One of my neighbors knows that I work on chevys and asked me for some help adjusting his valvetrain on a new flat tappet cam(Comp Magnum with a .525 gross lift-small block chevy in a '55 Bel Air wagon). While going through the cylinders (turning crank by hand with a torque wrench and doing the EO/IC method) I noticed that there was some sort of contact going on with something in the engine. I got through about four cylinders, when there was obviously some serious obstruction keeping the engine from wanting to turn. I asked him how he put the cam in and, because he was filling up on Budweisers while working on the engine, figured it there was a good chance that he might have installed the cam wrong, or it was the wrong cam altogether. To make a long story short, the cam was installed 180 off, a bunch of the pushrods were bent and the obstruction that was being noticed must've been the valves hitting the tops of the pistons. I advised him to pull the heads and check the valves and pistons, but he doesn't want to.

What would you do? He wanted more opinions as he wants to re-adjust everything, seal it up, and run it. Although it's his money and engine and he can blow it up for all I care, I told him that he really should do some more investigation.

I also advised him that he might want to lay off the booze when working on the car.

Mike

I would degree that cam, & without a doubt, pull the heads & look everything over...

Scott

Originally posted by obsessedwithmy72:
One of my neighbors knows that I work on chevys and asked me for some help adjusting his valvetrain on a new flat tappet cam(Comp Magnum with a .525 gross lift-small block chevy in a '55 Bel Air wagon). While going through the cylinders (turning crank by hand with a torque wrench and doing the EO/IC method) I noticed that there was some sort of contact going on with something in the engine. I got through about four cylinders, when there was obviously some serious obstruction keeping the engine from wanting to turn. I asked him how he put the cam in and, because he was filling up on Budweisers while working on the engine, figured it there was a good chance that he might have installed the cam wrong, or it was the wrong cam altogether. To make a long story short, the cam was installed 180 off, a bunch of the pushrods were bent and the obstruction that was being noticed must've been the valves hitting the tops of the pistons. I advised him to pull the heads and check the valves and pistons, but he doesn't want to.

What would you do? He wanted more opinions as he wants to re-adjust everything, seal it up, and run it. Although it's his money and engine and he can blow it up for all I care, I told him that he really should do some more investigation.

I also advised him that he might want to lay off the booze when working on the car.

Mike Mike,
While it indeed sounds as if the valves are hitting the pistons, you cannot install the cam "180 out" unless you are talking 180 engine degrees which is 90 crank degrees & the cam mark would be pointing at 9 or 3 o'clock.
I am assuming you are meaning he installed it with both marks up instead of dot to dot.
Doesn't make any difference to the engine, you will just be on #1 instead of #6.
If you turn the engine one revolution you will be dot to dot.
If the valves are hitting & he runs it assuming it wants to run he will destroy the engine in very short order.
Best case he will bend a few valves & it won't want to run good so he will take it apart.
Worst case a valve head will break off & it will disassemble itself in which case he can really start over :rolleyes:

Keep putting new pushrods in it until it all self-clearances itself. Might want to go to a real heavy wall pushrod.

It's not your engine!

the cam cant be installed 180* off. pop the timing chain cover off and see what he did wrong. I had a neighbor line up the crank dot with the dowel pin hole on the cam gear.

Originally posted by Wolfplace:
[QUOTE] you cannot install the cam "180 out" unless you are talking 180 engine degrees which is 90 crank degrees & the cam mark would be pointing at 9 or 3 o'clock.
That's what I meant. I re-installed the cam correctly for him, so it is lined up dot to dot with the crank gear dot at 12 and the cam gear at 6, however, like I said, he may have bent a valve or two, or four, maybe not.

do a compression test.
david

Give him another beer and head to the house. He is the one who asked for your help.
John

Instead of dry cranking (on a new cam)to run a compression check, why not just do a leak down test to see if any valves are actually bent? You wouldn't need a gage, just regulate the air pressure down and check each cylinder at tdc for leakage past valve into intake or exhaust.

Good Luck!

Jeff