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How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 1:24 pm
by BrazilianZ28Camaro
Hello Fellas
A buddy brought me his 350 four bolt engine from his '69 SS Camaro to rebuild, because it suffered a cylinder wall crack, due excessive CR and knock.
This block number match the car so he want to save it.
All Cylinders walls are tick even at 040 overbore, around .180"-.210". The crack at the #3 cylinder is 5" long and have about 0.02" gap in the middle where the distortion was worst. Thankfully this engine didn't hydrolocked.
My machine shop said this cylinder can be sleeved BUT the want me to weld that crack before sleeving so the sleeve might keep the interference fit better. I'm not sure if weld is really necessary, Id like to have your opinions and real life experiences sleeve correctly this block.
My plan is overbore the seven good cylinders to 060" and use a std piston on the sleeved bore to improve cylinder wall rigidity and hopefully avoid a crack between the head bolt hole to the bore wall.
I'm also be using head studs instead of bolts to help the block hold the load ok.
This engine will make about 425-450 HP, but not a lot of rpm and abuse.
Thanks in advance for helping.
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 1:56 pm
by ClassAct
BrazilianZ28Camaro wrote: ↑Wed May 20, 2020 1:24 pm
Hello Fellas
A buddy brought me his 350 four bolt engine from his '69 SS Camaro to rebuild, because it suffered a cylinder wall crack, due excessive CR and knock.
This block number match the car so he want to save it.
All Cylinders walls are tick even at 040 overbore, around .180"-.210". The crack at the #3 cylinder is 5" long and have about 0.02" gap in the middle where the distortion was worst. Thankfully this engine didn't hydrolocked.
My machine shop said this cylinder can be sleeved BUT the want me to weld that crack before sleeving so the sleeve might keep the interference fit better. I'm not sure if weld is really necessary, Id like to have your opinions and real life experiences sleeve correctly this block.
My plan is overbore the seven good cylinders to 060" and use a std piston on the sleeved bore to improve cylinder wall rigidity and hopefully avoid a crack between the head bolt hole to the bore wall.
I'm also be using head studs instead of bolts to help the block hold the load ok.
This engine will make about 425-450 HP, but not a lot of rpm and abuse.
Thanks in advance for helping.
The machine shop is nuts. Don’t weld it before the sleeve. Find a different shop. Use the correct sleeve, make them all .060 over and forget about it. If the sleeve is done correctly you’ll never know it’s in there.
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 2:28 pm
by rebelrouser
I understand their are some shops that are good at cast iron welding, there is just not any of them near me I guess. I have seen very few cast iron weld repairs that held up. I would think that unless you have an oven to pre heat and cool the block, it will just crack beside your weld when the new sleeve is pressed in. No welding shop close to me has an oven big enough to hold a block.
I have a buddy right now that had a sleeve installed to repair damage from a broken rod. The block started leaking after about 30 runs, cracks coming from around the area welded, on the out side of the water jacket. The sleeve seems to be holding well, the water jacket was welded after the sleeve was pressed in. This is about a 750HP mopar engine, I just don't think cast iron as brittle as it is, likes the stress that welding imparts. I have nickel welded a couple small pieces of pan rail, and that worked out OK, but it was not structural.
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 2:46 pm
by BillK
I have put quite a few sleeves in blocks exactly like that one. I have never welded them first. Lately I have been using flanged sleeves instead of leaving a step on the bottom but they are very hard to do without decking the block afterwards and if it is a numbers matching block he wont want to do that. I would just use a regular sleeve with a step at the bottom and put some green loctite or brown sealer around the bottom. Finish the top with a file and a stone and you wont have to deck the block. More work but if he cares about numbers matching thats what you have to do. I would definitely make all of the cylinders the same bore size.
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 2:52 pm
by prairiehotrodder
set the numbers block in the corner for safe keeping. Get another block so that when you enjoy driving the car you can actually enjoy it. Then if you ever sell the car, give them the numbers block to go with it.
Brian
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 3:47 pm
by F-BIRD'88
The shop that sleeved a 350 for me did not weld the
cracked cylinder first. Not needed. If the other 7 .040 over cylinders are servicable with a hone+ re ring just fix the one cylinder... if another 350 block is available (can be a 2 bolt) it is a consideration.
Make all the holes the same size reguardless.
A 2 bolt block is fine for your purpose.
