Pressurising 4.6

Hi new to this forum so thought I'd dive straight in with a problem for you!!

I've been away from v8's for a while but got the bug again and took a gamble on a p38 Range Rover with a 4.6 in it on Thor 106k miles 1999 reg.

When I bought it I had suspicions that it may have problems and that it may have already had some "instant block in a bottle repair" but it was cheap enough to stand me having to put an engine in it so I took the chance. There are signs of water overflow stains to the header tank and around the top hose on the rad and engine more stains, the guy I bought it from admitted that he had changed one head due to the exhaust manifold blowing and damaging the flange face, I took this with a pinch of salt!! when I questioned if it had any water issues he was very positive that it was not and never did use any water, again more salt!! He also assured me that he had not put any instant block repair in it...... more salt!!!

So I watched the temp gauge for the last 1500 miles, it runs mostly just above the blue section at about a 1/4 at worst when sitting in traffic or towing (nothing to heavy only about 1.5 ton so far) it will go to 1/2 up the gauge but never over. It has used perhaps about 1/2 pint of water at the most and I keep checking the top hose and no sign of excessive pressure.......

Then all of a sudden I'm sitting in it a couple of days ago and see wisps of steam coming from the bonnet after I switch off, open the bonnet to find top hose hard and a neat little jet of water coming from the waterpump end of it

I have kept using it mostly short trips of around 5 miles even towing the trailer again with only about 1.5 ton but up a couple of pretty steep hills, still the gauge does not go above 1/2 in about 150 miles it has used perhaps a pint of water from the hose when under pressure.

Since I have had it if you try and drive it hard it goes well but as the revs go up it will die down and feel like it is holding back....bit strange and hard to describe, it also has a bit of a missfire, if you are gentle with the throttle it goes fine and does not have the same problem....helps with the fuel bill though!!!

I have one of those sniff test bottles so did the test and says no problem, I have not checked other hoses or anything yet as I just seem to think cracked block so not worth messing with just get it out and top hats fitted, time is my problem with that job at the moment so I'm thinking bring on the irotite but how much time will that buy me is it really worth the money??

Any ideas to try before spending the big money??

Sorry for long post but guess you need all the info!

Steve

hi steve welcome to lz. i used irontite lasted a few months, then had to replace engine. only thing i would say is you will need a new rad and water pump, when you do your engine..

Hi J thanks for the welcome!

When you say I will need a new rad and pump is that because I should anyway or because the irontite will clog them up? I guess it makes little difference as I would change them anyway as in the whole job they will be out and with the money I'll be spending I'd rather do it right 1st time, if it is because irontite clogs them up now I'm thinking about the heater core getting clogged..... don't want to start adding work to the list!!

Steve

my rad was really heavy, when we took it off full of irontite we think. but to be honist it could have been anything, i got a short engine in the end used my own heads. it now runs like a dream well worth the bother..

Hmm, I've been doing a lot of reading up this w/e and sort of come to the decision that I will probably end up either sending my existing block to be top hat linered or just get an exchange one depending on what they will do and the cost difference, then check and reuse my crank etc with new shells and hopefully my pistons with new rings, refurb/reuse my heads with perhaps a slightly bigger cam while I'm at it with new followers etc, I know new pistons etc would be better but I guess it will only do another 50k miles or so before I sell it on ....probably as scrap or just really cheap by then!! so with that in mind not worth going overboard with expensive rebuild!

Where did you get your short engine from? I've been looking at v8developements and Turner and also v8tuner web sites all seem to be about the same prices on the websites just need to talk to them all to see what they offer and will do

Steve

There is a bit of a debate over the slipped liner top hat cure thing. Some opinion is that they only slip if the engine is abused, ie overheated and then ignored hopeing that the problem will go away and fix itself. Others say it just happens. Block cracks are easier to understand when you look at the thickness of some of the castings from Rover, there is some good information to support the train of thought that a bad engine cannot be improved by fitting top hat liners and the only way forward is to get a Coscast block others tender that top hat liners cant possibly move so they are only way forward..
The debate continues and I think the best idea is for you to do plenty of reaserch and weigh up the pros and cons of each route. Perhaps even consider taking a chance on a breaker engine. I would also say, dont assume the worst, check over the whole system and dont forget the drivers footwell. A tiny leak is all it takes for a void to appear in the cooling system over time which will lead to a boil up.

