Had 2 different guys look at my timing chain while I have the motor out. One says the the chain is a litle loose, and then the other guy says it should be that way?????? Is there some "rule of thumb" as to how much slack there should be? Thanx, Kelly

How much deflection is there? It's usually ok to have a slight amount of slack, but for cheap insurance, I usually will replace it with a double roller unit, and then I know I'm good to go! Or, you could really step up to the plate like Q and get a gear drive, with an adjustable gear... ohhhh.... ohhhhh.... ohhhh.... (as Tim Allen would say)

But if your not sure, I'd replace it.

Brett - 67 Drop Top 455!

Thanx Brett. I have seen those gear drive type. Unfortunatley, between all the new stuff for this one and the new '69, my Firebird slush fund has taken quite a hit and I am ready to get my '68 on the road. I would say there is about a half inch, maybe just over that of deflection. can I live with that, or just be more patient and replace? Kelly

A half-inch sounds like a lot for a stock chain.

Like Brett said, it's cheap insurance to run a new timing set.

Q

Yeah... I would probably get a new chain at that point. You can get a stock replacement or a double roller etc... either way the cost is minmal, but the peace of mind is priceless.

I didn't know you got a 69! That's great! But yeah, I know how it goes with multiple projects running you dry at the same time!

Hope it all works out for you!

Brett - 67 Drop Top 455!

I have 30K miles on the gear drive set in my beater F150 4X4. It's the only way it ever gets any attention, but my 'Birds getting a timing chain. I want to hear other things besides that blower whine!

Ok, went to Summit and got me some peace of mind........and a nice set of wire looms just because they were there. Went with Comp. Cams double roller as suggested. Thanx guys, I feel a little better already. Kelly

kelly, what did the double-roller cost you if you don't mind saying?

Click here nash, this is for chevy, I ordered part# CCA2112 for Pontiac and it is $46.39, chevy's are 39.95, of course chevy's are cheaper.....you are what you drive! web page , Kelly

To answer the Question of to much slack in a timing chain.
Put the hormonic balancer on and turn the motor back and forth. See how many degrees you can turn the crank before the cam begins to turn. How many degrees do you have 2,4,5,8 degrees of slack??
The more slack you have the more the timing is going to be off. It you have 5 degrees of slack the timing will be off 5 degrees "cam laging the crank".
To some it up, smart move replace it!! I always put a new chain set in if I got the motor torn apart.
After you put the new chain on see how much slack you have?? 0000 degrees!!!
Joe

Of course, it never hurts to advance one of them old cams by 4 degrees. I know Cloyes makes a set with -4/0/+4 keyways. I always like to go +4 to wake up that ol' bottom end torque.

Q

I was a bit dismayed to find the first cam that I checked the timing on to be almost 4 degrees retarded with the stock parts in the right place. At the time the common opinion was that having a retarded cam wasn't all that bad because even though the engine lost power at the low end, it made more power at the top end. What they didn't say is that this meant I'd lose power all the way to about 5,000 rpm before starting to benefit from the retarded cam timing.
Like Q, I prefer to have the cam advanced 4 degrees instead and have the power on the way up (horsepower is fun, but torque gets it done). Even the race engines that I build usually get timed at 4 degrees advanced (measured by lobe centerline - some cams are ground with the 4 degrees advance, check the cam card). It gives slightly better fuel economy as well. Don't forget to reset your distributor after advancing the cam!