cometic blown lol, brand new engine, reussable?

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ViperGT
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cometic blown lol, brand new engine, reussable?

Post by ViperGT »

so i got my head and deck, perfect at the machine shop, he said it was less than 10 RA, i installed it without copper spray as i was directed by the shop not to but anyways, you can see my build specs bellow, when i first started it, it blew rad cap above 3k, no blow by but did notice a slight amount of oil leaking from rear of head (oil drain) i drove about 40 miles after oil change and cap only blew when i got on it, no temp gauge at the time, i let it sit over night and re-torqued the head (arp studs) from 70 to 75 ftlbs, took it for a ride and installed temp gauge, didnt blow rad cap and stayed below 190, oil leak at back of head still present, and now after another 40 miles i got bad blow by w/ oil droplets spraying out of pcv, so i suspect hg blew between, cylynder#4 and oil drain, but not sure, im going to do a compression and leakdown test to see which cylinder its leaking from and most likely try torquing the head again but to 80ftlbs, and see if i can get the leaking to stop, and if it doesnt, my million dollar question is can i pulled the head clean everything and then spray the gasket with copper spray and reinstall? ive read on distributers websites that the gaskets can be reused up to 3 times? and im still NO turbo. Thanks guys
in a datsun 510:
arias 8.8 .020
eagle rods
clevite bearings
ferrea/exhaust supertech/intake stk
supertech springs and retainers
bc valve guides v2 cams currently crower 288/288 (no good)
port and polish
arp head, main, rod bolts
osk timing
current: custom log mani, TIAL mvr,
later: ati SD garret gtx3071 currently in my possession looking for gtx3576
custom downpipe
lol:
sdaigle240 wrote:beat that thing like it owes you money.
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500hpKA240sx
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Post by 500hpKA240sx »

i read somewhere that this guy torqued his head down with 95ft/lbs on arp studs and was fine. and i personally wouldnt reuse a hg b/c once its torqued down and then loosened up it loses its seal but i could be wrong with it being a cometic hg. but IMO if you pull the head just go felpro good luck hope you get it fixed
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supakat
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Post by supakat »

I did 80 ft/lbs on mine and adamky did 85ft/lbs. I went by the TQ settings of ARP and not the FSM because it is a different setup than factory.
12.96 @ 116.36 - 2.1 60ft - 11/2011
13.1 @ 114 - 2.3 60ft - 8/2012
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ViperGT
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Post by ViperGT »

Haha alright thanks, maybe ill go for 87 ftlbs lol and I really hope it will seal up
in a datsun 510:
arias 8.8 .020
eagle rods
clevite bearings
ferrea/exhaust supertech/intake stk
supertech springs and retainers
bc valve guides v2 cams currently crower 288/288 (no good)
port and polish
arp head, main, rod bolts
osk timing
current: custom log mani, TIAL mvr,
later: ati SD garret gtx3071 currently in my possession looking for gtx3576
custom downpipe
lol:
sdaigle240 wrote:beat that thing like it owes you money.
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Post by supakat »

I did not receive specs in my head kit and went by what calls for 10mm on the box. If you look up the part number, it says to do three steps to 60 ft/lbs.

http://arp-bolts.com/pages/technical_to ... tric.shtml
12.96 @ 116.36 - 2.1 60ft - 11/2011
13.1 @ 114 - 2.3 60ft - 8/2012
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ViperGT
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Post by ViperGT »

Yeah I think mine said 62 but I've also heard people torquing to 80-95??
in a datsun 510:
arias 8.8 .020
eagle rods
clevite bearings
ferrea/exhaust supertech/intake stk
supertech springs and retainers
bc valve guides v2 cams currently crower 288/288 (no good)
port and polish
arp head, main, rod bolts
osk timing
current: custom log mani, TIAL mvr,
later: ati SD garret gtx3071 currently in my possession looking for gtx3576
custom downpipe
lol:
sdaigle240 wrote:beat that thing like it owes you money.
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beercandrifter
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Post by beercandrifter »

did mine to 72 ft/lbs as was suggested to me, never had issues with seals on either cometic ive used even to 25psi. did the 3 step torque process following the order from the fsm. I also reused mine 3 times when I pulled my head (used the copper spray only on the block side to keep it from moving when I was putting on the head). have had 2 blocks with cometics, used each 3 times a piece. just saying, they are reusable as cometic states if you take care of them, but inspect it after taking it off if you do plan on reusing it. if the raised sections are mangled in any way you need a new one
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Post by 240sxfan6882 »

