My car: 91 turbo w/ targa top. rebuilt CT26 by ATK w/ 15K mi (previous owner maintenance), HKS 1.4mm MHG, 2.5" intercooler piping w/ HKS SSQV, 3" exhaust from cat back, stock boost - pretty stock right now.

Had a BHG back in April 05. Had a knowledgable mechanic take his time and put the HKS MHG in, replace all rubber hoses and vacuum lines, water pump, front crankshaft seal, camshaft seals, timing belt, and a few other things...maintenance before modification :eusa_ange

So I drove it easy for 800 miles on regular oil. Then changed to Valvoline 10W-30 full synthetic. It's consumed 2.5 quarts in 800 miles. It doesn't leak, checked that. It doesn't burn oil - I can't smell it (I'm familiar with that smell from my honda). The car runs like a champ, turbo sounds real good, no odd noises.

I've been told that there is a normal amount of oil consumed, but 2.5 quarts seems excessive - where is it going? I can't find any literature about it, maybe a few links if anyone knows them. Oil doesn't just up and vanish :confused:

Thanks - :D

My 1st guess would be the turbo, but you could also check compression. Do you have cats? Does the BOV have oil on the outlet?

when i asked about 10 people if i should switch over to synthetic i got a big NO answer from them. they all told me to switch over once i had about 3000-5000 miles on the rebuild. now i dont know if they are right or not but i am staying on the safe side and waiting till i get close to those miles. now my turbo spools up great but it does consume oil. every 500 miles i put in about half quart of oil so turbo would be my first guess on why your car is consuming oil.

The exhaust has both cats. There is no oil on the BOV outlet. I would hope the compression is good, but I haven't checked since rebuild.

My mechanic said normal consumption is 1 quart / 1K miles. Thanks for the input there. He also said not to be alarmed at the initially higher consumption, that over the next few thousand miles it would drop off.

Suprajjang: Were your friends referring to a complete rebuild or just the head?The block wasn't touched except to reapply crosshatching to one or two cylinders that were shinning a little. I did notice the turbo spooled easier with synthetic; lower viscosity - makes sense. Did they cite a specific reason for the mileage? How would synthetic cause a problem? The Mechanic said there shouldn't be any problems with switching - I'm inclined to agree. The only reason I waited to put the synthetic in was to let the initial oil batch collect all the ambient dust...etc that collected while the engine was apart (cheaper).

Thanks for the input guys.

These cars definitley like their oil. If you can't find a leak..., It must be going out the tail pipe.

Also get off the Valvoline, its absolute crap oil !!

Thank you hotsup!!!!! I have been waiting for someone to say that. Valvoline is what your wife should put in her 88 ford explorer. You getting where I'm going with this???

Thank you hotsup!!!!! I have been waiting for someone to say that. Valvoline is what your wife should put in her 88 ford explorer. You getting where I'm going with this???
The Supra deserves much better than valvoline!!

Also you can get someone to put the car on the lift and then start it and let it run for a few minutes and then crawl under it...., any leak would be more evident.

When I first read your original post, I assumed that you had meant that the engine was reman by ATK and not the turbo, since I didn't know they did turbos also until I just looked it up.... my bad!

Anyway, I put a ATK reman 7M-GTE into my '92 last March and changed everything else that doesn't come with it (water pump, EGR, etc) except the CT26. Completely leak free for the first time in years! The turbo had been rebuilt (with supposedly ceramic seals) less than 50K miles earlier, and I had assumed that the oil use problems that led to the swap were with the block and not it.

I started with regular (dino) oil (Castrol GTX) for the first 1,000 miles, as instructed by the warranty, then switched to Mobil 1. Oil pressure readings went WAY down, and I found out that the 7M engine isn't as tightly manufactured as newer types, so synthetic isn't the best oil for them. At first, the engine sounded and ran great, but that has quickly deteriorated to a point where all I want to do is throw in the towel. It has less than 8,000 miles on it so far.

Oil usage is up to a quart every 150 miles or so, tons of blue smoke, and knocks and rattles that drive me crazy. I'm sure that the turbo is toast, so I can't blame the heavy oil use on the engine. But you should hear the marble-in-a-coffee-can rattle at cold start for about 30 seconds (piston slap, I think, due to poor ring tolerances), and the bottom end rod knock it has all the time. It sounds like shit.

On top of all of this, now I can't seem to keep cam seals in it. The first set that came with the engine failed at about 7,000 miles, and the replacement set didn't last the distance from the shop to my house. The 3rd set went in right away, and are causing a puddle on my garage floor right now. yes, these are genuine Toyota seals and not some crap. and yes, they were put in by someone who knows what they are doing.

I know the oil use is primarily my turbo losing its seals because the IC piping is full of oil, as is the downpipe & cat. But the engine is crap anyway. I had a lab do a full spectrum analysis of my oil, and it came back full of chromium - a sure sign the rings are causing problems, which means I'm probably also getting blowby contributing to the oil use.

