4.6 cracked sleeves

Hi All
I'm a newbie on the track and would like some advice if possible.
My 4.6 has a cracked liner and I was looking at getting it top hatted, then I came across this site on internet for RPI Engineering who say they actually cast new V8 blocks to a higher degree of accuracy than Land Rover originals. The blocks are actually cast by coscast and RPI recon it with used parts from old cracked engines. They also claim that top hat liners are only a temp solution as the underliing problem is still behind the liner. My problem is wich way to go. Has anybody else come across or used a coscast engine or even used tophat liners. I would be very thankfull for any advice.

Thanks in antipation

Hooperman

do some more diggin..

http://www.ptp-ltd.co.uk/shop/238/land_rover/index.htm

the bodmin is right, do more diggin.

i'm in the process myself at the moment with my 4.0. as far as i understand, the liners are ductile iron and are fitted with a flange which when the head is clammped above them stopping them moving down in the block. now the theory is that the head, head gasket and flange form a seal that prevents water getting in and compression getting out of the combustion chamber. the piston and rings seal in the normal way to prevent leakage into an out od the crank case/block.

now the problem of water getting in and gases getting out is that the aliminium and ductile iron expand and contract at different temps and rates and part company this leaving a gap and or slipping to allow water ingress into the combustion chamber.

after fitting liners with flanges the only way water can go is into the crank case behind the liners. having the block machined and flanged liners fitted ensure that a seal between liners and block is acieved in much the same way as any liner and block of this type so in that way all are at the same starting point!! some people also recomend and use high temp silicone sealant to improve the seal negating the need for the cracks to be wellded if any. also the cracks are not visible to the naked eye and probably only open up under heat/high pressure.

now my worries are that the block will expand again and part company, letting water into the oil and cause damage in that way. it is very unlikely to happen tho but i will still be useing silicone when the liners are pressed in. once cured it should be sufficient to withstand any pressure that the coolant system hoses can.

now bodmin has had his engine for a number of miles with flanged liners and no problems so they do work. in my opinion the strength needs to be in the liners and seal to the head, thats where the high pressures are (140psi?) the coolant system will not achieve this high pressure.

the problem with rpi's coscast blocks is that there is nothing to stop the liner shifting downwards, thus you still have the same problem. they say that the wall thickness of the block is the deciding factor when infact its the fact that the liners shift when the the block expands, there is a company that put in o rings, this is even better as the o ring (in theory) would expand and contract with the block/liner and seal at all times, i reckon the silicone will also do the same but to greater effect as it wont perish under the heat!

i know its a long winded subject but after reding for days on end thats the short version!!

HTH

Gav

Even if water was to reach the liner like RPI say, surely it would would just work like a wet-linered engine? The bottom of the top-hat liner is sealed

3.5disco said:

Even if water was to reach the liner like RPI say, surely it would would just work like a wet-linered engine? The bottom of the top-hat liner is sealed


RPI are good salesmen I'll give 'em that.

Click to expand...

i am not sure how the bottom of the liner is sealed, is it stepped into the casting?, i assume the seal at the bottom on the original design is flawed in that it allows the liner to go down, i assumed there was nothing to seat the liner on and this allowed the drop???

i think rpi are probably a reputable company with more experience than me but i can't help wondering if they have a wharehouse full of coscast blocks somewhere!!

i will be going down the liner route with belt and braces silicone sealing, decking and skimmed/refurb heads cross bolting and cross honing. i wondered whether to buy a cheap elec oven and cook the block at 100 degrees c prior to inserting the liners to enable the block to contract onto the liners then finally pressing the liners in with the silicone once the block has cooled to ensure a good tight fit but wouldnt the final pressing void the heating process?

top hat liners would be my fav, lets face it where can it move

Thanks All
At the moment am waiting for reply from RPI on a few questions but am looking at going the tophat way as originally planned especially as it has been used by your selves.
again thanks.
Hooperman
Cardiff
:doh:

i think rpi are overpriced,for example a new front timing cover with oil pump they sell for £345,go to turner engineering the same part £195 +vat,so where do rpi get there prices,i would go for a top hat solution,i think it,s cheaper but top hat blocks have the proof,what about the coscast blocks who knows

I have had no problems since having top hats fitted to my 4.6, they have been in 2 1/2 years now.
I was browsing through a website of a company that tuned v8`s the other day, unfortunately i cant remember the name at the moment but i will try and find it again, and they used the costcast block for 4.0 engines up to 5.3 and as well as using this block they also fitted top hat liners into them all. So if the top hats were no good why are they still fitting them into the cost cast blocks. If i were you go with the top hats but get it done by a reputable company.
All the best
Mark



I have now found the site that uses the top hats with the cost cast blocks it is v8developments.co.uk

cos cast and top hats, by my reckoning that is a very belt and braces approach!!

