i just recently bought a car and the engine is an gsr block with ls internals with an b16 head. i did a compression test and all 4 cylinders are at 100psi. i noticed the timing belt was very loose. tomorrow im going to tighten the tensioner and hopefully it'll boost the compression. if not, what may be my problem?

also i have a question about my foglights that came with the car. it has a 00 front end with the flog lights already installed and the switch installed but the only problem is its not wired up. is there anyway to just run a wire and ghetto rig it to the switch or do i have to buy a wiring kit? if i do where can i purchase one?


Modified by shookones2 at 5:49 PM 12/9/2007

 

check your timing could be off a tooth

-Brett

 

How does the car run? Normal? Does it miss at higher rpms?? Any smoke coming out of the tailpipe? Just tightning the timing belt isnt going to boost your compression.

 

the car runs strong and normal, no knocking or anything. there is no smoke coming from the exhaust.

 

kinda funky, why would anyone put LS internals in a gsr block. the lower LS compression pistons in the block will make it have lower readings

 

If you're not burning oil (blueish smoke out the back) then your rings are probably fine. If that's the case then your valves might not be seating well. I don't remember what acceptable compression is on a B engine but my B16A2 is healthy at 200 psi so 100 psi must be pretty bad. Anyway, if you have an air compressor then set the pistons to TDC one-by-one and pressurize the chamber. Then use a stethoscope to see if you can hear air escaping through the intake or exhaust manifolds. If so then it's time to strip the head and have a valve job done.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fmrprojects &raquo;</TD></TR><TR><TD CLASS="quote">kinda funky, why would anyone put LS internals in a gsr block. the lower LS compression pistons in the block will make it have lower readings</TD></TR></TABLE>

They wouldn't be that low, would they?

 

Why would someone put the LS rotating bits inside a gsr?
Because LS crank and rods give you longer stroke... Its the smarter way to make "ls"/vtec.
(Im making this now)

However, you are correct in thinking the compression will go down... Youre looking at ~ 9.5:1, if the pistons are PR4's. Would kinda explain the low values....though not completely. I had 150 on my last build with 9:1 compression

Looks like someone was thinking when they built this thing, but didnt think far enough.

 

so i should try to get a valve job done first or should i just invest in new pistons and rings?

 

Have you put a little oil down the cylinders to see if that changes the compression?
If it goes up, you need new rings. If it doesnt change, its your valves.
Try it...its free.

BUT...
You really need to do a leak down test, instead of compression. It will tell you a LOT more.

 

so basically i have to take off the spark plugs and pour engine oil? how much oil is required ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shookones2 &raquo;</TD></TR><TR><TD CLASS="quote">so basically i have to take off the spark plugs and pour engine oil? how much oil is required ?</TD></TR></TABLE>
Only a couple of drops. It would be more around the amount of a small spoonful. (hey thats not a bad idea!) Dont go and pour half a quart of oil in each cylinder.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yoffer &raquo;</TD></TR><TR><TD CLASS="quote"> Dont go and pour half a quart of oil in each cylinder. </TD></TR></TABLE>

Yeah, I know what happens then. It wasn't half a quart but I was just pouring from the bottle and lost my grip on it. Thinking the piston was already at TDC was my first mistake when I figured I should just run the motor and burn it out.

 

Generally, a cap full of oil, from the quart bottle, is the standard amount. ...However much that is...