bendelaurence
New Member
I run a 3.9 on carbs and love it. never drivin and 3.5, but it is apprently the stronger engine - much less suseptable to slipped liners through over heating etc
It's true that the 3.5 is the stronger block due to having more block material between the water jacket and the bores, but from the 3.9 to the 4.6 all thoses engines share the same bore diameter but differ in stroke length. so are all as equally susseptable to enivitable failier at some point in there life. it is my belief and understanding (so don't quote me on it) The term slipped liner is not the actual cause of the overheating problems which lead to the self destruction but can be the result of the main problem which is the block cracking normally on cylinders 1,2,7 and 8 and allowing water to enter between the liner and the block and finding it's way into the chamber which would cause the steam from the exhaust and lead to the mystery water loss problem.It also allows the exhaust gasses to enter the water jacket thus the over heating issue and the pressurising. The slipped linner issue is caused by bad construction of the engine in the factory and not insurting the liner fully into the block to sit on it's seat at the bottom of the bore. So when the engine gets hot, as the alloy and the steel heat up at different temps it allows the ill fitted linner to move up and down with the piston, hence slipped linner. It's also my belief that one of the cause's of the block cracking is due to excess heat caused from the engines being worked to hard either from towing or being thrashed and those that run on gas as the gas burns at a higher temp than petrol. At the end of the day these engines weren't designed to push around 2 tonne plus 4x4's but american saloon cars so at best are already running under excess stress. You don't tend to hear as many horror stories of saloon cars running these engines but mainly landrovers. Altough there is no cure to stop the block from cracking there is a cure to stop the dreaded slipped linner and overheating issues which is to have top hat liners fitted along with composit head gaskets. This ensures that if the block cracks and allows water to enter behind the liner it wont be able to enter the chamber or allow gasses to enter the water jacket.
All that said these engines and there just like any good relationship, some days there your best friend others you want to kill them but you'll always love them lol
All that said these engines and there just like any good relationship, some days there your best friend others you want to kill them but you'll always love them lol
Mogwyth
New Member
Is my understanding too, although I am not totally sold on the LPG link, mine was a 4.0 on lpg and has just suffered this problem and I can chase it directly back to a major overheat caused by a poorly fitted coolent hose coming off. To make a link between LPG and "slipped liners" you realy need to take into account things like driving styles, maintenance and mileage too, it's not just as simple as more LPG vehicles (if this is the case) suffer from block problems therefore LPG causes the problem.
I agree there's lots of different factors involved and that poor maintainance and driving styles play a major part.
My old 3.9 rrc on gas cooked it's self although I never did find the cause of it.
I even think my 3.9 in my 90 is starting to show signs of the problem and it just runs on petrol,I think it's just a generic fault of the block.
I've got to admit I've just got some irontite to give it a try even though a lot of people say don't but for £30 oppossed to £800 plus for a new block or to have top hat liners fitted it's a no brainer for me lol
My old 3.9 rrc on gas cooked it's self although I never did find the cause of it.
I even think my 3.9 in my 90 is starting to show signs of the problem and it just runs on petrol,I think it's just a generic fault of the block.
I've got to admit I've just got some irontite to give it a try even though a lot of people say don't but for £30 oppossed to £800 plus for a new block or to have top hat liners fitted it's a no brainer for me lol
v8hotrodboy
Active Member
People slag off lpg so much, if its that bad why do they sell it? My 4.6 hse is running a single point gas system and runs fine. In fact when on over run down hills etc temp falls to around 1/3 !! And never goes above 1/2 EVER!! As in other posts blocks crack due to the lack of ally between the liner and water way.Later blocks are coded yellow, blue and red. Red is best as they have thicker "walls". Bet all the cracked blocks you get are "blue" blocks. Also there are other factors, over heating due to poor maintance, gasket faults etc. All engines are prone to H/G failure not just rover v8's and lots are prone to slipped liners, anyone owned an MGF?? LPG is not bad, its years of poor maintance and abuse that kills engines.
As for the 3.5/3.9 its the outside row of headbolts that cause trouble as if you tourqe them down to much they tilt the head over to one side and cause it blow into the valley, the later (4.0 /4.6) engines dont have these bolts fitted and better gaskets. My advise is to use "wellseal" when doing the heads. Should be a fit and forget job.
As for the 3.5/3.9 its the outside row of headbolts that cause trouble as if you tourqe them down to much they tilt the head over to one side and cause it blow into the valley, the later (4.0 /4.6) engines dont have these bolts fitted and better gaskets. My advise is to use "wellseal" when doing the heads. Should be a fit and forget job.
