J-Rod

Howdy,

I am posting this for my computer illiterate friend with the 88 Callaway. He just had the turbos gone through. But, if he run the car, stops and then restarts it again after about 5 minutes. It blows a cloud of smoke out the exhaust.

I remember that the car did this when he first got it in 88. He wanted me to aks if everyone else with a Calalway had the same issue. Or, if he needed to be looking at something being an issue.

I am trying to get him on a computer, so he can converse with you guys, and post for himself. But if that fails, I know that he would like to get in touch with some of you guys here in Texas.

I know he probably wouldn't mind coming up to Dallas to check out the fast Callaways up there. If there are any Callaway guys in Houston, send me a PM, and I will pass along your contact info to him. Same for any of you D-town guys.

RatRacer

His valve seals are probably gone. It's an inconvenience more than anything.

90Callaway

It sounds like he could possibly be having a problem with his oil scavenge pump. On a Callaway TT the turbos sit lower than the oil pan. There is a belt driven pump that scavenges the oil from the turbos and pumps it back to the pan. It's located low on the right side of the engine and also performs duty as a tensioner for the serpentine belt. If this system is having problems the result will be a cloud of smoke. I've never personally seen it so I don't know the exact conditions... such as start up, etc.

Here is a blurb from the Callaway Twin Turbo Corvette Owner's manual... which your buddy should call Callaway and get one if he doesn't have it.

Turbocharger Oil Scavenge Pump

Condition: Failure

Usually indicated by a cloud of smoke that engulfs the car! Can be verified by connecting a 4" section of clear plastic tubing to the turbo oil sump vent in place of the existing black hose. Route up to convenient location in engine compartment, and , with engine running, if oil level in sump can rise into the sight hose the scavenge pump has failed. Verify further by disconnecting the scavenge pump discharge line and monitoring oil flow BRIEFLY. Note: check the engine oil level before attempting this test and never run the engine for more than a few seconds.

USAZR1

Yeah,it sounds like oil is getting past the compressor seals. The scavenge pump would be the first thing I would troubleshoot,too. Bet Matt or Sam could help him out.


[Modified by USAZR1, 12:27 PM 9/3/2002]

RatRacer

If the smoke is just at start up I would focus on the valve seals. What happens is oil that has been pumped to the top of the heads drains down the valve guides, past the seals, after you shut off the engine. That oil the sits in the combustion chamber until you start the engine back up. This will result in a nice blue puff of smoke that goes away until the next time you stop and start the car. Another tale/tale sign of this is a cloud of blue smoke when you engine brake after a hard run.

If it was smoking all the time then I would look at the other areas already mentioned, as well as the rings.

8388

My 88 Callaway suffers from the same, only at start up. My guess is like Cam has mentioned, the guide seals. My thoughts are, that if it were a scavenge pump failure, you'd see smoke all the time rather than only at start up.
I had a similar situation once with my blower car back when I was running those trick blow heads(Trick Flow) the Valve guides were so lose that they allowed for the compressed air to pass by and push up the valve seals. The fix is easy but tedious, and can be performed with the heads still bolted to the engine.

P.S G.M makes a new generation type seal that has a steel body that can be pressed on by hand, that has a much stronger grip.


[Modified by 8388, 1:57 PM 9/3/2002]

*89x2*

Don't have much to add other than if it turns out to be the seals, the dealer can do them quickly w/ the new (in the 90's) "umbrella seals" that install w/ the heads on the car. Let us know what it was.

Ultra Slow

On 99.9% of small blocks, I would tend to say valve guide seals, but on the callaway, depending on actual mileage, I will dissagree on this one, only if the engine is untouched since new as far as the block and heads. The L98 head, even with trashed seals, does not leak too much oil down. Just look at all the 150-200K 87-89 corvette running around that dont smoke and have had very little maintinance. On this case, if the car never smoked before the turbos were went through, then its obviously the turbos in the area of an improper rebuild. If the car has smoked before and after the turbos were gone through, I still say its a big possibility that your problem is the turbo(s) way over valve guide seals. The turbos are near the lowest point of the oil system and the lowest poit of the water system on the callaway and if there are any small leaks in the turbo seals, new or not, then you are going to see this exact symptom. The other is a crack(s) in the turbo housing. I have talked to turbonetics extensivly on the callaway turbo over the years of messing with mine and a common problem with the units are, if splashed with water when real hot as in a daily driver through puddles, the turbo(s) can develop small cracks in the housings. A small crack to the oil galley area can causing this problem too just as a small crack to the water jacket will cause a water leak. The car may not show any smoke when driving, but turn it off hot for 5 mins and restart, you'll look like your in a 74 impala with 900K on it with a puff of smoke that will cloud up the sky. If the crack is real bad, you may see oil dripping from one of your turbos after you shut off the car.... This would be good because you have an easy diagnostic of which turbo is the problem, but the leak can be so small that just a few drops of oil are getting in causing a degree of smoke. You will probably use a quart or so of oil every 500 miles too even though you are not smoking 30 secondes or so after starting. As far as the scavange pump, I say no in this case too. If the scavange pump were not doing its job, you would notice it when the car is reved up and more oil is filling the turbo oil resevoir. The car will smoke so bad when running that you will sware you blew your engine, its a real mess. Check the turbos more carefully... This is more than likely where your problem is.

