compression loss

bigchalk · 08-03-2006, 09:51 AM

i bought my 1989 supra and was told it ran but doesnt hold compression in 2 cylinders i am hopeing its just a head gasket any ideas

Isphius · 08-03-2006, 02:03 PM

Headgasket, Valves bent/broke, Rings beat, Broken piston...Could be lots of stuff. I bet its the headgasket tho. Do a leakdown test, And see how fast it goes. If its really fast, Probably a broken metal part. I wouldnt run the car like this. Probably fragments in the cylinders, and that is not good! I got a spring in my gokart motor once, Ill show you a picture of it later what it did lol.

marc · 08-04-2006, 04:32 AM

ive seen dismembered engines where stuff has gotten into the cylinders..GAME OVER for that engine. u can see the imprint of where the piston head hit the object or watever was in it. ive seen half of a screw indented into an engines piston. and ive also seen water damage to pistons. the whole rod was snapped because water got into the cylinder and couldnt combust so the rod has too much pressure oushing back on it as it was thrusting and it snapped. crazzzy stuff.

tone loc · 08-04-2006, 05:41 AM

how do u do a leak down test??

rnoswal · 08-04-2006, 12:41 PM

A leak down test puts air into the cylinder then the guage shows if there is a pressure loss and if so, how much pressure is lost during a set time. All cylinders are going to leak some though. You can sometimes hear the air escaping through various parts though. Through the intake then probably an intake valve and same with the exhaust. If you can hear air coming through the oil filler cap then it is most likely worn out rings, if you get bubbling in the radiator, well that pretty much shows a gasket problem and if you can hear air coming out the sparkplug hole next to the pressurized one then it is again the gasket.

I'm sure more out there have more info, but probably a shop that you trust and would let you see what's going on would be best as the guages might be expensive.

Russ

Isphius · 08-04-2006, 03:32 PM

Yeah, Its a good idea to let a pro do it. But you can get a compression tester, thats pretty easy to use.

08-03-2006, 09:51 AM	#1
bigchalk Stock Join Date: Aug 2006 Location: germany Posts: 20	compression loss i bought my 1989 supra and was told it ran but doesnt hold compression in 2 cylinders i am hopeing its just a head gasket any ideas

08-03-2006, 02:03 PM	#2
Isphius 500whp yet? Join Date: Nov 2005 Location: Long branch, NJ Posts: 1,006	Headgasket, Valves bent/broke, Rings beat, Broken piston...Could be lots of stuff. I bet its the headgasket tho. Do a leakdown test, And see how fast it goes. If its really fast, Probably a broken metal part. I wouldnt run the car like this. Probably fragments in the cylinders, and that is not good! I got a spring in my gokart motor once, Ill show you a picture of it later what it did lol. __________________ Yay the supra assistant is gone!!! WEEE!!

08-04-2006, 04:32 AM	#3
marc 12psi boost Join Date: Jun 2006 Location: salem mass Posts: 329	ive seen dismembered engines where stuff has gotten into the cylinders..GAME OVER for that engine. u can see the imprint of where the piston head hit the object or watever was in it. ive seen half of a screw indented into an engines piston. and ive also seen water damage to pistons. the whole rod was snapped because water got into the cylinder and couldnt combust so the rod has too much pressure oushing back on it as it was thrusting and it snapped. crazzzy stuff. __________________ nothing but the best -mods- so far K&N intake fipk 3" megan downpipe 3"turbo elbow 4 washers on the wastegate highflow cat short shifter 89+ front bumper, pic soon to come many more upgrades soon

08-04-2006, 03:32 PM	#6
Isphius 500whp yet? Join Date: Nov 2005 Location: Long branch, NJ Posts: 1,006	Yeah, Its a good idea to let a pro do it. But you can get a compression tester, thats pretty easy to use. __________________ Yay the supra assistant is gone!!! WEEE!!

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08-04-2006, 05:41 AM	#4
tone loc 20psi boost Join Date: Jun 2006 Location: Chicago Posts: 706	how do u do a leak down test??

08-04-2006, 12:41 PM	#5
rnoswal Lexus & 550's Join Date: Apr 2005 Location: Bossier City LA Posts: 556	A leak down test puts air into the cylinder then the guage shows if there is a pressure loss and if so, how much pressure is lost during a set time. All cylinders are going to leak some though. You can sometimes hear the air escaping through various parts though. Through the intake then probably an intake valve and same with the exhaust. If you can hear air coming through the oil filler cap then it is most likely worn out rings, if you get bubbling in the radiator, well that pretty much shows a gasket problem and if you can hear air coming out the sparkplug hole next to the pressurized one then it is again the gasket. I'm sure more out there have more info, but probably a shop that you trust and would let you see what's going on would be best as the guages might be expensive. Russ