Good calm advise, will wine work?
Thanks

Checking for possible cracked 356 engine block

Postby Bill Butterworth ? Thu Jul 25, 2013 6:00 pm
Before doing a needed ring job on my 1940 356 engine want to check to see if the block is OK. Have some suspicions about the block due to the recent valve job when the exhaust valve guides were replaced. 5 of the guides had .002" interference the other 3 had .003" interference. After the valve job and starting the engine and getting it up to temperature, when the engine was turned off and was cooling down heard two cracking noises from the engine, sounded like our old house furnace when when I was a kid. Have no indication of water in the oil, but that may be due the guides sealing off a possible crack? What would be a good test if any for a cracked block?
Thanks, Bill

Anyone have information on the reason the top .400" of the guides were relieved to 3/8" in the 40 through 47 and not in the 48-50 356 engines. This has something to do with sticking exhaust valves but why then did Packard go back to non relieved guides in the 48-50 356 engines? Did other Packard engines also have this change?

Thanks, I feel much more confident now in just inspecting guilds an making sure they are clean (say with a "Qtip" and some acetone or is there a better method? What should I be looking out for regarding the valves stems themselves, plan to wire wheel the carbon off the face and underside of valves.

With this air test, the springs and keepers remained in place, so there is full spring pressure holding down the valves. Valves are now all out, that was another job, like the head removal, which turned out be quite manageable. Will at a minimum, lap all the valves. The next question are the valve guides. All the valves,after removing springs, have a slight lateral movement when holding valve face about 1" above block, does this mean new guides?
Thanks again for everyone's advice.

Have removed head and manifolds off my 356 engine due to bent exhaust valve. Although compression on other cylinders was good (not perfect) considering complete valve job. Have recommendation from a experience Packard mechanic how to determine condition of valves. Seat valve and flood top with motor oil. Wrap shop towel around air lance and check for air bubbles around valve edge. If two valves are on same port both valves must obviously be seated. If bubbles appear valve job is recommended. Has anyone used this procedure?

Thanks for the info. This jack appears to be used to lift the frame not the bumper, is this correct.

Jack and handle were missing when I purchased this Packard and have no idea what the original looked like. Does anyone have a picture or, better yet, know where I can purchase an operable one?
Thanks

One other point about grinding the top of the combustion chamber is the clearance of the spark plug itself. It appears to be just about flush with top of the combustion chamber. Is there such a thing of extra thick spark plug gasket?

Did not know about the cam lift spec. That kind of explains everything, my combustion chamber head depth of 0.30 plus the 0.040 of the head gasket is the cam lift! Was more difficult to measure the valve rise accurately as had to keep rotating engine to try to get maximum valve rise. Will think about the idea of grinding the head with a small grinder, nothing to loose at this point. Probably should grind all cylinders as the other exhaust valves have to be right at the edge as well. Can measure grinding progress with straight edge across top of head and a micrometer. Head appears to be thick enough around spark plug area to take a .015" removal?