82 Euro SC rebuild

[ninesixfour]

This is the original unopened motor, and it sure is dirty after all these years. Let the adventure begin. If there's anything I need to know specific to the Euro model that isn't mentioned in Wayne's book please feel free to share.




Screwdriver bit on the impact is no match for a rusty 29 year old screw.

[VFR750]

Modern "steel" is no match for good old German steel.

[ninesixfour]

The three long studs you see with the white spacers are where the air pump used to be. Is there a common way to replace those with something shorter that seals better? I rigged some o-rings to fit but I still had leaks there.

[Flat6pac]

Pull all 3 studs and them use a 8mm hex head or axle allen bolt on the 2 outside.
Bruce

[MBAtarga]

[QUOTE=ninesixfour;5962351]This is the original unopened motor, and it sure is dirty after all these years. Let the adventure begin. If there's anything I need to know specific to the Euro model that isn't mentioned in Wayne's book please feel free to share.




Looks like you already have a spare engine!

[ninesixfour]

A wonderful friend is letting me use his motor while I rebuild mine so I need to get that installed too.

The reason for this rebuild was a strange sound and zero compression in #6 after an over-rev. The broken head stud is fresh so I'm not sure what happened first.



4, 5, 6




This is #3.

[304065]

Nice autopsy photos!

[ninesixfour]

Originally Posted by 304065

Nice autopsy photos!

Yes I wasn't quite sure what kind of damage I was going to find. I am waiting for my new rings to arrive so I can check the side clearance on the pistons and the cylinder ring gaps. Hopefully the pistons are reusable and I just need two cylinders.

[1982911SCTarga]

What's the probable cause for the partial destruction of the CE ring on No. 3? One or more broken head studs?

Brian

[ninesixfour]

#6 has the only broken head stud. I don't know why it happened on either one. Hopefully one of the knowledgable minds here will chime in.

[ninesixfour]

I didn't think they were that dirty.

[euro911sc]

Nothing out of the ordinary for the euro re-build.

Cyls are infinitely easier to find then euro pistons in the same weight group. that was a real PITA for me.

while you are cleaning up the pipes, just pull all the injector gear out of them and bead blast them inside and out. Comes out really clean. While the injectors are out send them out to be cleaned and matched if you have a few spares. Replace all the o-rings for a good seal!

For the air pump studs, I just ordered some new shorter ones from Porsche/Pelican. takes time, but I was looking for a damn piston to match the other 5 so I had lots of time It looks like there was never an air pump there now

-Michael

[ninesixfour]

Originally Posted by euro911sc

Nothing out of the ordinary for the euro re-build.

Cyls are infinitely easier to find then euro pistons in the same weight group. that was a real PITA for me.

while you are cleaning up the pipes, just pull all the injector gear out of them and bead blast them inside and out. Comes out really clean. While the injectors are out send them out to be cleaned and matched if you have a few spares. Replace all the o-rings for a good seal!

For the air pump studs, I just ordered some new shorter ones from Porsche/Pelican. takes time, but I was looking for a damn piston to match the other 5 so I had lots of time It looks like there was never an air pump there now

-Michael

Thanks for the feedback. I did learn one Euro difference today; the intake boots listed in the catalog here for 1980-83 will not fit a Euro. Apparently you need the earlier SC ones.

[Flat6pac]

Yes, all the euro were the large runners of the 78/79US cars.
Bruce

[tom1394racing]

Here some data to help guide you for your P&C inspection.

This is typical for SC pistons and cylinders. The critical measurements are the top ring side clearance (less than 0.2mm) and the piston to cylinder clearance (less than 0.10 mm).

[euro911sc]

Originally Posted by ninesixfour

Thanks for the feedback. I did learn one Euro difference today; the intake boots listed in the catalog here for 1980-83 will not fit a Euro. Apparently you need the earlier SC ones.

hehee yeah I didn't think you would be changing those... I have a new set of US 80-83 boots in a box somewhere for that very reason.

[ninesixfour]

Thanks for the numbers Tom. Wayne's book says the top ring side clearance is 0.070-0.102. Am I missing something here?

Strangely, mine measure 0.15 with the old rings and 0.33 with the new rings. I guess it's possible someone re-ringed them in the past with larger rings to avoid buying new pistons?

[tom1394racing]

Ninesix

The wear limit for side clearance is 0.2mm.

The new spec tolerances are 0.075-0.102 mm.

It would be surprising to have larger side clearance with new rings.

Measure you old rings with a caliper and compare them to your new rings.

The rings should be around 1.45-1.48 mm in thickness.

You can measure the piston top ring grooves width with stacked feeler gauges. They should measure in the range of 1.55-1.65 mm.

Let's see what you find.

[ninesixfour]

Piston dimension "h" described in Wayne's book:
94.945
94.945
94.945
94.945
94.918
94.918

All the cylinders measured within 0.0254mm of the original diameter with no ovality.

[tom1394racing]

The wear limit is the allowable wear on the top ring groove before the piston needs to be replaced. The tolerance is the allowable new part variation. In determining if the used parts are reusable, the wear limits should be used.

It looks to me that your side clearances are all inside the wear limit and that the pistons are reusable assuming your piston to cylinder clearance is within the wear limit.