gazzawrx

iTrader: (11)

Hello all, the head gaskets have gone on my wrx, i'm handy with the spanners but have never done a scooby head gasket before, is there anything i should look out for when replacing them?

Also as the heads are gonna be off i'm gonna clean the heads, lap the valves and change the stem seals etc.

Where's the best place to get a cometic head gasket set and how thick will i need the gaskets, if for example only 5-10 thou is skimmed from the head?

Also has anyone got a data sheet of all the torque settings i'm gonna need as i've looked through the workshop manual on here and can't find them?

Thanks

gazzawrx

iTrader: (11)

anyone?

whats the best head gaskets to use? i've read about the cometic ones and they seem more than up to the job, but what about the cosworth gaskets, are these any better than the cometic gaskets and if so what makes them better?

stann01

plenty of info on you-tube about the tightening sequence mate and the gaskets i got the tightening sequence came in with them, i done mine but didnt skim the heads didnt need to, depends what year you got for thickness of gaskets.....

bigsinky

thickness will depend on what is skimmed from the block and heads. you know already that you need to keep the same compression ration and buy your gasket accordingly. if you are only running standard or slightly modded power the cometic gaskets will be fine. cosworth gaskets are for big power and i suspect overkill on your part.

gazzawrx

iTrader: (11)

ok thanks lads, my car is a 1994 wrx and as yet is pretty standard, i'll probably just use the cometic gaskets then if they're good enough.

I wasn't going to get the block skimmed tbh i normallyl clean up the faces with some wet and dry but i only usually get the heads done, i will obviously check block for warpage etc but cant see there being a problem with that as the engine hasn't overheated etc, i'll be getting the heads done regardless as i'm fitting MLS gaskets.

Anyone know a descent place to get the gasket set from other than ebay?

gazzawrx

iTrader: (11)

anyone

gazzawrx

iTrader: (11)

anyone offer any advice on what gasket thickness i will need to fit if the heads are skimmed 5 thou?

Car is a 1994 wrx

andy-m

iTrader: (1)

i'm only stating this because you said you have never done a scoob head gasket before, but as i understand it, the engine has to come out to do it. not enough room to get them off without removing the engine.

saiklon

5 thou is 0.13mm, stock headgasket is 0.6mm, you could fit a slightly thicker headgasket to compensate for the 0.13mm removed. However there is no issue sticking to the stock headgasket thickness, you will get a slightly increased compressed ratio which is no big deal.

gazzawrx

iTrader: (11)

yeah i've started to pull the lump out as i thought it looked a bit tight to do with the lump in situ, i want to change the big end bearings while it's out too, so it'll be easier on my bench.

gazzawrx

iTrader: (11)

ok thanks for the info, i dont really wanna increase the comp ratio by too much as i'll have to loose some boost to compensate and my chip is set at 1.1 bar now, i'm going to be fitting MLS gaskets so i think i'll go for approx 1.3mm thick cometic gaskets then the comp should be roughly the same as stock albeit only 5 thou is removed from the head.

Is it possible to swap the big end shells by removing the sump and accessing the big end caps or will i need to strip the block down and seperate the block halves?

Also is there anything else that's worth changing / looking out for whilst the engines out, i have already fitted a new water pump, stat and cam belt kit but i'd rather do whatever else is necessary while it's apart to save on removing the lump further down the line.

Thanks for the help so far lads.

gazzawrx

iTrader: (11)

surely some of you scooby nutters can help me?

saiklon

To swap the big end bearings you need to separate the block halves.
While engine is open, have a look at your oil pump rotor clearances (procedure listed in workshop manual) and ensure the oil pump backing plate bolts are secured with locktite, they have a tendency to come loose and cause low oil pressure.

gazzawrx

iTrader: (11)

ok mate cheers, i was hoping i could get away with doing the big ends with just the sump off , oh well looks like it'll be a busy weekend for me then.

I'll check the oil pump aswell then as i dont want this failing and ruining all the work i'm about to do.

When putting the block halves back together am i to use some silicone or is there a specific gasket i need to buy?

Thanks lads.

classicgc8

iTrader: (4)

hi to seal the block halfs use subaru threebond,silicone not advised,heard some horror storys
https://www.scoobynet.com/drivetrain...k-sealant.html