NITROUS OXIDE ( nos / n2o ) advice forum

Hi All,

I'm after a bit more advise from the wealth of experience from this forum.

My cooling system is ALWAYS pressurised when cold and I know this is NOT right.
There has to be combustion pressure passing into the system via the head gaskets.

At the moment the ARP head studs have been torqued to 65ft/lbs (both block and heads are alloy)
Can I tightened a bit more?

What have any of you torqued upto, with the same ally comination as I have.

IF the cause of the problem is leakage at the head gasket, increasing the torque is NOT going to cure it, because you already have enough clamping force to do the job, especially for NA use and even if you're using the 50 hp of nitrous now and again it should still be plenty for that.

In my opinion its more likely to be caused by one or other of the following;

1) Cracked head or block
2) Porous head or block
3) Corroded head or block joint face
4) Damaged head gasket

The ONLY solution is a close inspection and crack testing if there is nothing obvious.

Are you always this lucky.

Hi Trev,

I've just gone through the emails from ARP and I'm a bit low on their recommended torque settings.
Looks like I missed the instruction of torquing to 70ft/lbs as a minimum.

I'm gonna up by another 10ft/lbs before we goto the pod next weekend.
I have nothing to lose anymore

I don't think re-torquing is going to fix this ,if the head/block or gasket surface is damaged ,tightening it up more is unlikely to do anything . If you are sure it is cylinder pressure in the cooling system you can check for hydro carbons or pressurize the system and check for leaks , is it overheating or are you having to add water ? if not it may be the inlet manifold ,although that usually causes a vacuum.


Austin

It is not overheating and coolant loss is minimal.
Its bloody annoying

How long do you have to drive before you get coolent loss?


Austin

I guess its about a pint after 200 miles, as on saturday I did a round trip to Nothampton.

So if its going through engine are you getting any white smoke when hot or milky oil vapour in the pcv system, also check the plugs . I assume there is no sign of leaks out side the engine?

Austin

I was looking for a simple answer, but I guess the truth is harder.
Don't worry, its not going to stop next weekends activities
I've been waiting 18 months for this.

RWYB or test & tune ? going to wait until after the FIA finals for my next outing , hope all goes well you deserve it with all the problems this car has given you.


Austin

I aim to do both next weekend, so its at optimum set-up for the BMW show on 18-19 sept.
Vivienne will be driving at the show, and her first WON effect on her own

Hi Richard

If you can drive down to me I can run a Snap-On block testing kit on it if you wish ?

Basically its a blue fluid that has gases from your expansion tank pumped through it and if the royal blue fluid changes to green or yellow then its either HG or cracked head or rarely a cracked block...

I could do it any evening for you if you wish.... free of course...

All the best Brett

Hi Brett thats a very kind offer and yes it would confirm, but I feel there is little doubt that this is leaking cylinder compression.

I'm going for it big time next weekend and I'm not bothered if I have to come home courtesy of the AA

Thats my Boy
Shit or bust eh

I know exactly where you are on this Rich!!!
You only want this as a track slag now, so no worries about breaking it before you fix if properly again. As you are in a shit or bust situation it wont matter if you re torque the head bolts a bit more. Just dont slacken them off before you do nip them down. My ARP head setting is 68 ft/lbs. I actually pull them down to 75 ft/lbs in 3 stages. And recently I have been torquing to 80 ft/lbs.

As a side note. Befoe I had my block damage, I used to often see pressure in the cooling system on cold engine? The first thing I do when I open my bonnet is crack the rad cap, then check water level and then check oil level. I never lose any coolant though. My water level is always spot on. And I dont have any water evidence in the oil, and I dont see any mayonaisse in the filler cap, and I dont see any signs of oil film in my water?? I'm still pondering the reasons for the cold system pressure. And I have a few ideas. But I'll keep them to myelf until I have proof.

I'll be on site with you next Saturday for moral suppport mate. My copper head gaskets wont be ready until Haslett and 6th Sept so I cant get my engine rebuilt in time. I'll be at the Euro Finals on the Saturday meeting up with Insane Ron and the Fat boys. I'll be crewing for the Miss Guided Camaro in the SP/ET class as well as chilling with Austin. Then I'm going balls out to get my block fixed and bolted together so I too can do a Death or Glory pass on the Saturday 18th Sept along side you

I've only got one full bottle left. So I better do it in 3 passes

Perry

This is where I think it all went wrong.
All was perfect until the studs were re-torqued (slackened off first).
I reakon the seal was broken at this point, annoyingly ARP said just go round and nip them up.
I had no idea they were to be slackened off. I would have just nipped them up, had it been me.
Live and learn eh.

Hi Richard

Good for you going for it...

Ok here is how I would run it....

Take OFF the pressure cap, then get engine to normal operating temperature, then put cap back on BUT only to first turn/click (so its loose) and it will NOT pressurise the system... i e . do NOT fully tighten the cap....

It should help

All the best Brett

Thats what I used to do just before a run Brett ! I'm not sure if Richards is one of those fangled screw on caps though?
If it is Rich, maybe blow the pressure off just before staging??

I'm not aware of any need to slacken the nuts before re-torquing but after having done so I can't imagine there being any problem. Not all gaskets bond to the head and block surfaces and even if yours did I wouldn't expect the bond to break, because it's the Devil's own job to get the bloody gaskets to part from the joint faces even when you're trying to do that.

I'd be VERY SURPRISED if the problem was caused by;
1) The head gasket itself - unless it was damaged before fitting
2) Anything to do with the torque settings used
3) Anything to do with the re-torque procedure

I'm still expecting you to find something wrong with the block or more likely the heads themselves, as stated in my first response.

I'm wondering if the idea behind slackening off first may have something to do with adding more assembly lube between the nut and washer, or allowing the lube residue to seep under?? This is the only reason I can think of.
But why loosen a tiny part of a large item that is already clamped evenly. I wouldnt have thought that even removing one nut would allow the whole body to move to an extent where the seal would be disturbed?

The odd thing is! The problem was not there before the bolts were re torqued. The engine had covered a good few trouble free miles. And if memory serves me right, these were new factory heads??

I also wonder about how best to remove vapours that could be seeping into the water system. The big problem is the effect of the vapours causing a pressure increase, and how to remove this excess pressure without losing any coolant. ie, removing this excess pressure as a vapour only so as not to force coolant out of the system. I may have a simple solution for you Rich But I'l need to see your system again ??

perry

If it only showed up after re-torquing I'd put my money on that causing a crack in the head, rather than the gasket seal failing.

Cheers everyone
Perry, I'll see you at the pod on saturday.