Hello, I am new to the forums, but i have read them for a quite a while. I just finished my CR-Vtec, and am having a problem with 2 of my cylinders. My block was re surfaced, and so was my head, and I also got a valve job. My cylinders have been honed, and new rings and everything. I am running a GS-R head, and a b20b block with b20z pistons. The problem is that i have good compression in the middle 2 cylinders(2 has 230 psi and 3 has 235 psi) and cylinder 1 has 115 psi, and cylinder 4 has 110 psi. The motor runs, and sounds just fine, there is a quite a bit of blowby that smells like gas. Is it possible that the 1 and 4 rings are just not seated yet, as i have only ran it for about 30 minutes total since i put it together? Thanks for any help!
After the cylinders were honed, did anyone check to see if it was still in specs for the rings/pistons that were installed? Honing is fine, unless it is done incorrectly. It can cause “egg” shaped cylinders if done wrong. Which would cause the problem your seeing.
It could be the rings need to be seated (break the engine in) but it could also be a bad hone job.
Who did the engine work?
I would recheck the valves and see if they are adjusted right. If this does not fix it. Then I would do a leak down test. This will tell you if it is in the block or head.
OP: I honed the cylinders before i took the block down to have it re surfaced, and the crank micro polished. The machine shop said it was good.
I did everything except the machine work.
RX3: I will check the valves right now, and see if i can find anyone with a leakdown tester that i can use, or i will just go buy one.
Thank you both for your replies.
James
I checked the valves, and they are fine. the inside 2 cylinders were a little close, but the outside 2 were perfect. I was unable to get a leakdown tester, so i just used some compressed air, and put it into cylinder 1, and it leaks out fast. about twice as fast as #2 did. It seems like its all going out the rings, as i could feel a bit of air pressure coming out the dipstick hole.
If your hearing most of the air come out of the dipstick, its the rings, or the hone job is not round, but oval shaped. Unless there is a score on the cylinder. Regardless, it sounds like its going to need to be torn apart again.
wait a minute…p72 head, decked block, slightly milled head, b20z pistons & oem headgasket? are you sure your valves didn’t make love to any of the pistons? your piston to valve clearance i probably uber close. hopefully the motor was checked for clearances.
I am going to have to agree with operator207. Jimmy50941, you say you didn’t do any of the machine work, but honing is machine work. I am sure unless you paid them to spec the job you did, they just looked at it and said “looks fine to me”. In most cases you won’t be able to just hone the sleeves and slap it back together. There will usually be some distortion that is best left up to the pros to bore out and then put a proper hone job on it. This of course necessitates “os” pistons + “os” rings. I doubt you have much choice but to tear it down and start again.
take it all apart, get a bore gauge and check the bore throughout the cylinder, this will tell you whether or not it is egg shaped, if it is decide if youre going to resleeve it, or take a chance and bore it, remmember those B20 sleeves are thin as it is.
Alright, I have been running it a little bit every day, to see if it would help with the compression. It is not helping. So i am going to pull the engine in a few days. I have a question though. I have a B18a1, a B16a(JDM block), and this B20B4 block. The B16 block has left on it. I am wondering which block would be better to resleeve to 84mm where i can use my B20z pistons and crank. The B16a has a shorter deck height right? So i would probably not be able to use that one with the 89mm stroke? So which one would be cheaper to resleeve to 84mm bore where i can use my crank and rods and pistons from the b20. I know getting better rods would be a good idea, but i dont have the money for them yet. Let me know what you think. I am open to all ideas.
Thanks, James
Why resleeve? Why not just use the B20 block. If you want some extra insurance, upgrade the rod bolts to ARPs.
No matter what block you are talking about it will run you $1000+ to resleeve.
well, the B20 block is the one i have right now that has half the compression on the outside 2 cylinders. I have ARP rod, main, and head bolts/studs.
Sorry, I must have missed that part. Even still, it will cost roughly the same to sleeve any of the blocks you have. At that point I think it would be cheaper/easier to just purchase a used JDM B20. They usually all have guaranteed compression and low miles. This should get you back up for cheap. Or if you have the B18A block in “ok” condition, put that in and rework the B20 block as needed.
well if your wanting to get rid of that b20 give me a shout