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Discovery 3.9 v8 - rebuilds, reliability, options….
- Thread starter resto_d1
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If you worried about over-heating, I cannot recommend oil coolers enough. Worked great, even at 50° C, I kidd you not, ambient temp, engine never got even close to over-heating despite running very lean due to boiling carbs. Easy to install as well.
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boiling carbs?
Oh yes, I sprinkled some water on them, evaporated immediately. The engine was perfectly fine so. I think the carbs evaporated more fuel that day than the engine burned. Luckily, fuel was, for us not so much for the locals, dirt cheap. Only time I had in my life, that the outside air will driving was hotter than the air inside the car. Drank almost 7 liters of water, did have to go pee once. Now I know why the forst Paris-Dakkar RRCs had fuel injection instead of carbs.
It was a fun trip, have to do it again some day! But maybe a little earlier, like February or around Easter instead of late May.
It was a fun trip, have to do it again some day! But maybe a little earlier, like February or around Easter instead of late May.
Well, this was going to be off the cards but I’m quite keen on doing it still now! I should’ve bought the rotten d1 on eBay a while back but never mind.
So many different opinions on these rv8s and v8 in general. I’ve spoken with a few people, including turners, Nige from megasquirt (really nice chap). Shame mr noisy isn’t on here anymore - he would’ve been ideal to chat to.
Anyhow, I’ve worked out the below.
3.5 is favoured in terms of reliability, however, 3.9 seems the ideal middle ground.
4.0 gems will run nicely with megasquirt, believe the THOR presents issues and Nige advised against that and the 4.6.
4.6 - know for liner issues more than any others. However, I believe anything 3.9 and above has same bore, just different stroke. Seems, again, from reading, the later we get, the hotter the engines were run to try and dodge emissions laws as they came in.
The prefered option for me, would be a top hat linered block. That’s when you get into who to use etc. I contacted turners and they still do it on exchange basis. Turners, as I’m sure a lot of members will agree, keep high standards.
A top hat linered block is not cheap!! None of the building is but it’s quite painful that a big cost of the build is the remedy of the LR **** up.
So, I think I need to acquire a 3.9 serp or a 4.0 gems, hope that the block is ok (I can get tested locally I believe) and get that linered. If it’s not ok. I’m screwed. Gamble.
So many different opinions on these rv8s and v8 in general. I’ve spoken with a few people, including turners, Nige from megasquirt (really nice chap). Shame mr noisy isn’t on here anymore - he would’ve been ideal to chat to.
Anyhow, I’ve worked out the below.
3.5 is favoured in terms of reliability, however, 3.9 seems the ideal middle ground.
4.0 gems will run nicely with megasquirt, believe the THOR presents issues and Nige advised against that and the 4.6.
4.6 - know for liner issues more than any others. However, I believe anything 3.9 and above has same bore, just different stroke. Seems, again, from reading, the later we get, the hotter the engines were run to try and dodge emissions laws as they came in.
The prefered option for me, would be a top hat linered block. That’s when you get into who to use etc. I contacted turners and they still do it on exchange basis. Turners, as I’m sure a lot of members will agree, keep high standards.
A top hat linered block is not cheap!! None of the building is but it’s quite painful that a big cost of the build is the remedy of the LR **** up.
So, I think I need to acquire a 3.9 serp or a 4.0 gems, hope that the block is ok (I can get tested locally I believe) and get that linered. If it’s not ok. I’m screwed. Gamble.
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Nothing wrong with Thor if you get it linered. In my opinion.
Megasquirt would make it better
Megasquirt would make it better
I may be wrong but I think Thor is tricky with megasquirt as different injectors and high fuel pressures. I’m sure I was told the others are easier to work with ecu wise.
Am I correct in saying, (@Henry_b you also may know) once a block is top hat linered, it’s proofed from both slipping a liner and the block cracks on water gallery between the cylinders? I believe, the liner would be inserted onto a shelf at the bottom of the bore, creating a seal there then you’ve obviously got the top hat seated in. I’ll go for it if once linered the risk is gone but if it doesn’t prevent the issue of the thin walls and machining on the **** there’s not much point
Henry_b
Think outside, no box required.