I agree rewmer, there is quite a debate over coscast or top hats, and as the sellers of both options are obviously pushing their options and slagging off the oppositions options it does not make it any easier to decide, people are quite rightly saying that the coscast blocks are not old enough to have proved themselves, but then are the top hatted ones that much older to be any better?? I'm not sure but from what I have read the top hats seem to be the way to go, I guess it is a gamble which ever way I choose, as you say the other option is secondhand, but as they seem to cost the same or similar as a refurbed or new block I think I would perhaps prefer to steer away from that option.... the last p38 I had I took this option only to find that after a couple of months it started using a small amount of water, I never got any further with solving that problem as my dog wrote the car off!!! don't ask!!!! What I guess I would like to find is a low miles either top hat or new block secondhand complete engine to throw in save me all the work building one as time is short! The other thing pushing me to top hats is that they all seem to come with a 3 year warranty so they must have some good faith in them, RPI won't give 3 years on the coscast, also so many bad reports about RPI not sure I want to deal with them anyway!!

Footwells are dry, I will do some more investigation before I right this engine off but not really expecting to find too much good news

Steve

Ive decided that if mine gives up the ghost, Im going for a Chevy LS transplant....

it does not sound like you are suffering from a porus block problem i would be inclined to check the state and the cap are ok first been out to quite a few which garages have condemed and they have just been air locks due to water leaks if you are sure you have no external water leaks and the heater "O" rings are also ok then you will be ok ensure all the hoses are secure and that the rad is clean and not blocked.
as for the irontite sealer have done this to a customers engine 4 years ago and 60k ater still running fine even after hed had left only water in it over last christmas and froze it and blew the head gaskets

voguese39 is right. Dont always assume its a liner problem. It can be several causing it.
I've changed all my hoses thermostat, rad and o rings. Done the head gaskets twice (dont ask) and replaced all the jubilee clips . Only today after all that work is it finally running like a little gem. head gaskets are no good on these motors so it could be this.
I have water stains all over my engine , but thats loose connections after the rebuild and coolant shooting out all over the place.
If your sure its the block go down the irontite route before spending big bucks to find out it was a blocked rad or naf thermostat or leaking pipe.

Well thanks to all the encouragement and suggestions from everyone on here that it may not be the dreaded cracked block problem, I think I may have cracked it tonight!!

Hoping I've had some good luck, tonight I managed to find time to drain and flush the system, all the water looked very clean with no sign of any rust or muck in there, decided that being as I had a known good second hand thermostat that it would be worth the effort to fight with all the spring type hose clips and get the thing out from all the hoses.

Glad I did, looked inside the stat when I got it off to find the valve had come unseated from its spring retainer so was constantly open just a small amount so always a slight flow of water but I guess that as it was not properly seated I doubt that it would then work and fully open allowing full flow hence the pressurising..... I hope!!
My only concern now is that the previous owner may have been having pressurising problems so tried to bodge the stat open so it would take longer to warm up.

After refilling the system I took it for a hard 40 mile drive up lots of hills...... advantage of living in Wales!! The temp gauge went up to halfway and stayed there all the time! Since I've had the car it has always jumped up and down 1/4 and 1/2 with no real pattern which always seemed wrong. Just gonna run it and keep my eye on it for a week hopefully I have a happy cheap end to my problem

Thanks for all the help and advice with this one
Steve

rewmer said:

i would also say, dont assume the worst, .....

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rewmer said:

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Ha! good posting Rewmer I think with the reputation these engines have it's hard not to assume the worst!!

Thanks again for your words of encouragement!!

May this be a leson to all. Dont assume the worst. Simple first then panic !:crazy:!

Willos said:

May this be a leson to all. Dont assume the worst. Simple first then panic !:crazy:!

