Huge dilemma with my build Stroker GSR

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New Member
Ive got a GSR block and a B16 head. Originally i was running a whole GSR engine but i got a PR3 head and sent it to the machine shop to get looked over and install a full brian valvetrain. The valvetrain is OEM size valves, double springs, steel retainers, and stage 2 NA cams. When I put the B16 head on the car I pulled bad compression. None on 1, little on 2, about half on 3 and almost full on 4. Assuming the machine work was done correctly I figured I had bad rings or a gouged cylinder but i never tested compression before. So i pulled the engine and looked over the block and there were some rough spots on the cylinder walls. I sent the block to a different machine shop to get it bored over to fit a 81.5mm piston and clear the bottom of the cylinder walls for the connecting rods. Then came the time to save up the 2500 for the 2.16L bottom end. 4 months later I assemble everything, new OEM headgasket and ARP studs. Torque everything to the specs in the haynes manual, go to test the compression and Im back to square one... Exactly the same as it was before the new rings and complete bottom end. Checked the timing 15 times, the top marks are right, the inside marks line up, the crank mark is on point... So Im kicking myself in the ass because it seems like the first machinist didnt do something right on the head. What can I do? What can I test? Im not very experienced with internal work, but the person that is working with me is and he is stumped as well. Tomorrow I'm going to check the valve lash with a few tutorials that i found on the internet. Is there anything else i can do before i go to the machinist and have him double check his work?

Any help will be greatly appreciated. Leaving for a deployment to Afghanistan and I need this car on the road before I go. Im sure a few of you can understand my dilemma.


If the valve lash is way out of wack, it could cause your compression problem. Check that first because it is pretty easy & free to do if you have the tools.


New Member
Thanks for the timely response, that's my plan of attack tomorrow. I'll post as soon as I figure something out


Well-Known Member
Did they cc the heads and do the math to compute the compression ratio?

I'm not sure I would use a OEM head gasket on a build like this - suggest you look into a Cometic. :)

I"m just going to throw some stuff out there. Did you confirm TDC mark on balancer by putting a long socket extension or other tool in the spark plug hole of #1? When I did my last build we uesd a large dial caliper and a buddy held it against the head while extended through the spark plug hole and touching the top of the piston.

Is the woodruff key in the crank that indexes the balancer? (lower crank pulley)

Using stock cam timing pulley's? Pulley's compatible with the cams you chose?

Good luck on your deployment and thank you my brother.
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New Member
To be honest I would be lying if I said I knew. I'm ignorant when it comes down to internal building. I have a family member that works at cometic in Ohio that's the plan but right bow I just want it on the road before I leave


Well-Known Member
Ok. Not to throw a wrench in things for you. I suggest you contact the machine shop that did the head work and ask them if they can cc the head. All you need to do is measure the deck height on the block - the difference between the deck (top of block) and top of one of the pistons. Then, take 1 piston with rod connected along with the head to the shop.

They can then check the piston dome displacement and cc the combustion chamber. Knowing the deck height, they can tell you what the compression ratio will be with a given thickness of head gasket. Cometic head gaskets come in dirrerent thicknesses as well as custom thicknesses.

Ya really need to know that - then you will know which ECU map and such to use.

And yes, as 99sidude recommended - check the balve lash first - I would also put a long screwdriver or extension in #1 and comfirm the mark on balancer is TDC too - that just takes a minute and is a good sanity check.


If the problem started after the head work, and the timing is dead on, valve lash would be my next guess. Sounds like you already got that figured out.


Super Moderator
Sounds like the head needs to be resurfaced.

I totally disagree on the cometic HG. They are garbage, stick to OEM.


Well-Known Member
They should have done the head resurface when it was in the shop.

There's a communication problem in the equation.


Junior Member
going out on a limb here but, with that much of a variance in readings, I think it's all in your head.. Literally.

On a fresh rebuild after a boring you should have pretty tight readings (meaning at least 180-190psi depending on the compression ratio)

SO, squirt some oil in the cyl and recheck the compression by pulling ALL the plugs out and WOT throttle as it spins (one at a time) and spinning for more than 10sec. (c'mon, if the battery is just barely, charge it up and get it spinning at atleast 400rpms)

If it didn't change in any of them, take a air hose and pressurize the cyl with air for EACH cyl and listen at the throttle body for 'hissing' If so, BIG leak on intake valves..
Listen as the exhaust closes to the end of the pipe, Hissing there? Bad exhaust valve on that cyl.
Granted, you will be checking each and every cyl, but hey, it's free.. (take notes)

You see, the oil will take up some space within the ringset producing a 'tighter' tolerance raising the comp ratio.
If it DOESN'T change, it's in the head.

Pull the valve cover and take a close look at the adjusters.. Are they all at the same thread-count? from the nut up?
Do the rockers sit right OVER the tip of the valve stem, or slightly off?
Are the springsets straight up and equal between the others..? Or leaning?
Broken springs?
Missing locks/ canted retainers?

Spy the cam lobes.. Groved lobes? Severe wear patterns? 'Silvery' oil coming from the cam towers or around the lobes?

You see, there are several different issues that can arise and the heads can cause most. That's why they charge soo much to have it done right..

Take some time out and do a little investigation into why, but mostly HOW things work together

Just my .50



New Member
I don't think he is coming back here to check for this thread.

If I seen this back then, My .02 cent would be the head itself. Those reading leads to a leakege in the head.

this thread is old but what the hell!