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Sun Mar 25, 2012 2:11 pm

Hey guys, I decided to separate this problem from my head thread in order to try and get a better understanding.

So I have been fooling with getting the measurements all day today and finally gave up... I removed the rings and put the cylinders back on to get the positive measurement (best I can)... I am not able to bolt the cylinders down this way but looks like they seated pretty well so it will be real close.

Note by positive I mean sticking out of the cylinder... (it may be considered negative DH?)

My results:
Cyl 1 = 1.5mm (0.059)
Cyl 2 = 1.2mm (0.047) (give or take)
Cyl 3 = 1.5mm (0.059)
Cyl 4 = 1.1mm (0.043) (give or take)

Visually it did seem like 1 and 3 were a tad farther out... but agn no way to bolt the cylinders down.

So with these numbers what is the best way for me to set the Deck Height... should I just get an 0.100 shim and call it a day...

I know I could shave the piston heads to get zero deck height and then shim as needed for exact amount as well... but unsure who can do that near me... if the above is in speck, I will go with it...

thanks

Sun Mar 25, 2012 2:58 pm

I just switched the cylinders front to rear and now it looks almost even over 1mm under 1.5

And I did find these:
15166 94mm cylinder spacers, .098
http://www.proflowperformance.com/products2.html
Bottom right... looks like they may do it... thoughts?

Sun Mar 25, 2012 5:46 pm

I wish I had better tools... I can’t see a way to bolt them down with the piston outside the cylinder. I tried to bolt them down and then removed the bolts to allow the piston to go outside the cylinder agn...

best I can tell 1&2 are even and 3&4 are even

1&2 = about 1.4 (0.055)
3&4 = about 1.1 (0.043)

All I have is a micrometer to measure (not even digital)...

so what now? get the .098 spacers and deal with outcome or should I find a way to balance the sides so they are equal?

Approx numbers with the .098 spacer.
.098 - .055 = .043
.098 - .043 = .055

Mon Mar 26, 2012 3:53 am

I will try to use some sort of spacer tonight... I checked agn last night and only checked each side of the wrist pin and it looks like it’s about and even 1.35 (.053) - (best I can tell with my micrometer) so I am going to order the .098 spacer and install that...

.098
1.35 (0.053) = .045 Deck Height

I will still try to get some tubing or something to re check but I think it’s pretty close as is... Once I get the spacers I will be able to bolt a bar on and use feeler gauges to check as well.

Mon Mar 26, 2012 7:18 am

you might have better luck with responses if you post this over on the performance/engine forum.
I'll take a stab...
without the right tool, your just guessing... There are three big issues I see if indeed you managed to measure correctly and the cylinders are seated.
1. you should have NO positive DH. The pistons should be down below the top of the cyl by a minumum of .040" any less, and you run the risk of smacking the head if something goes south (like a rod bearing).
2. the measurements should be the same accross the board. if not, you have some dimension problems. the centerline of the crank should be exactly parallel with the deck so the top of the cyliders are perfectly alligned. if they are not, you will not have sealing problems at the head.
3. whatever dimension you are getting in one cylinder should be the same as the others. if not, you may need to have the case deck surface machined, or align bored, or both.
sounds like you have a bit of a mess going on here...

Mon Mar 26, 2012 9:41 am

It has a positive (or negative depending on how you look at it) DH because it’s a stroker motor...

I did chk them agn and got an average of 1.35 on all pistons when measured at teh wrist pin (the piston will rock a bit with rings off so that accounted for the dif. numbers). With a 1.35 positive DH and a .098 spacer I should end up with .045 compression... Once I have the spacers I will measure agn, and once the heads come back in I will chk with putty and measure agn for valve clearance... THis has just been hard due to the positive piston DH and not having the best tool for the job... however I do have a bar and feeler gauge to chk once I have the right spacer... the .098 should get me what I need... if not I plan on starting a new case this fall and putting the current on in stand by... so I will have the new one with fresh deck and all the other bells and whistles...

more info when I get the spacers and have measured...

thnx for you time and comment... everything helps.

