I just check my Compression its 240-243 on all cylinder

the car has a 10.8:1 compression ratio. but i dont know how to translate that to PSI per cylinder.

but this is the sparkplug after 400 MILES

I'm worry about it being so HIGH. i think it will blow a gasket or something

 

Yep looks good might want to do an impedance test to make sure, but looks like a platinum type plug after about 10k miles should. Too bad the 1st one is blurry since it shows the contact on the electrode.

Btw were those OEM plugs or just replaced 400 miles ago. They do show some normal looking wear, but if only 400 miles worth, maybe switch to a cooler plug, which might help slow the wear.

 

Its a replacement. it was Auto-lite Platinum spark plug.

and yes that's how it looks like after 400 miles.

Honestly i think its to hot. But i don't know what kind of spark plug i should get. I think your correct. it should be Colder. because my Compression is 240 PSI, i believe having colder spark plug will help it.


Any idea of what kind of spark plug i could used?

 

Well according to spec the compression should be about 10.8:1 which would make for about 150-160psi. I think you might have a combustion chamber issue on your car. This could be caused by an out of spec valve or camshaft if the camshaft was damaged.

I assume when the repair was done the head and piston were both cleaned of carbon, another possibility is that an improper head gasket was used(too thin) this would also cause an increase in compression ratio..... 240psi is about a 17:1 ratio and will damage your car over time, if the reading is correct and you continue to drive it.

So a colder plug will just make your plug last longer, it wont reduce the stress on your engine, before you tear it apart again check all of the cylinders and if they are all at that high of a ratio, then I would immediately suspect an improper head gasket, or an over zealous machining of the head surface..

 

Wow, the greatest post about my problem.

I order an OEM gasket from the dealer, so the size of it should be ok.

They where only 1 valve that was replace. so i assume its not the valve which is causing all 4 cylinder to evenly have 240 PSI.

The machinest who did the job on the head, suppose to clean and grind dirty parts and replace the exhasut valve. but they DID MESS up on one major parts.

I belive its call the V-tech Cam or something. The part which turn when you hit a certain RPM, and which it will move. something like that. i have no idea what it is.


Hey, i live here Santee, Cal which is about 30 from you. if your a Mechanic, can you check my car? and how much will you charge. HEHE. its hard to find a Mechanic that knows this kind of cars
But there was a Pin which connects two part together, it was lose, but it was replace, but not sure if it was the original parts.

 

I really have no tools right now other than the old noggin, but I would seek out someone who has a compression tester and check all the cylinders. If it is only the one cylinder, faulty cam timing which could be due to the VTEC being defective is one possibility.

Or from what you describe, it could be the system HCH IIs use to effectively turn off the cylinders until they are needed. If you are at idle for instance, you may find your car is only running on 2-3 cylinders which mine does at times, also as you let off the throttle the car shuts off the cylinders by decompressing them so the engine doesn't have to work against itself.

I think your shop may have had trouble servicing this system and lost a part or misplaced something, so now instead of releasing pressure from an unused cylinder it is somehow increasing it.

I hate to say it but it may be dealer time at least for a diagnosis. They are slightly better trained and have all of the electronic diagnostic equip to check that system out. I am constantly learning new things about how my HCH operates and I try to help if I can.

 

Hello,
I noticed you were experiencing some confusion about how to convert compression ratio like 10:1 into PSI. The math is pretty simple, it comes out as x=r*(atmospheric pressure) in other words your PSI will be atmospheric pressure(about 14 psi depending on altitude) times the 1st number in the ratio. I hope this clears things up.

Ps(edit) I noticed you added or I missed the fact that all cylinders are at that PSI, again this leads me to suspect improper combustion chamber size, now on a HCH there is a virtual compression ratio which changes as you drive as I have stated before, so the problem most likely lies there, either the head was improperly machined, or a part is defective/missing which controls the computer cylinder control function. The least likely would be they got the timing chain off by one tooth when they installed the head, I'm not absolutely sure it woiuld cause 240PSI in your combustion chambers, but it might be worth a look(does your car lack power or feel sluggish?)