Type 4 engine rebuild: take 3

[SGKent]

[orwell84]

[Clatter]

Good news!

FWIW,
I use an old oil pump cover from a type 1 to mount my mag base.
The face of these is ground flat so the mag base won’t wobble on the cover.
Right next to one of the four mount holes on the cover i have ground away the raised perimeter lip area,
That way,
Any 8mm stud sticking out of a casting can be used,
And the cover bolted down tight.

If that makes any sense..
Let me know if you need a pic.


You could make something similar/better if you had a piece of plate surface ground flat,
But VW provides you one for free with every junk Beetle motor, so..
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Bus Motor Build

What’s That Noise?!?

[orwell84]

So....

I received a machinist plate and straight edge, gear puller, 6" V blocks and dial bore indicator, so I ready to split the atom now. The puller worked great.

I am not out of the woods yet in terms of crank checking. That great close-to-zero measurement on the center main appears to have been a fluke which only happened once again by accident...the tip of the dial indicator not riding correctly on the journal.

Here is what I got:

In case half:

With #1 and #3 on bearings:

#2 .00175-ish (checked out about the same with #1 and #4 on bearings)
#4 .000

I zeroed the indicator and marked high and low on the #2 journal with a sharpie

Then tried:

#3 and # 2 supported by bearings and measured:

#2 was 0 when supported by its bearing shell, but #1 just under.003, so marked high and low.

The high spot on #2 lined up pretty much with the low spot on #1, as did where #2 was low, #1 was high.

I tried it on some V blocks (on #4 and #3) on a different bench and got pretty much the same thing, but also noticed:

0 runout on #4 when supported by a v-block. #4 measured just under .001.

I also took a shot at polishing the mains, just to see how it would clean up. I have been practicing measuring the journals but have not written them down in a systematic way mostly to avoid memorizing them. Measurement is an elusive thing. After coffee in the morning is when I get my best measurements, after work, the worst. If I spend too long measuring, it all goes to hell. This weekend I'll have some time and take a good shot at it, but I have gone over all of them and they seem to measure well within spec.

I still have to check the rods in parallel. I saw a Youtube video on that, it's a cool trick.

https://www.youtube.com/watch?v=p2HDaoIKzqI

I was at least right about the camshaft thrust bearing being wiped. I can see the wear on it compared with the old thrust bearing that did 45,000 miles in the GEX engine. The newer shell measures at least .010 narrower after only about 5,000 miles using a crappy set of calipers.

I also checked the case halves with the overly large machinist straight edge I got recently and found it is maybe .0015-.002 at most low at the 3:00-9:00 between the spigots. About typical from what I've read. I will bolt the case halves together to check the mating surfaces with a flashlight as well as the bores for the main bearings. The bearings are all a snug fit in the case.

I am going to have the case decked if the other things check out.

I am pretty confident in the trends I am getting in my crank measurements, though maybe not in the exact values. I think it very well might be bent. It would seem to explain some of the issues in the top end I am seeing with this engine. I am going to send it to DPR and see what they say. If they can't fix it, they can certainly set me up with a new one.

[Clatter]

Excellent..


Maybe send the crank/flywheel/Pressure plate/fan/hub and all the bolts along to DPR as well?

They have some really nice spin-balancing equipment IIRC.


And maybe get some counterweights welded on while you're at it.
Not only will it make the motor smooth as glass, it will last longer as well.


Hey,
Not MY money, right?

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Bus Motor Build

What’s That Noise?!?

[orwell84]

[airschooled]

[orwell84]

[sjbartnik]

[RWK]

PM me, I may be able to help with your case decking if you can't find anyone local, I have 2 T4 case's of my own to do soon, see my photo album.
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73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530

[orwell84]

Here is my first attempt at taking all the crankshaft measurements. There are some obvious oddball measurements, but I will try it again another day.

[orwell84]

A couple things I was looking at today that raised some questions.

I was looking at my old 93mm pistons that came with the GEX engine I bought in 1996. The engine had 1700 heads and the cylinders had been bored for the larger sized pistons.

The pistons are dished and marked on the crown with the arrow. It is marked in a circled TS on the inside. I can't find any information on who manufactured these pistons. It would be nice to know as I am considering reusing them. I don't have pictures of them at the moment.

Also, my case number is stamped GE008130 which is a single relief case for a fuel injected bus. My case has the provisions for a mechanical fuel pump including the brass bushing and holes for the fuel pump pushrod and drain hole in the fuel pump outlet. I know GEX sometimes mixed case halve, but theses features are both on the side of the case that is stamped with the number.

Thanks

[raygreenwood]

[orwell84]

I’m at work but did find some pictures ...

[orwell84]

More case checking. Wrench tight but not torqued.

[Clatter]

Uh oh..

I’m really hoping you had the case bolts not tight at all.. Loose, even?
If your case halves were not quite home yet, then you’re OK.

Otherwise, that’s a spread center main right there..



I love your main bearing measurement diagram.
Total Jim Martin..

Do it another couple of times without looking at your first numbers and see what you get.


Know that you’re going to have to spend your 10,000 hours to pull a tenth with a HF bore gauge...
So, if you’re well within a thou you can reasonably guess that your case was line-bored to the right size and you got the correct bearings.


It’s nice to throw a plasti-gauge in that center main to confirm your measurements.

A lot to be said by feel, and some clunk-age measuring side-slop of the crank in dry bearings as well.

If you get three measurement methods to give the same numbers,
You can be reasonably sure.

Nice work.
This motor will be clean going together.
I’d go ahead and get a spin balance job, even if by a local V8 type shop.
Set yourself up for success; it’s all here on the bench.
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Bus Motor Build

What’s That Noise?!?

[Clatter]

I don’t recognize those pistons,
But,
The steel plates cast into the sides are a good sign.
Cheap pistons don’t have those.

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Bus Motor Build

What’s That Noise?!?

[orwell84]

[orwell84]

These are the 94mm pistons and cylinders I recently got from the classifieds.

[Clatter]

Hmph..

Wish I had better news,
But,
A line-bore won't fix a spread center main.

Tighten that stuff up and re-check.
ANY light thru the gap at the center main is super no Bueno.

Can you take a real close hi-res pic of the area around the center main where the case thru-bolt comes across the parting line by the bearing?

If indeed you have a spread center main, the case halves have likely been 'fretting' - i.e. rubbing against each other.
The normal machining marks made when the parting line was cut will be worn away in this area, and it will be more smooth than the rest of the parting line surface.
if it does indeed look smoother than the rest of the case, fret city sorry to say..

it's actually pretty uncommon, especially in buses,
So if you have to find a case, it's not the end of the world.


Looks like those pistons are nice, but FML those broken fins.

Because so many cylinders aren't the roundest, and a good hone job on a nice Sunnen is the fix.
Maybe your local automotive machinist has a nice hone and knows how to use it?
Any old-school motor shop has one of those hones and -should- know how to use it.

You could have your old 93 1.8 jugs taken over to 94 and use those nice 94 Mahle pistons.

The end result would be super fine if the machinist knows what they are doing.
Cylinders can get out-of-round as they get seasoned,
And a proper hone over is a beautiful thing..

Food for thought.
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Bus Motor Build

What’s That Noise?!?