Scored cylinder wall
 

Hello,

I was in the process of replacing my cylinder head and gasket and noticed some scoring in a few places on the first cylinder wall. They feel pretty deep and you can catch your nail on them. The engine was supposedly recently rebuilt before I got the car; it's a diamond B block and has a counterbalanced crank. How should I proceed with this before I go any further and whats the cause? Thanks for help, I've included pics..

http://i191.photobucket.com/albums/z...scd681599.jpeg

http://i191.photobucket.com/albums/z...psaa69d246.jpg

http://i191.photobucket.com/albums/z...ps12588511.jpg

http://i191.photobucket.com/albums/z...psee4867b0.jpg

Re: Scored cylinder wall
 

Almost looks like the wrist pin came loose.

Bob

Re: Scored cylinder wall
 

That type of scratch usually means the wrist pin is moving out against the cylinder wall. I would remove that piston for inspection. I suspect the pin keepers are missing. This should be looked at before doing anything else as it could be disastrous. A proper fix would require either sleeving that cylinder or a complete re-bore, as without that you will have a lot of blow-by and some loss of compression in that cylinder. From the photos, I am not sure the weights are welded to the crank adequately, take a good look at that while you are at it.

Re: Scored cylinder wall
 

In addition to the deep vertical scores in the cylinder wall, which indeed look like they were caused by a loose wrist-pin, it looks like there's rust-pitting towards the upper part of the bore, and maybe a ridge ?

This engine might have been "overhauled", but how many miles / years ago ? Did they re-bore ?

Did it sit for a long time w/o being run ?

Re: Scored cylinder wall
 

I have had similiar damage and when the head was removed we found no clipring that holds the wrist pin was missing on the one end, when pan was removed the remains of the clipring was yet to be found it must have went out thru the muffler, we resleeved the cylinder wall and back on the road again,
Gord. B by the Bay

Re: Scored cylinder wall
 

The block doesn't appear to have been cleaned (hot tanked).
I was also wondering how the weights are held in place?
And, what's that strange cresent clean mark on #4 piston top? Has it been hitting the head?

I'd do a complete teardown and either sleeve or rebore and install new pistons and rings, after a complete block clean.

Re: Scored cylinder wall
 

Some Model A rods have the center lock ring to hold the wrist pins in place.

Re: Scored cylinder wall
 

I have seen this before on an engine I had, and it was the wrist pin. it was worn too deep to be cleaned up. Had to sleeve the cylinders. Don't run it get it fixed!

Re: Scored cylinder wall
 

Thank you for all the replies. I was afraid it would require re-boring/sleeving. I got the car a couple of years ago in Hershey at the RM Auction. It was being consigned for sale from Canada and was part of the Fawcett Movie car collection. Unfortunately, I don't know any history on it. It's like they did some things on it right, and skimped on others. Like someone posted, more of an "overhaul".. Nonetheless, it ran strong so at this point I'm going to pull it and get it fixed correctly. Thanks again...

Re: Scored cylinder wall
 

Like the rest I do not think the weights are on good enough. The wrist pin can force the keeper out if you have a bent rod or one with a twist in it. They should always be checked on a rod checking fixture before being used.

Re: Scored cylinder wall
 

Generally with movie cars looks is a lot more important then running condition

Re: Scored cylinder wall
 

road king, Your in there now, so why not pull that piston out and have a look at that wrist pin keeper, like they say. I think so too. some light honing on the cylinder and clean up and see whats going on with that pin. The wall damage you may get by with honing, it's not on a thrust side of the piston. a slight grove just holds more oil.

Re: Scored cylinder wall
 

I think those vertical groves will leak compression like crazy and suck oil up to the top and burn it. I once for a friend who was strapped with bills fixed some groves I think were deeper than this by cleaning them with acetone and then filling them with JB weld using a welding rod to smooth with. After it dried I honed them smooth. This was a 74 Ford pickup he drove 4 more years and traded it off but it still seamed alright.

Re: Scored cylinder wall
 

I had the same thing on my engine. Unfortunately by the time I found it there was a gouge in the cylinder wall and I had to sleeve the cylinder. In my case the piston pin retaining clip came loose, I found pieces of it in the oil pan. The piston was really chewed up.

Bob


http://www.modelahouse.com/images/piston04.jpg

http://www.modelahouse.com/images/cylinder01.jpg

Re: Scored cylinder wall
 

Nowadays I would fix it with a sleeve. 25-30 years ago, I found the same problem on two cylinders when I had the oil pan down for bearing adjustment. I found two clips in the oil pan and had two nice grooves in #2 and #4. At that time in my life I had small kids and a big mortgage so I honed the cylinders, replaced the rings (and wrist pin clips!!) and drove the thing another 6,500 miles before I replaced the engine. It never smoked and did not use a lot of oil. It still made it down the road at 50-55 mph.

Re: Scored cylinder wall
 

Yes, I'm finding that out. Here's some more pics of the added crank weights folks asked about. They aren't welded, the original has been drilled and tapped for the weights. Is this normal? Thanks

http://i191.photobucket.com/albums/z...psf86bf3a3.jpg

http://i191.photobucket.com/albums/z...ps44fdb905.jpg

http://i191.photobucket.com/albums/z...psfa18f960.jpg

Re: Scored cylinder wall
 

I have done them like that before but I always weld the bolt holes in so the bolts are locked and also weld the ends for further safety.

Re: Scored cylinder wall
 

OK, makes sense I can take care of that once I get this re-sleeved or bored. Also need to find out why wrist pin came loose. My problem is finding a good machine shop near me that works on these..

Re: Scored cylinder wall
 

If you have the crank welded on it will have to be re-balanced. That usually costs about 250$ so it is something to think about.