hi,
i have a euro b18c6 heavily modified integra but for the second time since rebuild its lost compression after only 3-4 thousand miles. oem head gaskets used both times. head was skimmed 12thou and pressure tested.
mods:
82mm pr3 pistons
port/polished head and manifolds
70mm TB port matched to oem intake manifold
aem cai
obx 2.5inch SS longtube 4-2-1 manifold (catless, heatwrapped)
2.5inch SS catback and performance backbox
obx stage 1 cams with untuned Tru-Time gears
oem springs/retainers/valves
oem ignition and fuel system
oem ecu
apexi VAFC2 (untuned)
AC removed
11.64:1 CR (on 95 ron)
1842cc (runs slightley lean)

both times i have not had overheating probs and noticed some coolant loss weeks prior to compression loss (this time it happened after road racing an e36 M3 btw) and was lost in cylinder 3 twice!!

the block is unsleeved and 'unblock guarded' so could this happen due to: 'cylinder walk'?
high cr with untuned ecu?
stretched oem headbolts (used several times btw)?

both times it was rebuilt by my self and torqued down correctly so help anyone..

thanks

 

Did you measure your cylinder bore any? Top, MIddle and bottom.

This will tell you if your sleeve is straight. The sleeves on number 3 could be damaged and leaking.

When you pulled the motor apart again did you have it honed?

You said you milled the head, did you deck the block?

Never run any thing untuned especially a vfac they are the biggest waste of **** out there.

Do a leak down test on the motor and see where you are loosing compression. If it comes out the intake its your intake valves, comes out the exhaust its the exhaust valves, comes out the pcv its the pistons, rings, or sleeves.

Hope this helps.

 

everything was measured from cyls to deck straightness and everything was ok including the sleeves. i have had everything checked out and valves, pistons rings etc are all ok.
i think the gasket seal is breaking due to the high CR coupled with slight excessive heat due to running lean because of an untuned ecu or headbolts are stretched and cant handle 11.64:1..as for the vafc, i know its **** and only used for display purposes..

so what do you suggest, new headbolts or lower the CR?

 

If all that stuff checks out ok then I would pull the head. Get it inspected again. Get a high comp head gasket from golden eagle or cometic. get a new set of arp head studs. and go from there. If your loosing coolant then its probably the head gasket or the head is lifting. You also need to get your car tuned. And if your not using the vafc put it in the trash can lol.

ARPs get about 2 cycles out of them b4 they are done. how ever I trash them after 1 torque cycle.

Im assuming your tourqing the head down in the correct 3 stage pattern?

 

thanks for your thoughts buddy, i suspect the head bolts are past their time and will be trying a new set, and yes it was torqued accordingley (i have rebuilt several b series engines before without probs). i will be getting it tuned on a dyno as i have got an obd1 recentley from phearable.net with a 'dyno proven' base map for my mods.

obx are **** for information as iv tried several times so have you got any suggestions/experience on the cam gear settings for the obx cams?

 

By RLZ cams, and valve train.. best in the business. OBX is knock off crap. to be honest. not trying to be a dick. but its cheap parts that break alot lol.

get a good set up built. and take it to the dyno. they will tun your car for u. all these generic tunes you can get from companies, in my opinion are trash. no 2 cars are alike.

 

are you boring with a torque plate? very important on these engines since the sleeves walk. if you don't the bore will shift when you assemble and that distortion will cause excessive wear. second what hone are you using? i hope it's 280 grit of finer. the rough hones you use to seat cast rings just don't work well on the thin steel honda rings

you also must use a diamond cutter to deck the block. i forgot the actual RA but it has to be ultra fine to prevent compression loss.

 

Its was bored and honed at the machine shop to honda manual specs...i removed the head today and gasket leakage was exactley where it was last time, both were different make gaskets but were cheap gaskets though, the headbolts have been used atleast three times so to elimate things:
Ring are ok (if it was them then compression wouldnt have been restored after last build)
Head is straight as it was milled
Headgaskets? (maybe 11.65:1 cr is too high and hot for them)
Headbolts? (reused but if they were ****ed they wouldnt have restored compression from build or would they?)
Cylinder walk? (iv ordered a block guard now so maybe it is due to this as its only cyl 3 thats leaked on both occasions
Arp headstuds needed? (Maybe it non of the above and its due to high cr and 215fwhp tha wont allow the headgaskets and headbolts to do their job?)

I think a blockguard and cometic hg should do it or even arp's in the mix too, its costing me around £260 for all three things so only want whats needed.
Please help!

 

where was it leaking? you said same place but that was where? if it's on the deck of the block i promise you the cutting wheel was too rough when they shaved the block.

OE headgaskets have proven to be extremely reliable. if you have a problem, fix the problem, don't blame the part

also, what the hell is "built to specs"? did they use a torque plate or did they not>? what hone was used?

did you just drop it off at some random machine shop and hope they knew what they were doing?

 

Gotta get the block decked after you have a block guard put in.

 

ding, ding I think we have a winner. OE head bolts are 1 time use only, get some new OE head bolts, ARP or GE head studs.

 

this too

if the bolts are stretched at all you will create high/low spots

still curious if the Op decked the block or just let r rip on the oe deck. if he did and it wasn't checked for true there could be compounding problems

 

Thanks for your input guys, damn delivery from ameriwca takes ages for parts..anyway will keep you posted.