Need timing chain advice on my 383

[ttraut@unlockit]

Well, I'm pretty sure my timing chain went today. I was about a block from home and ziiiiiiipppp, clank, and the engine died.

I'm out of town for a few days and want to be ready for my weekend thrash. I'm looking for general and specific advice. General advice is easy: what do I want to make sure that I do and don't do in replacing the timing chain?

Specific questions:

1) My service manual says "When installing timing chain, use Tool C-3509 to prevent camshaft from contacting the welch plug in rear of engine block. Remove distributor and oil pump-distributor drive gear. Locate tool against rear sid of cam gear and attach tool with distributor retainer bolt." What the heck is Tool C-3509 and can I use something else? What's a welch plug an why am I trying to prevent the camshaft from contacting it?

2) My service manual says, "Install washer and camshaft sprocket bolt, tighten to 35 foot-pounds. Check to be sure that rear face of aluminum camshaft sprocket is FLUSH with end of camshaft." What are they suggesting here?

3) Is there a preferred timing chain I should buy?

Thanks

Terry

[MoparMarcIdaho]

I have changed those before and never had any special tools.The plug in the back is just there to keep oil in it,dont beat on the cam and it wont give you any trouble.As far as chain selection,a roller is the best but if you go non roller,just get one that has a steel upper gear and you should be fine.

[dwc43]

The dist. drive will keep the cam from moving and you need to get a doulble roller. IT will outloast any stock type single roller chains for only a few bucks more. It's worth the money to go double roller since you loose cam timming and performance as the chain stretches.

[pishta]

They are just saying not to press the cam sprocket onto the cam as it will push the cam back and unseat the freeze type plug in the back of the cam galley. Use the cam nut to pull the sprocket back onto the cam. Just make sure the sprocket is seated at 35 ft/lbs to the cam face (no buggers). Use a quality chain with hardened sprockets. The chain stretches a tad, but the sprockets wear and that causes alot of the slack. You could go P.J. style gear drive for around 99 bucks and never have to worry about it again, just set it up correctly if you dont mind a little whine.

[DartGT66]

Are hotse gear drives available for single bolt cams? Anyway, ask any pro engine builder their opinion about those dual idler gear drives and they most likely will not recommend one. I have used them (pete jackson), and they work ok for a while. They do not stretch, but the plate and the shafts keeping the idler gears together will wear and cause problems. Mine lasted about 20000 miles. Another not so nice feture of tehm is the slack if/when you turn the engine coutnerclockwise. I have actually seen people with tight valve to piston clearances bend tehir valves because of teh changed cam timing. I would go with a good quality chain set instead, even the cheapo "double rollers" are better than production style morse set ups.

[dwc43]

Gear drives use a lot more hp to turn them, plus they send harmonics into the cam from the crank. NASCAR wont use them for this reason since it tends to brake cams in there cars. That's why they use the blower type kevlar belts to drive the cams now.

[DartGT66]

Don't know how much hp it eats, compared to a chain something comes back because of the more accurate cam timing. I converted from fixed idler gear drive to belt because I got tired about the noice, but didn't notice any other positive results. Jesel has belt drives for BB's, but they are expensive. Don't know if anyone currently sells belt drives for SB's, even our local guys have been pretty quiet about it lately. http://www.isokivijarvi.com/jir/jireng.htm

[dwc43]

Thanks for the link. I saved it for now, but that's a little pricey.

[pishta]

Saw an Australian belt drive set up that was around 350.00. Cant remember who made it, looked pretty nice. The dual idler only uses one drive idler, the other is for the reverse rotation on shutdown, and the clearances are so tight, I cant imagine the timing changing enough to hit a valve. That is some tight valve timing!

[DartGT66]

With current currency rates, the local set up is expensive. USD has come down almost 50% compared to €. Which is not that bad for us....
I have tested the forth & back rotating with the two dual idlers I have used, and teh effect with those cams to the valve to piston clearance was .060-.080". So, unless you have very tight clearances, that shouldn't be a problem