At Wits End - Please Help..

need4speed · Post by **need4speed** » Fri Dec 04, 2015 7:15 pm

I'm sorry. I thought my original post was very clear. Obviously not.

I know all about the various blocks and quality of them etc. The new blocks we bought were colour coded red, so the best that LR made.

Didn't know that the porosity problem included brand spanking new blocks not even out the wrapper?

Post by **Coops** » Fri Dec 04, 2015 7:19 pm

well I cant help you anymore,
if you think the blocks are good and everything is as per the 3.5 set up
I'm stuck,
hopefully someone else can help you now mate

need4speed · Post by **need4speed** » Fri Dec 04, 2015 7:25 pm

My apologies. It was Keith Gott we bought the blocks from.

Don't know why I said Eric Gorr. They make some specialist parts for my motocross bikes...

Darkspeed · Post by **Darkspeed** » Fri Dec 04, 2015 7:26 pm

need4speed wrote:Why are you confused lol.

A pair of 4.6 engines were built out of a pair of new 3.9 blocks by using 4.6 cranks/rods etc..

Confusion being that you cannot make a 4.6 from a 3.9 as the 3.9 has smaller main bearing journal diameters.

So is it a new 4.0L large journal block - which are known for being the weakest link in the RV8 chain in respect of liner problems.

The thing that gets me is the cold radiator.

Got some decent detail photo's of the installation - will save a lot of speculation

Post by **Coops** » Fri Dec 04, 2015 7:36 pm

maybe a stubbon airlock,

Darkspeed. what gets me is everything on this new engine is as per the old 3.5 etc which was good and seemed to have no heating/cooling issues.
only change is the block, so if everything else is ok still either an airlock or the block is a problem?

what worries me two brand new blocks for £600 makes me think there was a problem with these, as that is way to cheap,

sidecar · Post by **sidecar** » Fri Dec 04, 2015 7:38 pm

What inlet manifold are you using? Is it an Edelbrock Performer 180 by any chance?

JP. · Post by **JP.** » Fri Dec 04, 2015 8:05 pm

Wait wait wait....

Is the Capri gauge reading very hot ???
If so what does your fuel gauge do at that same same moment ?? these two gauges are related to each other. If both gauges are incorrect at the same time, voltage regulator at back of the gauge pod is shot.

Very common with the black transistor style regulators found on mk3. Older Capri's had tin cans with on/off regulators which are a bit less accurate but more foul proof ( interchangeable ).

Next have you true measured your temperature using one of those cheap infra red temp guns.. very handy to see if gauge is correct or false ( not uncommon in a Capri ).

Well top hose hot, is it very pressurized too??

By coincidence, did you swap temp sender also or used a different one on the newly build block. Capri's have specific temp senders ( colour coded ) to work with the gauge pod.

Ian Anderson · Post by **Ian Anderson** » Fri Dec 04, 2015 8:55 pm

Gat back to basics it does not sound like you have water flow!

Get a big bucket and connect it to the bottom hose

Route the top hose back to bucket

Stare engine

Do you have water flow?

If not either a blockage or the pump is not working. (Or there is a route of less resistance for the fluid Ie through heater and back instead of through rad, try restricting flow there with mole grip on hose.)

Ian

need4speed · Post by **need4speed** » Fri Dec 04, 2015 9:07 pm

Wow. Lots of replies since I last looked..

Ok. Let me start by dispelling a myth. The amount of times I've read/heard "oh you can't make a 4.6 from a 3.9 block...." Etc etc. Yes you bloody can lol. You start with a 3.9 block, 4.6 crank/rods/pistons. You get an engine shop to turn the 2.5" main journals down to 2.3". Fit the assemblies. Get the lot balanced. Boom!! A 4.6!

Next thing I want to clear is, yes the blocks were a steal but that doesn't mean there is anything wrong with them. Keith Gott are an extremely reputable company in the 4x4 scene and would not have sold them to us if they knew there was something wrong with them. I've used them many times, as have a few of my friends and had nothing but great service and advice from them. They originally wanted £600 for 1 block but I knew they had been gathering dust for years and got both of them for the £600.

Next is the fact that I don't think it's a gauge fault as a gauge couldn't cause the top half of the rad/top hose to get roasting hot and spew water out the header..

Yes it is an edelbrock inlet manifold he is using but it didn't cause any overheating problems on the old 3.5.

need4speed · Post by **need4speed** » Fri Dec 04, 2015 9:09 pm

Thanks Ian. Just saw your rely. I will suggest all you mentioned

sidecar · Post by **sidecar** » Fri Dec 04, 2015 9:39 pm

I've come across about 4 engines now which have suffered weird overheating issues, each time the cure was to drill two holes in the manifold just behind the thermostat chamber, the holes need to be about 7mm in diameter, they connect the chamber to two water passages on either side of the manifold.

I could be wrong but I believe Jim (JRV8) does this mod to the manifolds that he sells.

If you want to do this mod I can post up a link to a wiki site which gives details on how to do the mod.

As to why some engines are OK without the mod and others or not, well I ain't got a clue why this is the case!

need4speed · Post by **need4speed** » Fri Dec 04, 2015 9:48 pm

That's interesting sidecar.

I will follow Ian's advice above but I would also like the link to the mod you mentioned. Thanks

ChrisJC · Post by **ChrisJC** » Fri Dec 04, 2015 10:05 pm

To emphasise a previous point, some pictures of the cooling circuit would be very handy here.

If you remove the thermostat and start the engine, you would expect to feel the top hose warm up gently, and the rad will warm up from where the top hose enters down to where the bottom hose goes back to the block, and it too will heat up.

Have you measured the temperature with an independent thermometer?

Have you done a compression test to make sure you don't have gas being pumped into the water jacket and cocking it all up?

Blocks and heads are interchangeable as far as cooling goes, so no issues there.

My guess is that there is no circulation because you have combustion chamber gasses getting into the coolant circuit in significant volume.

If you run with the rad cap off, does it keep bubbling?

What about the water pump?, is it definitely a good one?

Can you get a bit of clear top hose?, so you can see what is going on in there? You should see a fair bit of flow, even at idle.

Chris.

sidecar · Post by **sidecar** » Fri Dec 04, 2015 10:32 pm

need4speed wrote:That's interesting sidecar.

I will follow Ian's advice above but I would also like the link to the mod you mentioned. Thanks

There you go, the bit you need to read is about 1/2 way down the page...

http://how-to-build-a-pilgrim-sumo.wiki ... e-plumbing

I drill the holes bigger than the 4mm that my mate suggests.

stevieturbo · Post by **stevieturbo** » Fri Dec 04, 2015 11:19 pm

As others have said...

Test that water is actually flowing. Does the heater inside the car even work ?

Run un-pressurised for any tests if need be.

Does your thermostat actually work ?

Ignore OEM temperature gauges, they're always woefully inaccurate. Get an IR heat gun or some other means of measuring temperature with a more accurate reading.

Are you sure all hoses are plumbed correctly ?

Persistent air locks and subsequent loss of flow in the system are usually a sign of cylinder pressure entering the cooling system.

Usually this presents itself as unwanted pressure in the cooling system, but not always. A sniffer test for combustion byproducts in the cooling system can sometimes help.

And you keep saying the blocks are new....so brand new, never machined or used in any way and as they came from Leyland/Rover ?
From what base ? 3.9 or 4.0/4.6 ?