Mon Mar 26, 2012 9:58 am

You are on the right path with trying to get the DH exact. With positive deck you will not be able to get a good measurement unless you buy the 0.100” spacers and recheck with the proper tool. Use a feeler gauge if needed. Make sure to check with the rings on the pistons as it will reduce piston rock. And don’t forget to deburr the barrel spacers as they are stamped. The key to building a strong, reliable engine is in the details.

Mon Mar 26, 2012 11:45 pm

Very seldom will you have all four decks exactly the same. A few thousandths either way is ok, its nothing to worry about. Posting this in the engine forum will get ya more replys.

Sun Apr 15, 2012 8:09 am

My measurements show (best I can tell) that if I had .080 and .070 I can get a .045 deck (or at least close). If I could do .075 and .065 I could get a .040 deck.

Looking around the closest I can find is the following:

Found a guy who has .080 spacers that measure .078
He has .060 spacers that measure .062
he has .020 spacers that he says measure .020
I have some .010 and .055 (per my mic)

now I could use the .078 and the .060 with my .010 to get me a .045 (will not be dead on but I don’t think many people are dead on for this stuff.

or

I can use my .055 and his .020 with my other .055 and my .010 to get .040 (this one would be a tight .040 on one side and lose .040 on the other.

No matter what I do I am unable to get exact numbers unless I have the case decked and have custom spacers made... or have my piston heads shaved to match each cylinder to zero the deck and then get the shims to even it out, I would still need to deck the case I think for this as well.

Should I just go with the above (.040 or .045 ) and forget about being exact? I think I am being far too picky.

Sorry for the lengthy question..

Mike

Mon Apr 16, 2012 2:32 pm

Chances are the case and the cylinders are not that far off. The differences will be in the piston pin height, rod length and crankshaft. Use the same thickness of shims on each side of the case. You want the top of the cylinders to be even, not one higher than the other. Dont worry if a piston is .005 off or so, its no biggy. If you must have every thing perfect measure the distance each piston is above each barrel and have the tops machined down equal to the top of there cylinders. Then add a .040 copper head gasket. wallah perfect deck height.

Mon Apr 16, 2012 3:35 pm

I am pretty sure if I do .080 on one side and .070 on the other side it will come out to be just about .045 for the deck height measurement... this is what I am shooting for... however at this point I realize I was trying to get an exact measurement with unequal things... Fall I plan on having the case decked and #3 reinforcement done... so at that time I will make sure they deck the case to an even measurement, and I will have the piston heads checked for flatness as well... and I may also zero the deck to make future changes easier. Honestly I am pretty sure most people are just rounding there numbers to the nearest deck height… I know for sure what it takes to get it exact at this point…

spacers are on the way for .045 (+ or - for now).

thanks

Tue Apr 17, 2012 7:58 am

myrddin wrote: I am pretty sure if I do .080 on one side and .070 on the other side it will come out to be just about .045 for the deck height measurement... this is what I am shooting for... however at this point I realize I was trying to get an exact measurement with unequal things... Fall I plan on having the case decked and #3 reinforcement done... so at that time I will make sure they deck the case to an even measurement, and I will have the piston heads checked for flatness as well... and I may also zero the deck to make future changes easier. Honestly I am pretty sure most people are just rounding there numbers to the nearest deck height… I know for sure what it takes to get it exact at this point…

spacers are on the way for .045 (+ or - for now).

thanks

So you're going to have one side of the engine slightly wider than the other, and have to run differnt length pushrods? I guess you could run a .01 shim under the narrower side and avoid the pushrod issue. Did you ever get the cylinders bolted down tight and get an accurate measurement? Without a way to get accurate measurements, you're guessing at best and just pissing in the wind. I'm sure it will run ok, but you will never get full performance out of it.

Tue Apr 17, 2012 9:07 am

yeah, I have the deck height tool to bolt the cylinder down with... Also replaced the rods with CB Performance H rods... I didnt think of the pushrod length... Is that going to be an issue?

I have two choices:
1. Run the .080 and .070 to get a .045 deck and measure and cut my pushrods per side. Or cut them even and shim the rocker arm on one side.

