Hi
I have a Rover 3.5 which I have rebuilt from scratch to put in my GD. This will do me for a while but the next plan is to get a 4.6 block and build a bigger engine with maybe injection on. My question really is that I don't understand about porosity and cracked blocks. I understand you can put top had liners in if the liners have slipped or cracked, but can you do anything with a cracked block? I want to know because how would I know If I had bought an engine with a cracked block without taking the liners out etc?
Is a cracked block repairable?
I understand I can buy a "New" block for peole like RPI and the like, but if I find a second had one could I be in the position where its just scrap, or would it always be repairable?
thanks Guys
Martin
Rover - Cracked Block Explained
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Re: Rover - Cracked Block Explained
martin_t wrote:Hi
I have a Rover 3.5 which I have rebuilt from scratch to put in my GD. This will do me for a while but the next plan is to get a 4.6 block and build a bigger engine with maybe injection on. My question really is that I don't understand about porosity and cracked blocks. I understand you can put top had liners in if the liners have slipped or cracked, but can you do anything with a cracked block? I want to know because how would I know If I had bought an engine with a cracked block without taking the liners out etc?
Is a cracked block repairable?
I understand I can buy a "New" block for peole like RPI and the like, but if I find a second had one could I be in the position where its just scrap, or would it always be repairable?
thanks Guys
Martin
Hi Martin,
I'm reading a book on RV8 lumps at the moment by Des Hammill. Its a real eye opener!
from what I understand is it OK to use a cracked block, he recons that at least half of them are cracked. The problem is that a cracked block loses grip on the liner, the liner then drops and this allows the coolant into the combustion chamber. The top hat liners can be sealed with silicone sealant just before they are pushed fully home and this gets rid of the problem. I'm not sure what stops the crack from leaking coolant into the sump, it must be that they seal up the bottom of the liner as well.
The other thing that the book makes a big deal over is main bearing caps fretting the block, this is something that you should check on any block that you are considering buying. I think that the block is scrap if this has happened.
That is the jist of what I can remember, I'm sure someone will come along with more details shortly.
(I'd recommend the book!)
Regards,
Pete
Last edited by sidecar on Thu Nov 15, 2007 2:50 pm, edited 2 times in total.
if you look around hard enough or wait long enough a 'decent' 4.6 will come up eventually. I've just got hold of one for sweet-FA but it does need new top hat liners in.
It would be cheaper to buy an old block and get the liners done than buy a new one - people like V8 Developments ONLY use seasoned blocks anyway due to the stupidly high failure rate of them from the factory (75% according to them!).
Buying a new 4.6 block is probably the worst thing you could do
It would be cheaper to buy an old block and get the liners done than buy a new one - people like V8 Developments ONLY use seasoned blocks anyway due to the stupidly high failure rate of them from the factory (75% according to them!).
Buying a new 4.6 block is probably the worst thing you could do
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badger
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Cracked blocks can be re-used no probs, the cracks are tig welded up before final machining for new liners. Silicon is only used around the lower edge of the liner as a belt and braces extra seal.
4.0 and 4.6 blocks have virtually no mains cap fretting issues as they are cross-bolted from new. It tends to be more of an issue with 3.5 than 3.9 or 4.2, due to the free-revving nature of the 3.5.
The best blocks I have found are remanufactured items from ACR - slightly more expensive than the rest, but an excellent product. Avoid anything from Lund like the plague!!
4.0 and 4.6 blocks have virtually no mains cap fretting issues as they are cross-bolted from new. It tends to be more of an issue with 3.5 than 3.9 or 4.2, due to the free-revving nature of the 3.5.
The best blocks I have found are remanufactured items from ACR - slightly more expensive than the rest, but an excellent product. Avoid anything from Lund like the plague!!
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martin_t
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Thanks Badgerbadger wrote:Cracked blocks can be re-used no probs, the cracks are tig welded up before final machining for new liners. Silicon is only used around the lower edge of the liner as a belt and braces extra seal.
4.0 and 4.6 blocks have virtually no mains cap fretting issues as they are cross-bolted from new. It tends to be more of an issue with 3.5 than 3.9 or 4.2, due to the free-revving nature of the 3.5.
The best blocks I have found are remanufactured items from ACR - slightly more expensive than the rest, but an excellent product. Avoid anything from Lund like the plague!!
but who is ACR?
Cheers
Martin
chodjinn wrote:Badger - lol r.e. Lund!!!!!!!!!!!!!!!
Guess you'd be hard pressed to find one now seeing as he went otu of business
I've (almost) given up on that twonk for now. Although I am saving a spare 3.5 rusty crank to insert in his rectum when I finally catch up with him hehe
You might even get your chance ................. I came across this the other day (no, I don't post on there !) .........please form an orderly queue.......
Steve in fact does know his stuff when it comes to V8's ....... but drugs, booze and woman got the better of him and everybody else paid the price................
http://www.orrp.com/smf/index.php?topic=41118.0
Ian
3.9 ..... Badger Pistons...... Comp Cam....... Ported Heads.....Top Hat Liners ........Rhoads Lifters ..... Cloyes .........MS2.2 V3.......... EDIS8.........
