shimmy shimming the cam towers

[78 280zcar]

Well I was trying to find my old post about this, and trying to find a new head, but I couldnt find it so I am starting a new thread.

OK, today I found this place, very small place that took me a few times passing it to find it, that repairs cracked heads and is a machine shop. Well I took my head in to have it surfaced on both sides and explain to the guy there what had happened when I got the head from ebay, he told me you know what I may have a head that is the same type that is professionaly rebuilt. Well it turned out it was a rebuilt P79 head and looked like it just came from the factory it was perfect. He tells me I will sell you this one for 125.00! After thinking about it for 5 seconds I said hell yeah. He told me it would change compression a little but there is no core charge for it:classic: . He was an old guy who rebuilt it like four years ago and it has been sitting there the whole time. Well I went over it and everything is set to spec. Now what kind of change in compression am I looking at? Thanks

[Arne]

What block and type pistons are you using?

[78 280zcar]

I am using dished shaped pistons and an N42 block. I know I cant afford the flat tops.

[jmortensen]

If you're not boring the block, just using standard pistons, and the head hasn't been shaved, you're looking at 7.38:1. Very low compression. Nowadays that's considered low even for a turbo.

With flat top pistons it would be 8.52.

[Zedrally]

Ah....now I'll never know why that shim was there......another sleepless night.

Bugger....

[78 280zcar]

IS the car going to run good with it on. Or am I looking at low power.

I forgot to mention that it has extra holes on the bottom for cooling is this OK?

[78 280zcar]

What is normal compression for a stock L28.

[Arne]

A normal L-series in a Z runs between 8.5 and 9.0. A P79 needs to have flat top pistons to make normal power. You will be way down on power with compression that low.

[Phred]

I have a set of flat tops on rods, taken out of an 80' F54. Very good cond. They should have new rings and bearings installed before assembling into an engine. If interested, PM me with how many gold bars you can part with.

Phred