FWIW, ATK paid about 1/2 of the cost of the first cam seal replacement under the full 3 year warranty I bought with the engine, but nothing of the second replacement saying that it was faulty installation. yeah, right. my certified mechanic not only messed up once, but now twice?!?!? What they don't advertise in their "full" parts and labor warranty is that they pay labor at the rate of only $42/hr. Do you know any mechanics that work at that rate? And they can't explain why it continues to blow seals (I can - shitty tolerances on the cams), and continue to argue with me about the source of the noises. They are not anywhere near to replacing/refunding the cost of the engine, which is what I want.

I wouldn't trust anything rebuilt by them, and I'll make a mission in life to trash their name everywhere I can if they don't fix my problem.

But enough about me....

Did your mechanic lap the head before installing the HKS? They are much more sensitive to differences in tolerances than other brands, like Cometic

You are right, oil doesn't just vanish, but it seems like it does with our engines. Leaky gaskets and seals are easy to diagnose, but you would certainly notice that kind of oil use if it was leaking out. Check the IC piping and downpipe. Intake/exhaust seals on the turbo may be going. An unscientific way to test this would be to take it out on a drive at night and make sure some cars are behind you with their lights on (small amounts of oil smoke are much more visible in your rearview mirror when reflected by other cars at night than anything you would see in the daytime). Cycle your driving between deceleration and acceleration. In other words, let off the gas and coast a little to let engine compression build, then gently give it gas. This transition from positive to negative vacuum is where leaky turbo seals (especially exhaust) will give you the smoke. I never smelled it either - until my oil use went through the roof recently. For most of the 8K miles, I've been using a quart every fill up (~350 miles), and never smelled a thing, but sure could see it at night reflected from whoever was behind me.

we all have our headaches with these things and they do make us want to throw in the towel but damn, they're so much fun to drive.

check out the rear main seal thread........., that's my ride.

and just for the record........., Castrol hard drive/ turbo approved, 10w 30 or 10w 40

synthetic oil is great for heavy modified cars with tight tolerances. example balanced bottom end new bearings, bpu and forge pistons synthetic is the way to go, but just not any syn will do for me this is one thing i'm picky about, it has to be lucas oil or royal purple hands down if i want my car to be one of the best on the road then dammit it gets the best. notice i said the best not the most expensive.

I have liked lucas products for a long long time...., everytime I have used them, they have never failed me. I'm surprised you didn't say mobile 1. Stay away from that castrol hybrid syntec shit!!!!!!!!! I think the regular hard drive oil is better. As far as synthetic, I'd run mobile 1 or castrols full synthetic. But you have to have those tight tolerances or you're just pouring it down the drain or right back into the pan. That's a thought though because if I catch the run off I can pour it right back in......, ya ya
I wouldn't just diss. castrol by the way. they are my favorite oil but that hybrid shit is WEAK!!!!!

Good thought on running the dino oil for the first 1k, personally after having my engine built I put in some dino oil for the first 300 miles, changed with more dino oil for the next 700 miles or so, then I went witht eh synthetic. I wanted to make sure there would be no debris in there, hence the first change at 300miles. I run Mobil 1, and have tried the Syntec, but keep going back to Mobil 1. I very rarely go through oil, now that I fixed my valve cover gaskets (be sure to use new gaskets, RTV sealant, and some good hex bolts with threadlocker). My bottom end is pretty tight. I don't seem to get much oil consumption, but I definitely have some nasty piston slap on cold starts (heat expansion, forged pistons). I would definitely find a new machine shop. I will definitely give a good word to East Coast Auto Machine in East Hartford/Hartford, CT. They did a great job. He has done work for a few 600+ RWHP MK3's.

Quote: Had a knowledgable mechanic take his time and put the HKS MHG in

Did he resurface the block and head? properly? MHG's need much more precise work done than a standard head gasket.

Check your compression. If that's ok, then check your seals. Front Main, Camshaft seals, rear main, and really check under the car for any leaks. Check you IC piping and your exhaust piping for oil. You may have a light oil residue in the IC piping, but that is normal due to the stock PCV setup. Have a friend follow behind you looking for blue smoke. There are so many possibilities. If you have to end up looking at the turbo, do yourself a favor and find a reputable shop that may have dealt with Supras before, or at least a shop that deals a lot with turbos. Don't go for the shop with the lowest prices, go to the shop that will fix your problem. Finding that shop may be difficult, but ask around. Talk to other "tuners" in your area and get an idea of who does quality work, and who just flat out sucks.

I have only herd of royal purple recently....., were you making a joke mark?

I have only herd of royal purple recently....., were you making a joke mark?

I don't think he was...Royal Purple is a really good oil. Costs a bit more.

I'll do some research on that, for sure. Once I get this car up. I'm @ a crossroad. Do I do an engine rebuild, only being mechanically inclined. I still have a bhg to deal with. My girl wants me to sell it and spend that much time on her. If that was an overshare, I apologize. I will not retract the statement. But serious cash can and needs to be thrown at the cars way. If I were only 5g's ahead.