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Well sadly I did the simple 1st ......... now I must do the panic

Today after I guess 100 miles since fitting the thermostat and thinking that maybe all was well and feeling confidant with it........ on just a 2 mile drive looked down at the gauge to see it rammed hard up to the max popped the bonnet to find it hard pressurised of the hoses and boiling like the big kettle it is!! Left it stand for an hour and then had to put best part of a gallon of water in it........ No sign of any burst pipes or leaking so guess it's going out the expansion overflow or the exhaust, no steam though!

Back to my original thinking, fooked block drove it back home no sign of over heating but thinking that I'm going the Iron tight way so don't want to get it hot more than I have to so ebay irontight search here we come!!

Steve

Latest update with this problem......

It's been a while as I have plenty of other cars and vans to use but not much spare time to fix them!

I have since last post bought a new stat and new water pump, I was going to buy a new radiator as well but when I took it out it was like new so not the original anyway, something in my favour!!

The water pump bearing was on it's way out and starting to show signs of water leak, I flushed engine and rad well both ways and put it all back together, ran it up to temp and all seemed well, took it for a run and overheated and blew the water out topped it up and there it all goes again hot water everywhere but not in the engine!!!

So now I have found and engine that has been built by RPI with stage 1 heads and a bigger cam, balanced crank and pistons etc, from what I am told it is a 4.6 block with the early front cover on to drive a dizzy and oil pump, my intention is to buy it, swap over the front cover to the serp front cover of my engine, use all my parts to convert it back to p38 4.6 and slap it in, I'm lead to believe that I will have to use my cam and followers as the dizzy drive cam will not work with my front cover. The crank sensor was my other concern, general thoughts are that if it is a gems block (mine is Thor) then the sensor should still fit the block as there is and insert to swap over as well, can anyone confirm this? Have I missed anything that would/could stop me going down this route?

Last thing anyone know if RPI ever built engines on old blocks without top hat liners? I know they used to use top hat liners and now rubbish them as they now use coscast blocks but did they ever just use plain old landrover blocks?

Steve

I know you have looked at the rad but mine was relatively new but had failed on the crimped joint on the bottom but was weeping so little it was evapourating but also allowing the pressurisation not saying it is but try a pressure test on the rad might save you a few quid.

dont know about the rpi bit, but i know you can change a gems to a thor. so carry on with your plan, i did it to mine..

Thanks J thats it then decission made i will just bite the bullet and buy it and get on with the swap, I will pull the heads off before pulling the complete engine out , just incase there are obvious signs that one of the headgaskets has gone but I'm pretty sure with all my testing it is the block, I could mess about clutching at straws forever if I'm not careful!!

Steve

Hmmm bit of a dilemma now.......

I've started taking out the pressurising engine, I decided to pull the heads of with it in the car as it's easier to get at the bell housing bolts this way and I have to strip most of the parts off later to convert my new engine.

Now I have the head of the passenger side I find that the head gasket has actually signs of blowing slightly into the rear water jacket from number 7 cylinder, also the second from front cylinder (3) has burn marks through the gasket leaving marking to the head and the block into the valley area, but not into any water way. The outer row of head bolts were a little slacker to undo. I'm yet to take the drivers head off yet that will be off after a cup of coffee, the dodgy bloke I bought the car off told me that he had done the drivers side head.... yeah there are signs of the bodging T**t being in there, complete with plenty of silicone and the second hand valley gasket that the tight T**t reused!!! along with the reuse of the stretch head bolts!!!

My intention was to just build the new engine up using the cam, followers and front cover from this engine then go back in at a later date to put in a new bigger cam, but the new engine has the older heads with the extra row of bolts, so my new plan was o use the complete top end straight of the original engine.

Now I'm thinking, slap this one back together with new head gaskets, all nice and tidy, this will then hopefully prove that this block is hopefully good, then by another complete but blown 4.6, rebuild the heads properly, do the new cam, all at my leisure and then do the complete swap, by then hopefully I would have been able to prove the original block as good and then get some decent money back on it.

What do you think? Do the head gaskets really go as often as people say or is it purely hopeful people trying to delay the fact that the blocks have gone porous/slipped a liner?

Steve