Cylinder Corrosion

[Jocko_51_B3B]

I just had my block thermally cleaned and the cylinders honed. I'm trying to do this right so I'm a little bit concerned about the #6 cylinder wall which has some pitting up near the top. (The other five cylinders are OK. All six cylinders are in spec for out-of-round and taper.) The pitting in #6 runs down about an inch from the top of the block on just one side of the wall. The cylinders are already bored .060 oversize and there doesn't seem to me to be a lot of steel between the #6 and #5 cylinders so I am hesitant to have #6 bored another 3/32 or 1/8 inch to have a sleeve inserted. The engine seemed to run OK when I bought the truck so I'm thinking about ignoring the pitting and installing new rings and just take my chances. How forgiving is this engine? Should I fix the pitting now before I reassemble the engine or should I ignore the problem? If repairing the cylinder wall is critical, is there an alternative to boring and sleeving?

 

[Dodgeb4ya]

I would get another block. That block deck @ #6 is extremely rusty and pitted... sorry to say...just my opinion.

You could sleeve #6 or bore it out more but then the cylinder wall heat transfer could be an issue. pretty pitted block.

[NiftyFifty]

I agree, I would hunt another block, sleeving that one would likely cost the same, and that block needs to be decked pretty badly or you'll go through a lot of head gaskets, so that means a shim most likely as well.

[Mike36]

I agree, that block will most likely have trouble holding a head gasket.

[Jocko_51_B3B]

I hated the idea of throwing the block away so here's what I decided to have done by the machine shop:

1. re-sleeve the cylinders

2. replace all valve seats and valves

3. The pitting on top of the block (especially around #6) as well as pitting around water jacket holes were filled in by spray welding.

4. block top surface machined

 

 

 

[T120]

I have to commend you on making a decision on your engine. I do hope it works out well for you and isn't too hard on the pocket book.

[Elwood]

Nice save.

 

These blocks have been sleeved before, so you shouldn't have any problems if the work was done correctly.  Some people would even argue that a sleeved engine is better than a non-sleeved engine.

 

Have you checked that the valve guides were installed correctly?

[T120]

Possibly, it also could be part of the history and interest in this particular truck.

[Jocko_51_B3B]

I had checked the valve guide dimensions before taking it in and they measured OK so I didn't have the shop replace them. I think the previous owner replaced them sometime before I bought the truck. The shop I dealt with took quite a while to do the work. The main problem according to them is that the spray welding process is time consuming. The block had to be heated to something like 450 degrees F before the pitted areas could begin to be spray welded. That only gave the welder about three minutes of welding time before the block had to be re-heated. Actually, the cost of the welding, sleeving, valve seat replacement and seat cutting wasn't all that bad - a little over a thou. They also spray welded the corroded water jacket holes on the bottom of the head and then milled a few thousandths off the head as well. Do I like spending money like this, well no, but for it's all about saving a nice piece of automotive history, keeping the original engine, learning some new skills,  making friends, learning patience, and hopefully ending up with a cool little truck.

[MBF]

Great way to look at it Jocko!  Good luck with the continuing process.

[thisoldtruck]

Nice job!  I'm glad they were able to spray weld that all out. 

 

Laser cladding that block would have been another alternative.  But if your doing that, might as well heat treat the cylinder walls with the same laser.  With that, you'd never have to deal with cylinder wear again!

 

But, I don't have a money tree in my back yard either....LOL! 

[Mike36]

Jocko, great job on saving that block. It looks great, hope it lasts you a long time. I love seeing these old Mopars saved, my hats off to you!

 

[Jocko_51_B3B]

I hadn't heard of laser cladding before so I had to look it up. It looks like a perfectly fine alternative to spray welding. If I need to do another block I'll see who does laser cladding in the Chicago area and then look at relative pricing. Thanks to all for the compliments on the block. Next step; putting it all together without goofing something up!

[Matt Wilson]

Wow, nice!  I also commend you on this decision.  While these blocks are still available, it's nice to see someone go to these lengths to save one.  They're not being manufactured any more,  and someday, we (or the next generations) will wish they could find these kinds of parts.  So the longer we can make them all last, the better it will be for all of us.

[RobertKB]

I like the fact you wanted to keep the original engine. I have three old Mopars and two have the original engine and the third has a replacement flathead. Lots of vehicles had the original engine changed out at some point when the old one was worn out. You were certainly willing to put your money down to get what you wanted. Please update as work progresses.

Edited April 11, 2018 by RobertKB

[Jocko_51_B3B]

Just finished lapping the valves and seats. The spec is for a 5/16 valve seat width. I made sure to give that spec to the machine shop. The contact width is almost perfect but the lapping does show that the contact area isn't centered perfectly on the valve seat. I don't think it looks too bad though. Does anyone know if this lack of perfect centering is a problem or am I being too picky? Here are a couple of my new exhaust valves. One pre-lapping and one post-lapping:

 

Edited April 12, 2018 by Jocko_51_B3B
clarification and correction

[dpollo]

looks good to me.