Help after cam and head swap

[davebloomer]

I swapped out my cam and heads and now when I crank it over to start it, it turns easily and doesn't seem like it's firing. Crank is turning accessories and cam is moving the litters but like I said it turns fast and sounds like there's no fire and/or compression. Any ideas?

[409impala1]

what kind of distributor,points or HEI, 12 volts to dist.?, could be a tooth or two off, check for spark by a screwdriver or plug grounded to block?

[GASoline71]

Have you been able to get it to run at all? Is it a flat tappet cam? If it is... the more you crank on it without the engine firing so you can break in the cam... you chance wiping a lobe off of the camshaft, and worse yet losing an engine.

Gary

[68GMCCustom]

are you sure you have spark at the plugs?

[davebloomer]

Thanks for the help guys. While I was typing this I was at my buddies house (whose shop I use) and his wife was on the phone with her dad. After they hung up it hit me... oh yeah! he owns his own mechanic shop. So we called him back and I started to explain what was going on and he was able to finish my sentence for me. He told me likely I over tightened the rocker arms when I was setting the valve lash thus hanging both valves open all the time. I agree with that cause it seems like i had to tighten them a lot farther this time vs times in the past (I normally do it with the engine running). His suggestion was to set each cylinder to approx zero lash and then set everything while it's running. (i have personally always set them this way in the past but I was worried about having to set them while needing to break in the cam), but that is what I will do. I'll get them to zero lash, start it up, and break in the cam then worry about fine tuning.

I'll update tomorrow. Can't wait to get the thing running. Lunati Voodoo 268 Dur. .489 intake .504 exhaust. Summit racing heads and a 2500 rpm stall. Should liven things up a little bit.

[davebloomer]

Originally Posted by GASoline71

Have you been able to get it to run at all? Is it a flat atppet cam? If it is... the more you crank on it without the engine firing so you can break in the cam... you chance wiping a lobe off of the camshaft, and worse yet losing an engine.

Gary

Yeah as soon as it didn't fire I knew something was wrong so we didn't turn on it anymore.


It is HEI and there is spark (backfire through carb)

Everything just turns really fast like there is no compression and I think that valves being kept open makes good sense to me.


THANKS for all the help guys.

[GASoline71]

Check to make sure you don't have your valves adjusted incorrectly. If you tightened the rocker nuts down too much the valves will never close, or open way too soon...

Gary

[rsavage]

It didn't have any compression because the valves weren't closing (rockers adjusted down too much). There are some little clips that you can get that snap on the end of the rockers that help keep the oil from spraying all over, but I've always had some clean up work after setting up a valve train.