Cylinder Head Questions

[TNBrett]

So as I’ve mentioned a couple of times, I’m going to be doing head gaskets and studs before too long. I typically don’t like to have things torn apart any longer than I need to, and I was thinking about having the heads from my trucks original N/A motor reworked before I tear it down. The engine now is a ‘93 factory turbo with unknown but presumably higher mileage.

Are there any differences between the N/A and IDIT heads?

On the N/A heads, there’s an exhaust valve or two on each with some play, so I’m assuming they will need guides. I think it’s safe to assume that the IDIT heads will probably need them too.
As a positive for the N/A heads, the precombustion chambers look to have very minor cracking, at least compared to some pictures I’ve seen. On the other hand though, it looks to me like both of the N/A heads had been off and had some work done to them. One head looks to have had new valves installed, and it looks like someone went wild with a center punch staking the precombustion chambers in place. It doesn’t however look like they were machined at all. The other head looks to have the original valves still in it, but there are obvious marks on the chambers from machining.
What do you guys think?

Also, does anyone have a recommendation for a machine shop familiar with these heads. In the Nashville area would be great, but I’m not afraid to stick them on a pallet and ship them.

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[IDIBRONCO]

I'm not sure, but I don't think those are machining marks. Machining marks are usually consistent, but those look like they were made in random directions. Some look to be deeper while others barely show. Look right around the valve in your last picture. Those marks appear to be about the deepest ones to me. If you decide to use the N/A heads, don't just replace one or two guides, do them all. That really goes for any 7.3 head. If you do one, do them all.

 

[aggiediesel01]

In the "Coffee Table Book" for the turbo engine, the exhaust valve is the only item that is listed as actually being a different part in the cylinder head vs the NA engine. I've always heard that something in the guides were different too but I've never seen it verified. Those valves are NLA but there are stellite valves available that are just as good.

You must be registered for see images attach

 

[IDIBRONCO]

I've always heard that something in the guides were different too but I've never seen it verified.

Here's my input on that. When I messed up a head on my 7.3 by grinding a hole through an exhaust port, the head that I got to replace it was a Turbo head. The (extremely poor) machinist that I took them to said that one head sure did have some hard valve guides. It took more effort to work through it to install the bronze liners. I can't confirm that. It's just what he told me.

 

[TNBrett]

So, are the staked in chambers anything to be concerned about?
If I expect to need valve guides in either set, and that means new stellite valves, then there’s no reason not to go with the NA heads right?

This week was pretty busy at work, but unless someone convinces me otherwise, I’m planning on taking these heads to the machine shop next week. I’ve been asking around locally, and I’ve only been able to dig up one recommendation, so I guess I’ll give them a try.

 

[IDIBRONCO]

So, are the staked in chambers anything to be concerned about?

Not really. Sometimes they just don't want to stay put in the head. At the shop I used to work at, we would have this happen occasionally. We would use the letter "X" from a set of number and letter stamps. This is similar to "pinging" the oil galley plugs behind the cam gear in order to reuse them. The intention is to SLIGHTLY deform the metal of both the head and the precup just enough to hold the precup in place. When the head is on and bolted down to specs, I don't think that a precup could go anywhere, but you sure don't want one falling out while you're trying to put a head in place. I do believe that this was excessive. It wasn't even close to being a good job placing the (off) center punch. If you're going to use the heads like they are, then I would gently run a flat file over the marks to clean up any ridges around the punch marks. If the machine shop is going to do any type of surfacing on the heads, then you won't have to worry about possible ridges.