From what i read/remember, they measure the blocks and the ones with the "best" tolerances become a 4.6
not sure how that equates to the later theory of head bolts causing the liner problem,,,:confused:
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From what i read/remember, they measure the blocks and the ones with the "best" tolerances become a 4.6
not sure how that equates to the later theory of head bolts causing the liner problem,,,:confused:
Yes , they xrayed all blocks and the blocks in which the sleeves were centred better in the block were only used for 4.6 . AFAIR they had a red paint slash in the valley.
The blocks that were less well cast with an uneven amount of alloy each side of the sleeves were used for 4.0. AFAIR they had a yellow paint slash.
The book says and it is hard to disagree as I have seen it happen, that most early 38A V8s had sleeve failure due to overheat as they replaced the top hose design several times before getting it right.
Great stuff eh?
Regards Philip A
Given what has been said here we have established the history and quality of the 4 and 4.6 blocks ie red and yellow paint marked and with a % failure rate.
But what about fitting a brand new cast block and reusing the old heads albeit with them being checked and refurbished?
Will the same old hassles resurface or will these new blocks be ok as is?
With a brand new alloy block as a replacement is there a need to use the top hat system with them?
Given That a lot of earlier loose sleeve blocks were overheated , it may be OK to use a new alloy block.Quote:
With a brand new alloy block as a replacement is there a need to use the top hat system with them?
However the later blocks from about 2000 seemed to have a different problem in that the sleeves were fitted too loose. there are videos around that show people pulling sleeves out by hand on a lukewarm block.
The "Coscast" blocks were supposed to fix all that. However when I asked 4WD Spares in Newcastle whether their new 4.6 engines were Coscast blocks they looked at me blankly, so there may be lots of those faulty post 2000 blocks still around. You can tell Coscast blocks as they are much neater than the earlier blocks particularly in the valley area.
I think the safest way would be to buy a Turner Engineering top hatted reco short engine , but then you take a lot on faith as warranty would be a big issue. Or a new one if you can be sure it is a Coscast.
I think that the D2 thermostat arrangement and higher operating temp would not help, and I would probably modify these back to the old system with the thermostat in the top radiator hose and run a 88c thermostat.
Regards Philip A
The V8 Tuner blocks appear to be Turner or ACS, as AFAIK they are the major suppliers and V8 Tuner is a retailer, but I do not know that for sure.
I dont know,
Ive had a mechanic rebuild it but it might be time to do it myself. Its been head gaskets everytime. A couple of times from water pump and overheating. Now the warning signs are there again and i dont know why. Id drop a new motor in it if i could find one for a decent price.
You have to stud the heads on these things. Whatever the block, it doesn't help when the bolts are designed to stretch and stretch they do. At alarmingly variable rates and also I'm sure while in service. The toyo UZ V8's have the same issues because of the same bolts.
flame me if you will but here is a trick that i was informed of....and used on my own rebuilt v8.
My engine had the slipped liner, cracked block issue, did 99% of the rebuild at home with alot of help from a mechanic friend, we sent the block away to be fitted with top hat sleeves, they found cracks in the block that were not repairable, so i sourced a second hand block to be re sleeved.
When it came time for the rebuilt heads to be installed the advice we were given was to tourque up the head bolts to the factory settings, but DO NOT tourque them up further with the angle gauge, this is what stretches the bolts, from what i beleive (and remember i am not a mechanic) these bolts are tourque to yeild, same as falcon head bolts, for what ever reason the theory is the factory settings is enough and they do not need to be tightened any further
My engine is now approaching 25,000kms without an overheating issue at all
The issue is that the factory settings are designed to stretch them, there's 3 stages by memory. Around 20, 60 and 80something lb's?
I tested a few sets and had a variety of stretch lengths result from the same settings and even ran a test by torquing them to each stage, removing, after marking the heads of the bolts for location and noting the turns from tight and replacing back to that point and tensioning further. Even at the initial torque point there was a variety of, admittedly small (2-3mm range) of length variation. I used a new gasket for each test and also did it with both composite and tin gaskets.
This also occurs with toyota bolts in their UZ engines. It's just too much of a risk considering the issues we're already faced with when dealing with these engines. Plus the cost of a set of studs that can be reused (quite a few times and a lot if they're looked after in fitting and tightening) if you record the info that ARP recommend you are covered for the future to check the studs and only replace those necessary.
If the engine wasn't removed, I'd suggest the mechanic didn't have the tophat liners fitted. That would have cost about $2200 extra for the machining plus mechanic's time to remove/refit.Quote:
Originally Posted by timdo1
If he's only been doing the head gaskets, there's the possibility you do have an underlying problem that will never be resolved that way.