1hz head gasket
Submitted: Thursday, Jan 01, 2015 at 14:41
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Martyn
First off Happy New Year to all.
I've had an awfull time of late with my 80 series. (1994 1hz)
First off got a ct26 turbo & huge intercooler fitted. 3" red devil exhaust & egt fitted. Very happy with set up. 48 hours later a 91 year old drove into it. Three weeks in crash repair & shes back looking like new. Four days later the head or head gasket has gone!!!
Egt temps were completely normal. I managed to catch it before it over heated thanks to a watch dog. I'm thinking the very
well known 4wd
shop has set up the system wrong. Overfueling.
I have had a compression
test done prior to turbo fitting & all was good. Also have a boost compensater fitted.
My question is, do i bother getting a refurbished head or take the opportunity to fit a new one? Also once back together, take it somewhere else in
Adelaide to be set up properly.
Thanks
Reply By: Ron N - Thursday, Jan 01, 2015 at 21:52
Thursday, Jan 01, 2015 at 21:52
Martyn - If you install an aftermarket turbo, the compression ratio should be reduced by the fitting of a thicker head gasket.
I presume this has been done? The crowd fitting the turbo should know to do that.
Overfuelling will be obvious by black smoke pouring from the exhaust under heavy acceleration.
Get someone else to drive the 80 series and get them to accelerate hard while you follow it reasonably closely in another vehicle.
The exhaust should only show a slight haze of black smoke under acceleration.
If the black smoke is thick and very visible while the accelerator is being floored, then it's overfuelling.
The fuel injection pump should have been adjusted to provide more fuel when the turbo was fitted, because the turbo delivers a lot more air than a naturally-aspirated engine can suck in.
However, the fuel delivery has to be in line with what is required for the amount of air available in the combustion chamber.
If the pump has been adjusted up too far, this will then create an overfuelling situation.
There should be no reason to buy a new head if the old head has no cracks or isn't badly warped.
It certainly pays to have the head surface ground, the valves ground and valve guide-to-valve wear checked, when the head is off.
Cheers, Ron.
AnswerID:
543584
Follow Up By: Martyn - Thursday, Jan 01, 2015 at 22:13
Thursday, Jan 01, 2015 at 22:13
Thanks for your reply Ron. There's no
sign of black smoke at all. I must admit since the install any smoke has all but vanished. I know for sure nothing was done to the head. Should i go Toyo gasket or upgraded???
Isn't a compensator suppose to take care of over fueling?
Thanks
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Follow Up By: Ron N - Thursday, Jan 01, 2015 at 22:40
Thursday, Jan 01, 2015 at 22:40
Well, no black smoke means it's not overfuelling.
The boost compensator is fitted to adjust the fuel injected to the level of boost.
It's essentially an aneroid that alters the rack position according to the intake pressure.
No, the compensator isn't fitted to take care of over-fuelling, it's fitted to take care of under-fuelling.
The injection pump still has to be adjusted so the fuel being injected on each stroke, matches the amount of additional air being pumped in.
Aftermarket gaskets are quite satisfactory. AA Gaskets make gaskets in 3 thicknesses. Toyota make them in 5 thicknesses.
The piston protrusion has to be measured when the head is off and the thickness selected according to the amount of protrusion.
I would be selecting a thickness one grade higher than recommended, but that depends on your personal choice and the amount of boost you are running.
Cheers, Ron.
AA Gaskets
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