Just trying to start the 322 nailhead - less than a week from the show - and I have a serious case of "no compression" - valve timing appears to be about 90 deg. out - so, I wisely suspect the cam is in wrong. My memory being what it is, I can't really remember timing marks we used - an internet search shows Chevy like timing marks on the 401's - but I can't find anything on the earlier engines - if they are different. Can someone give me a picture of how the timing marks line up on a 56 322 nailhead? If it makes any difference, it is a truck short block, 56 pass car heads, and an Isky cam. Thanks !
OK - I found an old Motors manual that shows how a 56 goes in - and as I remember that is how we put it in. But, obviously wrong. Is there something different about the truck engine ??
Buick nailheads were used in the big Chev and GMC trucks, as were Pontiacs. When GM came out with the 348 truck engine, that stopped.
Right - my '62 Motors manual shows the 55-56 timing gears with the dots to the right*, and 12 teeth of the chain between them. (teeth numbers 1 and 12 on the dots) The chain should have bright plated washers on these links. The cam keyway is at 6 o'clock and the crank keyway is about half way between 10 and 11 o'clock. (I'm guessing no.1 is at tdc.) the 57-62 engines have the cam and crank in the same positions, but the dots are in line with each other, on the center-line. Gotta turn in now, if you need a snap of the picture I can take one for you tomorrow. My Y-block has the same setup - must have been something popular at the time. I also set mine up wrong the first time round! Mart. * Dots to the right, when looking at the pulleys, strictly speaking, they are to the left side of the vehicle, or US driver's side.
I wish I could be of help, but I don't do/know 322's, I know enough to know that there is a lot different between them and the 364/401/425's
To add to the diagram that Chris posted here are the written instructions in the 1956 National Service manual
Thanks, guys. I think the cam was installed as shown on the 56 diagram - (I'm pulling it apart tomorrow to make sure). Since that doesn't appear to give the right timing, I'm wondering if the truck short block (which was a 57) went to the newer system ?? Anybody know ?? Then the other question is what parts changed an which do I have..........probably time to get out the degree wheel....
Chris or Mart - would you have the same diagram for a "Chev Thriftmaster 322" engine - 57-59 truck nailhead ? Thanks - Stan
I feel a foolproof way to check if a cam is in time is to check what is often called the rock over. That is when the piston is moving up and chasing the exhaust valve. Just before the piston comes all the way up the exhaust will close and just as the piston starts down again the intake begins to open. The valves should be "rocking" open & closed if you move the crank back & forth bringing the piston up and down. If you are off a tooth (or teeth) the valves will not be remotely close to rocking. Even with a heavy overlap cam the pistons and valves will be doing this dance. With a bit of creative thinking you can move the cam timing around in the rockover position and find the correct timing point.
My book states that the 57 engines are timed with the two dots pointing at each other on the center line. Mart.
The figure 8 is correct to 56 but i have no 57 book but in 58 they went to point to point.If you have a orginal small gear from key to right is 3 teeth this would be 58 So if you remarked top keyway down and crankshaft gear 3 teeth over to right like pic same thing.
Thanks to all of you that helped. Turns out we timed it like a later nailhead - OOPS ! Timed it like a 56 should be and - WOW - we have compression !! Thanks again.