Cylinder head refresh?

[Dave7CDMTYPER]

I want to do cylinder head gasket/refresh on my gs-r. It consumes a lot of oil, like 1 quart per 1,000 miles. I want to do the valvetrain work myself, just to learn how to do it.

It did overheat once during my ownership, which is one reason I want to change head gasket.

[aklackner]

I’m a big believer in a head refresh generally.

Also just to confirm is compression testing being done dry or wet? This can have a pretty big difference. If you haven’t been try a squirt of oil in the cylinder before you run the test and see what happens.

TLDR:
I had a great experience with Tom @ Portflow. He’s committed to quality and he has an incredible valve program specifically for ITRs based on flow testing. It’s CNC cut so precise it doesn’t require lapping the valves. If you’re in SoCal it’s super easy otherwise he has heads shipped come in from all over.

I personally kept original valves (unless damaged or going with aftermarket springs for high lift cams which generally require engine management) and valve springs. OEM springs and valves generally have a very long usable life and will take considerable abuse. OEM valves are lighter and allow theoretically for better flow than higher strength (supertech/Skunk2) similar sized aftermarket valves. Aftermarket valve springs put a lot more force on the valves (to prevent float with high lift cams) and generally recommend valves with beefier stems. ThIs additional spring force can also contribute to cam and rocker wear. ITR OEM valve stems actually step in to provide a narrower diameter. Jun was the only aftermarket option that I saw that has/had a spring set was close enough to OEM spring force specifically to limit cam/rocker wear and I iirc were compatible with OEM valves. Like nearly all modifications it’s all about balance not just something that can be swapped in without other consequences.

New valve seals might make all the difference but there’s also a chance that a burnt valve or damaged seat could be part of a low compression issue. Though this is less likely if low pressure is even over the cylinders. If adjustable cam gears/long duration cams are in play overlap could show up as low compression across the cylinders I think.

Pulling the head also allows some visibility into any cylinder scoring.

Replacing the head gasket with new oem (or mugen/spoon 2 layer) would also be a good thing and could itself help resolve some of the issue if no longer a perfect seal. You might also take the opportunity to upgrade to ARP head studs.

Finally imho the original hydraulic LMAs should be replaced with OEM spring based replacements as the hydraulic units are prone to failure as they age from what I understand.

[00DC2R]

Exactly. Missing oil can only go two places...on the ground or out the exhaust. My R hardly burned any when I worked close to home and would drive normal but when I started commuting on the freeway with its short gearing and high RPM, I would lose about one quart between oil changes .

Ah that sucks. But your rings are ok right 00DC2R?

Thanks for the info guys. I will check in the summer for any blue smoke and go from there.

Yeah, she's good. The best thing I did when I could afford it was to get a Fit as a commuter in order to take the R off the highway. She's been a garage queen for a few years which has given me time to collect some parts. I plan on doing the same thing as you with the cylinder head refresh first and a bottom-end refresh down the road to not spend a ton of money all at once

[d.n.d.]

Exactly. Missing oil can only go two places...on the ground or out the exhaust. My R hardly burned any when I worked close to home and would drive normal but when I started commuting on the freeway with its short gearing and high RPM, I would lose about one quart between oil changes .

Ah that sucks. But your rings are ok right 00DC2R?

Thanks for the info guys. I will check in the summer for any blue smoke and go from there.

Yeah, she's good. The best thing I did when I could afford it was to get a Fit as a commuter in order to take the R off the highway. She's been a garage queen for a few years which has given me time to collect some parts. I plan on doing the same thing as you with the cylinder head refresh first and a bottom-end refresh down the road to not spend a ton of money all at once

Ok good lol.

Thanks for the info aklackner, yes I plan to refresh it with only OEM parts. Thanks for the tip on the Jun springs, I will see if I can find the part number. That will be a backup, if for whatever reason I cannot re-use my valve springs.

And the compression test was done dry, the mechanic did not squirt any oil down into the cylinder. He hooked up the compression gauge and removed one of the fuses in the fusebox on the passenger side, and cranked it a few times per cylinder. I will look into getting the compression gauge so I can try this myself.