Brand New Heads, Doing Valve Swap

[Demersus]

Hi all,

I'm in the middle of an engine overhaul and realized after it was all done that one of the heads has a crack. Thankfully I hadn't run it yet. The rebuild had actually been done by someone else, I'm in the middle of finally finishing the install on this very stale project. Everything else seems fine, more or less.

So, I found a great deal on eBay for a set of NOS MAHLE 2.9L bare heads. My original valves were ground lightly, so I'm planning to just swap those and the springs over to the new heads. I wasn't sure about valve guides until I just pulled out one valve on an old head. The old heads and the new heads don't actually have any valve guides. It's just a direct bore. That's all fine I guess, since they are cast iron. But I have seen valve guides listed for parts for the Ford 2.9L (rockauto.com, for example). And that's just a bit confusing. Before I get to work on these heads I want to be absolutely sure I'm not missing something. Do you just use guides if the bores get worn, and then get matching valves for proper clearances?

Also, I don't think the valve grind took off enough to really change the mating of the valve to the seat but I could use any advice about that. Should I use some seating compound or anything?

Thanks,

demersus

 

[enjr44]

If I had gone to all the work of overhauling this engine, I would gather up the valves and the new heads and have a local machine shop check it out for you. Won't cost a lot for the peace of mind you will get from knowing you will have it "right".

And, IIRC, most Fords did not use valve guides originally in iron heads. There are guides available for installation when rebuilding heads and there are, also, over sized valve stems available so the heads could be reamed for repair of worn guides or, I guess you could call them valve stem "holes".

 

[Mike Tonon]

https://www.youtube.com/watch?v=O_1ruZWJigo