I think I have finally found the right forum. I want to aplogize to all the other forums for posting my quetions that didnt belong. So now that I have found the one I am supposed to use, I think, here goes.

I have a 1992 F350 dually with a 7.5 460 engine, I have a pinging problem under load, I am to the point where I think the timing chain may have to be replaced. Any suggestions concerning this issue. 162k on engine. I have been told to put a double roller chain. What do you think?

 

to check your timing chain, remove the distributer cap, then put a large socket and ratchet on the harmonic balancer bolt....now turn the harmonic balancer back and forth about an inch or so, meanwhile have someone watch the rotor bug, if it takes the rotor bug a sec to move when changing directions on the HB there is slack in the chain..... you can measure how much by lining the timing mark up to 0, then turning the crank the other way very slowly until the rotor moves, then see how many degrees the crank moved before the rotor did....post back the results....anything past a degree or two is too much slack, my old 460 that i recently replaced the timing chain in doesnt have ANY slack anymore, compared to the 8 degrees of slack before....

 

I've never seen a timing chain with NO slack....

 

Mine is so tight that is I have a vertical misalignment while installing it it'll stick until aligned again. Of course mine is a Comp Cam double roller 3 way, stock ones are prone to be a P.O.S that are a last resort IMHO.

 

the one i installed is a cloyes stock replacement, and i guarantee it had NO slack after installed...i could move the chain ever so slightly but i wouldnt consider it slack at all....now when i do the test that i wrote about, the only "slack" between the rotor and harmonic balancer is the slight amount from the dizzy to cam gear....

 

Thanks for the responses, I will check the play to see just how far it is off, maybe this week end.
Lets say it is off a degree or so, would that be directly related to the pinging noise I hear when engine is under load?

 

First Ken H let me welcom you to the FTI 385 series board. I would check the timing chain for slack. You might have some outher things causing your pinging problem under load. Does it happen under constant throtal or just under accelaration? You might have a carbon bild up in the combuston chambers increasing compreson. This new gas isn't verrey good. I have a friend that uses preium gas when he is towing his big horse trailer to stop the pinging.
I would still check the chain as you have a fairley high milage engin. You might see what the timing is.
Good luck
Bill

 

If it dose need to be replaced I recomend An Edelbrock set I put mine in msny mile ago and no problems with it plus it was warrentyed never to strech or free replacement

 

I agree with wildbill308! This is a modern FI and stock engine. 160K isn’t that many miles for a reasonably maintained 460. I think the knock is ignition/distributor or spark control system related and testing these is best accomplished in an well equipped shop that services Fords. It could be the chain, but I'd look elsewhere first. IMHO!

 

I would look for a vacuum leak as well.

 

Thanks for all the great replys. I should mention that I bought the truck used and it had some kind of after market timing ajustment put on it. There is a timing control **** in side the cab. This unit has been disconnected since I purchased it. Is it possible that when it was installed there was a different computer chip put in it for this system that could be causing my problem? I also have noticed a build up of carbon inside the distributor cap that looks to be excessive. I buy all my tune parts from Ford so I dont think its a parts issue unless something has been modified that I dont know about.
When I first bought the truck there was not an issue. Cant figure what has changed.

 

Without the benefit of a service manual handy, what are the recommended mileage intervals for replacing a stock timing chain? Mine runs fine hauling around a camper & towing but the motor does have 117,000 on it and was wondering?

 

117,000 is nothing if you have kept it full of clean oil! Take off the dist cap, put a socket on the crank pulley and turn the crank backwards and see how much it moves before the rotor moves. If it seems to takes a while say 5 degrees of crank verses 0 on the rotor, replace the chain. Or leave it be and worry about something else.

 

This is my first time owning a Ford truck & I'll have to tell you it's definitely got some muscle. We were camped out in the sand dunes over the weekend & getting out was a piece of cake with camper & all just aired down the tires a bit & put it into 4x4 low.

Thanks for the tip on the timing chain, a friend of mine is a fleet truck mechanic & said these trucks go well over 200,000 miles no problem.

 

I don't know where you guys got your info onchecking timing chains. But 35 years as a mechanic. The allowed movement is 3/4" of crank movement before the rotor starts to turn. Second 167,000 miles on a stock 460 timing chain is alot of miles. remember they have plastic gears on the cam gear. Mine at 178,000 miles was real wore out. Remember as a chain wears and stretches it advances the timing. If this is you trouble I can't be sure because pinging can be caused by many different things.
Different people believe different things. As for timing chain sets. Can someone tell me when you can get a chain set cheaper than $49. Yes, Jegs offers a Cloyes TRUE street roller chain set for that price. It has 3 timing setings 4 degrees retard, TDC, 4 degrees advanced. I tow with my 86 F250 4x4 460, C-6. I set mine 4 degrees adv. for torque. What a difference it makes. Also improved gas mileage when towing and empty. With some fine tuning to the Holley 4160 600 CFM I'm avg. 11.5 MPG empty. I believe mine will go 300,000 miles with no problem.