Is this head dead

[Hamish]

Does this crack ? Between the middle water ? Passages mean the head is scrap or unfit for competition modification and use. 

Thanks

h

[JRCWeedon]

Hi Hamish

My understanding is that it is OK but the more knowledgeable (like Mick) will no doubt advise

Regards

John

[RogerH]

Hi Hamish,

how precious is the head to you. 

It was probably working before it was removed. It will work if replaced as is.

Will it get worse - probably not as it has stop holes at each end.

I would use it as is for touring etc.

How is it caused - almost certainly stress. That area is quite thin in  new condition. With age related corrosion  etc it get thinner and thengoes pop.

 

Can it be repaired - almost certainly but would cost an arm and a leg and get you no further.

 

Roger

[Motorsport Mickey]

Fit it, run it.

Mick Richards

[Geko]

47 minutes ago, RogerH said:

 

Will it get worse - probably not as it has stop holes at each end.

 

Not too sure, it's very close to the action. I ditched this head a few years ago 

[RogerH]

Hi Stef,

the holes on Hamish's head, where the crack runs into, are quite clean and well defined.

On yours the surface up to and beyond those holes is quite corroded.  Each pit is a stress raisers and will not really want to stop a crack running. In fact it didn;t.

On yours it would have been worth the gamble to run it. On Hamish's  I would think it would last a pretty good time.

 

Roger

[Hamish]

It’s being offered on eBay. I had thoughts of unleaded conversion and raising the compression and a bit of porting/gas flow work 

but perhaps for these “upgrades”  I need a better starting point ???

[BlueTR3A-5EKT]

Problem starts if the crack extends to the stud holes.  My car ran fine with similar crack that did not extend to the stud holes.

 

Peter W

[Z320]

Looks like insects put their grubs in the drills.

[stillp]

Something I've wondered about... if there are stresses in that area that cause cracking, won't welding increase those stresses and therefore the chance of cracking? The head on my spare engine looks to have been brazed in that area, which might be less likely to crack.

Pete

[Waldi]

47 minutes ago, stillp said:

Something I've wondered about... if there are stresses in that area that cause cracking, won't welding increase those stresses and therefore the chance of cracking? The head on my spare engine looks to have been brazed in that area, which might be less likely to crack.

Pete

The stresses have relieved when the crack appeared. Crack-like defects are a concern in many situations, as they tend to continue growing; but in this case, with the nice, large radiussed holes, this much less of a concern. Welding cast iron can be done, but depending on material thickness, cleanliness, shape of internal part etc. And there is the risk of re-occurring cracks, warpage etc.

Mick has first hand experience, and I would follow his advice.

Regards,

Waldi

[Motorsport Mickey]

It's not necessary for that area to be absolutely free from a crack.

As Roger pointed out as long as the crack runs into the holes in the head and the holes are whole (English eh...) without a "frayed edge" the stress dissipates there and that's the end of it. It would be unlikely that if the head was removed from a car during it's first 20 years or so of life that many of them would have a crack there, but 2 generations of drivers have passed by and now this third generation (some who may have contributed to the previous generations driving) are finding less heads available without it.

Unless I was preparing a head for the utmost competition use with up to 36 hours labour being invested into it and then severely used, where sensibly you would use the most sound casting available, then for modest competition and normal road use I'm sure this head and many others like it will do a good job.

Mick Richards

PS: Aaah beaten to the post by Waldi. 

[Waldi]

Mick,

it is an honour for me to beat you. Not many have:)

Cheers,

Waldi

[Motorsport Mickey]

Mick Richards

[qkingston]

Useful advice, my 4A head is similar with more pitting between the 2 tear drop shaped holes(the rest looks fine), interesting that the copper head gasket has an oblong hole rather than 2 seperate coolant holes, guess the crack isn't going to cause any coolant flow issues???