Dry decking, pros & cons + improving cooling on pot no. 4
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I've just done a quick stripdown of my engine ready for the rebuild to find it's been detonating on cylinder no.4. All the other pistons are fine with no signs of damage at all. So my guess is that no.4 has been running a lot hotter than the rest.
What are your thoughts on dry decking, will this improve cooling in this area ? Or are there any other good ways ?

Unfortunatley it's scored the bore, so it's going to need a rebore & a new set of pistons. I think I read you can order directly from Accralite & this is the cheapest way, is that correct ? If so does anybody have contact details ?
It's not all bad as I've a few things I want to change & a few trick ideas to try, maybe a new cylinder head .......
Thanks
Phil. :)

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on a metro turbo challeng lump i noticed that the holes in the block were restricted, iirc no4 was not so the water would flow through 4 better.

I'd say to go with the dry decking mate - I personally have not done mine yet, but as soon as it comes out for rebuild it is on my list of must do's.

Alternativly I have seen people make up and fit restrictors in the waterways to try and limit the flow around 1 and 2 hopefully pushing more water round the back to number 4.

Personally I think this would take a lot of time and effort and the results would not be as good as a dry deck.

Have you modified where your water pump sits as per Vizards Bible? He grinds away metal from certain places to increase the flow to number 4. (not sure if it helps in practice, but its in the bible)

Will you have it done in time for Avon Park?

Cheers chaps. Yes Sumpnut, the block is cut away around the water pump. I was hoping to have it done for Avon park, but I've been so busy doing heads I've not had/or got much time at the mo.

Phil. :)

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have you blocked the heater tap hole on the head or is it water flow out there?

Heater's connected.

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okay, do you run with the heater on all the time? It may be a good move to connect that pipe into the upper radiator hose, to have continous water flow there.

what's involved in dry decking? I know it involves no fluids passing through the head gasket, but how exactly is this done? do you have to plug all the holes in the head and the block? or is a solid head gasket used with no oil/water holes to stop the fluid transfer?

is it usually just done for water via the core plugs/hole in the flywheel end of the head, or is it done for the oilways too?

Sorry to Hijack the thread a little, just considering it as an option for when i build my new engine later this year.

Mr. Prawn, the friendly Crustacean- slowly making steps towards forced induction.

that's right , this the best trick to eliminate n°4 overheat.

I thought you were already dry decked phil?

No, not dry decked at mo Nic. Right, I've been weighing it up & I'm going to go for it, but I'm not paying £65 for a hose & a couple of fittings, so I'll make my own.
Does anybody know what size ID hose/fittings I should use, or what the available kits use ?

Thanks
Phil.

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seem to think 1" will be more than enough, its all the rest uses remember

Cheers Iain, that's what I was thinking. :)

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Top of my block has been done like that. Brazed, then drilled.

I'm using 32mm pipe for mine.

carl made my outlets and thats the size he made them.

yep, Carl made the outlets for mine and I asked for 32mm. The 32mm samco 180 bend is about the right radius.

the racers use dry deck as it may be the difference between finishing a race and not. If the head gasket fails, it wont fill the cylinder with coolant or oil, and the engine will at least still run.

Number four overheat is another factor to consider dry decking as all the coolant will go right past number 4 cylinder, into the head right past number four combustion chamber.

I think Visards theory on modifying the water pump area on the block is bollox, it goes against the design of the water pump and how it works. There is no way you will get eny more coolant down round the back of the cylinders through that little gap.

It is said that 75% of cooling is done in the head with the other 25% in the block. Some of the top fuel drag racers dont even put any cooling through the block, it all goes through the head.

There are a couple ways to dry deck. You could use a gasket without coolant holes, but its not exactly dry is it. Or you could do it correctly and plug up all the coolant holes in both the block and the head.

The heater is connected, but I certainly don't have it blowing all the time. It would get a little warm in the car in summer.

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Sorry to highjack this answer but you do not have to run with the heater tap open all the time.

If you use the later bottom radiator hose that has the second return pipe built into it you can run a fabricated copper pipe from the fitting above numer four behind the rocker cover and then split it into a y with one path leading to the heater and the second into the bottom hose. the second return is where you plumb the heater return into. Works a treat :)

Own the day

This is what I was planning on doing.

If something is worth doing, it's worth doing half of.

Crack on its a good fix over the compromise of a boiling cabin and sweaty feet. I could make you one if you so wish.

On a related question, in this thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=291523
I asked was there any reason for the restrictions in the head especially around No.4, I was planning on drilling the plug's to allow for the water to flow more around No.4 as the standard setup seems to stagnate it.

Edited by Mr Joshua on 15th Jun, 2009.

Own the day

yeah, dropping the already hot water from the heatertap/heateroutlet in the head into the water that is supposed to cool the engine is a good idea?! NOT so! Much better to plumb it into the upper hose so the water gets cooled in the radiator, or even better fit a heatcore in the grille to cool the water that goes between the heateroutlet and lower hose.

Edited by miniminor63 on 15th Jun, 2009.

I can't see any cons of doing this, it can't make things worse can it? It works well on 90% of the miglia's. I used quite small dia pipe on mine, also some of my water pipes are only 16mm ID. My engine can handle 20 mins on the track flat out without overheating. I also have quite a small rad.

Team Racing

Edited by Mr Joshua on 15th Jun, 2009.

Own the day

secound Jim's words, all mine have worked like this, though when I hadn't the right rad , it helped to have a heater matrix from this line behind the grill.
Since I use the 2 core, never seen over heat