Rebuilding a 964 3.3 turbo

[staffanbe]

It looks like I will need to rebuild my 964 3.3 turbo engine.



I have a phat-phat-phat sound, that at first sounded like an exhaust leak from one cylinder, got much louder, this time from two cylinders and with a dramatic decrease in power. I then shut down the engine and haven't run the car since then. Got it back from Germany yesterday and will perform a leakdown test the next few days to get some more information.

Decided that I will document my rebuild on this forum to get advice, potentially help future 964 turbo rebuilders and to keep the momentum going.

I have a $350 usd/month budget on this project so I will probably hang here for a while....
My car is only run on the track, what I am looking for with my rebuild is reliability balanced with the tight budget I am on (don't want to wait forever to get out on the track).

I will update this post with som more information about my engine.
Edit:
- B&B headers
- KKK 7200 K27 HF turbo 0.9 bar boost
- K&N air filter
- RS engine and gearbox mounts

I have read Waynes book twice before and will now read it again.
Spend the last few days browsing this forum collecting links and useful information.

My first questions is about cylinders and head studs.
What type of cylinder and head studs do I have on my car (I suspect it could be broken head studs)?

[staffanbe]

After doing some research I believe my cylinders are Mahle and all Dilavar head studs.


Removed intercooler, airbox and exposed the crank vent hose.


Looking into the intercooler at the end connected to the throttle house.
Never seen oil here before.
There where also oil inside the airbox just above the air measuring flap (CIS), never seen that before either.


Looking down into the kompressor part of the turbo, there is some oil here but I had that before, perhaps a little bit more than before (the turbo is newly renovated). The inside of the intercooler (at this end) was completly dry.


So far only removed the upper right valve cover, checked 5 out of 6 head stud bolts and they all seems fine.

Pressurized cylinder 4-5-6 at TDC just to test the concept of doing a leakdown test (never done it before). I opened the throttle but couldn't hear anything, nothing from the exhaust either, but there is air coming through the crank ventilation hose. I gues I should be able to conclude my valves are okey on cylinder 4-5-6?

Next time I will use a real leakdown tester and put oil in the cylinders for better ring sealing.

[A930Rocket]

Oil in the intercooler could be a couple of things: turbo seals, ball missing in the check valve at the pressure sending unit (IIRC).

If you were getting a lot of blow by, then you might see oil in the air box. This is what I had on my 3.3 Turbo (from the 96 piece piston ring option caused by detonation).

But before you take it all apart, check your turbo, hoses, clamps, exhaust for holes, etc. With out the turbo working right and the exahust pushing the turbo you'll be down on power.

[staffanbe]

Thanks Rocket!

Looks like a dodge a bullit
I am a bit embaressed (and "happy"), when I was going to pressurize cyl 1-2-3 I found that the #1 sparkplug was out!!
Couldn't believe my "luck"
The sparkplugs in cyl #2 and #3 came off with very little force.

I remember being worried about over tightening the plugs when I changed them .
The threads on the #1 sparkplug looks okey, but I haven't tried installing a new one.

Does the missing plug explain the oil in the throttle house?

I cut the oil filter in half, found nothing.
Checked all head bolts, seems fine.
The plan is still to do a "real" leakdown test (hope to borrow a tester) and check the numbers.

[staffanbe]

Is this rocker arm axle, or has it started walking?
Looking in Waynes book, to my understanding the axle should be flush with the "thin" side, right in this case, could anyone confirm?

[A930Rocket]

It's walked a little bit. It should be flush. I'd loosen it, flush it up and retighten it.

Good news on the sprk plug!

Originally Posted by staffanbe

Is this rocker arm axle, or has it started walking?
Looking in Waynes book, to my understanding the axle should be flush with the "thin" side, right in this case, could anyone confirm?

[staffanbe]

Thanks!


I have some "serious" oil leaks around the rocker arms and elsewhere, decided to deal with them while the valve covers where removed.


