'75 99 Rally Car Restoration

[SwedeSport]

Have you played with the car enough to determine the extent of the damage from BRS?

[Luke]

Have you played with the car enough to determine the extent of the damage from BRS?

Blown head gasket, slightly warped head.

[SwedeSport]

You and I need to get together so you can look thru the box of gaskets I have.

Can the warpage be milled out?

[rsp57]

Luke, remember to get the head hardness tested before machining. ( they go soft) you can use soft heads but the life before another gasket failure is somewhat short unless you re-tension periodically. But i'm sure your all over this!

[Crazyswede]

Luke, remember to get the head hardness tested before machining. ( they go soft) you can use soft heads but the life before another gasket failure is somewhat short unless you re-tension periodically. But i'm sure your all over this!

I think we determined the head has already had .060 in milled off of it and we were trying to determine how much further it could go. I know there is a min spec but do not remember what that # is or the exact place to measure it.

[Geoff]

As I remember there is a half circle cut into the bottom of the head at the edge, about 1" diameter. I think the circle is cut to the max recommended depth for surfacing. If you see no circle then you shouldn't go deeper. I also think the spec is in the factory manual.

I wonder what SAAB used to determine max resurfacing depth: Head integrity (prone to future warping), cam going out of timing, increase in compression ratio, or something else (?)

[Crazyswede]

As I remember there is a half circle cut into the bottom of the head at the edge, about 1" diameter. I think the circle is cut to the max recommended depth for surfacing. If you see no circle then you shouldn't go deeper. I also think the spec is in the factory manual.

I wonder what SAAB used to determine max resurfacing depth: Head integrity (prone to future warping), cam going out of timing, increase in compression ratio, or something else (?)

Ahh...in that case Luke mentioned there was no sign of that circle anymore. Maybe we should use this head as a test..do a few mill passes at a given removal rate until something bad is exposed...this would give an idea on the thickness of the head and distance to cooling passages etc.

[SwedeSport]

On the first motor build in my 86 8v car, I used a bottom end from an 87 900s. I took an 8v H head, and had it shaved down by .075. I was talking to the guys at Lititz Auto at the time. They had an 8v head shaved .090 and stuck on top of a 2.1 block. I figured I would go a little less in an effort to be conservative.

It ran well, and I never had a problem with the head. When the motor failed it was due to worn connecting rod bearings. It could probably have been rebuilt, but I opted to use the 2.1 block for the new powerplant.