low compression Q's

[daboosted93]

So I found a cheap sr20 swap that I picked up a month ago. I didn't have a car yet, but recently found a 91 hatch with an sr in it already. I traded my del sol for it, but it doesn't run. The kid told me he "jumped" timing and bent valves in 3 of the cylinders. Since it runs off a timing chain, it is really hard to jump timing, unless he was a retard and messed with the tensioner and didn't know what he was doing. I did a comp test today, and the first 3 cylinders are at 100 psi, and the fourth is at 130. I know that those are low numbers in the first place, but typically, from what I have seen, bent valves give lower comp numbers than that. I poured some oil down the cylinders, and tried it again, and pretty much got the same numbers.

After that, I pulled the valve cover off, and the timing looks to be good. the crank is lined up to the second mark, and the cam pins are at 10 and 12. I then turned the motor by hand, and you can hear a hissing noise from what seems to be around the valves. I can't quite tell exactly where it is coming from. The car sounds like it wants to start, and it is getting fuel cause there was fuel on the plugs when I took them out. I just thought I would throw this up on here to see if anyone else has had a problem like this. Now I do have an entire other complete swap. So if the head ends up being bad, I will pull my other one off and get it all machined and throw it on. I have a new cometic mls headgasket and a set of arp's. Let me know if you have any ideas.

[LA_phantom_240]

Sounds like you have bent valves. Trust me, my KA jumped time (tensioner failure) and the head appeared fine, but had no compression. They could be bent ever so slightly enough where it won't start. My valves didn't appear bent at all, but all the exhaust valves had to be changed.

[fliprayzin240sx]

Hell, if you already have an engine, just pull the blown one and throw the block you have. Dont bother just swapping the head, just change the whole engine. Its simple enough...

Then take your time and rebuild the other one. Re-do the whole head, fresh valves (or aftermarket), better valve springs and retainers, clean it up a bit. Rebuild the bottom end with some CP pistons bored out to 87mm, fresh bearings and you pretty much have a brand new engine.

[daboosted93]

Ya, I think thats what I am going to do. I was thinking about switching heads, but that would be more of a pain in the ass than throwing in the other swap. Then, like you said, I can build the other one and throw it in when it is done. I just thought it was wierd that the kid had it running, then said he jumped timing and it would not start. then when I look at it the timing is still good.

[SirWarrior]

dont forget oil pump when spending all that $$ on rebuild.

[daboosted93]

So does the stock one not flow enough? I am used to hondas, but I decided to try something different. I picked this s13 up and I got a turbo toyota pickup also.

[fliprayzin240sx]

Stock oil pump barely flow enough. But there isnt much option unless you wanna go JUN oil pump and theyre expensive as shiet. People refrain from re using their oil pump when they rebuild just cuz well, theyre old. Its a possible point of failure in a rebuilt engine. Then it kinda snow balls from there, since your replacing th oil pump, might as well replace the chain and guides and the tensioner...etc etc etc.

[daboosted93]

Allright! So I finally got the motivation to try to find the problem with my motor in my s13. Yesterday, Me and my buddy decided to take off the cylinder head from the sr while still in the car. Pain in the ass, let me tell ya! all the support brackets, wiring harness, and coolant lines. So I finally got it off, and took it into the garage to inspect for bent valves, or other obvious damage, when my friends shouts to me if I was ready to pull the entire motor.

I set the head down and go to look at the block, just to find out the the #1 piston was melted on the passenger side. then the #2 and #3 pistons had heat scoring on them. Looks like someone had some detonation! So now I have ordered ARP's, cometic mls hg, complete regasket kit, new stage 2 clutch, new intake manifold, water pump, and soon to be oil pump. Hopefully all my parts will be in soon and I can get it running by next week!