how much psi for ls/vtec compression test?
#1
Thread Starter
Join Date: Jun 2005
Location: Vista, ca, usa
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
how much psi for ls/vtec compression test?
i have been searching for the correct psi for a compression check, but i cant find any deffinitive answers. i am running a gsr head, and itr pistons on an ls bottom end and i was wondering if any one could help me with the right psi to look for.
#2
Re: how much psi for ls/vtec compression test? (itrsleeper)
in all actuality, all gauges are different. no two will sho the same #'s even if ther is a set amount of psi per compression ratio. i did two different compression test on my motor. one was 195 195 193 195. the other compression tester i used said 225, 225 220 and 225.
its not so much the amount of the numbers, but more so if one is lower by a large amount above the stock specs. or if a set is lower, for instance, 195 195 70 70 either your h/g is leaking between those two cylinders, or your rings are shot or ring lands busted.
if a number is low and its because rings, you take a spray bottle and put some 30w oil in it and spray it in he cylinder thats low, if it comes up quite a bit its your rings.
its not so much the amount of the numbers, but more so if one is lower by a large amount above the stock specs. or if a set is lower, for instance, 195 195 70 70 either your h/g is leaking between those two cylinders, or your rings are shot or ring lands busted.
if a number is low and its because rings, you take a spray bottle and put some 30w oil in it and spray it in he cylinder thats low, if it comes up quite a bit its your rings.
#3
Thread Starter
Join Date: Jun 2005
Location: Vista, ca, usa
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
Re: how much psi for ls/vtec compression test? (rexsk8er)
thanks for the info but i was wondering if there is supposed to be an actual psi. because if i check it and it reads the same across all for (lets say 190) then i still dont know if i have lost compression in all four cylinders. from my searches i have found it to be about 230-235 and i was just wondering if some one knew this for a fact. especially since i have higher compression.
#4
Honda-Tech Member
Join Date: Jul 2004
Location: a fuzzy happy place, USA
Posts: 4,337
Likes: 0
Received 0 Likes
on
0 Posts
Re: how much psi for ls/vtec compression test? (itrsleeper)
how many times did you let the engine turn over on each test? My ls vtec has 9.1 compression ratio dish pistons and it reads 180-182 psi all the way across the board on 5 strokes. I would think that the @11.1 compression ratio that you're hitting should be closer to @220
as far as the dude stated before if you add oil to the cylinders and it greatly improves the compression test you rings may be shot. Depending on how long they have been in there is there any chance that they may not have been broken in properly?
as far as the dude stated before if you add oil to the cylinders and it greatly improves the compression test you rings may be shot. Depending on how long they have been in there is there any chance that they may not have been broken in properly?
#5
Thread Starter
Join Date: Jun 2005
Location: Vista, ca, usa
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
Re: how much psi for ls/vtec compression test? (dohcdelsol93)
im not sure, the guy who built my motor let his buddy drag it after the build, but i still drove 500 to try and break it in.
#6
Honda-Tech Member
Join Date: Jul 2004
Location: a fuzzy happy place, USA
Posts: 4,337
Likes: 0
Received 0 Likes
on
0 Posts
Re: how much psi for ls/vtec compression test? (itrsleeper)
use the oil technique and get back to us. The rings may have not seated and it may need to be pulled apart and re-honed
#7
Thread Starter
Join Date: Jun 2005
Location: Vista, ca, usa
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
Re: how much psi for ls/vtec compression test? (dohcdelsol93)
thanks, i was more worried about piston slap, than loss of comp. but i was hopping that if i was lossing comp. then it was just the rings instead of a bad hone job. my motor has only about 6000 mi on the fresh rebuild.
Trending Topics
#9
Honda-Tech Member
remember that the results will differ greatly everywhere because of height above sea level, temperature, humidity. everyones are different, your looking for steady numbers that are withen like 5 or so % of eachother.
#11
Thread Starter
Join Date: Jun 2005
Location: Vista, ca, usa
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
Re: how much psi for ls/vtec compression test? (itrsleeper)
finally checked compression, #1 peak=180 hold=175 #2 peak=180 hold =175 #3 p=155 h=150 #4 p=180 h=175. so obviously my rings are probly bad in the #3 cylinder.
did test with eng. at norm operating temp with 5 cranks each time and did each cylinder 3 times. motor only has bout 6000 miles on fresh rebuild with new pistons and rings. is this too early for bad rings or is it a sign of a bad hone job??
did test with eng. at norm operating temp with 5 cranks each time and did each cylinder 3 times. motor only has bout 6000 miles on fresh rebuild with new pistons and rings. is this too early for bad rings or is it a sign of a bad hone job??
#12
Thread Starter
Join Date: Jun 2005
Location: Vista, ca, usa
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
Re: how much psi for ls/vtec compression test? (itrsleeper)
and just incase you guys think these numbers are low this is my build
98 gsr head port & polish
ctr cams
98 itr valves w/3angle
jdm itr .25 over pistons
ls rods
ls balnaced crank
b18b block
should these numbers be this low??
98 gsr head port & polish
ctr cams
98 itr valves w/3angle
jdm itr .25 over pistons
ls rods
ls balnaced crank
b18b block
should these numbers be this low??
#13
Re: how much psi for ls/vtec compression test? (itrsleeper)
That's way too low. Do you have the gas pedal pressed down when you do the compression test? The throttle body has to be open to get a good reading. My LsVtec with b16 head and p30os pistons has almost 240 all across.
Thread
Thread Starter
Forum
Replies
Last Post
xiLLtegRax
Acura Integra
4
07-06-2009 10:23 AM