[jtraynor86]

I have a n 83 Trans Am that I have been working on for a while now. have swapped the turdly 305 for a 454. I had the thing running great for while before I pulled it out to make a few changes. I went to replace the oil pan and was doing an inspection of my crank assembly when I found something that I did not like. I had found a small portion of the rear main cap to be chipped and worn off which exposes the oil pump shaft. A buddy of mine told me that I needed to replace the rear main cap and send the block off to the machine shop for a line hone job. I purchased a set of used caps online and got them in the mail today. I pulled the caps out of the box and low and behold, the cap I was chipped in the exact same place. Has anyone heard of this before? It seems to coincidental for two caps to be messed up in the same spot for this not to be a semi-common problem. Then to make matters worse, today I pulled my valve covers off and spotted something else. I have the 781 heads and , on both sides in the corner oil passages, the outsides are what appear to be chipped out. I am wondering of the guy I bought the motor from did this for a particular reason or what. I am not sure what to do now. Do I run the motor the way it is or am I going to have to buy some new heads? Man, this week has been rough. Any advice is greatly appreciated!!! I attached the best pics I had.

[lmsport]

Both areas look to be normal casting issues. If worried, load it up and take it to a machine shop. I recall grinding a BBC main cap around the driveshaft and dont think it is a problem.

[ericnova72]

You're all worried over nothing, and you don't need to put new caps on the block, there is nothing wrong with the cap you have. The area you are worried about chipping in the cap is a non-load and non-locating area, the chipping is just the consequence of drilling a hole through the edge of a casting and in all likelyhood happened when it was machined at the factory, 90% of the caps you check will be the same way, and was that way right from the factory. As a matter of fact, a race engine builder would take a Dremel to that chipped area and carve it smooth slightly into the thicker section of the cap material around the hole, making the hole bigger but removing any thin metal that may be subject to coming loose in the future, just to be safe.

Same deal with the oil drain hole in the head, it came cast that way and who knows when the edge of the hole chipped, but any engine builder would get in there with a Dremel or die grinder and cut that casting flash back to more solid metal just to prevent any chance a another small piece of this thin left over casting material from coming loose and damaging another engine part., like the oil pump or worse.

[JoeMo]

I've been spending alot of time with my 86 454 and your picture labeled 454 4.jpg looks just like the oil return passage just in front of the #1 cylinder on my engine. I didn't think it was ok but seeing yours makes me feel better. I'm thinking it's just lazy GM not cleaning up casting waste. Good luck!

[SDLuck]

I have seen this many times it is normal.

[ericnova72]

You young guys are maybe spoiled by the casting quality of modern vehicle parts. what you are showing is par for the course in the old days, the factory rarely ever cleaned up castings. Areas were either as-cast or machined, no hand blending or deburring of any cast surfaces.

[jtraynor86]

Wow, that makes me feel better, I will grind the flashing down and lay that one to rest. I am pretty particular about my stuff so maybe I just worried too much. Thanks Guys. Saved me a lot of time and $$$$$$$.

[muddi1]

Originally Posted by jtraynor86

I have a n 83 Trans Am that I have been working on for a while now. have swapped the turdly 305 for a 454. I had the thing running great for while before I pulled it out to make a few changes. I went to replace the oil pan and was doing an inspection of my crank assembly when I found something that I did not like. I had found a small portion of the rear main cap to be chipped and worn off which exposes the oil pump shaft. A buddy of mine told me that I needed to replace the rear main cap and send the block off to the machine shop for a line hone job. I purchased a set of used caps online and got them in the mail today. I pulled the caps out of the box and low and behold, the cap I was chipped in the exact same place. Has anyone heard of this before? It seems to coincidental for two caps to be messed up in the same spot for this not to be a semi-common problem. Then to make matters worse, today I pulled my valve covers off and spotted something else. I have the 781 heads and , on both sides in the corner oil passages, the outsides are what appear to be chipped out. I am wondering of the guy I bought the motor from did this for a particular reason or what. I am not sure what to do now. Do I run the motor the way it is or am I going to have to buy some new heads? Man, this week has been rough. Any advice is greatly appreciated!!! I attached the best pics I had.

I took a small grinding wheel to mine to clean everything up and smooth everything out. I figured that cleaning the flash wasn't going to be much work but it may add a little bit of open volume area for oil and water to pass through, even if just a little.
I cleaned up the flash inside the water ports in my heads while I had them off during my rebuild. I looked for some pics but cant find any of the flash I removed, It only took a few minutes while I was rebuilding the heads.

[Guy Hiltz]

The oil drain back slots in the lifter valley also probably have casting flash around the edges.You may as well clean that up while you have your Dremel tool out,heres a picture of mine;

I polished the valley at the time,some people pain it with Glyptol or Rustoleum.its thought that either way will help with oil drainback.
Guy

[cobalt327]

You don't need to do anything- all the "issues" are non-issues, as has been said. Unless you disassemble the engine, leave the deburring until next time- you do not want to attempt to grind metal on an assembled engine.

[muddi1]

I did all mine while dis aasembled, I would never suggest doing anything while assembled. I deburred everything including the leading edges of the crank to help with windage. I figured "since I was there"

I wouldnt have done any of it had I not rebuilt.

[jtraynor86]

On that note, I'll button everything up and drop her back in. I have plans to run her out to a 496 in the future so I'll take care of the flashing then. I was also planning on smoothing out the flashing on the outside of the block too. That should be some project!

[muddi1]

I did my block and heads, I tink i'm going to do the water pump too, I used 1200deg primer (2 coats sanded between each coat and 2 coats of 900deg engine enamel) heres a look..I also redid the timing cover,pan, and valve covers after bead blasting them..

[muddi1]

I also redid the valve covers, timing cover and pan with 1200deg black, the block itself took about 4 hrs in 1 hrs sessions, I have an injury so it could be done in shorter time.

[ericnova72]

Originally Posted by muddi1

I did my block and heads, I tink i'm going to do the water pump too, I used 1200deg primer (2 coats sanded between each coat and 2 coats of 900deg engine enamel) heres a look..I also redid the timing cover,pan, and valve covers after bead blasting them..

You've got machined surfaces painted that shouldn't be, namely the thrust surface the timing gear runs against and core plug bores. I would never have painted the timing chain area either.