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DOHC Install - does swapping cams require valve adjustment?

Posted: Fri Jul 15, 2011 6:51 pm
by wtdash
Edit: Quick answer= YES

EJ22T with '98 EJ25 DOHC heads (shimmed bucket lifters) running EJ20K turbo camshafts.

When I swap in the EJ25 stock cams do I need to re-adjust the valves?

They were recently adjusted when I had the heads done w/the turbo cams for the swap (have less than 2500 miles on 'em).


History: Car is slower than ever off the line (yes, even slower than the stock EJ22T w/SOHC heads), which is most likely due to the low 7.5:1 CR I'm now enjoying w/the stock EJ22T head gasket. Before I go to the trouble of swapping the HG to a thinner one, I thought I'd try swapping the cams. I've read online that the EJ20K cams are more for HP/RPMs than Torque. Read POST#20. My original thought process was, "I have a DOHC turbo, I should use turbo cams."....notsomuch?


Thanks
Td

Re: DOHC Install - does swapping cams require valve adjustme

Posted: Fri Jul 15, 2011 6:54 pm
by Legacy777
Do the DOHC heads you're using have mechanical or hydraulic lifters? If they're mechanical, they should be readjusted.

Re: DOHC Install - does swapping cams require valve adjustme

Posted: Fri Jul 15, 2011 6:58 pm
by wtdash
Shimmed bucket lifters, per Wikipedia...damn! Those shims are PITA to get the right ones, and supposedly there is a special Subaru tool to hold the bucket while replacing the shim.....otherwise the engine has to come out to do it correctly. Double Damn!

I'm getting an updated 'Rob tune' EJ20G chip w/more timing advance...Hoping that helps.

Td

Re: DOHC Install - does swapping cams require valve adjustme

Posted: Fri Jul 15, 2011 11:40 pm
by wtdash
According to a well-respected member on here, Matt Monson, in response to changing cams:
Just make sure that someone who knows those heads well adjusts or helps you adjust the lash once you get the new cams. It will require new shims pretty much on every valve...
Td

Re: DOHC Install - does swapping cams require valve adjustme

Posted: Sat Jul 16, 2011 3:23 pm
by MikeyMeyagi
shouldnt be slow, urabusturbo on here is still running a stock 22t ecu with that same motor setup and a vf34 and he made about 220whp on 14psi.

i have the turbo cams in my engine and it was a upgrade from the n/a cams for sure

Re: DOHC Install - does swapping cams require valve adjustme

Posted: Sat Jul 16, 2011 3:33 pm
by wtdash
^Slow off boost.....but still doesn't hit as hard it should on boost either.


Thanks,
TD