Decided to remove all the rocker arms and install RSR o-rings.
I will post some pictures on the shafts, would like an oppinion on the wear.


Borrowed a leakdown tester, dialed it in at 50 psi and tried on a cold engine.


All the readings came out between 46 and 47 psi, if I got it right that should indicate a 6-8% leakage.


Seems very likely that the plugs where the problem...


The wheel in my power steering pump was damaged (right one), has destroyed the seal towards the cam shaft, probably a good culprint for the leaks I have.

[WERK I]

staffanbe,
If you have oil "above" the metering plate, the only place it can come from is the oil breather hose from the oil accumulator or oil tank. Maybe the oil accumulator has failed or filled with oil? Keep in mind that as our engines age, the amount of blowby through the piston rings increases which in turn increases the amount of gases being forced back through the oil tank. Of course, in the pursuit of more HP, we increase the boost pressures which exacerbates an already bad condition. You may be ok since your leakdown results are pretty good. But then you should try to perform leakdown on a warm engine.
If you track your car a lot, you should consider baffling your oil tank as well. These cars generate some serious cornering G's and you would be amazed on how little oil it takes to move up into the intake tract and start coating everything.
Also, when any engine has oil in the intake tract, this contamination is effectively lowering the octane rating of the combustible mixture. This will increase the likelihood of detonation.

[staffanbe]

Originally Posted by WERK-I

staffanbe,
If you have oil "above" the metering plate, the only place it can come from is the oil breather hose from the oil accumulator or oil tank. Maybe the oil accumulator has failed or filled with oil? Keep in mind that as our engines age, the amount of blowby through the piston rings increases which in turn increases the amount of gases being forced back through the oil tank. Of course, in the pursuit of more HP, we increase the boost pressures which exacerbates an already bad condition. You may be ok since your leakdown results are pretty good. But then you should try to perform leakdown on a warm engine.
If you track your car a lot, you should consider baffling your oil tank as well. These cars generate some serious cornering G's and you would be amazed on how little oil it takes to move up into the intake tract and start coating everything.
Also, when any engine has oil in the intake tract, this contamination is effectively lowering the octane rating of the combustible mixture. This will increase the likelihood of detonation.

Thanks Dave!
I don't have any ventilation from the turbo oil accumulator (running B&B headers with an aftermarket turbo oil accumulator).
There is oil inside the oil tank breather hose (at the end where it connects to the airbox), so this is something I will follow up on.
Will do another leakdown when I get the engine running.


Removed all the rocker arms on the right side, had no problems with cyl #5 and #6, could easilly push the shafts out. The #4 was tougher, had to use heat and pull the shafts out.




One of the shafts looks like this, seems to have been rotating?
Should I replace shafts that looks worn ?
Read that you should have them polished, should I be worried about the clearance between the shaft and the rocker arm bushing?

[WERK I]

staffanbe,
Things are looking good! That closeup photo of the suspect rocker arm does not appear that worn. How does the bushing look for the associated rocker arm? If there is galling on that bushing but the other rocker arm bushing look normal, I would take a look at the oil spray bar and make sure it is not clogged for that cylinder.
I had one of the spray bar holes plug up on #6 cylinder and it ruined the rocker arms, shafts and lobes for that cylinder.

[staffanbe]

Thanks Dave!
All the bushings seems okey I think.


I put RSR o-rings on all the rocker shafts (right side).
Decided to wait with the left side, it isn't leaking today so it will have to be a winter project.


There was very little space to get a 8mm allen key in the bushing at the #4 intake, had to cut the key real short.


Installed all shafts dry, with very little problems.
Will check the "oil spray bar", when I find it...



A friend reminded me about the fact that the shop overfilled my car with engine oil, could be the reason for finding oil in the airbox. But I will do a new leakdown with a hot engine when I got all pieces together.


Adjusted all the valves.