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The off set water galleries are due to poor casting due to land rover using tooling from the fag end of RV8 production.
Top hat liners don't prevent coolant from punching though the headgasket all the water has to do is work around the lip.
if you think about it if the block fails and the liner is "sealed" at the top there is little to prevent coolant working its way down and getting in to the sump.
Rover v8's can lose liners without cracking the block the upside with Top hats is they won't move which is the bonus and the reason to use them.
Tuning and megasquirt, to be fair don't have much experience with megasquirt systems, however i fail to see why the thor would be harder to tune injectors can be swapped to deliver more fuel if required i thing tornado supply them?? iirc...
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Was it megasquirt or tornado that worked with Thor? I can't remember
Yes if it's done properly then it's sealed top and bottom so if there's a crack in the future, the coolant can't escape
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It depends who does the top hatting. They should engineer a lip for the bottom of the liner to press onto, but not everyone does. The top lip seals against the fire ring on the HG so coolant can't get past that.
If it's done properly, it's a good block for life.
Rant - there's no reason LR didn't do this at the time, they thought it wasn't necessary!! It would have been better still if they had ribbed the liners during the manufacture, but again.. probably cost 10p more on the top of the £75k car
Thanks for replies chaps. I understood it as you do and have asked Frida to confirm. I thought point A and point B were impenetrable and even if you had a block with cracks around the jacket the tophat would seal the lot off. Point B would be a shelf to prevent any issues on the bottom of bore I.e. downward movement and then your head prevents upward movement.
I assumed some kind of compound was also used.
Drawing and thought was correct. Becomes a wet liner in a dry block. Just spoken to turners. Very helpful as always and thats where I’ll be going. There’s 3 year guarantee on the liners. Yes big expense but future proof and you pay for skill and experience.
I was always under the impression .
That the top hat part basically stops the liner moving up and down because of the extra clamping force/Area of the head. The block cracks and loses grip of the liner which then batters the fire ring on the head gasket which leads to the blown head gasket and coolant all over the place, as combustion gases can now get down the back of the liner from the top to the coolant cos of a cracked block.
A head gasket could still blow with or without top hats.
We shipped a top hat block from the UK (sucked up the core charge as it was hassle to send back) After having 2 sets of head gaskets replaced and 1 too many rides on the big yellow taxi. It was great from then until it was retired with the arrival of the L322.
Engine/gearbox sit on my garage floor awaiting.
But at the end of the day, if you are talking to turners why not buy 1 of the Turner top hat engines from that Evilbay supplier? then send it to Turners for a good refresh?
They can actually go out on CC quite a bit, I was offered 5.2.
But remember the 4.6 would need ECU trickery the 3.9/4.0 not so much.
J
.That the top hat part basically stops the liner moving up and down because of the extra clamping force/Area of the head. The block cracks and loses grip of the liner which then batters the fire ring on the head gasket which leads to the blown head gasket and coolant all over the place, as combustion gases can now get down the back of the liner from the top to the coolant cos of a cracked block.
A head gasket could still blow with or without top hats.
We shipped a top hat block from the UK (sucked up the core charge as it was hassle to send back) After having 2 sets of head gaskets replaced and 1 too many rides on the big yellow taxi. It was great from then until it was retired with the arrival of the L322.
Engine/gearbox sit on my garage floor awaiting
.But at the end of the day, if you are talking to turners why not buy 1 of the Turner top hat engines from that Evilbay supplier? then send it to Turners for a good refresh?
They can actually go out on CC quite a bit, I was offered 5.2
.But remember the 4.6 would need ECU trickery the 3.9/4.0 not so much.
