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Another 944 Turbo Engine Rebuild Thread

So I resumed the engine rebuild pretty much as soon as I returned home.

First job was to split the rods and pistons and remove the rod bearings.

Rod #1 (left) Rod #2 (right)


Rod 3# (left) Rod #4 (right)




Then a lot of RP90, heat from my propane torch was used and a pair of stilsons to remove the old head studs. I was lucky none of them snapped, a few came out easy and the others were quite tight. At the same time I also removed the water pump studs using the double nut method and got them out without any snapping.



Finally the block was ready for the machine shop.



A very kind person donated some parts to me early in January and I got 2 spare 944 crankshafts, one is very good and the other has some surface rust on the journals.

Original on far right, good spare in centre.


On Monday I took the following parts over to Knight Engine Services near Daventry, spookily the owner has the same name as me...

  • Complete Cylinder Head
  • Engine Block
  • Flywheel & Clutch Kit
  • Crankshaft (original and a spare)
  • New Valve Springs
  • Connecting Rods

Currently looking at 4 weeks or so before they can start on this, I'm getting the following jobs done:

  • Port and Polish inlets on Cylinder Head
  • Machining Cylinder Bores to 1st oversize retaining alusil
  • Check original crankshaft wear with the option of using the spare if badly worn (thrust bearing was toast)
  • New Valve Guides
  • Skim Cylinder Head and Block as required
  • Rebuild head
  • Balance Crankshaft
  • Balance Flywheel
  • Block and Cylinder Head Vapour Blasted (baked and thoroughly cleaned of blast residue)

Hopefully I will have some pictures of lovely new shiny bits to show you soon!
 
I know there are different requirements and budgets, and my engine has very likely got the same rods in it. But as the engine is apart, I'd chuck a set of forged rods in it. I think you can buy them for under £500 now.
 
blade7 said:
I know there are different requirements and budgets, and my engine has very likely got the same rods in it. But as the engine is apart, I'd chuck a set of forged rods in it. I think you can buy them for under £500 now.
Click to expand...

Good shout, I went through the same thought myself. Also, David at Knight Engine Services said it's up to you but by the time you've had the original rods checked and new bushes fitted (if required), then you are almost at the price of a set of those Bridgeway rods (although I will have him check over them to make sure all good before fitting). So, I made the decision, and they are already on order from Part Box along with some other goodies! 👌

He did say though that the original rods are well made and perfectly usable for my build.

BTW if anyone is interested in the Bridgeway rods, they are currently on clearance sale at Part Box, get them while you can!
 
So a few more jobs done last weekend and in the evenings, whilst I waiting for orders to be fulfilled and my place in the queue at the machine shop.

First off, I started to reseal the gearbox with the reseal kit from Porsche.

I change the left side output shaft seal, according to the manual there is a stop, but posts on rennlist and elsewhere suggest there isn't and to push the seal in to a depth of 6/7mm. My seal would only go to a depth of 6/7mm, I then put some general purpose grease on the inside of the seal as instructed in the WSM.



Next up was the selector shaft seal (although I don't think it was leaking and probably could have left it). First off you need to remove the reverse lockout spring from the top of the gearbox. Then you can remove the selector shaft cover and slide the entire assembly out. The seal was quite hard to pry out but did eventually succumb.



New seal inserted, shaft lubed up with gearbox oil, new paper gaskets for the cover and lockout bolt.





Next up remove the diff cover and inspect for damage, will also be cleaning the magnets on the cover, pump strainer, and possibly dismantling and cleaning the pump itself (think I may have to do so to clean the strainer anyway). I will then need to measure the drive with a dial indicator to select the correct thickness gasket for the oil pump cover (there are 2 thicknesses available). Diff looked OK to my untrained eye, lots of furry metal bits on the magnets which I guess is to be expected at over 200k miles. No debris at the bottom of the box thankfully.







I've parked the gearbox work for a few days whilst I measure the play in my turbocharger before I send it down to Turbo Dynamics.

End play was within spec (0.08-0.105mm vs 0.16 max) but the radial play was about twice what is allowed in the WSM (0.73mm vs 0.42mm max).

You may have noticed my fancy dial indicator stand, it is a copy of the VW 387 tool which I was able to obtain from Bartek Motorsport in Germany.





Finally I made an error late one evening, thinking I had found the deal of the century on a full set of crankshaft bearings from Autodoc for around £70 :ROFLMAO:

When they arrived the packet looked right with a picture of crankshaft bearings, but the part number and contents gave the game away! I've ordered some ACL Race Rod Bearings so I will hang on to these for now (just in case) and have the extended return period (200 days).



Lastly a new standard (2.5 bar) fuel pressure regulator from URO with the slip on hose fitting (my existing one has the threaded fitting) and a full set of seals for my front brembos.

 
Time to update!

Pistons arrived from Mahle Motorsport (via Design 911 - with the 10% PCGB discount), production date is 23rd January 2003! I hadn't even purchased my 944 Turbo then, was still on my first Porsche 944, a 1988 2.5 NA (also black).

They have a black phosphate coating (supposedly to control heat) and the Mahle Ferroprint skirt coating for alusil applications.







I finally got the right set of crankshaft bearings from Kfz-Kauert in Germany (they sell on ebay and have their own webshop) for a bargain price of 176 euros. This was way cheaper than I'd seen them anywhere else. I still *might* have to get the different size thrust bearing depending on the analysis of my crankshafts by the machine shop (they are only available from Porsche and silly money).



Collected a bag full of nuts, bolts, washers, and other larger items from the electroplater! Then I spent several hours, split over consecutive days, sorting through them with the notes I'd made and putting them into labelled bags ready for reassembly.



Progressing along nicely with the gearbox reseal, I replaced the input shaft seal (again) this time using a piece of plastic waste pipe of the correct diameter (30mm?) to gently tap the seal into place.



The oil pump has been thoroughly cleaned and reassembled with a fresh 0.20mm gasket. Next job was to measure the end play of the pump, the WSM gives a figure of 0.05mm + 0.1mm. I got a repeatable figure of 0.09mm so well within spec. Gaskets are available in 0.15mm and 0.20mm, the 0.15mm would have been too small taking the end play down to 0.04mm.





Used some Permatex Form a Gasket No.3 on both sides of the paper gasket (we don't want any leaks). All torqued up to 8Nm.

A new output shaft seal is already installed, just need to reinstall the magnet and seal the side cover back in place with Loctite 574.

Whilst waiting on other bits I've taken the time to remove the intercooler (see the other thread in this forum) and also clean the engine bay.

BEFORE

AFTER

Will get the cross member and steering rack cleaned up separately. Couple of patches of surface rust to attend to, on the wheel arch where the coolant tank has rubbed on the paint and at the front under the intercooler. Will deal with those when the car is back in the garage, and I can properly mask it up to avoid overspray.
 
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Awesome stuff as ever David! I'm getting everything under my front bumper tidied up at the moment as it has been removed for repairs and paint. Well worth doing these things when you have the chance.
 
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