degreeing a cam

[Knanthrup]

Hey guys,

It\'s winter again which means I get to pull my toy apart and get her ready to run stronger next season when the track opens! Now, I want to fix a problem that has been plauging my truck for some time. When I installed my cam, I had no instructions so I basically pulled out the old one, and threw in the new one while matching the dot from the cam gear with the one on the block. I figured that doing so would put my cam timing where it needed to be. Well, I have a funny suspision that it has been off this entire time. First of all, my ignition timing mark does not read anywhere close to where it needs to be. The mark on the balancer is way down about 80-90 degrees off, so I have to time it by ear. On top of that, she doesn\'t seem to have the kind of spunk that I expected out of her. If my cam timing is off, I can see that it would probably affect performance a lot and I\'m sure it doesn\'t compliment my \"tuned by ear\" ignition timing either.



My question is, how exactly do you properly degree/time a cam? Other than sliding it in and putting the gear on to line up with the mark on the block I don\'t see how to adjust it. Can degreeing the cam even fix my timing mark problem or is this a deeper issue? Thanks guys..

[mr_will]

your timing mark may just be in the wrong spot some sbc had the timing tab on the right some was on the left

your best bet is to locate absolute tdc and get a timing tape and put it on your balancer and to degree a cam you need a degree wheel to get the proper power out of it you may need to degree your cam depending on your application

[Scotty_S-15]

Yep, Mr_Will said it all. Another thing that may have happened is the outer ring on the balancer can slip. It happens.

........ If you want to degree the cam, you\'ll also need a dial indicator, and a means of fastening it on a rocker stud or the like. (presuming the engine is all togther) I made a pushrod for this by cutting the end off, and tacking on a \"cup\" to receive the dial indiator \"nub\".

............ As for TDC, check out this thread:



Finding TDC (http://s10v8.com/viewtopic.php?topic=8031&forum=4)

[Knanthrup]

Hey I just want to confirm.. is it ok to use a pistom stop on these engines? The reason I ask is because I went to napa today and asked the guy if they had piston stops. He said they only had them for lawnmowers and you couldnt use them on chevy V8\'s because it would be angled coming in from the head and not straight on.



I thought it would be fine as long as you\'re turning the engine lgihtly by hand. I saw like 5 different piston stops from Summit, and id like to order one permitting that i wont ruin my engine or that it will work.



Thanks guys.

[Scotty_S-15]

Are you talking about the spark plug type stops? Yeah, should be no problem, like you said, you\'re just gently cranking engine by hand. Just make sure the bolt end is rounded with no sharp edges to mar the piston. I\'d pull all the plugs just so you can \"feel\" it better, and not be fighting any compression, etc.

[spacecadet]

I would agree with the info suppiled. I did mine with the heads off. Put a magnetic block on to mount the run out gauge and measured against the lifters body. I have never used a tru the plug piston stop. I have only ever used a bar bolted to the block with a bolt. It has always seemed to work.



If the balancer is off that far, wither the balancer was marked for the oppostie pointer than you have. (Which I would think would be highly unlikley.) OR the balancer slip. It happens alot more than we would think.

The three dots on the new cam gear are only a few degrees different. A @ 90d off I would definitly think that it had slipped.

[Knanthrup]

Ok cool. One more thing. When I finally find TDC and mark it on the balancer, where should I tune my ignition timing to? It varies by cam right? Will I find this information on my cam card or on their website? What\'s a good universal starting point for ignition timing?



oh and also, if the balancer slipped there is probably no way for me to reset it myself right? Probly need a new balancer?