J
That is a good point re the freshen up and buying one off the eBay supplier. But, I think I’d be more comfortable with it built fresh and having the 3 year guarantee out the box. Unless I can find a rotter with a v8 I’ll likely be looking at buying the v8, stripping it then taking to turners. Either way it would be running megasquirt so doesn’t really matter if I go 4.6 but I’d rather the 4.0.I was always under the impression
That the top hat part basically stops the liner moving up and down because of the extra clamping force/Area of the head. The block cracks and loses grip of the liner which then batters the fire ring on the head gasket which leads to the blown head gasket and coolant all over the place, as combustion gases can now get down the back of the liner from the top to the coolant cos of a cracked block.
A head gasket could still blow with or without top hats.
We shipped a top hat block from the UK (sucked up the core charge as it was hassle to send back) After having 2 sets of head gaskets replaced and 1 too many rides on the big yellow taxi. It was great from then until it was retired with the arrival of the L322.
Engine/gearbox sit on my garage floor awaiting
But at the end of the day, if you are talking to turners why not buy 1 of the Turner top hat engines from that Evilbay supplier? then send it to Turners for a good refresh?
They can actually go out on CC quite a bit, I was offered 5.2
But remember the 4.6 would need ECU trickery the 3.9/4.0 not so much.
J
The top hat liner is sealed at the top by the top hat liner then at the bottom it’s an o ring seal against a shelf. It becomes wet liner in dry blockI was always under the impression
That the top hat part basically stops the liner moving up and down because of the extra clamping force/Area of the head. The block cracks and loses grip of the liner which then batters the fire ring on the head gasket which leads to the blown head gasket and coolant all over the place, as combustion gases can now get down the back of the liner from the top to the coolant cos of a cracked block.
A head gasket could still blow with or without top hats.
We shipped a top hat block from the UK (sucked up the core charge as it was hassle to send back) After having 2 sets of head gaskets replaced and 1 too many rides on the big yellow taxi. It was great from then until it was retired with the arrival of the L322.
Engine/gearbox sit on my garage floor awaiting
But at the end of the day, if you are talking to turners why not buy 1 of the Turner top hat engines from that Evilbay supplier? then send it to Turners for a good refresh?
They can actually go out on CC quite a bit, I was offered 5.2
But remember the 4.6 would need ECU trickery the 3.9/4.0 not so much.
J
LetsHopeItFits
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I have also read highly of RPi, so it may well be worth having a look into them.Well, this was going to be off the cards but I’m quite keen on doing it still now! I should’ve bought the rotten d1 on eBay a while back but never mind.
So many different opinions on these rv8s and v8 in general. I’ve spoken with a few people, including turners, Nige from megasquirt (really nice chap). Shame mr noisy isn’t on here anymore - he would’ve been ideal to chat to.
Anyhow, I’ve worked out the below.
3.5 is favoured in terms of reliability, however, 3.9 seems the ideal middle ground.
4.0 gems will run nicely with megasquirt, believe the THOR presents issues and Nige advised against that and the 4.6.
4.6 - know for liner issues more than any others. However, I believe anything 3.9 and above has same bore, just different stroke. Seems, again, from reading, the later we get, the hotter the engines were run to try and dodge emissions laws as they came in.
The prefered option for me, would be a top hat linered block. That’s when you get into who to use etc. I contacted turners and they still do it on exchange basis. Turners, as I’m sure a lot of members will agree, keep high standards.
A top hat linered block is not cheap!! None of the building is but it’s quite painful that a big cost of the build is the remedy of the LR **** up.
So, I think I need to acquire a 3.9 serp or a 4.0 gems, hope that the block is ok (I can get tested locally I believe) and get that linered. If it’s not ok. I’m screwed. Gamble.
Out of interest, roughly how much does it cost to have top hat lines fitted? How many standard blocks could you get for that money?
Ive got 2 here with your name on them, but you have to take the cars with them...
(Or the offer for a free one still stands)
If you are gonna run mega squirt then why not the 4.6?
But can see the rest of your points.
Yes.
But the main thing is it won’t move, which is the main problem in the first case.
J
Maybe you should ask how many “good” standard blocks could you get? And did you even consider rebuild cost?
J
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