Blue Smoke

kotu100

Active Member
Nov 23, 2006
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did you do the oil check? put a capful of oil in the low comp cylinder and do the compression test again. if it doesnt go up its probably your head (valves, seals)
 
Mar 14, 2006
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Brooklyn, NY
ok did the compression test this morning

1st cylinder dry-65 wet 89
2nd cylinder dry-75.5 wet 90
3rd cylinder dry-90 wet 114
4th cylinder dry-120 wet 155
5th cylinder dry-115 wet 134
6th cylinder dry-129 wet 154
 

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
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Valley of the Sun
kotu100;1366560 said:
oil return, its how the oil goes back from the valve covers to the block.

Bzzzz...wrong! The oil return holes are in the head on the same plane as the head bolts.

That large hose behind the alternator is part of the PCV...it's how crankcase vapor get to the top of the head and exit out the cam cover nipples.
 

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
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Depends on how the rest of the PCV is routed.

In your case (based on compression), it looks like rings to me.
 
Mar 14, 2006
144
0
16
Brooklyn, NY
update.....a couple of weeks ago i forgot to put my oil filler cap back on and drove the car unknowingly. Oddly little to no smoke was seen out the muffler. I tried the same thing today purposely and the same thing happened. Little to no smoke and i was racing the car to see if smoke would come out. Yeah there was a little slippage under the hood but the smoking stopped. any incite?
 

lewis15498

Don't blame ebay cheapass
Sep 28, 2008
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Raynham, Massachusetts, United States
Your compression test suggests bad rings. Just speculating here but with the cap off the crankcase pressure is zero, so your af mix was blowing by the piston rings even easier, thus less oil was finding its way up into the cylinders, does your oil smell like its getting fuel in it?
 

radiod

Supramania Contributor
Dec 13, 2007
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Abbotsford, BC
i forgot to put my oil filler cap back on and drove the car unknowingly. Oddly little to no smoke was seen out the muffler. I tried the same thing today purposely and the same thing happened. Little to no smoke and i was racing the car to see if smoke would come out.

So what you're saying is that your engine bay is full of oil all over the place now?

And I give the +1 for rings based off your compression test results. All of them seem very low overall...TSRM spec is 142psi with a MINIMUM of 128psi. You barely hit that dry on your best cylinder.

7MGTE Compression Check: http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=21

If you go back to the 7MGE page it gives you the possible reasons for low compression.
 
Last edited:

tlo86

Ninja Editor 'Since 05'
Jul 24, 2005
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Colorado
+1 for piston rings, and if your PCV system is not functioning as well as it should be, then thats the culprit. dont think your turbo is to blame for any of the smoke.

assuming you dont have a BHG... and took care of it before you decided to race it :):)
 
Mar 14, 2006
144
0
16
Brooklyn, NY
lewis15498;1370688 said:
Your compression test suggests bad rings. Just speculating here but with the cap off the crankcase pressure is zero, so your af mix was blowing by the piston rings even easier, thus less oil was finding its way up into the cylinders, does your oil smell like its getting fuel in it?

sometimes. sometimes it smells like a oil mix
 

kotu100

Active Member
Nov 23, 2006
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36
Easton, Ma
has a HG been done on the motor before? it seems that with the progressively better compression in the rear cylinders. perhaps the block was machined but the rear timing cover wasnt machined with it.

just an idea.
 

7thousandpiecesMGTE

Boostin USA
Apr 9, 2007
469
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Harford County, Maryland
I didnt see the mileage posted on the 7mgte you swapped in.... but I am guessing it was used ? JDM low mileage or ?

As previously stated by many others the rings are likely bad with the comp test results you posted. The PCV system or your oil cap off will have not cause lower compression readings.

It sounds like you are looking for a magical answer that you will be hard pressed to find. I hate to say it but, It sounds like your motor needs freshening up, plain and simple. If its rebuilt or low mileage something went wrong. I just went through this myself a few months ago with a rebuilt motor with less than 1000 miles on it.. its sucks, I know.
 

lewis15498

Don't blame ebay cheapass
Sep 28, 2008
1,397
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0
Raynham, Massachusetts, United States
I know this wasnt what you wanted to hear but pull the motor again. My advice is to do everything now so you dont have to pull it again.
Have the block machined, measure the cylinder for out of round per tsrm specs, if its out have it bored out, eitherway, you need to have the cylinders honed for the new rings to break in properly. Get all new seals for it. new rod and main bearings. Change the oil pump while you have it out. I reccomend you use an OEM unit.
Have the cylinder head checked for hardness. If it fails, find a new head, if the machine shop doesnt know how to do a hardness test find a new shop. If it passes, have the head machined and have the valve seals replaced as well as anything else that shows wear such as the valves or guides or springs. Put it all back together with a new HG and timing belt as well as well as all the other gaskets. Be sure to replace the EGR cooler gasket with an OEM as the felpro is junk paper (a leaky egr cooler plate can easily cook your brakelines and boil the fluid, learned this the hard way). use Toyota FIPG or equivilent on the oil pan, and relpace the clutch if you didnt when you put the motor in. The egr cooler and oil pan are super easy to remove when the engine is out and a super bitch to remove when its in the car, so always check those two things while its out. Finally make sure you break it in properly. Its alot of money and time, but once its done you will have a solid reliable setup that will put a smile on your face for many years to come.

good luck

Guys feel free to chime in if I forgot anything.
 

Another MkIII

Member
Feb 22, 2009
697
0
16
Chicago
lewis15498;1371167 said:
I know this wasnt what you wanted to hear but pull the motor again. My advice is to do everything now so you dont have to pull it again.
Have the block machined, measure the cylinder for out of round per tsrm specs, if its out have it bored out, eitherway, you need to have the cylinders honed for the new rings to break in properly. Get all new seals for it. new rod and main bearings. Change the oil pump while you have it out. I reccomend you use an OEM unit.
Have the cylinder head checked for hardness. If it fails, find a new head, if the machine shop doesnt know how to do a hardness test find a new shop. If it passes, have the head machined and have the valve seals replaced as well as anything else that shows wear such as the valves or guides or springs. Put it all back together with a new HG and timing belt as well as well as all the other gaskets. Be sure to replace the EGR cooler gasket with an OEM as the felpro is junk paper (a leaky egr cooler plate can easily cook your brakelines and boil the fluid, learned this the hard way). use Toyota FIPG or equivilent on the oil pan, and relpace the clutch if you didnt when you put the motor in. The egr cooler and oil pan are super easy to remove when the engine is out and a super bitch to remove when its in the car, so always check those two things while its out. Finally make sure you break it in properly. Its alot of money and time, but once its done you will have a solid reliable setup that will put a smile on your face for many years to come.

good luck

Guys feel free to chime in if I forgot anything.
Torque the head to 75 and use ARP head studs and rod bolts.
-AM3