[staffanbe]

Put all the pieces together and started the engine.
I am back on square one, still have a "hard" sound from the engine.
The terrible "phat-phat-phat" sound is gone (from the loose spark plug), but something isn't right.

The sound is there at idle, when I raise the rpm (no gear) it's gone.
While driving it's only there when under load.
The sound is "hard", but in my mind not metallic.

I will start by checking for exhaust leaks.

[WERK I]

Well, it doesn't sound like a rod bearing. Generally, they will knock when the throttle is released after being under load. They will knock when the engine is idling, however. You may have a crack in your exhaust system somewhere. I've heard of cases where the headers had a crack in the heater boxes.

[MBEngineering]

HI staffanbe
Has the info turnd up?? as it was sent to you last week.

regards mike

[jpnovak]

Is the sound there when you push in the clutch pedal? I have a sound on my 3.0 that is related to the throwout bearing. It's only present at really low idle speed and goes away with rpm and depress of the clutch.

Great work finding the spark plug.

[sand_man]

Originally Posted by WERK-I

Well, it doesn't sound like a rod bearing. Generally, they will knock when the throttle is released after being under load. They will knock when the engine is idling, however. You may have a crack in your exhaust system somewhere. I've heard of cases where the headers had a crack in the heater boxes.

Those look like B&B headers...I'd check them!!! Especially where the heater boxes attach to the pipes. My B&Bs cracked only after a short while! I thought I had a broken head-stud on my 930 when I developed that "PHAT PHAT PHAT" SOUND. I was pulling a low mileage engine, anyway, to perform a rebuild to fix an endless array of oil leaks, and just got carried away with "while you're in there". However, I didn't think to investigate the headers since they were almost brand new. When my rebuild was complete, I also ran an open "zork" straight pipe on the turbo. The exhaust sound was soooo loud, I never realized that I still had a header leak. It took me installing my current Borla muffler (quieter) to realize that I had a problem.

When I pulled my B&B headers, I shined a light into them and the cracks where VERY apparent! Unfortunately I was just outside of B&B's warranty and ended up running a new set of OBX headers (no heat). I'm amazed at how smooth my engine sounds and runs!

[sand_man]

Also, are you sure your rocker shafts are still properly installed in the cam housing? They have a tendency to "walk" if they aren't properly aligned and torqued. Mine did this....was the only gotcha I had with my engine rebuild. I made the mistake of installing them with assembly lube and they kept moving about after the engine had run. I finally had to pull them, insure that their place in the cam housing was totally clean and free of oil, install them dry and then oil them once torqued.

[staffanbe]

Originally Posted by WERK-I

Well, it doesn't sound like a rod bearing. Generally, they will knock when the throttle is released after being under load. They will knock when the engine is idling, however. You may have a crack in your exhaust system somewhere. I've heard of cases where the headers had a crack in the heater boxes.

Thank's Dave, been worried about the headers since I installed them, heard all kinds of stories. Even though I only spend 10-12 hours on the track after installing them, I rather take a bad weld or cracks than most of the other things that comes to mind.

[staffanbe]

Originally Posted by MBEngineering

HI staffanbe
Has the info turnd up?? as it was sent to you last week.

regards mike

Thanks so much Mike, could have arrived the last couple of days without me knowing, let me check.

[staffanbe]

Originally Posted by jpnovak

Is the sound there when you push in the clutch pedal? I have a sound on my 3.0 that is related to the throwout bearing. It's only present at really low idle speed and goes away with rpm and depress of the clutch.

Great work finding the spark plug.

Thanks Jamie, it doesn't seems to be clutch related.
A friend of mine had a bad throwout bearing just a few weeks ago on his GT3, it was more of a rotating grinding sound, and as you described it, you could make it come and go by playing with the clutch pedal.

I hope to have time to jack the car up tomorrow and use a hose to pin-point the sound.

Edit:
About the spark plug, it wasn't just loose, it was (caugh) out....oh well (blush)