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v8hotrodboy
Active Member
Its a bit like Hylomar, only very sticky, you paint it on thinly over both sides of the gasket,let it dry a bit then refit heads. Be carful not to get it on eanything else as its a sod to get off!! Stag Wellseal Jointing Compound 100ml
Beast o Bodmin
Banned
get a 47a block.there the strongest.
V8jon
Well-Known Member
If it's for playing in the mud my opinion would be stay away from efi,lots of electrics and mud is a big no no,but also the su carbs are a pile of sh*t so I'd go either 3.5 or 3.9 but with a 4 barrel holley carb, just make sure you've got a good filter or you'll be sucking small children off the pavement!
v8hotrodboy
Active Member
I aggree about efi, but id go for an Edelbrock carb.
tacr2man
Well-Known Member
Yankee carbs for offroading on a V8 are not a good idea, as they are external float chambers and go rich or weak depending on angle . Su carbs properly set up will give excellent results , they have been doing so for donkeys years in all forms of motorsport. JMHO
by the way my 1990 Disco V8 3.5 on carbs 111000 miles no h/gasket probs , 18mpg with aircon on pulling a twin axle caravn but did have a 3,9 vogue on lpg that cracked the block on number 3
by the way my 1990 Disco V8 3.5 on carbs 111000 miles no h/gasket probs , 18mpg with aircon on pulling a twin axle caravn but did have a 3,9 vogue on lpg that cracked the block on number 3
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Mr Noisy
Coming in your ears.
Yeah its an issue - I was once at cowm quarry and a lad there had a 90 with a Holley - it was all good until halfway up the hill where the float chamber ran out and the engine died, repeatedly!
I will vouch for efi lads, 14cux is a dead simple system, and the electrics are oldskool so are unlikely to be fussy about a bit of water.
I've never had an issue with the Efi, and I think tbh when it's working it's better than carbs. Obv there are parts which expire with age in the efi system, but not easily with mud & water!!
Tbh I wouldn't fancy having the riak of carb adjustmets etc - the efi sorts itself out and has been very reliable for me, and the idle control is great for offroading at idle as it often prevents a stall
Cheers anyway!
I will vouch for efi lads, 14cux is a dead simple system, and the electrics are oldskool so are unlikely to be fussy about a bit of water.
I've never had an issue with the Efi, and I think tbh when it's working it's better than carbs. Obv there are parts which expire with age in the efi system, but not easily with mud & water!!
Tbh I wouldn't fancy having the riak of carb adjustmets etc - the efi sorts itself out and has been very reliable for me, and the idle control is great for offroading at idle as it often prevents a stall
Cheers anyway!
v8hotrodboy
Active Member
The Edelbrock carb has an internal float chamber, and its made in Italy as its really a webber carb. RPi Engineering - V8 Engine - Carburetion and fuel Injection
As for the 3.9 block, again all the 3.9 4.0 4.2 4.6 tvr etc engines are the same bore size, only the stroke is longer to get the increase in cc. Therefore all these blocks have thin block walls. The 3.5 has far more metal between the liner and water way thus less likey to crack. And although a 3.5 may show no HG failer signs (over heating water loss etc) i bet if you take the head off the side nearer the valley will be buggered, letting compression gasses into the crank case and causing oil leaks etc. http://www.v8engines.com/engine-4.htm#gaskets
Im by no means an expert on the subject but ive rebuilt a few now and have learned a bit over the years.
RPi Engineering - V8 Engine - Carburetion and fuel InjectionAs for the 3.9 block, again all the 3.9 4.0 4.2 4.6 tvr etc engines are the same bore size, only the stroke is longer to get the increase in cc. Therefore all these blocks have thin block walls. The 3.5 has far more metal between the liner and water way thus less likey to crack. And although a 3.5 may show no HG failer signs (over heating water loss etc) i bet if you take the head off the side nearer the valley will be buggered, letting compression gasses into the crank case and causing oil leaks etc. http://www.v8engines.com/engine-4.htm#gaskets
Im by no means an expert on the subject but ive rebuilt a few now and have learned a bit over the years.
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err...is it suicidal for me to confess that I've just bought a 200tdi from a defender. :5bblush5:
I know...I know...I'm really sorry, but I just couldn't bring myself to start changing engine mounts on a new chassis - will teach me to think harder before I buy the next time.
going to run now before you boys stone me or somethin...thanks for the top to bottom education in V8s - class!
I know...I know...I'm really sorry, but I just couldn't bring myself to start changing engine mounts on a new chassis - will teach me to think harder before I buy the next time.
going to run now before you boys stone me or somethin...thanks for the top to bottom education in V8s - class!
