Cracked head in 1990 Patrol

[NiXoN]

Howdy Folks,
My mums patrol has been worked hard over the years and has decided to crack it head!
Her mechanic aid that this is a common thing, id like to know if that is the case? I was under the impression that these engines are tough as guts!!?? Its a 1990 4.2 (carby) on gas (probably the culprit??!!)
Also, what are the best options? A new head will cost her up to $2k (mechanics suggestion), maybe get it welded if thats a possibility? 2nd hand?

Many thanks

rob

[bogged]

Her mechanic aid that this is a common thing, id like to know if that is the case?

yes it is
new bare head is around $1200

[nastytroll]

I've had the tb42 heads welded up n machined before if you take it to a good head shop they will crack test it n check if its repairable it usually is n is alot cheaper then a new head n this is a common fault on tb42 engines good luck

[TassieTroll]

Went through exactly the same thing and, using my physic powers, I predict (with a 95% accuracy) that it has cracked from a Rocker Arm bolt!

I had a discussion with quiet a few people over here and on the mainland and it was determined that the best fix, if you wanted to keep the car for any extended period, was buy a new Casting and have your valve gear fitted.

Due to the design of the head and their propensity to crack in the same places, I could not get a guarantee on the durability of a repair.

About $2,000 for the Casting and Reco sounds about right. If that's a fitted price, all the better!

Oh, the LPG has nothing to do with it either, they crack, Petrol or dual fuel.

[mavnis?]

Halls 4x4 in bayswater did have reco heads ready to go for around $900.00

[NiXoN]

Excellent advice kids! Many thanks!
i might give halls a hoy, they're just up the road!

I think she is keen to use this as an excuse to upgrade, otherwise $900 for a reco sounds alright!

thanks again, fingers crossed!

rob

[mcgill4433]

i had the same problem, all cracks in these heads tend to stem from the six hexed bungs, which im led to belive thier only purpose was for the origional casting process. I had all six holes welded up and the crack fixed at the same time. no problems so far, i have been told once these holes are welded up the tb42 head is much less prone to cracking.

[Brunsy]

im also in kilsyth and just sorted my TB42 head out. 200,000 kms on gas was enough for mine to crack front to rear. Speak to Orger engines in bayswater, they have done sooooo many of these heads, will tell you strait away if yours is repairable, unfortunately even with a repair you wont save your self much on buying a new casting. I spent 2k did all the work myself but for god sake USE NEW HEAD BOLTS best $50 i ever spent.
If ya have any questions just ask.

[MyGQ]

When i had my mav it decided to crack the head after 252,000K's

I took it to Central Coast Engineering, they quoted me $600 to weld her up, did a fantastic job of it too. I also had the valve's replaced at the same time to hardened ones for dedicated gas use, as i was planing to go that route at the time, never got around to doing it, but never again ran any flashlube in her till the day i rolled her.

The TB42 has a weak head, you can go between the 200,000 and 260,000k's mark and u are 90% likely to crack a head, if you don't in the life of the car, your one of the luck ones.

when i was looking at repair or replace option, i found a place in Newcastle (can't remember the name) that cast new Alloy heads for the TB42 with alot stronger design and new water jacket system that delivered better flow then the original, but wanted over $2K for one, wasn't an option for me then

[GQ Bear]

Has the mechanic pulled the head off and definately seen it is cracked? Cos it's very likely to just be a blown head gasket, as this happens too.

My head was knackered for about 18mths. I continued to flog the f'ck out it on many more offroad adventures, cooked the hell out of it on every hill. Finally i pulled the head off last year and to my delight it was fine, just the gasket blown out. Had it surfaced and new gasket kit, whammo drives like new.

[mcgill4433]

i had my head welded up, new seats valves and stem seals also had stronger springs put on the inlet side all up with genuine gaskit set and new head studs cost me $960 at the time it seemed like alot because i was quoted around $700 but im pretty happy with it now going by some of the prices posted on here.

[zen]

just a thought.....

but fiting a pyro may well help you not recracking it...
its common practise on diesels to fit such a gauge..the reason to stop you cracking heads/pistons...
the idea is to keep an eye on those egt's and espically to watch they have dropped before switching engine off....
and if using lpg it would give a real good idea of richness/leaness...

just a thought..

[NiXoN]

Cheers Fellas!

The head is still in place, so may well just be the gasket! ya never know!!

Looks like a few options and paths to take, my cousin worked at Orgers for years, he will be the one to have a look at it and tell us what the story is and go from there! Unfortunately I dont have the time to get in there and have a look myself!

Many thanks again

Rob