I'd look into the Cosworth one if your going to swap it. I still haven't seen anyone use one yet
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Post by ViperGT »

ok well i pulled the head in an hour and a half, no obivious leak spots, noticed 1 leaky valve guide seal which i will replace, lol eating lunch now hope to have it back together by 5. if it blows again i will either go stock or cosworth, oil leak at rear of head was due to leaky valve guide also, i really hope i dont have broken ring lands.
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in a datsun 510:
arias 8.8 .020
eagle rods
clevite bearings
ferrea/exhaust supertech/intake stk
supertech springs and retainers
bc valve guides v2 cams currently crower 288/288 (no good)
port and polish
arp head, main, rod bolts
osk timing
current: custom log mani, TIAL mvr,
later: ati SD garret gtx3071 currently in my possession looking for gtx3576
custom downpipe
lol:
sdaigle240 wrote:beat that thing like it owes you money.
robsterzallan
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Post by robsterzallan »

Ive reused cometics 6-7 times with copper spray after the first time, and torqued to 62lbs with arps that were reused every time as well, withought ever having trouble. i feel like ive gotten lucky though.
Always got extra parts laying around, KA, KA-T, S14 Body, S14 interior, you name it. I even got 3 s13 kouki conversion duraflex fenders, PM me!
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Post by Berserker »

500whp and below Felpro is just fine with ARP headstuds (used 11mm though). I ran that for 2 summers.
Then I kicked it up to 600whp and It started to leak. Then I switched to crosworth, drove for 300 miles broke my trans, So I don't have a lot of miles on the new headgasket so I cant really say how it is but did not have any leaks. No copper spray.
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Post by airman »

A cometic MLS head gasket blew? That's surprising. Where did the blow occur? I can't see it in the picture
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ViperGT
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Post by ViperGT »

i couldnt find it either i belive it was lifting the head slightly as it only happened over 3k, but its been good after i reinstaled it w/ copper spray
in a datsun 510:
arias 8.8 .020
eagle rods
clevite bearings
ferrea/exhaust supertech/intake stk
supertech springs and retainers
bc valve guides v2 cams currently crower 288/288 (no good)
port and polish
arp head, main, rod bolts
osk timing
current: custom log mani, TIAL mvr,
later: ati SD garret gtx3071 currently in my possession looking for gtx3576
custom downpipe
lol:
sdaigle240 wrote:beat that thing like it owes you money.
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supakat
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Post by supakat »

One of the possible issues with Cometic is that around the bore of gasket, it is just the compressed gasket and the layers are exposed. With enough cylinder pressure, it could seep through the gasket and pressurize the cooling chambers or crankcase.
Cosworth High Performance Multi Layer Head Gasket
Cosworth gaskets feature a stopper sealing layer for additional torque around each cylinder. The width of sealing area is specific for each application thereby providing ultimate sealing properties. Cosworth High Performance Multi layer steel head gaskets are designed to seal in power under the most demanding conditions.
12.96 @ 116.36 - 2.1 60ft - 11/2011
13.1 @ 114 - 2.3 60ft - 8/2012
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Post by ViperGT »

man lol cometic needs to get there **** down haha, well if this one goes again i suppose i will fork out the $$$ and get the cosworth
in a datsun 510:
arias 8.8 .020
eagle rods
clevite bearings
ferrea/exhaust supertech/intake stk
supertech springs and retainers
bc valve guides v2 cams currently crower 288/288 (no good)
port and polish
arp head, main, rod bolts
osk timing
current: custom log mani, TIAL mvr,
later: ati SD garret gtx3071 currently in my possession looking for gtx3576
custom downpipe
lol:
sdaigle240 wrote:beat that thing like it owes you money.
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Post by supakat »

I bet they will come with a new design down the road to compete with cosworth.
12.96 @ 116.36 - 2.1 60ft - 11/2011
13.1 @ 114 - 2.3 60ft - 8/2012
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robsterzallan
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Post by robsterzallan »

wow, this is all news to me. i always thought if your head gasket said cometic you didnt have any problems to worry about, at least i didnt.
Always got extra parts laying around, KA, KA-T, S14 Body, S14 interior, you name it. I even got 3 s13 kouki conversion duraflex fenders, PM me!
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Post by project-c2 »

I hated my Cometic head gasket. Go Felpro.
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Post by ViperGT »

trying to push 550+ and a felpro will leak i only have 10mm studs
in a datsun 510:
arias 8.8 .020
eagle rods
clevite bearings
ferrea/exhaust supertech/intake stk
supertech springs and retainers
bc valve guides v2 cams currently crower 288/288 (no good)
port and polish
arp head, main, rod bolts
osk timing
current: custom log mani, TIAL mvr,
later: ati SD garret gtx3071 currently in my possession looking for gtx3576
custom downpipe
lol:
sdaigle240 wrote:beat that thing like it owes you money.
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