TB42 cracked head

Post by **familybus** » Thu Oct 29, 2009 6:12 pm

ok prety simple ive just become a member of the tb42 cracked head club! im sure im not the only one andseams like its a common place for them to crack and around the 200k milage mark!
dont know what ill do next maybe put a second hand one on after getting it crack tested and trued, hope that will fix it for a while!
i wouldnt mind knowing how many others out there have had a craked head only on petrol models in ratio to people who own one and havnt had a prob!

ive heard welding them up is a waist of time but thats just hear say so yeh if yould had one welded, how reliable has it been?

cheers Harv

Post by **waandy** » Thu Oct 29, 2009 6:19 pm

mine cracked at bout 210 000, got a second hand that had been recod a few months prior, i have also heard after welding they just re crack, but my mates has been repaired and it blew a gasket and he ran it on the hot red line continously and it didnt re crack, i saw new tb heads on ebay for 600 bucks roughly, worth a look

Post by **cmcd** » Thu Oct 29, 2009 6:52 pm

Yeah, mine cracked at what I think was about 240,000.. Paid $600ish for a crack tested ready to go replacement (off here of all places).

Post by **ozy1** » Thu Oct 29, 2009 7:30 pm

i have a whole TB42 that was running perfectly when remove, we owned the car for 2 months, ever over heated or anything in that time,
$500 and its all yours, no alternator or fly wheel,

Post by **bogged** » Thu Oct 29, 2009 7:55 pm

I think Nissan sell the bare head for round 1300 trade.

Post by **rut rat** » Thu Oct 29, 2009 8:04 pm

Our TB42E/Gas cracked at around the 200 000 but we decided to get it welded. We had it done in March 2008 and had no problems what so ever. It did cost $1200 but we got a lot done. They did a real neat job. We did hear bad stories about welding but as it turns out it worked for us.

Post by **familybus** » Fri Oct 30, 2009 10:43 pm

ok so i take it more people are having this prob than not! ive been looking at new heads and there prety costly! now i just gotta decide which ways cheapest yet most effective way to go! ill put a used one on and wait till funds are better and perhaps buy a new one and be done with it!

i spoke to a headjobber today and he said it has something to do with the allan key studs in the head that are steel and the head being alloy, they heat, expand and contract at different pace and thats what causes it in his opinion!

nice to see Nissan have such a major floor and ask sooooooooooooo much to replace a part that should last alot more than they are!

asshats

Post by **bogged** » Fri Oct 30, 2009 10:44 pm

familybus wrote:ok so i take it more people are having this prob than not! ive been looking at new heads and there prety costly! now i just gotta decide which ways cheapest yet most effective way to go! ill put a used one on and wait till funds are better and perhaps buy a new one and be done with it!

nice to see Nissan have such a major floor and ask sooooooooooooo much to replace a part that should last alot more than they are!

asshats

Landy heads are $10k... feel better now?

Post by **familybus** » Fri Oct 30, 2009 10:46 pm

bogged wrote:
familybus wrote:ok so i take it more people are having this prob than not! ive been looking at new heads and there prety costly! now i just gotta decide which ways cheapest yet most effective way to go! ill put a used one on and wait till funds are better and perhaps buy a new one and be done with it!

nice to see Nissan have such a major floor and ask sooooooooooooo much to replace a part that should last alot more than they are!

asshats
Landy heads are $10k... feel better now?

nah!

Post by **toy77** » Sat Oct 31, 2009 5:22 am

Hi mate,

My last GQ did this. this one may have as well - havent pulled it off to look yet...

Anyways - it generally cracks from one of those allen bolts to either a cam post or to a valve. If it goes to the cam, the weld can be successful. if to a valve - better off finding another head.

Mine had cracked to a valve. i bought another second hand one that was supposed to be fine. it to was cracked, but to the cam post. had it welded with no probs.

The VL motors had a similar issue. ALL heads in melbourne (i believe) did them under a recall. they removed the allen bolts and welded up the holes.
I didn't tell my head guy to do this - but when i got the head back, he had done that to mine as well.

My uncle (gas specialist) and i believe this is part of the reason people believe that Gas causes heads to crack on patrols.

If you have 2 different metals expanding at different rates there is a risk of cracks. If you fit gas - it taps into the heater lines - ie your cooling system. There is a place where these joins should be made, but some people do it in a different place as it is easier to get to.
This could cause a coolant flow issue at the back of the block, and hot spots. so have areas with 2 different meatals and different head gradients would seem more likely to crack.

Cheers
Stew

Post by **BowTieGQ** » Sat Oct 31, 2009 7:13 am

The new heads from Nissan are the later EFI casting. Thicker around the areas prone to cracking. Can be had for just over $1k. Earlier ones are obsolete.

Mine didn't crack but did a head gasket. Still cost $1k for freshen up, 6 new exhaust valves and a little porting.

New one is cheap insurance I reckon.

Post by **familybus** » Sat Oct 31, 2009 9:09 am

ok ok so in theory after just taking a look at my head, the crack goes from the allan key to the cam post, so id say a weld might be succesfull! now what ive done is ive pulled out the allen key plug and noticed that it does jack shit, it looks like its only there to help clean out the head, so in theory as you say if i were to get the holes welded up aswell i cant see how it would do any harm!

does any one see what would be a disadvantage in weldin em up?

cheers Harv

Post by **pigletracing** » Sat Oct 31, 2009 9:56 am

I got a cracked head in my shorty, then after 2 more heads, I traded it without a motor for a DSL GQ wagon....

gotta luv the old brikette burners

Post by **bogged** » Sat Oct 31, 2009 11:16 am

Damige has been runnin chemiweld in his for 2 yrs.

Post by **brendo4b** » Sat Oct 31, 2009 4:22 pm

hey bud i have a tb42 and it has 328000 and ive never touched the engine she still runs like a dream maybe i just got lucky

Post by **familybus** » Sat Oct 31, 2009 4:29 pm

brendo4b wrote:hey bud i have a tb42 and it has 328000 and ive never touched the engine she still runs like a dream maybe i just got lucky

id say you bought it second hand yeh? its probably already had a headjob! ive spoken to a few blokes and that has been the case where theyve got heaps of millage and never a prob but there heads have been welded before they got the vehicle!

Post by **brendo4b** » Sat Oct 31, 2009 9:40 pm

yeah i got it second hand from my grandfather he had it since new but its never had the head done ey like i sid i must have been lucky

Post by **cycomut** » Sat Oct 31, 2009 10:43 pm

hey my fathers Tb42 has 29X XXXks on it had it since around 7X XXX, never had a problem. it is a EFI model if that makes a diff.

Post by **MyGQ** » Sat Oct 31, 2009 11:57 pm

my old Mav cracked its head at 252,042K's exactly

Gas setup may not have helped but these heads are known to crack, you get a good one or a bad one, mine was bad, but was repaired

Post by **raptorthumper** » Sun Nov 01, 2009 9:01 am

Dont bother repairing. Just add Bars Stop Leak or Chemiweld. I'm staggered you blokes spend that amount of money fixing the TB42's up.

You can get a 40,000 km old Ford BA-BF 4.0 DOHC motor for $400 - $1000 on ebay. I know what i would do. I like the aluminium adaptor that Iron Horse made to fit his XR6 turbo in.

http://www.patrol4x4.com/forum/showthread.php?t=34460

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