TR4 cylinder head reliability

[foster461]

One of my fellow NET club members is rebuilding his TR4 engine. He took all the parts to the machine shop for the usual testing and machime work and his cylinder head was found to be cracked. He had a spare head, that was cracked too, different location. He sourced head number three via the triumphs list and that also is cracked, different location. Is he just unlucky or do these TR4 heads have a reputation ?

 

Stan

[vivdownunder]

Stan, it's not that the 4 potter heads were any worse than others of that era, but it's more a function of failure to see that the water pump has let go, or similar, and the temp guage has gone off the dial. It's mostly when they have been run at boiling that it happens, particularly if someone doesn't know the consequences, and pours in cold water without having the hot engine ticking over.

 

I have had TR heads with as many as 8 x cracks repaired successfully using a metal stitching process.

 

See if you have people in the States by the name of "Metalock", (Google ?) as they are who I use here.

 

Regards,

 

Viv.

[marvmul]

Some years ago I had 2 cracked heads on my TR3 race car : the first one was caused by corrosion of a thin wall : it was during a race en because the crack was between a coolant way and an exhaust port, a huge steam cloud escaped. The second 'crack' was actually a casting fault : it was a new head, it should have been pressure tested by the manufacturer but it wasn't, and the crack was only apparent when starting the engine. I bought it through TR Enterprises : they sended me a new replacement without any cost.

[TR 2100]

The very centre of the head is a major weakness but it's only the water

jacket so you can usually get away with a crack there.

 

Obviously not belt and braces like welding but worth trying out before the

expensive options are tried.

 

Carry some water and if the gasket does blow again, at least you'll get home.

 

AlanR

[ianc]

There seems to be a weakness between the inlet and exhaust ports on TR4A heads in particular, as a crack can appear between the ports. Sometimes the situation can be remedied by the use of valve seat inserts. This problem may also occur in the TR4 head.

Ian Cornish

[foster461]

Thanks for all the info. After three duff heads he is going to get a fully assembled unit from TRF. Hopefully they mag them before they rebuild them.

 

Stan