So I have a 92 7mgte I just recently purchased the car, its been freshly built <1000 miles on build. The previous owner had many BHG issues so this last time he had the block and head machined, pistons replaced and cylinders over bored crank balanced and micro polished and many other little miscellaneous things done to it. Car is completely stock at the moment only thing done to it was a lexus afm because he no longer had the original afm. I've put about 300 miles on the car since I've gotten it, i put in original arm as to be safe and not run lean. Anyways after running the car for awhile i decided to push a little and I'm hitting fuel cut, all hoses have been checked and i have even performed a boost leak test and everything has checked out fine, i also have developed a fluctuating idle, nothing too serious but it wasn't there before. and lastly the last tie i pulled off the afm to perform a boost leak test i found an excess amount of oil on the afm and in the accordion pipe, could this be a cause of some of the problems? also car has no cel, except after hitting fuel cut which goes away after a free seconds. Did i screw something up??
Fresh build weird issues need some help
- Thread starter jg5899
- Start date
Oil issue I believe is due to a bad turbo seal.
Took compression readings after reaching the 3500 mile mark and the test results are as follows:
#1 80 with some oil in the cylinder pressure went to 105
#2 148
#3 148
#4 145 pressure would slowly come down though.
#5 142
#6 142
I'm lost should continue to run the car and see if cylinder #1 improves by the 5000 mile mark or is there some other step I should take? Please someone I need some answers.
Took compression readings after reaching the 3500 mile mark and the test results are as follows:
#1 80 with some oil in the cylinder pressure went to 105
#2 148
#3 148
#4 145 pressure would slowly come down though.
#5 142
#6 142
I'm lost should continue to run the car and see if cylinder #1 improves by the 5000 mile mark or is there some other step I should take? Please someone I need some answers.
Oil in the intake is somewhat normal. Excessive is not tho.
The compression won't change. Either rings hg or valves.
The compression won't change. Either rings hg or valves.
Even though it's a fresh build, a buddy of mine said that ring could just not be seating right yet.
Rings generally seat within the first 50 miles. If there not by then they usually won't.
Also since its on no1 there could be some issues with the build. Like rear timing cover or over torquing the t belt tensioner.
Also since its on no1 there could be some issues with the build. Like rear timing cover or over torquing the t belt tensioner.
i will be doing a leak down test because i really dont want to replace the rings, again i might add. This engine has been taken apart 4 times in the last 4 months, 2 BHG, then I did a whole rebuild over bored pistons, micro polished crank shaft, had the head pressure tested, had the block and the head resurfaced, and block hot tanked. When i was all done I did a hard break in and one of my rings broke.
Thats the history of this motor, this last time i just replaced the pistons and rings and now I have low compression on #1 I dont know what to do anymore.
How likely is it that its just a valve? Im getting a leak down tester to check the motor tonight or tomorrow morning.
Thats the history of this motor, this last time i just replaced the pistons and rings and now I have low compression on #1 I dont know what to do anymore.
How likely is it that its just a valve? Im getting a leak down tester to check the motor tonight or tomorrow morning.
The timing belt tensioner bolts through the rear timing cover, and to the block.
Overtorquing it will actually 'pull on the #1 cylinder wall slightly, causing blowby.
As Hvyman also mentioned- you should have had the rear timing cover bolted to the block when it was decked.
If it wasn't, then the rear timing cover(which sits under the front edge of the head gasket) will cause the head to remain lifted off of the deck surface,
causing you to leak from the head gasket. So...
DID you have the timing cover decked along with the block?
If not, you may be able to get away with pulling it off and having it cut down slightly. Thing is, you'll still need to disassemble half the engine to get to it.
Overtorquing it will actually 'pull on the #1 cylinder wall slightly, causing blowby.
As Hvyman also mentioned- you should have had the rear timing cover bolted to the block when it was decked.
If it wasn't, then the rear timing cover(which sits under the front edge of the head gasket) will cause the head to remain lifted off of the deck surface,
causing you to leak from the head gasket. So...
DID you have the timing cover decked along with the block?
If not, you may be able to get away with pulling it off and having it cut down slightly. Thing is, you'll still need to disassemble half the engine to get to it.
Seeing as you've lost compression in the #1 cylinder, and that where the timing cover is, we could suspect this as the cause.
But it's not certain.
But it's not certain.
A few months later and I finally got the chance to take it apart and see what was going on. Cylinder 1 and 4 had broken ring lands, turned out to be a little more than what I had anticipated.
Time for a rebuild, I will be going forged this time around, hopefully they'll withstand more abuse.
Time for a rebuild, I will be going forged this time around, hopefully they'll withstand more abuse.
Now I know this is an off topic question but thought maybe someone could help me out, I will be putting on 680 injectors after the build is done in conjunction with Lex AFM and a SAFC. I was told I should finish the build with the stock injectors as i would not be able to start the car with the 680's. Does that make any sense? or should I just stick with the 680's as I had originally intended? Car is going straight on the dyno after build is done to get broken in also thats why I figured I would put the 680's on.
Why are you going with such a large injector size? did you just happen to have a set of 680's laying around or are you going to buy them?
edit - i dont know what all modifications you have done to your vehicle bro, but if it's just the lex afm and the safc i just dont see the point of running such a large injector size.
edit - i dont know what all modifications you have done to your vehicle bro, but if it's just the lex afm and the safc i just dont see the point of running such a large injector size.
89niner;1828863 said:
I had them already. I will also be running a 60-1 upgraded ct26, full 3in exhaust, and an upgraded intercooler.
They look like NPRs. If the P.O. put a lexus AFM on with stock injectors that could easily run lean enough to turn your ringlands to dust.. Like pictured.
Yes, this will cause a BHG if not done. Make sure it is done this time around or you will have another BHG.jg5899;1800856 said:
-AM3