John's t-4 engine rebuild

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wwebner
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Re: John's t-4 engine rebuild

Post by wwebner »

TRL wrote:Who is doing the balance work?
K&B engine and machine in N.Olmstead.
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wwebner
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Re: John's t-4 engine rebuild

Post by wwebner »

Prior to dropping the engine components off at K&B, I remembered that at teardown,we had a couple of lifters that were hanging up in their bores. One of them actually had to be knocked out with a drift. While I make a habit of doing this anyway, this motor definitely needed the lifter bores polished.
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A dremmel lite abrasive buffing wheel works good for this.
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The new lifters slide in nicely and drop through.
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The machine shop has promised 2 weeks for their work. While we wait,we will clean up the ancillary parts,pressure test the oil cooler, clean and inspect the oil pump and probably install the new rings on the pistons,except for 1 of them. It is easier to mock up 1 piston and cylinder without the rings to measure the deck ht. Also install one set of rings in a cylinder and check the ring gap. NEVER assume anything.
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wwebner
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Re: John's t-4 engine rebuild

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While we are waiting on the machine shop. (the machinist had a pacemaker surgery a couple of weeks ago), John came by and did a little prep work. first he cc'd the heads.
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For this I use a 70cc syringe. Since we know that the chamber volume should be less than 60cc, we fill the syringe to exactly 70cc.
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These chambers measured 60cc.
Normally these heads have about a 52cc -55cc volume. The 60cc is due to the step that is cast into the head's chamber.
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This was done on late air cooled Vanagon heads to replace the .030 shim originally used. This shim or metal gasket was later eliminated by VW tech bulletin to solve cylinder to head sealing problems. They did,however, want you to make up the difference with a thicker shim at the bottom of the cylinder at the case. Remember,this was the 80's. We did not have engine and fuel management systems and in order to meet U.S. emissions,most manufactures were lowering compression ratios in order to meet these standards. The trade off was a decrease in HP. The stock comp ratio on these motors is 7.1:1. We may be stuck with this. We'll see what we have when we mock up and take the rest of our measurements and see what we have. I really would like to see about 7.6:1.
John then installed the new rings on the pistons. We left them off of one piston as it is easier on mock up to measure the deck ht. without the rings. Since we are not blue printing this motor,we will go with checking one cylinder for this.
Picture 004.jpg
Next,we took the oil pump apart for cleaning and inspection. This one looked quite good. No scoring. The gears look perfect. There was some slight wear on the tang that engages the cam slot but this is normal and not of concern. The O ring will be replace with a new one from the gasket kit.
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borrowed Sean's camera for this pic :lol:
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John cleaned and paint all his tin and other than pressure testing the oil cooler,there is not much to do untill we get everything back from the machine shop.
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Marla
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Re: John's t-4 engine rebuild

Post by Marla »

That looks really good! Hopefully the machine shop won't be too much longer.
It's Marla with an " L"
(My list of assets is just too long...)
John
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Re: John's t-4 engine rebuild

Post by John »

1- Rick, K@B machine sent the balance work out to a third party, location unknown.
2- What Marla said, (hopefully soon).
3-
Never asked for a motorcycle...
Mopar's Rock...
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21window
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Re: John's t-4 engine rebuild

Post by 21window »

John wrote:1- Rick, K@B machine sent the balance work out to a third party, location unknown.
2- What Marla said, (hopefully soon).
3-

Probably Delzani's :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:
John
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Re: John's t-4 engine rebuild

Post by John »

3- What he said, :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:
Never asked for a motorcycle...
Mopar's Rock...
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wwebner
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Re: John's t-4 engine rebuild

Post by wwebner »

while I was out in the shop today,trying to clean up a bit for Tune up day, I pressure checked John's oil cooler.
I made this jig a few years ago just for this purpose.
Picture 019.jpg
100lbs in and holding. ( the slight,1lb difference is a fitting leak)
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while I was at it,I pulled all of the hardware out of the solvent tank,where it has bee sitting for a month.
Separated out he case hardware.
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there are a couple of important ones.
This one is a 71mm bolt that holds the oil PU and threads into the opposite side of the case. If you use one that is too long it will bottom out in the case and strip the threads in the case havlfwhen you go to torque it.
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This one has the ground tabs that ALL the FI grounds attach to. Cleaned it up on the wire wheel.
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Also,don't loose this one. the washer/spacer that goes at the bottom of the dist drive gear,T4 only uses one and it is special.
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The machine shop tells us that the case,rods,flywheel ,PP and crank should be done early this next week. Then the fun begins ;)
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wwebner
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Re: John's t-4 engine rebuild

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Early this past week,John picked up the crank,rods,cylinders,fly wheel and PP from the machine shop.
First step was to replace the pilot bearing which lives in the end of the crankshaft on T4 engines ( in the flywheel on Porsche 914's) and in the gland nut on type 1's. This bearing supports the transmission main shaft. If this bearing fails( it happens) The transmission main shaft and the engine become one,like a Chinese finger, whatever gear you are in at the time of failure is where you are stuck until you pull the motor (with a degree of difficulty do to the trans mainshaft being stuck in the crank) and replace it.
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Pack it with grease just as you would for a wheel bearing.
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install
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Next we mount the crank on the holding fixture for cleaning. remember,this crank has been in 2 machine shops,welded on ground on drilled and polished. So,we need to make sure that the oil passages are clean and free of any obstructions. A gun cleaning bore snake is great for this.
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Next,clean the oil passages in the case. Again,gun cleaning brushes work well along with blowing them out with air.
This gun cleaning brush kit is about $3.
Picture 028.jpg
Even though the case had been cleaned at the machine shop,there was a fair amount of aluminum debries, this was most likely from our drilling and tapping the main oil galleys. sorry for the blurry picture.
Picture 027.jpg
We will move to the build next.
Six Volt
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Re: John's t-4 engine rebuild

Post by Six Volt »

This is a great thread. Watching it closely for the subtle distinctions involving Type IV's.
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