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 3:56 pm
by PackardV8
prairiehotrodder wrote: ↑Wed May 20, 2020 2:52 pm
set the numbers block in the corner for safe keeping. Get another block so that when you enjoy driving the car you can actually enjoy it. Then if you ever sell the car, give them the numbers block to go with it. Brian
Core 350" SBCs are cheap trash here, but I believe our OP is in Brazil, where they're unobtanium.
X2, sleeve that cracked hole and bore all eight to .060". Done every day here. Having said that, a numbers matching guy just had us sleeve all eight holes back to STD.
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 4:52 pm
by ijames
Just curious, is there any concern about the crack continuing to get bigger? Do you leave it alone, or do you stop drill each end for insurance?
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 5:33 pm
by ClassAct
ijames wrote: ↑Wed May 20, 2020 4:52 pm
Just curious, is there any concern about the crack continuing to get bigger? Do you leave it alone, or do you stop drill each end for insurance?
I’ve sleeved blocks with HOLES in them. One was a 390 Ford that lost a wrist pin, gouged the hell out of the bore, failed the piston and shoved the rod right through the cylinder and put a freeze plug hole.
I used a little green sealer around the top of the bore and a little around the hole and drove it home.
Sealed and worked. Setting sleeves isn’t that hard. Don’t let the machine shop make it a major deal. If they are that nervous, find another shop.
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 5:58 pm
by cgarb
Any way you can get in there to drill and pin the crack shut with lock and stitch pins rather than welding?
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 7:14 pm
by KnightEngines
I've sleeved blocks with fist sized holes punched in bores (well, maybe no quite, but big holes!).
Step at the bottom, green loctite everywhere, .002" press fit.
Run at 600+hp no issues.
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 8:12 pm
by shoedoos
OP, I take it the block isn't usable at 40 over? If it is, why would you go to 60 if the thing can be salvaged at a smaller overbore?
Pistons are available at 40 over and as you are having to ship them out your way, then that part of the equation will be the same. I'd be saving another overbore for later on that unobtanium block if I were you...
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 8:59 pm
by Ericnova
PackardV8 wrote: ↑Wed May 20, 2020 3:56 pm
prairiehotrodder wrote: ↑Wed May 20, 2020 2:52 pm
set the numbers block in the corner for safe keeping. Get another block so that when you enjoy driving the car you can actually enjoy it. Then if you ever sell the car, give them the numbers block to go with it. Brian
Having said that, a numbers matching guy just had us sleeve all eight holes back to STD.
You couldn't make him understand the block is now far weaker than stock because of the the material bored away to put a sleeve in all 8 bores??
Not much tying the bottom half to the deck when you bore 1/2 of it away for sleeve.
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 9:03 pm
by houser45
Find a shop with a Berco style block boring/decking mill, use a thick wall melling sleeve. Indicate the top of the deck square with the boring head. If using a bhj style fixture the cam tunnel bar may have to be shimmed off of perfect 90•. Bore for .002” press fit, leave a ledge at the bottom And allow for the sleeve to stick out. Use a square cutter to machine the sleeve down to the deck. Leave it up a .001” or .002”. You could go .060”. You might get away with .045” over if you use an expensive piston available from je or Cp ect. I wouldn’t advise trying to leave the others at .040”. The notes next to the sleeved ones will be out of round. Green loctite the heck out of the sleeve. It will work fine
Re: How to sleeve a 350 the right way?
Posted: Wed May 20, 2020 9:16 pm
by rustbucket79
Ericnova wrote: ↑Wed May 20, 2020 8:59 pm
PackardV8 wrote: ↑Wed May 20, 2020 3:56 pm
prairiehotrodder wrote: ↑Wed May 20, 2020 2:52 pm
set the numbers block in the corner for safe keeping. Get another block so that when you enjoy driving the car you can actually enjoy it. Then if you ever sell the car, give them the numbers block to go with it. Brian
Having said that, a numbers matching guy just had us sleeve all eight holes back to STD.
You couldn't make him understand the block is now far weaker than stock because of the the material bored away to put a sleeve in all 8 bores??
Not much tying the bottom half to the deck when you bore 1/2 of it away for sleeve.
Sleeved a few 340 Chryslers back to standard, not much you can do when the block is max oversize and no other blocks are available.
Trying to weld a crack in cast is asking for the crack to spread. Seal around the crack if it concerns you. (And installing the sleeve cold) We've been heating the block in the cleaning oven and dropping the sleeve in dry, a .002" interference isn't letting much coolant pass.
