I built my first motor (383) to go into my 67. The motor started, and generally ran strong after the initial break-in. However, I had various issues that have forced me to take the motor back and tear it down.

1) Rear main leak - I snagged the inner lip of the seal on the one-piece rear-main crank surface, leaving a dimple in it that leaked like a sieve.

2) Spring break - I had a beehive spring break and drop an exhaust valve partially into the cylinder. The valve seemed ok, and a replacement spring got it running again.

3) Rich mixture, lots of carbon - I had trouble getting the Holley carb dialed in, so it was running massively rich for a while. I fouled the plugs, and the oil turned black really fast.

So, all things considered, I decided to tear the motor down, replace the rear main, and pull the heads. I pulled the intake and heads today, and what I'm seeing has me a bit concerned. I'd like some advice on what these 'signs' mean and what I can do about it.

1) Intake runners really carboned up. See Pic1

2) Coolant droplets/residue on intake/head gaskets in places I didn't expect. See Pic 2, 3

3) One cylinder (the one where the spring broke) excessively carboned and a little 'oily looking'. It also looks like there is a dimple next to the forward-most valve relief where the exhaust valve it the piston. Note, the valve looks fine (no marks whatsoever). See Pic 4.

So, a little history. I turned the motor upside down on an engine stand to replace the rear-main and pan gasket. Not sure if residual coolant may have sloshed out and around where it shouldn't be and that explains #2 above?

Second, the motor has about 500 miles on it. It's spent a fair amount of time doing pulls on a chassis dyno too (included in the 500 mile figure). I have AFR 195 Street Elliminator heads and an Edelbrock Performer RPM manifold.

Thanks for any advice...

Mitch

 

Quick thought. The heads have the heat riser passage. Is it possible an intake gasket leak could cause the carboning I'm seeing in the intake runner?

Is is possible that just residual coolant in the water jacket/etc. dribbled out/condensed as I was pulling the motor apart?

Finally, I used ARP teflon thread sealer on all the head bolts and on the center bolts of the intake. One picture shows the sealer migrated out of the threads where it all packed up a ways up the bolt. Is that normal? Will these bolts eventually leak coolant?

 

Mitch,

As I was reading I was thinking the coolant was if you rotated the engine on the stand. I'm glad that as I read further that's exactly what you did so that's probably all the coolant issue is. As far as carbon I think it's interesting that it's the cylinder with the damaged spring. I'm not sure how long the car ran with the broken spring but that might explain the carbon if the valve wasn't completely opening and/or closing. I know this is about 6 weeks late so hopefully you've got everything back together with no problems.