Pulled the head and am looking for advice

[Shifticus]

I pulled the head to get it milled .060", however I came upon a nasty little surprise in cylinder #3

Now, the loose pieces are carbon buildup, and I poked at what I presume to be the top ring revealing that it was present and intact (atleast through the big hole).

I wanted to show you guys some more pictures illustrating the condition of the valves and such, and wanted your advice concerning my next course of action. The motor leaks very little oil, runs pretty good-and reliably at that. I figure option one is to drop the pan and replace the pistons, or I could really dive in, pull it and contract a rebuild. My preference would be to mess with as little as possible. Let's hear your two cents.

Edited August 23, 2009 by Shifticus

[Don Coatney]

My original engine had a piston that looked just like that. If you want a dependable engine pull it and rebuild it. Or find another engine.

[Plymouthy Adams]

from the picture the ring does not appear to be froken, you did not mention any vertical scoring of the cylinders..you are in luck that the engine cylinder appears not thave been damaged and just a piston is burnt..being number three could indicate a lean condition in conjunction with a stuck het riser keeping that area very warm and contributing to the lean running of 3 & 4 chylinders in particular..

time for a rebuild, check you cylindrs for taper and wear to determine if the engine has ever been bored before and a get a general indication of the amount you may hve to go to clean the bore..keep it at mnimum clean up bore, don't be tepted to go max bore for that extra bit of power..it is not that signifcant amount of gain to shorten the life of the engine should somthing ever go wrong and require yet another "clean up"

[greg g]

I also had three or 4 pistons in that condition in the 230 engine I rebuilt. Quite a few other over the years have reported the same condition on one or more pistons.

Call Terrell machine in texas of Egge in california for pistons and rings.

Old school would be to fix that oe cylinder and let the rest go. (My uncle had a Pontiac straight 8 woitih at leat three differnt diameter pistons in it.) but for extended reliability it looks like at least pistons and rings are in your future.

[grey beard]

What I've found on the several I have been involved with is that even when the cylinder taper is within useable limits, the top ring groove on the pistons is usually wallowed out so badly as to no longer be useable. Back in the day, machine shops used to machine these ring grooves and install a steel spacer, but those days went away along with the $75/100 per hour shop labor rates. There should be no more than .002" side clearance with a new ring in the top groove. The top groove always wears most on accounta' it is the hottest and the least lubricated by engine splash, etc.

I was able to find new pistons at VPW for like $20 each - this was a year ago. New pistons and rings will surely improve any of our older engines, especially in cylinders where the taper is still in single digits - like .008" or less, JMHO.

A very good indicator of this cylinder taper you are now looking at is the amount of ring ridge present at the top of your cylinders. This you can see even before you pop the pistons out - just scrub the area down with some coarse sandpaper to get the carbon off and see if there's enough meat there to really catch your finger nail solidly. If such exists, it's time for a rebore - a pretty expensive proposition at most machine shops today, but a good long-term investment.

If you go the full route, please do not overlook the connecting rod bushings on the top end. Some pretty good men have been bitten in the tail by this little item - easy to overlook. And, while the shop is renewing those bushings, you may wish to consider having the rods trued. They are often bent a little, and often stretch with use, over time. In a perfect world, they'll all be the same length.

[Shifticus]

Thanks for the input. My local speed shop referred me to these guys for my head which is currently in their posession, so I might sit down and have a chat about the motor.

http://www.lnrengine.com/

Have a shop to reccommend in SoCal? Anyone had a bad experience with the guys I listed above? I'd love to hear it..

[dezeldoc]

L&R has been around a long time and have a pretty good rep. i would not have any problem using them.

[blueskies]

Found the same thing in my '50 218...

Had holes in two piston edges, but when I pulled them all out, all of them were in similar condition even though they had not yet busted through. All six had broken top rings, and all six had severely wallowed top ring grooves.

I went for the total rebuild and used a 230 crank and rods while I was at it for the extra cubes.

Pete