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-   -   No compression. Help me supra gurro!! (http://www.toyota-supra.info/forums/mkiii-supra/19256-no-compression-help-me-supra-gurro.html)

Semper_Fi 06-10-2011 10:37 PM

No compression. Help me supra gurro!!
 
Ill make the description short annd sweet.
No compression in engine.
head went to the shop.
New piston rings.
The cylindars were honed...
The gap in the piston ring is .030 inch, which is in range by the book.
New headgasket.
What am i missing?

El Supracabras 06-11-2011 12:46 AM

Post up the actual test numbers for each cylinder. No way they all have no compression. Otherwise a shot in the dark guess would be you somehow installed the cams with a valve open on every compression stroke. Not sure if it's even possible.

87hilux7mge 06-11-2011 01:00 AM

my guess would be improper cam timing. the valves are probably open during compression strokes.

did you make sure to use a proper compression tester? those "hold in" ones arent worth a damn. a screw in type with o-ring gaskets works great and are only about 15-20 bux.

another option is improper tq specs on the head bolts, left a gap somewhere maybe?

Semper_Fi 06-11-2011 06:19 AM

Quote:

Originally Posted by 87hilux7mge (Post 95954)
my guess would be improper cam timing. the valves are probably open during compression strokes.

did you make sure to use a proper compression tester? those "hold in" ones arent worth a damn. a screw in type with o-ring gaskets works great and are only about 15-20 bux.

another option is improper tq specs on the head bolts, left a gap somewhere maybe?

Yeah i checked it with a renter from autozone... i believe the last three were getting some kind of compression, but after checking the first 2. i jumped to the conclusion that i installed the piston rings wrong. So i ripped it apart.. were do i start?? thanks for the support everyone.
Thanks again. Carlos

87hilux7mge 06-11-2011 10:08 AM

check ring gaps if you took the pistons back out, and also make sure they are all indexed properly, cuz if you have all the gaps in the same spot, they will not seal as well. u can find the proper index chart in a repair manual or the cygnus TSRM.

then just carefully reassemble everything. id make sure your head/block surfaces are very clean, then when you put the gasket back in, spray it down with some copper spray, or if your using a MHG, put a thin coating of gaskecinch on it (they both improve the seal of the gasket).

double check all your valve seats and valves themselves, to insure they arent bent. you could have your head vacuum tested to see if you have any leaks (usually pretty cheap or free at a engine shop).

then just double check your install of the timing belt to insure proper valve timing. also, make sure to coat the cylinder walls with a thin layer of clean motor oil, and putting a tiny bit in the upper cylinders helps with compression tests.

then try your test again, hopefully you get better readings this time, GL!

Semper_Fi 06-11-2011 11:30 PM

thanks everyone again for the help. The last 2 post, got me researching like there is no tomorow. Thank you all.


but i guess i can set my fate as a noobie with this one question... My block Just sais 7m... is it soposed to say 7mgte? the timing cover sais 7mgte, but that can probably be changed to say whatever on it.
:eek2:
thanks. Carlos

87hilux7mge 06-12-2011 12:01 AM

all the 7m blocks were stamped 7m. they didnt differentiate between the ge and gte. as far as i know...

cre 06-12-2011 02:59 AM

Even if the rings aren't properly indexed you should still get decent compression across the board (probably close to the minimum allowed).... A wet test should pass fine though. My money's on valve timing.

87hilux7mge 06-12-2011 03:45 AM

yea i just wanted to cover all his bases, my money is on the valve timing too.

Semper_Fi 06-12-2011 05:19 PM

Yeah im guessing the head was poorly done. were taking it to get vaccuum tested monday morning, and were gonna attempt to put her back together. Is there any way to tell if the head is warped???

cre 06-12-2011 06:56 PM

Pull the cams and do a leak down test.

Semper_Fi 06-12-2011 08:19 PM

Quote:

Originally Posted by cre (Post 96013)
Pull the cams and do a leak down test.

I pulled the head off, and im taking it to the shop to get a vaccuum test done. Lets see the results, or im guessing we put the time offf.

Semper_Fi 06-15-2011 04:47 PM

Quote:

Originally Posted by cre (Post 96013)
Pull the cams and do a leak down test.

OK.So the head passed the leak down test. Everything was sitting right. No leaking whatsoever. Head is perfect.... Now should i go as far to say, i did'nt tq down as reccomended? Also, can my head bolts be stretched out? i baught new arp bolts. well... here goes breaking my head some more.

thanks
Carlos

Semper_Fi 06-16-2011 04:40 PM

ok... so i found the problem. valve adjustment was way off...

87hilux7mge 06-16-2011 08:35 PM

there ya go, good job man. hope you can get it together now!

Semper_Fi 06-18-2011 08:56 AM

Quote:

Originally Posted by 87hilux7mge (Post 96088)
there ya go, good job man. hope you can get it together now!

Thanks. Hey i saw in your sig, it said 7mgze. What is that?

87hilux7mge 06-18-2011 08:54 PM

Quote:

Originally Posted by Semper_Fi (Post 96115)
Thanks. Hey i saw in your sig, it said 7mgze. What is that?

well a "Z" was toyota's designation for supercharged engines, such as the 4agze and the 1ggze.

they never made a 7mgze, but mine is in the works right now. im putting an M90 supercharger on mine in leu of a turbo, cuz i like the idea of instant torque.

i still have a ways to go, but im making progress.

cre 06-20-2011 01:38 AM

I want a ZT configuration... twin charge! :gotnos:

87hilux7mge 06-20-2011 06:40 AM

Quote:

Originally Posted by cre (Post 96162)
I want a ZT configuration... twin charge! :gotnos:

lol, well im actually pickin up a whole truck load of gte stuff, so if i get a wild hair later on, and some funding, i might just have to build a twincharged one. prolly have to upgrade to an m112 tho, the m90 will be maxed out with mine essentially, and on a twin charged setup it will be dying.

but it would be sick, stay tuned! ill post pics of all the stuff im gettin.

Semper_Fi 06-21-2011 08:00 PM

Quote:

Originally Posted by 87hilux7mge (Post 96171)
lol, well im actually pickin up a whole truck load of gte stuff, so if i get a wild hair later on, and some funding, i might just have to build a twincharged one. prolly have to upgrade to an m112 tho, the m90 will be maxed out with mine essentially, and on a twin charged setup it will be dying.

but it would be sick, stay tuned! ill post pics of all the stuff im gettin.

yeah i looked around to see the status of your build. Great job researching. im exited to see your build prosper.

Well i just recieved a call from my machine shop. the head was just finished. Apparantly the guy keep ons saying the head was dropped, but he fixed it free??:nuts: So on to removing the pistons just to double check my work, and proceed onto my next problem. Thanks everyone.
Carlos

87hilux7mge 06-22-2011 07:11 AM

Quote:

Originally Posted by Semper_Fi (Post 96197)
yeah i looked around to see the status of your build. Great job researching. im exited to see your build prosper.

Well i just recieved a call from my machine shop. the head was just finished. Apparantly the guy keep ons saying the head was dropped, but he fixed it free??:nuts: So on to removing the pistons just to double check my work, and proceed onto my next problem. Thanks everyone.
Carlos

thanks man, im excited too, lotta work left too do tho!

sounds like yours is moving along better now. so they dropped your head, and fixed it for free cuz they screwed up, im guessing?

i guess thats kewl, lil clumsy but at least they owned up, good luck with it man!


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