welded up head waterways

[steve_k]

hi guys
hope any of you out there can help me? i have seen a few e30 325's running turbo's in a few of the bmw mags & most of them have had the waterways in the head welded up
what i want to know is what it does & how it works & would it be any good on a non turbo m20 engine?
i hope any of you out there can help me with this?

[kam-325i]

I think that the Turbo'd M20's have this done just to strenthen the head.
There is no benift on a non-turbo'd M20

[steve_k]

had to drag this back up as hopefully over the next year or so i'll be building up a turbo lump for the sport.

& seeing as i've allready got a spare head (griffin motorsport stage three ) the only thing it hasn't got is the waterways welded up for a bit of extra strength & what i would like to know is where would i be able to get this done & at what sort of cost??

so come on folk's someone on here must have the answers i'm after??

[maggspower]

The reason for the welded waterways is for added friction to keep the head gasket in place under boost.

IMO the effect of this is marginal at best, when you take a head off a block and examine the gasket, you will find that it will have swelled up in to the void of the water ways in the head. This will keep the gasket where it should be. There are some m20s running boost without welded waterways, and no HG problems.

You will lose cooling around the ports, not a problem on the inlets but will be on the boosted exhaust's, among other problems.

[HairyScreech]

The only benefit i can see to this is to put a little more meat under the exhaust port where the floor is exposed to the coolant, would help with the increased exhaust pressures and temperatures and might allow for more porting without cracking.
However as stated above the coolant flow could be seen as more benefit.

I must admit i have no idea as to the intention of this modification, it wont do anything for coolant circulation, any increase in contact area will be offset by reduction in pressure as headbolt force is a constant, cracking benefits are debatable as the welding will cause its own issue, head gasket blowing by the waterway may be the case but it is just as or more likely elsewhere.

I can only gather it is a mod carried over from another engine where failure in that area was common.

[HairyScreech]

With a bit of research the only other instance of this that i can find is on jaguar 6's where it is done more for corrosion repair in the same area the e30 heads can corrode.

I wonder if this started because someone had a corroded head that was blowing under boost and the welding prevented the failure, with credit being given to the weld job rather than the blame being pointed at the corrosion.

I can't find any other plausible reason and when asked everyone just says its "to stop the head gasket blowing" which is not the case as byron points out, also many other engines have similar waterways and are never welded, it seems to be just an M20 thing.

Edit - alternative it is an attempt to make the m20 head like the m30 head, where there can be an issue with the head gasket shifting at this point.
However the m30 head gasket can shift here and the head is solid thus making it a meaningless mod.

Plenty of heads have gaps like this:
2002 turbo
Toyota supra turbo
escort cosworth
ford falcon
nissan 300zx
various turbo mopar engines

Now none of these are exactly light duty turbo engines.

[ross2009]

as pointed out about coolant circulation my heads been welding and ever since ive had it done not once has the temp ever reached half way on the gauge so as for keeping it cool it does just fine wih a welded head but they must be done properly as like screech said that in there own right can cause problems
i suppose i just jumped on the band wagon coz i thought that it would help stop pushing the head gasket out under boost but now im in the realms of 1.5 bar im glad i have had it done

[steve_k]

Old thread alert!

Right then folks, has anyone got anymore info/pics of this? Got a spare head that's getting a few bits done & I want to try & make the head as strong as possible as longer the winter I'll be looking at going down the FI route.

So any pics??

[ross2009]

I've got some steve I'll post later when I'm at home

[steve_k]

Cheers Ross, top bloke

[Morat]

You might want to look into the head mods they do on e30tech for boosted engines. They "O ring" the head by cutting a circular channel round each bore and letting in wire to make a sort of raised ring which clamps down on the gasket just outside the fire ring. I presume the idea is to reduce the movement in the gasket and make it even more gas tight. Whether it is necessary, and if so, at what level of boost I don't know.
It looks fancy, though

[ross2009]

arps and a standard head gasket is just fine

here steve

[steve_k]

Ross, thanks for that dude just what I was looking for

Morat, thanks for then heads up I'll have a dig through the site& see what I can find

[ross_jsy]

How much boost are you planning on running?

[steve_k]

Don't know yet bud, just at the planning stage at the moment, slowly collecting all the parts & reading up as much as I can.

Also, does anybody have a rough idea on cost of welding up the head? Just a ball park/rough estimate?

[ross2009]

if it's a standard block and cr I wouldn't go much more than 1 bar

[ross_jsy]

Drop an m50 in, they love a bit of boost!

[bss325i]

And sell me the Griffin head!

[kam-325i]

Fook Me, who did the welding on that head....Mr Magoo ??????

[steve_k]

And sell me the Griffin head!

Lol, I'll think about it if I ever win the lotto

[b12rlw]

Some pics of my gasket with waterways as standard:



Heres one of the prep:


Welded:




Skimmed:

[Morat]

Just for fun: http://www.e30tech.com/forum/showthread ... 5&t=105557

Please remember, I know shit about building engines so don't take this as a recommendation from anyone vaguely competent. It just looks shiny

[Demlotcrew]

To me that looks like the M20 piston and head chamber is completely wrong for the forced induction! I bet that combination is costing everyone about 20% power!

[steve_k]

Just for fun: http://www.e30tech.com/forum/showthread ... 5&t=105557

Please remember, I know shit about building engines so don't take this as a recommendation from anyone vaguely competent. It just looks shiny

thanks for that morat

i'll have a good read through it later.

[steve_k]

To me that looks like the M20 piston and head chamber is completely wrong for the forced induction! I bet that combination is costing everyone about 20% power!

andrew, what would you recomend as the "ideal" combination??

[Demlotcrew]

You would need different pistons and a slight rework of the head chamber. Theres way too much compression at the inlet valve.

I would guess that proper FI pistons will help elevate the issue, but it wont cure it, the nature of the design is the problem.

Andrew