So after working through all other leads on a bad running condition, I finally jumped in and replaced the timing chain. The original chain and gears had about 8 degrees of slop by turning the damper back and forth while watching the distributor rotor for movement. I just got it back together yesterday, and the mid range hesitation/jumpy feeling present when revving up in park is much improved, but not totally gone. I drove it around the block a few times and it seems fine, so I’m going to consider this done.
I am wondering about the replacement chain, though and hope someone can provide info.
The replacement timing set (cheap Cloyes from Oreilly) still had some play in the chain. Less than the old one, but still more than I expected. I bought another set from Napa to compare. It was a Napa line product, but the part number was similar to the Cloyes, so I assume that’s who made it. In any case, the Napa set was looser than the first one I bought and was loose enough that I never would have used it. Unfortunately, nobody else in town had anything and I wanted to get it together, so I ended up putting in the Cloyes from Oreillys.
So, how much play is normal for new timing set? With one side of the chain tight, there was probably about ½” play on the other side. I’m thinking that remaining slop is why I’m still seeing a little bit of unsteadiness in the motor when revving it up. Thoughts? This was my first time doing a timing chain so it was a learning experience. Thanks.
Timing Chain Slack on New Timing Set
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- shorty73
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Timing Chain Slack on New Timing Set
1968 F250 2wd 360/c6 PS PB (disc) Camper Special
- Ranchero50
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Re: Timing Chain Slack on New Timing Set
This is why I buy the best timing chain I can and make sure the crank sprocket has multiple timing key ways. I always install the timing sets advanced and end up pretty close to straight up. Ten years ago $65 would buy a decent true double roller timing chain.
'70 F-350 CS Cummins 6BT 10klb truck 64k mile Bahama Blue
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Re: Timing Chain Slack on New Timing Set
It may seem insignificant, but there are some brands that offer custom sets. There are production variations of cam to crank centerline. Also if the block has been align bored/honed it reduces that distance. I called customer support with a known centerline distance and got a custom set. It barely slipped on.
- shorty73
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Re: Timing Chain Slack on New Timing Set
I suppose the motor could have been rebuilt, but it had what appeared to be the original nylon cam gear and the ID tag is still on the manifold top. Also, the speedo reads 94K, so I'm thinking that's the original miles. Oh well, lesson learned. If I have to go in there again, I'll know how to do it (and all the nasty oil crud is already cleaned up). I drove it again today and it runs good enough. And I haven't seen any leaks! Of course, that means I'll go out tomorrow and see one. I'm just surprised the timing cover seal was close enough to not leak. Getting the cover on with sealant and gaskets was a pain and I know it's not fully centered on crank.
1968 F250 2wd 360/c6 PS PB (disc) Camper Special