39 replies to this topic

[TopCatCustom]

As title really, on a fairly well tuned 1310 used for competition is it worth it?

If number 4 getting hot is the main problem to get over is it not easier to just tap the water holes in the head, insert plugs and drill out to restrict the flow slightly on the first cylinders progressively less towards no. 4? Cant say I've had problems in the past but as I'm building this from the ground up I thought it would be worth considering cooling mods.

[Tupers]

What you're describing isn't dry decking it's just re sizing the water ways. When you dry deck a block you plug all the water ways between the head and block a run a new pipe from the outside of the block up to the head.

For a competition engine I'd say yes it's definitely worth it.

[TopCatCustom]

I know what dry decking is, the second part of my post was an alternative to get over no.4 getting hot if that is the main issue.

[Globule]

I'd say if your that concerned, just dry deck it properly. By restricting the others you never know what damage you may cause, as your just moving the overheating issue along, whereas dry decking spreads it throughout

[TopCatCustom]

I cant see it like that- if by restricting the others too much then it will only have the same effect as a dry deck where less flows up through them anyway.

The normal way of dry decking a mini engine if anything must not provide good cooling to the exhaust valves/ports of no.1 as it is last in line for the coolant, ideally the dry deck should be done with 3 or 4 bypass pipes along the side of the engine rather than at the end, with each one restricted to get perfect flow/heat. Then all cylinders and combustion chambers get equal cooling unlike the normal way of doing it. But not much space and lots of hasstle on an A series transverse!

[DaveVader]

I would have thought your alternative method would increase pressure massively in the waterways which could lead to further issues.
Dry decking is a tried and tested way of helping cooling and being a bit of a safety net if a headgasket goes so I'd just go with that.

[samsfern]

itll actually be slightly more difficult to do it on an inline a series, as normally the gearbox covers the two end coreplugs, at least it does on spridgets anyway. Therefore, it would be easier to do it on a tranverse a-series.

[mini93]

the idea isnt to pass fluid equaly between cylinder (of a sort) its because all the take off's for the cooling system are at one end of the block..as you know. its not a flow problem its that at the end of the block the water stays more stagnent, giving the water remaining around that cylinder will have more time to heat up. and of course more chance of hot spot in the cylinder...the dry deck for those who doesnt know just means water HAS to flow along the block past 4, into the pipe, into the head at 4 and out the outlet past 1
its not a mahoosive job, for piece of mind i would go ahead and dry deck it. im not convinced that restricting would be the way to go

[mini13]

i have seen somthing like this on metro turbo challenge engines, the holes rear the spark plugs were brazed up and redrilled smaller.

As title really, on a fairly well tuned 1310 used for competition is it worth it?

If number 4 getting hot is the main problem to get over is it not easier to just tap the water holes in the head, insert plugs and drill out to restrict the flow slightly on the first cylinders progressively less towards no. 4? Cant say I've had problems in the past but as I'm building this from the ground up I thought it would be worth considering cooling mods.

[TopCatCustom]

I would have thought your alternative method would increase pressure massively in the waterways which could lead to further issues.
Dry decking is a tried and tested way of helping cooling and being a bit of a safety net if a headgasket goes so I'd just go with that.

I only meant restricting the holes by a little bit, and probably slightly open the end ones out to compensate.

itll actually be slightly more difficult to do it on an inline a series, as normally the gearbox covers the two end coreplugs, at least it does on spridgets anyway. Therefore, it would be easier to do it on a tranverse a-series.

If you mean what I said about full on multi-bypass dry decking, you wouldn't need the end plugs as it would be done down the length of the block not at the end. It wouldn't actually make any difference on an A series, only for endurance racing high output engines with very fine tolerances which need coolant temperature to be perfect throughout the whole engine.

I may go ahead and do it then, the only bummer is getting the block decked but I may sink the plugs in a couple of thou past the surface so it's not an issue, the head is no problem.

[Cooperman]

I've never done it. The things I do are to always run the heater valve on the other end of the head from the stat housing with the heater valve always open and I use a blanking sleeve instead of a thermostat.
That's what used to be done on the 'works' rally cars and they were fine. Maybe if you had an A-series putting out in excess of c.125 bhp+ it could be a benefit.
What has happened is that people with well-modified engines have had a bit of overheating generally and have removed the thermostat and not fitted the blanking sleeve, with a consequence that the water flow around cylinder 4 suffered and piston failures or some other related problem occurred.

[Ethel]

I like your idea, if the flow isn't sufficient to max out the passages nearest the stat then restricting them to bias the flow towards No4 shouldn't necessarily reduce the overall flow. You could do some simple calculations to tot up the cross sectional areas.

I don't think temperature distribution will be such an issue with a dry deck either; there'll be far more of temperature gradient between the combustion chambers and the water jacket than there will be in the water. Also, the temperature differential will run from around cylinder 1, at the lowest, to the far end of the block and back through the head,picking up more & more heat, to No. 1: the effect being to average out the cooling of each bore.

The key is to keep the water moving.

[TopCatCustom]

I intend to run a stat, probably a 74° one, and I'm also intending on just using one of those fancy T9 design (?) little tiny heaters with a matrix and fan built in. I will probably make a slightly smaller heater outlet on the far end of the head to restrict flow there slightly too.

I don't think I will dry deck this one (yet) as it is a fairly easy mod for the future, I'll do some button pressing and perhaps modify the coolant holes to persuade more flow around no. 4 cylinder though.

Thanks for all the input!

[HUBBA.HUBBA]

Can you dry deck an spi head, or do you need the the normal by pass type as well as the kit at the other end?

[Tamworthbay]

The things I do are to always run the heater valve on the other end of the head from the stat housing with the heater valve always open.

Is this on 12G940 heads as well? I take it you just use the holes that are already there but not tapped and open up the outlet hole?