Tear down a seized 340

[mgm1986]

Also, according to the PO, the heads had been rebuilt prior to storage. The gasket does look newer but man that is a lot of rust. Shame he didn't dump oil down the plug holes before storage, probably would have prevented most of the rust I am finding.

Speaking of heads, does anybody know how I can decipher the heads? The only marking I saw was 'I I' stamped next to plugs 1,7 and 2,8. I guess it doesn't matter much as I plan to have the intake valves opened up anyway.

 

[moper]

That's normal. There are always one or two cylinders where the valve stay open. Over the years those get condensation in them and rust everything up. If that only has one or two rusty bores then have it sleeved and run it. Std bore 340s are getting more pricey - so depending on what you aid you might get out fine even if you don't want to do it yourself. Make sure it's airless shotted to clean it, and have it magnafluxed. If it passes, it's a good block even if the bores are punky.

 

[MrMoparCHP]

Mine was pretty bad,

In the end it was bored 30 over and everything is fine.


Alan

 

[mgm1986]

That's normal. There are always one or two cylinders where the valve stay open. Over the years those get condensation in them and rust everything up. If that only has one or two rusty bores then have it sleeved and run it. Std bore 340s are getting more pricey - so depending on what you aid you might get out fine even if you don't want to do it yourself. Make sure it's airless shotted to clean it, and have it magnafluxed. If it passes, it's a good block even if the bores are punky.

Thanks for confirming my suspicion about the open valves!

For those curious, I paid $700 as it sat. I believe/hope it will be fine, best case keeping it at standard bore, worse case bored 30 over. I haven't seen anything yet that makes me think the block is cracked. My goal is to take it apart and bring it to a good machine shop (Recommendations welcomed!) and see what they say.

Thanks much for the input, I will keep you all posted on my progress. I might try to make a trip up to Carlisle in July and pick up some valve covers, they did not make it through storage!

 

[mgm1986]

On Saturday I noticed 1-3-5-7 cylinders had almost no fluid left, good sign. To tackle the more problematic even numbered cylinders a bit more aggressively I turned the engine so the block surface was parallel to the floor and filled up all cylinders to the top with the 50/50 mix. Yesterday morning the most offensive cylinder had lost about 3/4" of fluid, either acetone evaporation or seeping through cylinder walls. Either way, I continue to top it off and hopefully this week/weekend I can get it to move enough to pull the cylinders. Hopefully I don't have to deal with reaming the cylinder to get the pistons out as that would force me to the machine shop.

More updates this week.

 

[MrMoparCHP]

To make matters worse, the four cylinders that are at the top and bottom of the stroke are the ones that will be fighting you the most. The top ones are most likely the problem as those had the open valves. On top of that the pounding will have minimal impact and the crank is in its lateral point of its rotation.

Alan

 

[mgm1986]

To make matters worse, the four cylinders that are at the top and bottom of the stroke are the ones that will be fighting you the most. The top ones are most likely the problem as those had the open valves. On top of that the pounding will have minimal impact and the crank is in its lateral point of its rotation.

Alan

This doesn't sounds like the encouraging news I wanted to hear! The #8 cylinder and piston are the worst and the piston is all the way down at the bottom of the cylinder. Gonna be fun.

 

[MrMoparCHP]

Mine was still on the frame and I was standing one the breaker bar while I was pounding on the board, I would brush it down with the 50/50 mix and the next day rotate the other way and continue. The other 4 cylinders should be moving 2-3" within the middle range. If those are not moving I would beat on them first, those are the ones with the leverage on the crank.


Alan

 

[MrMoparCHP]

If nothing is moving and you have just about givin up you can alway cut them out.

Die grinder or cutoff wheel to the tops to open them up and the spit the webs holding the rods with a sawzall.
From there some careful cuts on the piston walls and implode them, I was prepared to do that but I got lucky.


Alan

 

[mgm1986]

If nothing is moving and you have just about givin up you can alway cut them out.

Die grinder or cutoff wheel to the tops to open them up and the spit the webs holding the rods with a sawzall.
From there some careful cuts on the piston walls and implode them, I was prepared to do that but I got lucky.


