Thread: Cracked Cylinder Head

Cracked heads on these engines are quite unusual - most likely associated with skimming an early type 7:1 head, but possibly either a manufacturing fault, or it has been badly overheated at some stage. (I have never seen one cracked, or heard of anyone else who has first hand experience of it before now.)

There should be someone on here who will be able to supply another head - try "wanted" in Markets.

John

Originally Posted by JDNSW

Cracked heads on these engines are quite unusual - most likely associated with skimming an early type 7:1 head, but possibly either a manufacturing fault, or it has been badly overheated at some stage. (I have never seen one cracked, or heard of anyone else who has first hand experience of it before now.)

There should be someone on here who will be able to supply another head - try "wanted" in Markets.

John

Thanks John,

Im going thru some quotes for cast repairs now, at $130/hr either solution wont be cheap

I would not bother even trying to repair it - there must be a lot of engines around gathering dust, and even if the engine is worn, the head is almost certainly uncracked - at worst you would be looking at new valve guides and possibly seats, assuming your head has good valves and gear.

John

Chemiweld

That is a weird crack. Almost as if those middle 2 bolts were overtorqued and the others left loose so the head could flex in the middle.

I have seen a couple of cracked 2.25 heads (one 7:1 and one 8:1 S3 head). If memory serves they were both cracked between the valves though. The latter 8:1 head I bought and then later found out it had been repaired some time ago. The engine machinist I was using at the time was happy with the repair and had no problems with using it.

Thanks for your input guys, I have got 2 quotes for a repair job, both being $250 plus!!

looks like i will be sourcing another head at that cost!

loose bolts on one side of the engine, Seen that before but usually only after the donks been then overheated and abused while hot or hydrauliced.

It can be gouged, welded and ground back, but its a little costly to do as youve found. If it passes a pressure test you can chemically bond it and you wont have a problem with it, the trick is getting somewhere to do that. If it can be made to leak coolant through the crack then you have more options. But if its leaking coolant through the crack I'd suggest you're better off replacing the head.

Check the deck and the piston heights just in case its been cooked and warped the block or its been hydrauliced.

Cracked heads aren't common in these motors but they do happen. The first Landy I could have had turned out to be beyond my means because of a small crack like that one radiating off a cooling gallery. I also understand that they can sometimes crack across the valve seats too.

I wish I had a photo I could share of the worst crack I've ever seen in one of these motors, I still have this motor in my wrecking yard though. Both the block and the head are cracked between cylinders 1 and 2. The cracks are probably more then half an inch deep in both and as wide as a fingernail is thick! Obviously scrap but I've kept it for spares (eg. valves, studs, etc).