'66 427 Timing Chain Slap?

[Mark]

I have a noise that is driving me nuts....at about 1700-1800 RPM, I get a rattle/slap that sounds like it's coming from the front of the engine. I've listened to it with a stethescope, but it isn't as pronounced when the car is not working through the gears so I can't pinpoint it in the driveway. It needs a little load, but not much to be fairly obnoxious. I think it's the timing chain, but don't want to tear into it without being sure. Unfortunately, I haven't owned the car that long and don't know all of the engine history, so I'm not sure how long ago it was gone through/replaced.

Is this common on 427's or should I look somewhere else for a solution? Any advice could help preserve the remainder of my sanity....

Thanks,
Mark

[Clem Z.]

Re: '66 427 Timing Chain Slap?

turn the engine with a wrench on the balancer in the CW direction while watching the distributor rotor till it starts to move. then turn the engine in the CCW direction and see how far the engine rotates before the distributor rotor starts to move in the oposite direction. if the chain and gear are in good shape the balancer should not move very far CCW before the rotor starts to move.

[David M.]

Re: '66 427 Timing Chain Slap?

Could be the crank vibe damper or a pully rubbing on something? Had a simular noise description/complaint with a BB Olds and that is what it was--Bubbas work!

[Mark P.]

Re: '66 427 Timing Chain Slap?

Don't think so, but I could be wrong. It sounds a little too "clacky" for that. It sounds like a bad lifter from the drivers seat, but once you get out of the car, it's definitely leaning toward the timing chain area. I'll take a look tonight.

Mark

[Mark P.]

Re: '66 427 Timing Chain Slap?

Clem,

I tested it last night and the harmonic balancer moved what equated to about an inch and a half CCW before the rotor turned. That really seemed like a lot to me, but let me know what you think. If that's still borderline, then I may be back to square one, but I would replace the chain and gears based on what I saw.

Is there a tensioner that can be added on since I've heard that there isn't one there originally? Maybe based on the fact that I won't be using the car as a commuter, I shouldn't worry about it.

Thanks for your advice,
Mark

[Clem Z.]

Re: '66 427 Timing Chain Slap?

sounds like a lot to me also and there is no tensioner that can be added. just replace the gears and chain with a good quality set

[Mark P.]

Re: '66 427 Timing Chain Slap?

Thanks, Clem. Sounds like I'm headed in the right direction. Sure appreciate your help!

Mark