Timing chain slack and DD

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Nov 23, 2011 | 12:11 AM

bamaf150

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Joined: Dec 2009

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From: Mississippi

Timing chain slack and DD

The other day while changing my fuel pump, I felt considerable slack in the timing chain on my 360. Hard to say how much as you cant feel much through that small opening but it has me concerned.The truck runs smooth other than a stumble on acceleration which I'm thinking is the accelerator pump , no smoke, doesnt use oil, no knocks no weird noises etc. Plans were to rebuild and stroke the motor but that will have to wait hopefully.

Hard to say what the actual mileage is but when I spoke to the original owners wife (elderly lady) she guessed 100k, (she sold the truck 5 years ago) odometer reads 84k, judging from the condition of the pedals, seat, carpet etc when I got it I'd guess her memory is off. She said and I believe she is correct, that the motor has never been apart. Just changed plugs and all were a nice tan color. Due to circumstances, the truck is going to be my daily driver for awhile and I'm wondering if I should replace the timing set in the very least.

Nov 23, 2011 | 05:08 AM

jowilker

Fleet Owner

Joined: Jun 1999

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From: Creedmoor, North Carolina

Stretched timing chain syndrome is not uncommon with FEs. It likely will run on for a while as is.

Change it now or wait for a better near future time period. Plan on changing the water pump, heater hoses, T-stat, while you have it apart & down.

John

Nov 23, 2011 | 08:06 AM

Argess

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Joined: Aug 2008

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Even my brand new, very expensive, Made in Germany, chain did stretch a bit. A small amount of play should be normal enough.

However, I wonder if your engine has the plastic covered cam gear. My 289 did, and I think FEs may have used them as well. Over time, the plastic breaks off. You can find pieces of white plastic in your oil pan.

At any rate, this leaves the chain very sloppy. Perhaps some who knows for sure can verify if FEs used plastic covered cam gears?

On the other hand, sometimes we look for perfection when it's not needed. Try to check the slop again. It may move like a fan belt moves, but won't take any pressure to do that. If it really flops around, you may want to remove the timing cover and have a better look.

Nov 23, 2011 | 09:27 AM

69cj

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From: Middle Tn.

My 428 cj had the plastic cam gear and I found it just in time. I could almost jump the chain with my fingers. It had 77,000 miles on it at the time. Take an afternoon and change it for peace of mind. If it jumps you will be going no where and true to Murphy's law, it will jump at the most in-opportune time.

Nov 23, 2011 | 10:43 AM

Rogue_Wulff

Post Fiend

Joined: Dec 2007

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From: Lost

I would almost bet on 76 having the fiber tooth cam gear. As others have said, these degrade over time allowing the chain to loosen up.
The fiber/plastic teeth were used to help silence the noise that can come from steel gears, but that noise is very minimal compared to the peace of mind from knowing the teeth won't just fall off the cam gear, leaving you stranded, typically at the worst possible time........

Nov 23, 2011 | 12:06 PM

85e150

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Get a double roller with the "straight up" timing for the cam. '72 and later 360s may have a retarded cam timing set as OEM. A minor improvement, but an improvement nonetheless.

Nov 23, 2011 | 01:01 PM

travelerest

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Joined: Jul 2010

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Just remember, removing your timing cover is going to expose your oil to contamination. There are many ways to help reduce the contamination, but best way is to replace oil and filter after timing chain replacement, even if you tape off the exposed parts of the oil pan. If this is your first time, and if you tear the oil pan gasket, just remove the gasket material and replace with your choice of gasket sealer.