2. Run .075 on each side and deal with whatever compression that will give me... and cut the pushrods to meet my needs.

.075 on both sides will give me like .040 and a .050 Deck Height... With a quick guess...

Seems like I would want the deck even ??

Tue Apr 17, 2012 9:20 am

Performance wise, you would be amazed how many national speed and ET records have been set/broken with mis-matched engine parts.

One current record was done with a welded up pushrod. The push rod broke on a burn out and they stick welded it together, used a hammer to straighten it and ran it. Main and rod bearings sanded to clearance with 320 grit. Galvanized flat washers stacked under a waste gate spring to achieve a higher boost. Camshaft lobe ground on a bench grinder. Mis-matched heads. One engine that set a record, ran so hot the valve guides kept coming loose. They drilled the valve guide boss and ran sheet metal screws in the boss against the guide to hold it still for another pass.

Shimming the barrels different side to side to "close in" on the compression has been done for a long time. No biggie.

The only concern I would have is to measure the barrels to make sure the tops are even so the head sets and seals on the barrel tops. This is critical.

As far as pushrods go, split the difference. Make all eight the same length. Just have 4 that will be 0.005 short and 4 that will be 0.005 long. 0.005 short or long will not make any difference on longevity of the engine or on performance. 0.005 is hard to measure the difference on the geometry of the rocker on the valve.

Tue Apr 17, 2012 10:24 am

thanks man... I tend to be over picky... I read one thing and understand that it’s just how it’s done... but all in all I see that with metal and motors... in most cases rounding up or down and splitting the diff. on small numbers seems to be more common than not.

I will post my numbers when I get the new shims and let you guys know how it turns out... will still shoot for .045 then with the above info mentioned... and as recommended I will try to split the dif. for the pushrods.

thanks for the info.

Tue Apr 17, 2012 10:42 am

If you can shorten all 8 push rods to within 0.010 inch in length, you really have done something and should be considered a master.

Just as a pushrod bench mark, the major players in Big Block Chevy racing supplies offer custom pushrods made to length to within 0.050 in length. So depending on what length you need, you could be up to 0.025 long/short depending on what length you pick. At that, the 0.025 difference cannot be seen on the valve tip. I just helped a buddy set up his valve train on a race 468 BBC three weeks ago and 0.050 variance did not change the geometry to where we could measure it.

Now on splitting differences and ball parking, never compromise on bearing clearances. Always be spot on with those.

Tue Apr 17, 2012 2:07 pm

thanks man... that makes me feel better too...

Fri Apr 27, 2012 1:00 pm

OK guys, I finally got the new spacers...

After I had time to try to set the deck I learned 2 things...
1. my mic I am using is junk
2. this is a pain in my ass

but really... after checking the shim and seeing they were all slightly different in size the closest I can get to an even deck is as follows:

1 and 2 (.088) gives me a .052 DH
3 and 4 (.078) gives me a .049 DH

might be a bit closer but looks like it will fall into the .050 DH range. which still gives me 9.4.1 compression... that should be good for high octane pump gas I think.

I am going to mic the sob agn tomorrow and will do so until I am 10000% sure of the exact numbers... then I think I will call it a day... as long as I end up .050 or less (I know it’s not exact, but I don’t think many are) I will be fine... I will have the case decked over the winter and make sure I can set it to an even tighter deck height after I have some case work done.

you guys think I will be good set up this way? thanks for your thoughts...

Fri Apr 27, 2012 8:41 pm

What are your cam specs.....you need a pretty big cam to run 9:4.1 compression......

Sat Apr 28, 2012 5:50 am

w110

The Engle W110 Classic VW Bug camshaft grind is designed for 1.1 or 1.25 rockers, and it's specs are .392" Cam Lift, .430" Valve Lift (1.1 Rockers), 284 degrees of advertised duration, and 247 degrees of duration at .050", on a 108 Lobe Center.

This is in a buggy too not a street driven motor... track and trail only. I see the recomendation is 8-8:5:1 but all the guys I talk to say it will be fine with my set up and better for trails.

thoughts? I know the other guys run some race gas too...