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**danny_nelson** · 20-03-10, 07:17 PM

Re: I have an MOT!

Well done paul There is something very special about the sound of a V8.

**greyV8pete** · 20-03-10, 07:40 PM

Re: I have an MOT!

Well done indeed Paul. Also welcome to the V8 hot running club! Have a look at Pete Crowther's article in the latest pitstop. I have also written a bit about hot running on the forum. Even my 3 row crossflow radiator from Marlin has has only about 35% of the cooling area of a Range Rover rad. What rad do you have? Do you have louvres in the top of the bonnet? Do you have a remote oil cooler?Peter.

**sam.pej** · 21-03-10, 01:20 PM

Re: I have an MOT!

Thanks Danny and Pete. I had a radiator built specially by a local firm that was basically the biggest I could fit in. It is 18" by 14" by nearly 3" deep. The suppliers thought it would be adequate when I explained what it was for and advised against aluminium as it is difficult to repair. I don't have louvres in the bonnet so I'm looking into that nor do I have an oil cooler. The problem would be where to put it. My radiator sits on top of the front chassis cross member and hanging the oil cooler below this would be too close to the road. The only place that looks possible is under the front nose in front of the steering rack. Airflow would then be partly blocked by the front bumper and number plate. Any thoughts? Paul

**Peterx** · 21-03-10, 01:54 PM

Re: I have an MOT!

Paul said..."I realised the push rod from the servo was having to travel a quarter of an inch before it made contact with the rear of the pistons in the master cylinder and so I was not getting the full travel of the pistons in the master cylinder."

I had the same problem on my Sportster build and made up a little spacer.
http://www.flickr.com/photos/peters-bmwmarlin/1660019712/in/set-72157594447011861/

http://www.flickr.com/photos/peters-bmwmarlin/1659156819/in/set-72157594447011861/

It was Robin Martin's idea.

**KitCarGirl** · 21-03-10, 10:53 PM

Re: I have an MOT!

Well done Paul! Good luck with the hot running!

Sue

**greyV8pete** · 22-03-10, 12:09 AM

Re: I have an MOT!

Hi Paul. That radiator sounds good but you need to consider how much air is actually going through it. The louvres in the bonnet reduce the pressure build up in the engine bay so air can flow more freely thro the rad. I have made up a ram air duct which fits between the rad core and the G/Fibre nose so all the air entering the grille passes through the core and not around the rad itself. Is your rad a crossflow type or does it have top to bottom tubes? My oil cooler is hung on brackets off the steering rack attachment bolts so half the cooler is hidden behind the rack :-( I plan to move it lower imminently! Peter.

**dave_kitson** · 23-03-10, 05:57 PM

Re: I have an MOT!

Ahhh, the V8 hot runners! These engines struggle on that front even in their home environment, let alone in the confines of a kitcar. I've heard that they commonly run to 120 deg in the likes of TVRs & Morgans, so 105 deg may not be too bad if the system is pressurising ok. Having said that, mine now operates mostly around 95 deg now that the engine has bedded in. Have you rebuilt the engine? If so it will improve after a few thousand miles.
I've done all sorts to get mine to keep its cool. Marlin radiator, heavy duty Kenlowe fan (it takes so much current the lights dim at night!!!), louvres in bonnet top, exhausts lagged and heat shields on them as well. And an oil cooler - I mounted mine horizontally under the front apron with an air scoop on top, and a thermostatically controlled fan underneath. The fan came from a motorbike, but I think you can get a complete kit like this now from the likes of Europa. I thought of it first though!
If you can get to Stoneleigh, you can bury your head under everyone elses cars and pick what you think are the best solutions. But believe me, you will still be looking for further improvements in 5 years time! Perhaps the only real answer is to fit a BMW straight-6, but where's the fun in that? Good luck and keep at it, the sound of a V8 on song is worth it!
Dave

**sam.pej** · 24-03-10, 06:40 PM

Re: I have an MOT!

Hi Dave. The engine is fully recoditioned (from JRV8 in N. Ireland) and has only done 25 miles, to the MOT centre a couple of times, so hopefully it will run cooler as it runs in. I'm going to try louvres and oil cooler while exhaust alreadt lagged but on looking at another forum that typically uses V8s (some sort of snake, I think!)I spotted someone with a similar problem. I have no header tank, just an expansion tank connected by a small hose from a T-piece in the radiator top hose. My radiator cap with pressure relief valve is on the T-piece with a valveless one on the expansion bottle. The chap on the other forum had his caps the other way round. I'm not sure which is correct. Does it matter?

**greyV8pete** · 24-03-10, 08:50 PM

Re: I have an MOT!

Hi Paul. On my hunter my valveless cap seals the top hose connection. A small bore pipe goes to the expansion tank on the bulkhead. This expansion tank has the pressure cap and a small bore "overflow" pipe. The set up is as fitted by Marlin. Your set up won't let the coolant flow to and from the expansion tank very well as it will have to overcome the cap pressure first.Peter.

**greyV8pete** · 24-03-10, 08:52 PM

Re: I have an MOT!

Sorry I meant the snake chap's cap set up not yours. Peter.

**dogoncrazy** · 25-03-10, 10:52 AM

Re: I have an MOT!

Agree with Peter, the pressure cap should be on the expansion tank

**dave_kitson** · 25-03-10, 05:24 PM

Re: I have an MOT!

Pressure cap on the expansion tank. Also make sure there are no air locks, especially through the heater. Simple test - does it get hot? Curing may be easier said than done if there is a problem. Also, is your gauge accurate?
Incidentally, on the standard inlet manifold with twin SU's I believe there is a bleed point which needs connecting to the small pipe on the filler neck (the one with the valveless cap!). I didn't have to do this, as I have a 4 SU setup on Boxer manifolds, and it may not apply on other setups, eg EFI, big single carb.
I still keep looking for ways to increase cooling such as an extra radiator or more capacity. The problem is where to put it! I even thought about moving the battery under the wing to free up some space at the back of the bonnet, but it looks a lot of effort.
Finally, returning to the heater, on a hot day with the hood down, the heater can provide a bit extra engine cooling by blasting it up the screen and over your head!
Keep at it!

**greyV8pete** · 25-03-10, 11:55 PM

Re: I have an MOT!

Just remembered that my heater hose has an air bleed point at the top of the bend in the hose about 12" from where it comes out of the cylinder head. It's a "home made" bleed screw using a 2BA screw with a fibre washer fitted into a 2BA nut which is brazed onto a short length of metal tubing with a small hole in it. Used carefully when the engine is hot (ie the coolant is pressurised it is very effective in removing air from the heater line. Peter.

**robcawte** · 13-04-10, 08:21 PM

Re: I have an MOT!

I know your all going think I'm mad ( hey don't answer that ) But I think your missing a big thing here. To get the air in ( that's the radiator )you have to get the air out. A bit like an engine, if the exhaust isn't efficient you put as much petrol in as you like and you won't get any more power. This does work, put a scoop under the floor where your feet sit, both sides with a duct running down the side of the chassis ( on the inside so you can't see it ) to the back of the car, and the air flow will increase by a margin that all this other stuff will be unnecessary . That's put cat among the pigeons.

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