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My machine shop guy that I used for years got killed in an accident. A new guy is running the shop. I took a straight 8 head there and he said he would have to reconfigure his head surfacing machine to do it. He said he was going to try it on a big table top belt sander. Its the same one he uses to surface exhaust manifolds. I'm not sure I want to experiment with an 80 year old head. Last time I checked the Packard plant stopped making them. Has anyone done this.

I would not experiment with a belt sander resurface. I don't think that it will hold the tolerance needed. You want to remove the least amount of material possible.
You don't want remove any more material then is needed. the head is 70+ and no way to know how many times it's been shaved.

I would look for a shop that does diesel engine work as the head size is pretty normal size to them.

John

I could not agree more. A belt sander is not a precision cutting tool. If that is there modis operindi going forward find another shop. A diesel shop is a good option. However a question as to why you need to plane it in the first place ? Who says it needs to be planed ? Did you have a blown head gasket? more than once? A proper cooper clad head gasket can take up a lot of deviation across the entire surface of a typical straight 8 cly head. Unless absolutely necessary I would forgo surfacing any head or block that was not out by more than a good gasket could account for. A properly set up dial caliber will tell you what the deviation is and then make an informed decision from there.

originally i had the head off and noticed the gasket looked like it was about to blow in a certain location. I had an issue with the engine 6 months later. The engine had a miss. I removed the head and the new head gasket was blown in the same location. The block and head had been cleaned carefully before the last gasket was installed. Copper spray was also used It was also torqued 3 times before driving. and retorqued several times after driving over the next couple months. I spoke to the guy at the machine shop today and he said he would reconfigure his machine to surface the head. And he would not use the belt sander thanks for the replys

I would spray some light black paint on the head sort of a tell tail like a body shop does to show high and low spots. Then take a new clean mill bastard
( file) and take a couple passes at the head. It will show the low spots or even high spots and then you will know for sure where they are. You could also do that on the block but you will have to remove the studs first but in my opinion would be worth it to know for sure exactly where the problem is. Good luck.

I have a perfectly straight bar from a machine shop with the top of the block cleaned the worst spot is about .001 out The machine shop called and the head is another story. He said he had to take off .032. He said that was the minimum amount. So before I install it im going to try to make some measurements of the valve lift height. Any other ideas. Im a little worried about that much being removed.

The most basic and simple test for valve clearances to the head; just drop the head over the studs onto the block (NO FASTERNERS) without the gasket and crank the engine over slowly, by hand preferred. If the head wobbles or moves in the least, you have negative clearance (i.e. at least one valve is hitting the top of the combustion chamber). Time to go shopping for a new head.

I'd think very hard about that much coming off particularly if you cannot be sure the head was never machined before.

If you do decide to try it by all means do not bolt the head down before testing. Use something like a layer of thin modeling clay on the head above the valves. Lay the head back on the block without any nuts or the gasket and turn the engine thru a complete valve cycle looking for any evidence the head is raising. If you don't see anything then pull the head off and check the clay for signs any of the valves raised high enough to leave an impression. Go from there if there are impressions to decide whether it is minimal and a slight clearance grind of the combustion chamber above the imprint is enough of if the head will need to be scrapped.

If you are lucky that much off will be tolerable but also keep in mind that if the car has hydraulic lifters, those were probably low so in use could raise the valves slightly higher.

Thanks for the replies

My experience is to take as little as possible, these heads can bow but only slightly often less than .020. I would recommend taking it to a automotive head specialist with the latest machinery. If you know anybody who races drag cars and regularly gets heads worked over the workshops those people use have state of the art machinery. You are not looking to increase compression by a lot if at all. The compression on the early eights is only 4.8 to 1 and cranking pressure is only 72 psi at sea level, the higher the altitude that will drop. The last head I had done took off .017 on a robotic machine. You are not looking at increased performance just to tidy things up if or as required. These engines are not designed to give high performance mainly due to the surface area of the compression chamber. I would be a little conservative. If you are replacing a gasket I would stick it down with a sealant like Permatex Aviation Gasket Sealer which you paint on, or a product called Hymolar which comes in a spray can. Also give both the block and head a good clean up plus clean up around the valves. Give the head a good clean by getting the machine shop to flush it out. Any scale inside the head can hit the gasket and damage it. Once the head is on you will need to torque it down. No more than 50 foot pounds, go to 40 foot pounds and run the engine to temperature and let it cool then go to 45 foot pounds and run it again to temperature and let it cool overnight. Come back and go to 50 foot pounds and leave it there. After a long run you may get a couple of pounds as the gasket bedded in and sealed. Leave the torque wrench at 50 foot pound and the nut may go down quarter turn at maximum. I would use a good quality calibrated torque wrench ideally deflective beam they tend to be the most accurate.