[torqhead]

Originally Posted by 68grandprix

I took the block, rods/pistons and crank to the machine shop yesterday. The owner(Beaver)measured the crank right there and said the mains had some taper, but were standard. He said it should have been ground(I told the previous builder this, he said it would be fine)and it will now be ground .010".
Beaver thinks the rod damage is most likely from detonation, although he hasn't checked the rods yet. He also said the detonation could have been caused by oil leaking through the valve guides, so I will be taking the heads in today to get checked out. The rings also show signs of washout, like the engine was running too rich, although I checked the plugs after the first day of my trip and they looked perfect.
So, the rods will be checked and resized if necessary, crank turned, mains checked and align bored if necessary, cam bearings checked/replaced, new rod/main bearings, piston rings, bottle brush hone cyls, block cleaned and hot-tanked, valve guides checked, new gasket kit, motor assembled by me(it'll be my first bottom end assembly)and I'm looking at about $1000, and I don't know if it'll run on pump gas. I asked about piston dishing, Beaver says no-go on the Speed-Pros. Jim

I wouldn't claim to be an expert here Jim, but something doesn't sound right. First if it was detonation you would have heard it, without a doubt, unless you were running open headers/exhaust. The whole thing about bad valve guides which allows oil leaking past them causing detonation I've never heard of (could be my ignorance). That problem is going to cause foul plugs and smoking when u first start the engine, but I don't think detonation. I would be leary at this point with the machinist, don't know the guy from "adam" but a number of machinist out there are very good about taking peoples money and that's it.... Best of luck.

[Lightfoot]

Originally Posted by torqhead

I wouldn't claim to be an expert here Jim, but something doesn't sound right. First if it was detonation you would have heard it, without a doubt, unless you were running open headers/exhaust. The whole thing about bad valve guides which allows oil leaking past them causing detonation I've never heard of (could be my ignorance). That problem is going to cause foul plugs and smoking when u first start the engine, but I don't think detonation. I would be leary at this point with the machinist, don't know the guy from "adam" but a number of machinist out there are very good about taking peoples money and that's it.... Best of luck.

I'm not an expert either, but here are my thoughts of what Beaver said about the valve guides (possibly) leaking & causing detonation:
I think that he is theorizing that the unwanted oil being burned would eventually cause carbon in the CC which would result in 'hot spots'. Then you have pre-ignition.
My own experience with worn valve guides is that it usually only causes smelly exhaust in a closed throttle @ road speed senario.

I had a '66 Chevy with 283 that detonated terribly, but I sold the car without ever finding out the cause. It ran beautifully up until the last couple months that I had it. Under 70K original miles. And I was feeding it leaded gasoline (1979).