The V8 Owners Forum -

Hi all,

I apologise firstly if this has been covered. I’ve done lots of searching first and spoken to a well known builder but get conflicting info.

I’d live to build a v8 for my d1 Land Rover discovery. The vehicle in question was originally 300tdi so I’ve got to take care of the mounts etc.

Anyway, my biggest query is around cracked blocks, top hat liners and longevity. I’ll list what I’ve assumed and please red pen me if I’m wrong!!

My plan is to take a 3.9 or upwards and run it on megasquirt. I’ve spoken to Nigel already on this.

I don’t want to install an engine and worry about the cracking of block, slipped liners etc.

When I’ve spoken to a builder, the top hat liner install has o ring seal/s at the bottom of the liner and maybe at the top?

Am I correct in saying, if the block did crack around the water jacket, the top hat liner will isolate the block and the HG from the water creeping past it? I.e. once the top hat liners are installed, I’ve no worries about the dreaded liner slip/block crack around the water jacket?

Fitting the liners will be a huge amount of the build cost and I don’t want to go ahead doing it if it doesn’t actually give me the security that I’ve assumed!

A different builder, has claimed that the top hat liner doesn’t prevent water creeping past, hence the conflict of info I’ve found.

Thanks in advance

Well the 1st thing to do is to check your block by pressure testing it because far from all of these blocks actually crack .
My 3.9 had over 100,000kms on it so I assumed that if it was going to give that sort of trouble it would have done it by now , so I pressure tested the block and it held 40psi (way more than normal use ) for days . I even soapy watered around the tops of the liners and its all good . You may not need to go to all that expense . You can also use a t/stat thats a bit cooler than standard. As long as you keep it cool a good used block shouldnt go bad on you .

I have had all of mine fitted with top hat liners. I used Turner Engineering as they properly o-ring theirs.

Never had a failure since. And one of them was a cracked block already!

Chris.

If your fitting an engine with an unknown history - I would first hot pressure test it.
I believe 4.0's were the 'most' effected from leaking liners.
4.6's used better blocks - but doesn't mean they are immune.
My second hand 4.6 block had 3x leaking liners when tested - so I had it top hat linered.