911T 2.0 engine rebuild

[siimlane]

Hi

My plan is to totally disassemble and rebuild the 2.0 engine. Engine has K&N rain shields installed and distributor is changed from dreaded Marelli to Bosch 008. First move was to put the patient to the operating table.



As this engine has not been running for 20 years and it feels like that somebody has made interesting tweaks to the engine i think it was a good idea not to try to start it before rebuild.









Somehow one shim is also missing.



Also first chain tensioner that i removed was from a turbo version and has been fiddled with.
Second tensioner was original but suffered the same upgrade.

[911Freak]

Home made versions of solid tensioners?
Looks like the PO liked silver paint huh? Sheesh! Reminds me of when some young fool wants to paint his wheels "chrome" and paints the wheel with the tire still on and doesn't bother to tape said tire off for over spray!

Apologies to the artist...

Anyway, good on you for saving another nice 2.0!
I'm in and along for the ride. .

Good luck and post lots of pictures.

[haasad]

Irrespective of how well the PO executed the work thats not a bad "solid" tensioner set up in my view. I could see a simple nicely made kit to do that having some appeal ...?

Keep us posted with other "mods" you find...

[docrodg]

I feel for you. Just restarted on the rebuild of my 68 S engine. Not owner-modified, but motor-meister murdered.

[siimlane]

Hi

Disassembly has been quite long and I'm far from finished. Reason for the first stall was the lack of long hex sockets - so couldn't remove heat exchangers and now im waiting for the cam socket to arrive. Luckily i once bought a 46mm wrench that fits the cam nut because at the moment crowfoot is on backorder and wont arrive before september.

I already sent the distributor away to Vintage Werks for a proper rebuild. PO had installed Pentronix electronic iginition and also MSD, Ill probably keep these. Yesterday i removed the alternator and this one need a proper cleanup and rebuild as well. Any recommendations?

Also when i removed the upper cam covers i found out that one oil squirter tube has been damaged. Is it available from Porsche?

[siimlane]

Hi

Yesterday i received the cam socket and finally removed the heads to see really whats going on inside the engine. So when i said in the first post that i thought that starting the engine that has been standing for so long time is not a good idea - here is the reason

Cylinders and heads 1-3





Cylinders 4-6 and




Piston nr 4 is totally bust.





My plan from the start was to rebore the cylinders and buy JE oversize pistons for it so it's not really a sad moment. Im not sure which type of pistons though at the moment.

[Lapkritis]

Those cylinders are on upside down...

[safe]

Maybe upgrade to 2.2 with 84mm P/C?

[siimlane]

I finally opened the case and found some interesting stuff. Because of the piston damage there is some of the piston melted onto the rod. How can i get it off? With heat or with mechanical solution? There is also some metal debris near the oil plug hole that i think is a piece of piston ring.

Third thing that i noticed is that aluminium gear is damaged on the teeths. Im glad that gear is 0 version because new gear is readily available.

Will make some more pics and start cleaning parts - then there will be a second closer look on what to reuse and what to source.

I have a question on case savers - how many are actually needed? 24pc for the head studs but do i need to reinforce any other places?

[docrodg]

There are a few more places. I sent my case to Ollies and let them handle it all. They also strengthened the webs on the flywheel end and did the oil pressure upgrade.

[Raceboy]

It does not make sense for Siim to send his case to US and back for machine work, the cost of transportation alone will be 1000+ €.
I will be doing the same thing soon, here locally.
Siim, kui tahad, siis vőin lasta sinu plokile ka case-saver'id sisse panna. Nagu aru saan, siis sa mu 2.4S'i ei taha enam osta jah?

[siimlane]

Hi

Now when the engine is fully apart i have had time to inspect the parts. My engine is something what Wayne calls "catastrophic failure"(read "very expensive") in his book.

Crankshaft - I measured up the crankshaft and it's within standard tolerances so i can use it. I will let the machine shop to micropolish the journals though.

Intermediate shaft - I read from the Service manual that Porsche recommends changing whole shaft because the aluminium gear is machined on the shaft. As i want to change chain sprockets and aluminium anyway which is better option - new shaft or all new gears?

