Welding cylinder heads..

[adam73bgt]

Bit of a should I/shouldn't I this one..

I've been considering getting a better head on my MGB recently as I don't know if the one I have is unleaded converted plus the head is one of the main areas for gaining power on a B series.

So while browsing ebay for various bits and bobs, I happened to come across what claims to be a stage 3 big valve ported head for an MGB, only problem is that it has been skimmed and broken a small hole into one of the waterways

Now I'm a bit of a novice when it comes to heads so basically I'm wondering whether this is a potential bargain that I could get welded up and re skimmed cheaply or whether I'd just be better off getting a new head done/ my cylinder head worked on?

Would a stage 3 head even be any use on my otherwise stock (as far as I know) B series engine? I do have other mods planned for the future however as time/funds allow

Thanks in advance and apologies for the continued emphasis on cheapness, I'm a typical student

The item in question: www.ebay.co.uk/itm/331082634615?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648

[MrSpeedy]

To have that welded properly (ie, pre-heated in an oven, welded with cast iron rods, cooled in oven etc etc) would be expensive.
Probably around £200-300.

You might find someone who would just attack it with a universal cast iron rod with an arc welder, but tbh, I wouldn't want to trust that on a head. Especially one that's being worked on.

You also have to consider that if it's gone through in one place, then it may not be far away from going somewhere else

[adam73bgt]

Mm I was thinking it might be a too good to be true scenario, I need the engine to be reliable so I guess I'll save up the pennies and get a good one done I reckon

[ferrousbuler]

I wouldn't worry too much about that hole that has appeared in the head face, its between two small waterways. the gasket should be able to contain the water, but you could poke a bit of jb weld or the like into the hole if your worried about it.

ive run a series heads that have gone through like this before when they have skimmed and never had any problems with them, your clamping a solid cast iron head up to a solid cast iron block after all.

its cheap enough to at least try after all

[v8ian]

Dec 13, 2013 14:36:41 GMT ferrousbuler said:

I wouldn't worry too much about that hole that has appeared in the head face, its between two small waterways. the gasket should be able to contain the water, but you could poke a bit of jb weld or the like into the hole if your worried about it.

ive run a series heads that have gone through like this before when they have skimmed and never had any problems with them, your clamping a solid cast iron head up to a solid cast iron block after all.

its cheap enough to at least try after all

I'm of the same opinion, that is a manifold mating surface, and as such, should not be detrimental to its function. its caused by corrosion, for peace of mind I would be tempted to open the damage up with a Dremel, get it nice and clean, get a bevel on both sides and fill the corrosion with a plastic metal, Gently file it smooth and leave as is, the only other thing I would be tempted to do would be run the engine with a bottle of K-Sill in it.

[Clamity]

Dec 13, 2013 13:16:00 GMT MrSpeedy said:

To have that welded properly (ie, pre-heated in an oven, welded with cast iron rods, cooled in oven etc etc) would be expensive.
Probably around £200-300.

I had that done and paid something like that a couple of years ago. Results in this thread. That repair is still good though I've only done few thousand miles since the rebuild.

[composimmonite]

I can't comment on the actual head but a "stage 3" big valve won't be much use by itself. You need to sort out other aspects of the engine to get the benefit of the head. With that in mind carbs, exhaust, ignition, camshaft etc will all need attention as well. Without the other improvements you might actually find the engine is worse than at present by just fitting such a head !

Paul H

[Nozza]

For cast iron press tools we used to grind out damage, heat up with a gas axe till it started to smoke out the impurities (mostly oil) and the secret is to gently peen the weld as it cools to avoid the parent metal cracking.

Mostly the 2 things that can go wrong is porosity, caused by bad prep. And cracking caused by the weld contracting as it cools.

I would either leave it or use some chemical metal and see how it goes. If you weld it you will need to get it skimmed again as iron can grow once its been heated believe it or not.

[adam73bgt]

Hmm some interesting thoughts here, may see how cheap it stays..

Dec 13, 2013 17:59:10 GMT composimmonite said:

I can't comment on the actual head but a "stage 3" big valve won't be much use by itself. You need to sort out other aspects of the engine to get the benefit of the head. With that in mind carbs, exhaust, ignition, camshaft etc will all need attention as well. Without the other improvements you might actually find the engine is worse than at present by just fitting such a head !

Paul H

This was my concern, I was only looking for a mildly upgraded head from standard really as this seems to be the first port of call for B series mods. The fact its cheap may not outweigh the fact that its a bit overkill much like the cheap race cam I saw on ebay some time ago....

[ChasR]

I beg to differ .

On an A and B series the head will yield the biggest gains over over modifications in terms of 'bolt-on' modifications if the engine is otherwise sound. Saying that I would want to compliment the head with a set of richer needles, K&N filters (a DCOE may be overkill, but at least it should stay in tune (but good SUs tend to stay in tune to be fair). an LCB manifold in addition to ideally a rolling road tune (the latter you could experiment with yourself, but most have seem bigger gains after a session on the RR). The other bits I would say you have covered (Electronic ignition, sound running car etc.)..

I'd also be willing to go with Paul on this on one (he builds engines for a living IIRC) .