0 compression with dohc swap/ I think I have a bigger proble

waldo320 · Post by **waldo320** » Fri May 25, 2007 6:08 am

Well I am headed out of town for the weekend so I will get wrenching on monday or tuesday. Will let you all know what happens when I re time it.

waldo320 · Post by **waldo320** » Tue May 29, 2007 4:33 pm

Well took the timing belt of this morning and rotated the cams a couple of times and nothing felt out of the ordinary. Did a compression test still 0 compression on both driver side cyclinders. Could there be a bolt or plug missing or something other than the head gasket that could be wrong?

gto7419 · Post by **gto7419** » Tue May 29, 2007 4:45 pm

Are you putting air in and its simply not building any pressure? As in, its going straight in and straight out?

Are you sure a valve isnt stuck?

I would pop off the intake/exhaust manifolds and SEE whats going on in there....

It kind of sounds like the valves are stuck open.

gto7419 · Post by **gto7419** » Tue May 29, 2007 4:47 pm

Also, are the heads known to be in good shape?

waldo320 · Post by **waldo320** » Tue May 29, 2007 5:22 pm

Yah the heads are in good shape I had them checked and milled so I know they are flat and hold pressure.

waldo320 · Post by **waldo320** » Tue May 29, 2007 7:02 pm

Here is the problem I believe!

one on the right

And the other one

one on the left

What valves are interchange able with 99 rs dohc heads will sti valves fit?

Matt Monson · Post by **Matt Monson** » Tue May 29, 2007 8:24 pm

get stock valves...

waldo320 · Post by **waldo320** » Fri Jun 01, 2007 5:16 pm

Here is a possible bigger problem it looks like I have valves hitting pistons?

You can see the valve outlines in the pistons.

Here is a picture of the bad valve.

Next question is their a diffrence between a manual or automatic crank?

Matt Monson · Post by **Matt Monson** » Fri Jun 01, 2007 7:54 pm

Valves hit pistons because the timing was off. The timing off is what bent the valves. Since you never got it to run, I doubt the damage to the pistons is enough that it matters. Take some fine grit paper (1000+/-) and take any edges off the nicks in the pistons. Replace the valves. put back together.

No difference in cranks. Why?

waldo320 · Post by **waldo320** » Fri Jun 01, 2007 8:36 pm

I have an ej25 that I have forged internals for that I am thinking about throwing in thats why I asked about the crank. I have the valve on order from subaru right now.

Matt Monson · Post by **Matt Monson** » Fri Jun 01, 2007 9:28 pm

Which EJ25 variant? If it's not an STi semi-closed block I would personally stick with the Ej22 bottom end. Forged internals will not rectify the inherent weaknesses found in the NA Ej25's. But it all depends on how much power you really are shooting for. Crawford has built a number of open deck EJ25's with Ej257 STi internals that deliver 300chp and stand up fine. A lot of it is in the tune...

SemperGuard · Post by **SemperGuard** » Sat Jun 02, 2007 1:42 am

First of all, the timing was never the problem. The problem was the cams were switched. You can set correct timing with incorrect cams.

Secondly, a leakdown test, and I'm sure about five other things, could've told you the problem.

Anyway, when you put it back together, double check everything.

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0 compression with dohc swap/ I think I have a bigger proble