How much can I mill a Willys banger?

Do a static timing procedure for TDC, to get it started. Then use a vacuum gauge to set it at max steady vacuum at what ever rpm it wants to run at.

 

That should work. There is a procedure to set it static at 9 BTDC. But there is no idle or anything on this motor, just exactly 1800 rpm. I can start there and advance, using the vacuum gauge. Thanks.

 

Yep, your setting may differ with the increase in squeeze and the difference in the stuff that call gas today will have an effect on where it should be in relation to the conditions it left the factory for and the headwork/fuel diffference.

 

It's been a long time. Here is an update. I had the head cut .040 as noted, and I installed it with a new head gasket from Amazon.

Everything went back together nicely. Interestingly, the genset seems to respond a bit more crisply and it actually runs cooler. Fuel consumption was shy of two gallons per hour before at full load. It is now at 1.3 gallons per hour. Much better.

This was with the timing set where it was. After the shakedown (about 40 hours running) I tried setting the timing by watching the vacuum. I found that significant swings of the distributor (advanced or retarded) did not change the vacuum. Maybe that was because the governor was hooked up. I ended up advancing the timing a tiny bit from where it was but I have not tested it this way at full load.

So far I am happy with the slightly higher compression, an I thank everyone who provided advice.

 

Thanks for updateing. This is very interesting for my '45 cj2a. I've got a brazed head I might have to try this on..

 

Thanks.

Here are some pictures of the work - the shot of the top of the block was taken before I finished cleaning it up. It was as shiny as the head when I was done:





If you look closely you will see tiny holes in the head. They seem to be artifacts from when it was originally cast. I do not know it they were always there, or if they were beneath the surface and came to light as a result of milling the head. I was concerned about them and thought about coating the top of the head gasket with copper spray. I decided against it and installed the head gasket dry. So far, so good.