bulit motor low compression

[cody92talon]

ok im getting sick of my freaking dsm i boutght it turned up boost a little an blew head gasket. tore it down put new lifters, stainless valves an 272 cams in well i bent valves so i i replaced them again along with titanium spr& retainers an ferra guides. well i repeated this valve pending an fixing 4 timings so u can c im now getting jacked then finally someone told me i had to bleed lifters. this last time the 5 time i had it tour down i built the motor i had the block honed, put manley h-beam rods in weisco pistons my ring end gaps are 19 top 23 second. an i used an mitsu 4 layer HG with spraying the copper gaset spray on it, along with everytihng is arp. as u can c i have a fully buitl motor an d every thing is balanced to i forgot that. but any way i broke the car in an every thing has like 200 miles on it. i was bored an fixing a small oil leak the other day an desided to do a compresion check just for the hell of it. well i was not happy to say the least i hae 30psi in 4, 125 in 3, 115 in 2, 135 in 1 so yea im very pissed off to say the least im not getting any were and havebin spending every paycheck an all of it on this car an im ready to just drive it. i dont understand ### is wrong this time if any one can give some in put it would be helpful

this sucks

 

[95gskid]

i don't want to admit that i know this kid, but i help him build this motor. you'll have to excuse his horrible grammar. but the motor like he stated is fully built and every things pretty much new, and for some reason he only has 30-35psi on cylinder number 4. if that makes it easier to read i've done my job

 

[mikelv]

Sounds like you guys did a poor job building this motor, but I don't want to point fingers or offend anyone. I've seen some ghetto builds turn out this way.

Did the motor seem smooth at first start up or did it sound kinda funny? (like you were off one tooth maybe).

Did you try and re-do the compression test just to double check yourself? Maybe we can get an engine guru in here to help ya out.

There could be any number of things going on here, and I'm sure the only why you're going to find out is tear everything back down, check your measurments, and see what happened. At least you're looking at the cost of an engine gasket kit. (about 200.00).

I would start with checking the timing and see if it's off a tooth. Then from there you might be looking at a tear down.

 

[95 'clipse RS]

how much boost did you break it in under? also, how exactly did you break it in? can you describe what you did to break it in?

if you can do a leakdown test it will tell you what happened without tearing it back down. if you have an air compressor take the one way valve out of the hose you used for the compression test and hook it up to an air compressor. you will have to rotate the engine over to shut the valves on the cylinder you're testing but that should be simple enough for you since you have had this engine apart 5 times. this will tell you if you have leaking valves, un-seated rings from improper break-in, or a bad head gasket. to help you determine if the valves are shut as far as possible it would be helpful if you have the valve cover off to verify they're closed. what you will have to do when doing this is listen for where the air is seeping out of, if any. it'll either be through the headgasket, intake or exhaust valves, or rings.

this test will tell you where you are loosing compression without having to tear the engine apart so you will know ahead of time.

i hope this helps you out

 

[cody92talon]

it was hard to tell about an strange noises on start up ### i had bled my lifters so they were a little on the ticking side for a while but i dont think i bent any valves if thats ### your suggesting ### the other times i did that i got a vibration through out the car an i dont have any vibration this time. i broke it in on 5 to 10lbs of boost on a 16g. my waste gate was screwed up thats why i say 5 to 10. my breakin consisted of first start up letting it ittle a t 2k for like 15 min then let it cool down to a little below the first notch on the temp guage. then started back up let warm up an just drove it around for bout 15 miles stopped at buddies house let cool down agian. drove around some more just shifting at like 3k 35 hundred buliding like no boost. i drave around stop an go type driving while everynow an then just taking the rpms a couple hundred higher with like 5lbs of boost i put bout 70 75 miles on before i WOT it but then i had also stopped an let it get completely cold a couple more times before i had done that. but any way even with the wot i was only pushing about 10lbs and only took it to like 6500 my wideband saying 10.0 the whole time my foot was down.

 

[cody92talon]

also no it wasnt ruff or anything on the insuall start up it idled smoothly

 

[95 'clipse RS]

oh, according to the manual, break-in consists of letting it warm up. then taking it out for 6-12 WOT runs in third gear from 35 to 55mph, then letting engine braking bring it back down to 35mph. that is what actually seats your piston rings into the cylinder walls and enables good compression. i've rebuilt several engines and have never had a problem with this method. in fact my N/A is at 225psi on all cylinders, the absolute highest it can go. but maybe if you could do a leakdown test that could tell you what it is.

 

[cody92talon]

an just to say this isnt a ghetto bulid!!!!! this is my first full engine build!!!! im trying to do everything to the T. im not cutting any corners or anything

 

[95 'clipse RS]

just to add a classic headgasket sign. the eclipse n/t i just bought has compression of 190-190-130-86. where do you think the problem is? between the last 2 of course. i did a leakdown and when air was put into cyl 3 it shot out cyl 4. the headgasket between cyl 3 and 4 was blown out. just an example i wanted to give you or anyone else who needs it.

 

[90rslaser]

you want to break in an engine the right way, then read this and follow it very carefully. it really does work and i have done this. hope it helps. Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

 

[rush2252]

Do a leakdown.

 

[acdavis25]

Did you have the head and block decked before you tried to put that MLS hg on?

 

[Killa_dsm]

Holy crap that was hard to read. Please revise your post so people can actually read what your writing. But yes, I second the leak down test and let us know what you find out.

 

[cody92talon]

no i did not have the head an block decked an ill do a leak down test this weekend my work schedule is a little crazy during the week. ill post ### i find out

 

[cody92talon]

ok i did a leak down test yesterday an i ve come to the con concluson that its my rings. i could slightly feel air coming up through my oil passages between the head an the block. an wen i pressurized like cylinder 1 i could feel some air coming out of the spark plug hole in cylinder 2 an 4 so im pretty sure its my rings. ### do u guys think?

 

[Kastigir]

It's the headgasket, it didn't seal properly.

 

[e85_4g63]

Sounds like head gasket to me also. Take the head to a machine shop and have them resurface it. You'll want a 40 R.A. or better finish on the head when it's done.

 

[BogusSVO]

from what I have read, you been told the right thing to do.

You may want the machine shop to vacuume check the valve to seat seal too while the head is there.
min spec on the test is 27 inches of vacuume.

 

[cody92talon]

so u really think its the head gasket?? even though all my compresion levels are different. is there any thing else i can do to make sure before i tear it down so i dont tear it down replace the head gasket and have the same problem yet ?