Alan

I have not given up just yet! Hopefully it doesn't come to die grinder or cutoff wheel though. I haven't tried to turn it at all since I filled it, figured let the mix do its job for a good week before trying to free it up. Thanks for the advice and sharing the experience, this is very good info to have.

 

[moper]

You're going to the shop anyway. Unbolt the rod caps starting with the ones taht are down in the bores (so the crank journal is up away from the block). Unbolt, remove the cap (should come off easy, or you can carefully tap the ends fot eh rod bolts and they will push out of the rods. Then pull the cap.) Then use a steel bar and stick one end on the pistin pin boss and hit the other end witha dead blow. It should move. If it doesn't stick the bar on the other side of the same piston's pin boss and hit it harder. Drive it out of the block without hitting the rod or sticking the bar on the piston dome. It will damage the rod, and break through the dome possibly causing bore damage. I've done this dozens of times. You will need to bore it - so you don't need the pistons. You need the crank and rods and bores, so don't directly impact them. The rod bolts will be replaced so they can be removed too - but don't hit them hard as you can bend the rod end itself.
Then drag it all to the machine shop and have the block cleaned well (I like airless shot rather than tanking it) and then have it magged. No need to throw time or money at oils or lubricants. Just break it down...lol.

 

[mgm1986]

You're going to the shop anyway. Unbolt the rod caps starting with the ones taht are down in the bores (so the crank journal is up away from the block). Unbolt, remove the cap (should come off easy, or you can carefully tap the ends fot eh rod bolts and they will push out of the rods. Then pull the cap.) Then use a steel bar and stick one end on the pistin pin boss and hit the other end witha dead blow. It should move. If it doesn't stick the bar on the other side of the same piston's pin boss and hit it harder. Drive it out of the block without hitting the rod or sticking the bar on the piston dome. It will damage the rod, and break through the dome possibly causing bore damage. I've done this dozens of times. You will need to bore it - so you don't need the pistons. You need the crank and rods and bores, so don't directly impact them. The rod bolts will be replaced so they can be removed too - but don't hit them hard as you can bend the rod end itself.
Then drag it all to the machine shop and have the block cleaned well (I like airless shot rather than tanking it) and then have it magged. No need to throw time or money at oils or lubricants. Just break it down...lol.

I have been soaking it for a while but not much more. If I get time over the weekend I am going to drain everything and start taking more things apart. This is good info to have though, thank you for the details!

 

[mgm1986]

Then drag it all to the machine shop and have the block cleaned well (I like airless shot rather than tanking it) and then have it magged. No need to throw time or money at oils or lubricants. Just break it down...lol.

Curious, why the preference of airless shot over tanking?

 

[mgm1986]

Slow and steady with this breakdown. Four pistons left to remove and then off to the machine shop. Still not sure if I will use stock heads and intake yet. I've also been reading up on upgrading to a roller cam. Seems like a worthwhile investment while I'm in there. I'm hoping to be able to reuse the crank even though I think it's cast, not forged.

Been a fun project so far!

 

[mgm1986]

Has anybody upgraded to a Crane hydraulic roller cam and lifters? My understanding of such things is very limited to what I read on this forum and on the interwebs. My research has led me to believe a hydraulic roller cam is the best option for longevity and based on all the things I read about new oil and the lack of zinc additives, this would be a non issue if I went this route.

http://www.summitracing.com/parts/crn-699611
http://www.summitracing.com/parts/crn-69532-16

 

[moper]

Hot tanking chemicals are not what they used to be - at least in CT. I recall watching American Hot Rodder, and reading the amgazines about guys powerwashing outside, and hosing blocks out after tanking onto the ground. In CT you'd get arrested for it. Airless shot does a few things: it is the same process that strengthens rods (shot peaning) so the surfaces get a little stronger, it blasts everything off the iron it can reach so what's left is not scale or mineral build up, or stuck sand from the casting, and it leaves a great surface for painting. It used to be the block would come out of the hot tank as bare iron. Now chemical-cleaned blocks just are not that clean to me. The EPA "happy" solvents leave paint, paint residue, rust & scaling on and inside the blocks. So I will always use shot blasting now. Plan to tap every hole, protect the main bores, and prtect the lifter bores (shop will do this as part of the prep for blasting) and let 'er rip.