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Hi there, i have currently a blown head gasket on my 1994 GQ 4.2 petrol carby engine, and as i was ordering a new head gasket set, water pump and thermostat, the shop said i should also buy new head bolts as the old ones stretch? Is this true? Also is there anything i should be wary about while attempting this job. thanks
Head bolts do stretch so it's best to replace them every time.
You should have the head crack tested and surface machined while it's off the engine, a full head reco would be even better.
Also a good idea to have the radiator reconditioned at the same time.
Have fun torqueing the head down, last time I did one the specs said to tighten the head bolts (all 20 odd of them) down in 3 stages, loosen them all off then do it all again. A bugger of a process.
Tony
Roger that old mate....................lolQuote:
Originally Posted by YNOT
thanks for the tip ynot, i'll get the radiator done and head tested while its off, pays to do the job properly. I'm looking forward to this job, some people tell me to get rid of my patrol and update but she's done me good over the last 2 years, so i'll keep her,and get rid or update those people instead. Thats why i joined this forum!!!
Word of advice....... Never trust a Tojo driver, they only want you to swap side cos there blinded with jealousy & hate, I mean really really hate being shown up by Patrol owners.. (They hate being recovered buy us also..... I have first hand in this....lol)Quote:
Originally Posted by Taiamai_Rebel
Stick with us mate, you'll be right..............hahahahahaha
P.s. The TB42's are renown for doing there heads, so if its got a few K's up & you can swing it, I'd take Tony's advice & go a reco head. It may save you redoing the job in the near future.Quote:
Originally Posted by patch697
Generally I'd lube the new bolts aswell, just in case you didnt know :)
ahh thats why you get rid of it and get a landie lolQuote:
Originally Posted by Taiamai_Rebel
you only have to replace the head bolts if they are a torq to yeild " ie a stretch bolt" or in other words if the tension is ,say 1st step 40nm 2nd step 60 deg 3rd step a further 60 deg , then these are a stretch bolt and are single use only.
yeh and that aswell ^^^^^^lol hmmmm lubeQuote:
Originally Posted by yakumo
under the head of bolt and washer and on the thred .
'tojo driver'..love that name heheheheheheQuote:
Originally Posted by patch697
i had the same problem and did not test the head sadly it as cracked and the head was ruined totally after using itQuote:
Originally Posted by YNOT
does anyone have torques for the head bolts? as im about to have a crack at the gasket myself
For a GQ TB42
Stage 1 - tighten all bolts to 29nm
Stage 2 - go back to original starting bolt and tighten all bolts to 57-67nm
Stage 3 - loosen all bolts completely
Stage 4 - tighten all bolts again to 29nm
Stage 5 - final tighten of bolts to 64-74nm
Not sure why on the stages, but that's what's specified.
What model is yours mate?
hey mate, all the info you need is in the GQ Factory Manual.i definately reccomend downloading and having a look. i just put a brand new head on mine and the manual was an invaluable tool to get it back together. are you getting the head machined and valves re-sleeved? or just whacking a new gasket on?Quote:
Originally Posted by BIG PIG
A word of advice, don't get recon heads, do it once, do it properly - get an original
some of the aftermarket heads are absolute rubbish and you can almost guarantee that if rewelded they will fail in the same spot. Have seen it happen three times.
and as others have said, buy another set of head bolts - don't reuse your old ones - thats just inviting grief later on. and tighten them in the sequence shown in the manual - again, have seen people who didn't and who "made it up" and then ended up with a cracked head down the track