Cost wise, it's probably around the same price for machining and fitting top hat liners as a new short engine with conventional liners. Usually the liners slip because of overheating problems as the ally block expands more than the cast iron liner. There are engines out there which are original and have covered well over 150k without any problems. It's a matter of debate whether the slipped liner causes the overheating or vice versa-I prefer personally to believe the latter but others will differ. Another cause can be corrosion caused by incorrect coolant mix. From my point of view, I would prefer to go for a new short engine and keep a regular service regime. I have replaced engines on a 3.9 Classic and my 4.6 HSE with new short lumps and had no further problems with either after covering many thousands of miles. At the end of the day, it's your cash and choice.

mines gone at 170 - 180 k so its not a bad engine in many respects and has been well looked after, that is one of the reasons i am dubious about changine the engine. although there is going to be other wear i dont think nearly 200k is bad for an engine of this sort! if i can recon it who says it wont last another 200k or even more???

gavbriggs said:

mines gone at 170 - 180 k so its not a bad engine in many respects and has been well looked after, that is one of the reasons i am dubious about changine the engine. although there is going to be other wear i dont think nearly 200k is bad for an engine of this sort! if i can recon it who says it wont last another 200k or even more???

Click to expand...

Your lucky mate. Mine went at 66'000 miles.

Personally, I think that spending even 1p on a RV8 is a waste, as there are much more reliable engines out there, offering greater power / torque, at significantly less cost than a decent spec RV8.

However, if I was spending money on a RV8 and the engine / car was going to be a keeper, I'd go down the CosCast & top hatted route. You could do worse than speak to John Eales about the subject. What that guy doesn't know about RV8's could proberly be written on the back of a stamp.

Most people buy a 2nd hand P38 and despite listening to the salesmans patter ("Full dealer history etc. etc.) they are buying an unknown quantity. I would not rate the "Official" service as anything special compared to that provided by an enthusiastic owner.People tend to think that the LR stamp counts for everything when all it means is £££££'s in the stealers pockets. Let's face facts, the V* has been around for years an LR in teir wisdom decided to uprate the 3.5 to 3.9 then followed with the cross bolted 4.0 and 4.6. Prior to the 3.9 update, ther was not a problem with "Porous Blocks", "Slipped liners" and the such like. O.k. there are poor sods out there who have been caught out, and I am one of them, both with a 3.9 and later with a 4.6, but the fact remains that the majority of later V8 owners do not suffer problems. All this talk of Coscast and Top hat liner conversions, I feel are over dramatising the situation with owners feeling paranoid that their engine is suddenly going to give up the ghost without warning and major surgery is the only solution. Okay, I have religously changed the oil etc. every 3000/5000 and only used deionised water/quality anti freeze mix at 50% and still had to replace the lump. The point I'm making is that, apart from that, despite the multitude of LR official stamps in the book-I do not really know, from first hand experience, the service history. I know what I have done since and how I have done it first hand-how many of you can say the same from the day the motor left the factory???

ive got to agree with you IR.A dealership service is probably oil and filter plugs and filters,and a quick once over,i can,t see any dealer changing coolant,brake fluid diff oils,as part of any service even when they are supposed to be done at specified intervals.every car i have bought,i always fully serviced them and i do the lot,all the oils engine transmissions diffs,coolant every filter,plugs and leads just so i know they have all been done.

My thoughts exactly Andy. Gav, you state that yours has a good few miles on the clock without many mechanical problems to date. My thoughts are-I buy the car,give it a good going over, change the fluids, filters, plugs etc., put lubricant on the hinges & catches etc., etc., as per the check list on RAVE & more, just to be sure...BUT...what has (Or, more importantly) not been done prior to me getting the car during, say the previous 3-4 or more years. My experience is that although the pretty oval LR stamps look good in the service book, they don't mean Jack sh*t in reality when it comes down to QUALITY of service. If like the vast majority on here, you want the most reliable motor-pride in work done is the most important thing and there is nothing like a P38 to catch you out with lack of care.

she has done a good milage and with a history but, as i always say, the history just means that the owner got someone else to do what he can't or wont. it also has reciepts for some major stuff and this is also attractive as it means the more common stuff has already come and gone.

a good maintenance regime is critical wit a car that has a lot of design faults! when the makeover is complete i will be treating her to all the best services i can possibly do and they wont be by some apprentice lr lad! they will be done by me and then i know where any hazards are!