[68grandprix]

The bearings are Clevite. Jim

[wheelspin]

Jim,

What's the machinist say?

By the way, the SCCPOCI monthly mtg. is tonight @ 7:30 in Brea, and the SCGG (Southern Cal. gathering of Goats) club mtg. is next Weds. night @ 7:30. You could come to my house and we could drive down to Brea/Paramount together for the dinner mtgs. and you could meet some of the SoCal Pontiac folks. PM me for my phone #, if you are interested in attending one or both of these mtgs..

Les

[vidguy]

Curious:
What did you torque the Rods to? These have the 7/16 8740 wave-loc bolts correct? I have those rods.

[Ken K]

The rods I used did not have wave lock bolts. I can't rember what I torqued them to but I think it was around 63 ft lbs. I used a 10/10 crank. I could not feel much tension turning it over until I had the 5th piston in it. It turned over easy with just 4 pistons in it. I used Clevite bearings.

[webfoot]

I think the factory torque spec for those bolts is 43 ft lbs.

[68grandprix]

The torque for the PPR rods is 75ft/lbs. It says that on the order sheet. Jim

[Ken K]

I know I didn't torque mine to 75 ft lbs. 63 ft lbs is stuck in my mind. 7/16 inch rod bolts is basicly what a performance BB Chevy uses.

[Half-Inch Stud]

Been quiet. Could this problem be STD bearings uses on a Crank with -10 on the Rods?

[Ken K]

Originally Posted by Half-Inch Stud

Been quiet. Could this problem be STD bearings uses on a Crank with -10 on the Rods?

If he removes the bearing halfs the number will be on the backside.

[67bonnie455]

Did you put solid lifters in the motor?

[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

[68grandprix]

The lifters are Rhoad's. Jim

[Ken K]

If the problem might be detonation, why don't you go to the next bigger size chamber on the heads. You can just as easy get a set of bigger chamber heads rebuilt before you assemble the engine.

[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.

[Mr_GTO]

Have it rebuilt by a PONTIAC GUY. Take it as a lesson learned.

[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).

[Big Injun]

Originally Posted by Mr_GTO

Have it rebuilt by a PONTIAC GUY. Take it as a lesson learned.

You have a great local resource in Ken Brewer at Pacific Performance Racing at 310-832-4596.

As for your pistons, you can mill a grove the depth of the valve reliefs. I have done that on another 400 and it works great.

[Bruce Meyer]

Excessive oil consumption WILL cause detonation. If those are forged Speed-Pros they CAN be dished. HO racing used to dish them and sell them right out of their catalog. Get a new machinist!

[67bonnie455]

I am not convinced detonation took out the bearings. It certainly would not be from leaking valve guides. Think of how many motors are running with worn out valve guides and no bearing failure. If the mains show scoring I would still be thinking oil pressure. If the mains are perfect, then I would be thinking rods too tight or maybe detonation.

The kind of detonation that can hurt bearings comes from NOx not set up correctly. We sold hundreds of 231v6 motors and they didn't run correcly unless they spark rattled loudly like you were going to break a piston. No bearing damage. I think the kind of compression damage to bearings would have shown other problems like hard to crank or locking up, severe spark nock, etc.. That my experience so I am just not convinced it was detonation.

I asked about the lifters thinking of a problem with the oil pressure to the bearings. (like solids without restricters). Does anyone know if you can put in the wrong cam bearing?

The other thing I thought of is a plugged oil filter. After breaking in a coated cam, you need to change the oil filter or it becomes restricted. The last thing is an exploded oil filter. I have seen this take out a motor. With the oil filter bypass plugged off, if the oil filter is not flowing properly, oil pressure to bearings suffers. The gauge showing pump pressure before the filter.

A few thoughts.