rb20 guy said low compression

[bobob729]

Well I bought a rb20 in kc, mo for 500. and he said that the rb had 90 compression all the way across. It was torn apart when i got there. But to say it has low compression just didnt sound right because 90 in all six cyclinder just sounds weird. He said the car ran great before he tore it apart which is nice. But its been down for 2 months and im ready to throw the head back on and do another swap. So my question is what do you think i should do before i throow it back together cuz i personally dont think it has bad compression at all so that is why i ask? Any help is appreciated thanks. Byron

[krayton]

[bobob729]

it just sounds wrong

[Joe]

why does it sound wrong?

[bobob729]

it just doesnt seem right for a car to be at 90 in all cyclinders

[nekoabandoned]

erm for one , a rb20 needs somewhere around 129psi on each cylinder to run properly....i had 90 on 3 cylinders on my old rb...... i had bent valves

[krayton]

i like how YOU dont think it has bad compression.

loltastic

guy selling engine: here is this cheap engine, took it apart, has low comp all around

guy buying it: naaaa, that aint me. (puts engine together as is)

[bobob729]

I know what im doing when im building a motor. But I figured i would get some other opinions before i go and do anything with it and the only reason the guy sold the engine was that he was doing a 302 swap thats it. He wanted the 500 for the rest of the parts. But what i was thinking is the cam gear was off a bit or it was bad valves being that someone did the timing belt wrong that is a good guess though

[RustspecS13]

So instead of trouble shooting the low PSI, you just slap the POS back together and wait for a problem to happen?

That's brilliant. You didn't hint at trouble shooting it your self or at the least having a machine shop check the valves for sealing or even that you did a visual inspection of any of the valves.

And I agree with you, 90 psi across the board doesn't seem right. Not "doesn't seem right" as in the old owner doesn't know how to do a compression test, more like all the rings have blow by or all the valve seats on the intake or exhaust are either a little bent/tweaked or have bad seats. Its possible cam timing is off yes, but there's a good/bad reason for that. If your so great figure it out. But we can only guess, and since you know so much us guess is pointless isn't it?

Any way good luck with your engine. I hope you have a lot of free time.

~Alex