Rods - Although crank survived the piston pieces in the oil all rod bearings are damaged in the center area where the oil hole is.

I think i should change the oil cooler as well or is there any way to clean it thoroughly? I wouldnt want to risk the whole build for saving from the oil cooler.

[docrodg]

No real way of saving the cooler by cleaning that I am aware of... just can't be 100% sure it is clean.

Good news your crank is good. Could probly get the melted piston off the rod fairly easily by just a light tap, the rod did not get hot so it is more like a cold solder joint than a weld.

Double check the gears on the crank. Also plan on new valve guides.

Sorry about the recommendation for Ollies for machining... did not notice your location. Would plan on having rods, heads, crank, case, all sent to a good machinist. Cam housings can be done yourself (spray bars removed and cleaned) as long as surfaces are good.

[siimlane]

I was watching intermediate shaft pictures in PET and there is three models. My car has type two that means that one end runs on case and other on bearings. Is type III(both ends on bearings) exactly the same except bearings or is the shaft itself somehow different in diameter?

I need to repair the mag case bearing surface and wondering if i need to locate a different shaft or not.

[docrodg]

The case can be machined for the bearing and you can use your old shaft.

[Walt Fricke]

You can tell if your aluminum gear is or is not machined onto the shaft. I suspect it is not, so you can unbolt it and get a new one. If it won't unbolt, then you have to do something more. I think you may not be reading the manual correctly on that, though - those shafts never were, and couldn't be, aluminum. Not tough enough. A steel gear could be a one piece part, but you don't have that.

You can rig up a pump and filter, and pump light oil or diesel fuel through your oil cooler. A stainless folded mesh filter would be best, as you can inspect it periodically to see what has come out of the cooler. Then you can add something to cut the oil, and blow it out.

If you never see much, that might give you confidence. If you see a lot to start with, and you are still getting a little in the filter after quite a lot of pumping, maybe not so much confidence.

Lots of guys are very conservative about this. There are airplane engine repair facilities which will open these to clean them, I believe, and then solder them back together. I've used a couple which had survived an engine blowup without causing myself problems, but that's no guarantee.

But any big stuff is caught in the pump filter. Examining the scavenge gears in the pump may give you an idea of whether it sucked up stuff which scored the housing or the gears.

The shop polishing your crank should pull the plugs in the crank and clean it out thoroughly. Ask them to see if there is any debris in the crank passages. That would indicate that debris was pumped throughout the motor, including - most likely unless the motor was cold when it blew up - which is a bit unlikely - the oil cooler. Of course, have them put plugs back in.

[Walt Fricke]

Oh - unless you see wear that you don't like, there is no reason to machine the bearing area for the intermediate shaft. That's an aluminum case, isn't it? I've got one of those for a race motor, and using the case as a bearing surface is not a problem. Guys have some tricky machine work done so they can run the later IS shaft (which is made to run in bearings) because the early shafts are hard to get.

Plus I see bolts holding your aluminum IS gear to the shaft, so that ought not to be an issue.

When I installed a straight cut steel gear in place of this aluminum one on my early shaft, I found it wasn't lined up right with the gear on the crank. The steel gear, a special racing piece, was made from dimensions taken from a later shaft. You should compare the mounting depth of the gear you are going to get rid of with that of a replacement. If they don't line up, perhaps the new one could be machined. In my case, I put the gear on backward, but it was straight cut so angles didn't matter.

[Flat6pac]

Thats a mag case. You dont need to case save the head studs as there is no tension on them as was the 2.7. You need to do a timecert on the intermediate shaft stud, the long stud because they do pull from the case...after you have it together.
Bruce

[siimlane]

Rebuild planning:

I still haven't made up my mind on engine specs. I spent whole evening reading all subjects on the 2.0 to 2.2 upgrade but everything is not clear yet. Which version seems wiser?

My options:

Rebore iron cylinders to 80.5mm or 81mm and use T version JE pistons with T cam profile

Or

Use 2.2t cylinders with machined 2.0t heads and 2.2t pistons from Wössner. Cam stays the same or regrind to E spec.

Im wondering if 2.2S piston would fit into 2.2t cyl/2.0t head without valve to piston problems and do i gain anything from that move?