308 Turbo, sell or fix?

If you compression numbers are right then there is just no way you're head gasket is bad. No way. If you doubt the numbers, re-do the test.

It would be a good idea to do a leak-down test as well. since you can warm uo the engine, I would recommend doing the test on a warm engine, the numbers are more acurate. A leak-down tester is about $70 for summit racing, but I'm sure there are many other places to get one.

The coolant leak needs to be fixed. That is your next step. Remove the intake and find the problem. You can not drive a car that is spraying out coolant, so fix it.

After that, either put you old turbo back on and by happy or fix the new one and add a scavenging pump.

 

Is the turbocharger water cooled? Does your car's coolant level drop or overflow?

There are some coolant hoses under the intake that can leak. The ones on my 328 did several years ago.

It sounds like you have leaking oil seals on your turbo(s). A happy foot before the oil is at operating temperature can cause this. Even in hot weather, my car takes about 10 miles to fully warm the oil. I do not think the oil system has a thermostat. But I am not sure of this. If I get into high revs on my 328 before warm, oil pressure climbs way up. I ruined an oil cooler doing this years ago before wising up.

I have read from listers on another list that some brands of turbos are more susceptible to high oil pressure ruining turbo seals than other brands. Personally, I like turbos. I have a car with 148K. I purchased it with 90K and put a larger turbo in it and run 1.1 bar boost, nearly doubling the original power output of the engine. But the engine was designed for a turbo. I have over 50 track events on it.

 

Very good point. 3x8s run much higher oil pressure than most other cars, especially when cold.

I'd check with RayJay or the other turbo's mfg on the max pressure the oil seals can take & compare it to your car's pressure.

Your symptoms do sound like turbos with blown seals. Not sure about the metal bits tho.

 

The oil pressures seen at the turbo are no more than any other car I have worked on. I have had three of these converted cars in over the years, and the troubles have all related to lack of oil scavenge. The returns can block easily if the turbo is shut down when very hot, that's why you must allow a cool down period after driving, especially if ther is not a scavenge pump, all three I saw had pumps. One did have a detonation problem at max rpm as you shifted, and it spark knocked and puffed blue/black smoke. Hard to determine what is going on with yours, I would suspect at least the Turbo bearings, the noise is also worrisome on start up.

 

If the old turbo is a plain bearing type, then it would need decent oil pressure. There would be a decent flowing line to minimize pressure drop and the clearances in the bearing itself would meter the correct oil flow. The new turbos are all ball bearing if I'm not mistaken there is normally a flow restrictor such as a small (.060" orifice) somewhere in the feed line which also has the effect of dropping the pressure and setting the correct oil flow rate since a ball bearing is open and can not act as its own flow restrictor. That could easily be your problem.

 

I agree with Brian. If there is no scavenge pump fitted, the oil return from the turbo has to enter the engine above the oil sump oil level. Looking at the photo, the turbo is mounted very low, hence it would need a scavenge pump.

BR/Ulf

 

Any update on your car? Do you think you are getting closer to finding the problem?

 

If you still have this problem, I've come up against this twice. All though it was on other car's, it's probly the return line from your turbo to the block. I have had the same problem where it leaked oil, smoked and didn't have the performance that the other turbo cars had. If the oil doesn't cool, fresh oil coming in through the presure system the oil cooks and blocks the drain line. This cause's lot's of problems, oil leaks, oil into the manifold and if the turbow has a water cooled housing, can create problems there too. Hope you have already fixed the problem. Good Luck Mike