and stacked two together with a piece of 400 grit on top. Started working (making sure to stay perfectly flat) until I could see a perfectly shiny uniform edge. There are 2 cylinder tops that look to have a slight downward angle on the outside edge. It is shown in one of the pics I posted.
I dont think there is anyway to get rid of that without taking a lot of material off. I was kind of hoping the softer head material would deform to those spots. Is this a problem? |
That outside edge on that one cylinder should not be a big issue.
The lapping looks fine but finish with some 800 grit. 400 is not all that fine.
You need to pull that last galley plug and replace it.
No....NEVER leave old galley plugs in. Even if this case has only 50k miles on it....its unbelievable how much crap finds its way into those dead ends.
And.....when a galley plug comes out while driving...and they eventually will.....because of heat cycling of the case.....about 9 out of 10 times.....your engine will be toast if you are at highway speed. Ray |
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RalphWiggam
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Joined: February 02, 2018
Posts: 906
Location: SouthEast
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| Posted: Mon Mar 19, 2018 12:03 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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Literally everything that I've read says not to mess with the one galley plug behind the mechanical fuel pump rod bore. The 2 reasons mentioned are that the oil pressure is extremely low at that point and it is almost certain that I will drill or tap into the fuel pump rod bore (and cause a very bad day).
Is this not true? |
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Clatter
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Joined: September 24, 2003
Posts: 7546
Location: Santa Cruz
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| Posted: Mon Mar 19, 2018 12:47 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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Correct.
Leave that one by the fuel pump pushrod alone, if you have an early case with the provisions for the mechanical fuel pump.
Later cases have the pump pushrod bushing deleted,
So that's why you see them plugged,
And there's a lot more of the later cases out there.
Details at the bottom of the page:
http://shoptalkforums.com/viewtopic.php?f=1&t=145853
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Bus Motor Build
What’s That Noise?!? |
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raygreenwood
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Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Mon Mar 19, 2018 1:07 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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| Clatter wrote: |
Correct.
Leave that one by the fuel pump pushrod alone, if you have an early case with the provisions for the mechanical fuel pump.
Later cases have the pump pushrod bushing deleted,
So that's why you see them plugged,
And there's a lot more of the later cases out there.
Details at the bottom of the page:
http://shoptalkforums.com/viewtopic.php?f=1&t=145853 |
No...the pushrod bushing is NOT deleted on fuel injection cases. Maybe on very late bay cases...but its still in there on many early fuel injected 1.7L cases even with no fuel pump drilling.
I can see it probably being fully deleted on hydraulic cases but its still there on far too many.
And no the oil pressure...while its low here.... is not low enough IMHO to risk either losing that galley plug or risking the crap that builds up behind it...and there is a lot. One of the biggest chunks of crap that came out of the 1.8L I am building now....came out of that galley.
I use a similar method to pulling the plugs that you do...but I do not use a long screw. I use a short 6mm screw and tap the threaded hole especially in that plug.
I have not screwed up a brass galley orifice yet.
Also...there is "0" need for drilling on that galley plug to tap it. In fact...I only had to drill ONE galley for tapping...ever. Thats the small 1/8 NPT plug up near the fan seal on the 1/2 side.
Typically you just need to enlarge a few of the 3/8" NPT holes "slightly"...and unshroud around the oil cooler mount plugs to get a straight shot at them with the tap. Just use a dremel tool with the 1/4" sanding drum and no drilling is required.
Just start with a tapered tap...use lots of tap magic and grind the tap shorter at least twice. Use a shallow screw plug and grind the outer and inner end slightly.
Replace ALL of the galley plugs....always.
While the pressure may be lower here...its still at least 50% of whatever the main galley is running. At cold weather start up that can still be 50-60 psi. At highway rpm...that can still be 25-30 psi. The volume is still high regardless of the pressure
If that plug comes out....it will still kill your engine.
Oh...Edit/Correction. I forgot that the two 1/4 NPT plugs on teh outside end of teh oil cooler mount...those benefit from a little drilling too. Far easier than the sanding drum where they are.
Ray |
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RalphWiggam
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Joined: February 02, 2018
Posts: 906
Location: SouthEast
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| Posted: Mon Mar 19, 2018 5:37 pm Post subject: Re: Sealing rings at top/bottom of cylinders |
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Dangit. Can we compromise by peening it really well? The other plugs were very difficult to get out and I don't want to mess this up now.
Just got through making a nice clean radius on the bearing saddle for the double thrust cam bearing install. Cleaned the lifter bores and distributor bore with scotch Brite and a dowel. Cleaned all the bearing saddles lightly with scotchbrite. Cleaned up some case flashing with the dremel. Went around the case mating surfaces very delicately with a file looking for any high spots and then cleaned those surfaces with scotchbrite as well. Also took down the edges for the pushrod tube seals and cleaned those bores really well with scotchbrite.
Anything else I should do to the case besides tapping for the plugs before I take it to get cleaned for the final time? |
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