Each case is different, but as a reference, one of my callaways has 60K on it. The valve covers have never been off the car. It uses no oil, even less that my 19K ZR1, and if you follow some posts you can find out how its driven. I did have a problem that might be like yours, but it was a water leak from one turbo instead of oil and a sending the turbo off for repair yielded a small crack in the housing to the water jacket area along with a bad seal that were both repaired several years back.



[Modified by Ultra Slow, 1:37 AM 9/4/2002]

J-Rod

Thanks guys. I will pass it on to him.

A couple of things. The car just had new valve seals installed a few weeks ago since it had been sitting up for so long. In fact if I understood correctly, the exhaust didn't have a valve seal installed on them origianally. I thought that was very odd. We are using a good postive seal made with Viton.

The turbos were just re-done by John Craig @ Limit Engineering in AZ. They were very reasonable on the price of re-doing the turbos. They are who handles all of my GN stuff, so I referrred my buddy to them.

Anyway, I will give him the info especially the sump info and see what we can find. Thanks. I just wanted to see if everyone else had the same issue.

8388

My problem as best as I can tell started right after the install of the wonder bar. Me and Ultra took the car for a pass on our race track before backing off on the waste gate and the first time the needle on the boost gage nearly broke as it went so hi. I backed off instantly, but my guess is that some of that extra boost pressure made it up past the guides and pushed the seals off. The car never smoked prior to that. I could be wrong but given the amount of oil pressure on a Callaway (80 psi just off idle), a crack anywhere and you'd have oil/smoke all the time, not just when starting up.

Ask your friend if he has ever over boosted his engine, even if it was for a split second.


[Modified by 8388, 9:46 AM 9/4/2002]

TA

I guess I've just been unlucky, as I've never had a TPI motor that didn't blow a little smoke on start-up.

Ultra Slow

Sure its oil and not black smoke (fuel) from a leaking injector? This is a very common problem from 85-88 before they went to the newer style injectors. Also, if you have a high mile small block, L98,Lt1, whatever and you run 5-30 10-30 oil, you bet your going to see smoke. The problem I am refering too is an extreme amount of smoke on start up from a callaway, not the typical small block valve guide issue with a little puff of smoke.

SurfnSun

My L98 with almost 200k miles didn't puff at startup. However later in its life I switched to 15-50 Mobil One b/c it started fouling plugs, that fixed the problem. But the Callaway should already be running that weight of oil.

scorp508

My '87 L98 puffed oil at startup from valve seals from day one that I got it at 98.5k miles. Doesn't anymore with the new heads. :) Fastguy's 88 L98 did also, but his was from leaky injectors and was black fuel smoke.

J-Rod

The injectors were cleaned, balanced and flow checked since they had been sitting for so long. So, they are accounted for. No, this is definitely oil smoke.

TheCarVette

For "Ultra Slow"...with what you drive, how did you come up with your username!? Seriously, sounds like you know what you are talking about with the TTs. Couldn't resist and just bought an '87 with 24,000 miles. Great looking black/black/graphite 'vert. Runs very well - now. You have me a little nervous about the future and would like to know what you recommend for reference material or manuals. It won't be a daily driver, but, I want to be able to drive it and not worry too much about getting stranded on a club outting. Appreciate any help.

Ultra Slow

Sounds great and congrats on the TT. Its a good car and since you have many others and dont drive much, its a great car! The cars are tempermental, but dont let it scare you off. Just be carefull of letting others/shops work on it. No matter how good their intentions, I have seen rarely anything done right on these cars and it usually causes more damage to the car than good. If you have a problem, just ask some of the guys here. There are a few that know very well. I will also go as far as saying that you are much better off with the advice you get here on this forum on you callaway than from callaway theirselves. There is a basic overview that you should have got with your car that is a basic schematic of the turbo system. Knowin g how it works is 90% of the grief and understanding that is mainly mechanical and "computers" have very little to do with it, so watch out for those shops/guys pointing the fingers at the computer. If you are not trying to mod the car to make it real fast and are happy with the power your 87 has, you should not have too many problems driving it a few miles a year and doing the basic maintinance a corvette needs. Dont run thin oil, change it often and keep everything tight as far as hoses, fittings, clamps, etc. This is my basic recommendation to keeping these cars alive and grief free. If you want to make it fast, 87 is a tough one but its very possible. Either way its a great car and take care of it and congrats!



[Modified by Ultra Slow, 12:32 AM 9/10/2002]

TheCarVette

Good morning...and thanks for the quick response. I didn't sleep real good last night pondering everything I read in this and a later thread rearding the TT. You can bet I will be watching CF religiously. Still interested in some references to material/tools to accumulate. I do try to do my own work as much as poosible and have a son that is young (14), but, persistant and loves the TT. I was leaning towards an LT4 or Z, but, Mark loved the looks and feel of those turbos. I do take care of my cars and they do not get over driven - but, I won't have one I can't drive. I was looking at your pics, you have a very nice stable. Greatful for the "Forum". Have a good day.

carter200

:yesnod: