Do i have bhg or bad turbo

[89supra7mgte]

The car idles good has a slight stumble runs great at rpm, but smokes alot at idle and rpm. It smells kinda rich, really rich. Have no adjustable fpr or any aftermarket mods, all stock 7mgte, except the fact i have no cats(previous owner) I have not performed a cylinder leak down yet(tomorrow) I have noticed the engine itself get hot fast, before coolant can fully circulate, no coolant loss or excessive psi, no coolant in oil, no oil comsumption either. I do however have excessive crankcase psi and lots of smoke or whatever from vc breathers and oill cap, smells almost like exhaust......

....So i guess i am asking is it possible to have one of these engines blow cylnder to oil on the gasket, creating a high ammount of psi in crankcase? Or could this be a case of turbo being bad internally forcing exhaust back into oil? trying to get as much info as i can before pulling it apart and find out what i might need to do as far as replace/rebuild turbo or hg.

 

[CajunKenny]

What color smoke?

Have the coolant tested for exhaust gases.

 

[89supra7mgte]

i wanna say the smoke is greyish blue, it smells like fuel and burns your eyes. I am gonna bring a coolant/block tester home from work tomorrow to check, but would i have high coolant psi? i can let it idle or drive it without blowing coolant into the overflow. what are the other options that would cause the eye burning exhaust?

 

[wardog]

Excessive crankcase pressure , from experience, means

1. bad valve stems
2. Bad rings

I have had this when two or my cylinder ringlands cracked. Do the test and post the results and while you at it a compression test wouldnt hurt.

 

[CajunKenny]

Greyish blue would be oil. It could be bad turbo seal, bad valve stem seals, worn rings. How many miles on the engine?

Does coolant come out of the overflow ever...does the overflow cap pop off while under boost?

 

[89supra7mgte]

I bought the car and the guy said it was one of the jdm engines offline, somewhere betweem 35-60k. The engine and head you can can tell, from the outside, are in NEW clean condition. I had the vc's off and there is hardly any wear on cam lobes. He said he sent engine out soon as he got it to have it checked before installing, supposed to have been refreshed with seals, guides and valve job. Metal head gasket and arp studs. I knwoo the studs are on there cause i seen them...... Anyways he stated he still had a leak, when purchased i noticed oil level low and milky. flushed oil and cooling system, have not gotten milky oil now coolant loss. I assume he just didnt drain the oil enough.

aside from that, i believe the engine to be in decent condition, internally. It has great vacuum, but that doesnt say much. I will compression test, leak down and block tester tomorrow.

 

[CajunKenny]

Well, when I bought my second supra, it had purchase receipts and install receipts of an HKS Metal Head Gasket. I had no reason to believe otherwise. I turned up the boost and POP!!! BHG.

I pulled the head and guess what?! Yep...no HKS Metal Head Gasket. It was OEM.

Ok. Enough about that!

If you have a MHG, how do you know the block and head have been properly prepared for it? Each MHG Manufacturer have minimum RA (smootheness) specs that have to be met in order for proper performance of their MHG.

If the surfaces are not properly prepped, the chances of BHG/BHG Symptoms are high. I've read post after post of it happening.

Hopefully, that's not the case here; but, it sounds like it.

If your findings lead you to take off the head, you would be better off installing an OEM Head Gasket and using the ARP's. Now if you're tearing the engine apart for a rebuild, then have the surfaces properly prepped for the MHG of your choice.

With a good tune, great power can be made on an OEM HG with ARP's. Good tune being key there!

I don't know what your power goals are; but, 10-11 psi of boost, the OEM HG/ARP setup is VERY reliable.

Good luck and let us know what you find!

 

[radiod]

Is the rumble kind of like a miss? I know that this can be caused by something (excessive oil or coolant) getting in to the combustion chamber and not burning properly. I know when I had my cracked head my car would run rough for about 30 seconds after a cold start due to some coolant in cylinders 3/4 that just simply wasn't getting burned.

Do your leakdown and compression test, check your results there. Look for your classic BHG milkshake. Check for oil swirls sitting on top of your coolant in your rad and overflow. Check for an excessive buildup of oil goo under your oil cap. Check for some water/coolant in the bottom of your oil pan by cracking the drain plug a bit and seeing what comes out first (oil sits on top of coolant and water, therefore if there is something in there OTHER than oil, it will show itself by draining first).

 

[89supra7mgte]

I am about to do the compression leakdown now. As of right now the oil is oil and the coolant is coolant no mixing. About the previous owner, he said the head was prepped but no idea on the block it does have the arps i seen them. Anyways i think i am gonna tear the head off and do an oem soon just wanna verify before hand. And this engine will be a light mod so the oem should be good the other block and head will be the project, with high numbers. One question i already have an hks 1.2 gasket that i was gonna use before i found out about the surfaces, anyways what would be a good machine of the other block and head that wont blow my compression to high, just for future reference.


Test results soon..........

 

[89supra7mgte]

The results:
Compression test: Disable fuel and ignition cranks for 5 sec engine cold cylinders dry. spec is 142psi or more on warm engine and min of 128psi.
1- 125psi
2-120psi
3-125psi
4-125psi
5-125psi
6-125psi

Leakdown: brought each cylinder up to tdc compression and calibrated gauge each time
cylinders 1,2,3,4 and 6 all had 15% leakdown, LOW on the gauge heard from oil cap and valve cover breathers
Cylinder 5 was around 23% still LOW on gauge and also heard through the same area

When pulling plugs out they were all evenly sooted up like a chimney, dry

I am hoping i have valve problems i can get the head fixed right for cheap, i cant afford to pull the engine out to re-ring it, any suggestions on help the rings seal, or any ideas of what i might be looking at as far as my problem? will any of this cause the car to die or stumble after letting off throttle?

 

[CajunKenny]

Regarding MHG thickness: You get your machining work done and then figure out what thickness gasket you need. It will vary depending on how much material they have to remove.

Just for reference, the stock HG is 1.37mm compressed. That's off of memory so someone correct me if I'm wrong there.

Cold compression numbers are sort of ball park figures. Until you can get warm compression numbers, all bets are off.

Stumble or die after let off. Is your BOV venting to atmosphere?

Have you pulled codes?

 

[89supra7mgte]

I have the stock turbo system on the car right now was trying to get it running right before i did any upgrades. I had a thread before a couple actually and IJ got pissed that there were so many relating to my stumble issue but it did have code 31, it comes back most of the times when it idles down and dies, not when it stumbles though. i figured it was the cold start being stuck open so i plugged the injector with a ball bearing temporarily and still same thing, if you find my thread it is "in need of help code 31" it has all and everything i have checked from the basics, to sensor readings. I would go into it more but dont wanna upset anyone.

As far as my head gasket or issue with this one i am taking my other head in and have them go through it see what the condition is and make sure its flat no milling if possible, gonna through an oem on it. Pull the current head off the car have it fixed up along with my other block and build the power engine with it.

 

[CajunKenny]

I found it; but, didn't read all of it.

Have you tried a known good AFM?

Did you spray carb cleaner in it?

 

[89supra7mgte]

My original i did spray cleaner in before reading any posts on it. Have tried 2 others as well one from ebay supposed to me a lex in good working condition, the other from the junk yard. I have went and tested all and everything i can think of.

I def have a few issues with this car, and i am thinking its all related to the po and his head job. Would make sense having bad valve seals/guides, creating lots smoke out exhaust, leaking down in cc crappin out my plugs, and leaking cylinder compression up into head? Does that make sense, it did when i was saying it to myself but not too sure how possible it is?

 

[CajunKenny]

Your findings do point to the head. Valve Seats and/or Valve Stem Seals. Which? Either or both...

The fact that you have an extra motor/head puts you ahead of the game. I would do as you've described. Get your second head checked out and then install it along with an OEM HG.

 

[89supra7mgte]

its probably the cheapest right now anyhow. specially being that i am not gonna be using mhg. I will need to replace or rebuild turbo soon too noticed some side to side movement in there also. but first things first head. btw i checked out your build thread damn son that is one mean ass supra. looks damn good, only in time will mine be worthy of its own thread with pics

 

[CajunKenny]

You'd be surprised how long a turbo will last with a little shaft play. I'd definitely hold off on doing anything with that.

Thanks for the compliments on my car! She's come a long ways and has a long ways to go! Got to get the new clutch in...rebuild the tranny...big brake upgrade kit...on and on and on it goes...

Eh, you don't need anything fancy to start a build thread. It's like school pictures. You'll love to look back on them. Plus, if you ever want/need to sell the car, a build thread is a detailed log of it's life with you and will help a lot with the sale!

 

[89supra7mgte]

Ill wait on the turbo plan to eventually get a new one. One question about the car, what do you think the raw fuel smell could be caused by?

 

[CajunKenny]

When/where do you smell it? Startup...tail pipe?

My buddy's DSM had a fuel smell at startup. That case ended up being fuel in the vac lines.

 

[89supra7mgte]

I smell it whenever the car is running, along with the smoke. I can smell it and see smoke when i remove the oil cap, as well as at the muffler. I was thinking it had to do with cold start but never goes away. Completely bypassed the cs to make sure. My theory i just came up with: Leaking valve causing plug to not fire that well allowing unburnt fuel to exit exhaust? Smoke from burning oil and some fuel? I dont know how to adjust the fuel psi or if its possible on stock system? I found the screw in the second regulator towards firewall but unsure of its main purpose? Hold fuel in rail or adjust fuel to tank? Either way adjusting it makes no diference even tried a spare i had. And as far as fuel in vac lines none. at this point i am only running the necessary, no egr or its components. Was acting the same before removal, just wanted to eliminate any possible vac leaks at the time.


I took the intake off and can smell BAD GAS, i think that is what is causing most of my issues. I am still going to pull the head and inspect everything, i see fresh machine marks on the block that is good. I am hoping that everything is straight and i can reuse everything without having to re-machine it all. even the cams have no sign of wear.