Pinging at high RPM

[Schroder's 84 Bronco]

Hey all I came back to the states last Oct and and decided to wait to bring my bronco up because I was getting deployed. I just got back in Oct and I finally got my Bronco from my parents house, it had been parked since June 8th 2003, I was pretty lucky that it wasn't flooded or broken into during Katrina. Any way I brought it up here the end of Oct. and replaced the plugs, wires, distributor cap, rotor, alternator, and got a K&N air filter. All of that got it running good enough to drive to and from work but after about 3 weeks it started running pretty bad, I didn't have a timing light so I brought it to a shop and they hit it with a light and said it was only off by 4 and it wouldn't make a difference. I decided to change it anyway so I borrowed a gun from a guy I work with and set it. Now its running much better but pings at higher RPMs, so any info or tips yall have would help.

'84 Bronco

351W 4bbl (Elec. Choke Inop now)

Headers into flowmaster 40's

31x10.5x15 Bridgestone Dueler A/T

 

[bronco351]

use higher octane gasoline as a start

 

[gatorbronco]

I always use at least 89 in my bronco, which I'm sure is pretty standard...If you just adjusted the timing though, you might have it advanced too far also. You can always try retarding the timing a degree or two and see if that makes a difference.

 

[Broncobill78]

Either start using more octane or ****** your timing a bit at a time until it stops, that's what I'd do at any rate.

Glad to have ya back.

 

[Seabronc]

Ditto on Broncobill's comment. Your engine was designed to run on 87 octane. Did you set the timing with the vacuum advance disconnected? I run mine between 12 and 13 BTDC, the tag on the radiator support says 10 but it runs better this way.

Good luck,

>-

 

[Schroder's 84 Bronco]

Thanks for all the advice I will try adjusting the timing again.

 

[ford_zilla]

i dont think changing the octane is going to solve much unless you have excessive HP. its just the resistance of detination.

 

[Seabronc]

i dont think changing the octane is going to solve much unless you have excessive HP. its just the resistance of detination.

That is true, it is a relative number based on fuel formulation. The higher the compression, the higher the octane rating needs to be in order to prevent pre-detonation. A stock Ford engine is designed for 87 and using a higher octane, if it helps, is treating the symptom rather than the cause. On the other hand, if the compression was bumped up then a higher octane may be in order.

>-

 

[gatorbronco]

Yea...I keep forgetting my 351 isn't exactly "stock". Keep on using the cheap stuff if you can!

 

[Schroder's 84 Bronco]

I readjusted the timing and it doesn't ping but it "seems" like it doesn't have as much power as when it pinged, but the main reason I am back on here is because now its hard to start. It now keeps turning over and over and I have to play with the gas and it won't start till the second sometimes third try. I know I need to adjust my electric choke but it does it when I go to restart it right afer I shut it off. I am about to take a look at my plugs and see if they are dirty, they are the Bosch platinum +4. Any ideas would help.

Thanks

Ps when I plugged my vacuum advance to adjust the timing I noticed there wasn't really any suction, I don't know how stong it should be but I am not sure if there was any at all.

 

[Justshootme84]

I'm like Seabronc, had my 351W H.O. set at 12-deg. It made more power but had slight pinging at 300 rpm/60 mph. IF you take it back to 10 deg, the pinging should go away. But so will your throttle response. I had a ton of problems with the electric choke on my reman. HLY 4180 4-bbl. Check the power lead that goes all the way around the engine bay and back to the alternator. If it still has the blade-type connector onthe alternator, replace thatr with an eyelet and bolt it to the alt. That way it won't fall out all the time and make you think the choke is messed up. I carried a small twig about 1" round x 4" long to wedge the buttlerfly open inside the carb. Your engine will not start if the buttlerfly is completely closed. The electric choke is supposed to opne it part way to start. LAst, check the vacuum port on your Edelbrock intake. Make sure the fitting isn't broken and that you're getting proper vacuum to the dizzy and carb. I don't recall the part number for the plugs, but I don't believe the Bosch Platinum's are the correct one. JSM84

 

[Schroder's 84 Bronco]

I'm like Seabronc, had my 351W H.O. set at 12-deg. It made more power but had slight pinging at 300 rpm/60 mph. IF you take it back to 10 deg, the pinging should go away. But so will your throttle response. I had a ton of problems with the electric choke on my reman. HLY 4180 4-bbl. Check the power lead that goes all the way around the engine bay and back to the alternator. If it still has the blade-type connector onthe alternator, replace thatr with an eyelet and bolt it to the alt. That way it won't fall out all the time and make you think the choke is messed up. I carried a small twig about 1" round x 4" long to wedge the buttlerfly open inside the carb. Your engine will not start if the buttlerfly is completely closed. The electric choke is supposed to opne it part way to start. LAst, check the vacuum port on your Edelbrock intake. Make sure the fitting isn't broken and that you're getting proper vacuum to the dizzy and carb. I don't recall the part number for the plugs, but I don't believe the Bosch Platinum's are the correct one. JSM84

Thanks for the info I will check that out tom. I got the plugs form Autozone and they had them as a replacement option for my truck in the computer.

 

[Broncobill78]

I got the plugs form Autozone and they had them as a replacement option for my truck in the computer.

Well, AutoZone is *cheap* I'll give them THAT much but I think that's about *all* anyone here will say about them & I don't say that lightly, I lived in Memphis for better than a decade & that's their homebase & world HQ. They DO have inexpensive parts, I'll give them that much.

 

[bidibronco]

Well, you get what you pay for most of the time. I have always ran the cheapy walmart champian plugs in my truck and the one time I did pay for the Platinum I hated them. Not sure what the deal was but it seemed like they hated my truck or vise versa. No power for some weird reason. Then again, I didn't know there was a drain plug on the torque converter either. Oh well...

 

[BroncoJoe19]

Brett, and all,

If the truck was lying for three years, and your folks didn't use it, the fuel may have gotten a little gunky. I would throw in a can or two of some kind of fuel additive/carburetor cleaner for a start. It may not help, but only costs a buck or two.

If the truck was running fine, is it possible that you got a bad tank of gas?

If so, set your timing back to where it was, and you may be done.

You gentlemen can correct me, but as I recall, engine pinging has to do with engine compression, octane and ignition timing.

I haven't checked the timing on a vehicle in about thirty years, so I am a bit rusty, so if I recall properly, ( and anyone jump in to correct me please) set your timiing at idle. Then to check to make sure that your vacume advance is working, goose the engine. The timing should jump immediately as a result of the vacume advance. Then plug the vaccume line, and run the RPMs up a bit, to make sure that the timing advances by way of the mechanical advance. IF it doesn't advance, then there is a problem with the centrifical advance.

Gentlemen: I am thinking that there can really only be two problems with a centrifical advance:

1. it is stuck and needs lubricant so that it fully advances,

2. the springs are worn, or are weak, and it advances too far, too soon.

is there a chart somewhere that would indicate the proper timing settings at any given RPM, for any given engine?

joe

Just playing mechanic without really being one.

 

[Broncobill78]

Gentlemen: I am thinking that there can really only be two problems with a centrifical advance:1. it is stuck and needs lubricant so that it fully advances,

2. the springs are worn, or are weak, and it advances too far, too soon.

is there a chart somewhere that would indicate the proper timing settings at any given RPM, for any given engine?

Well yes, admittedly those two issues WILL cause the engine to ping but they aren't the *only* two problems that can cause it. Bottom line is that if the timing is advanced too far it will just plain ping until it's dialed back. ****, the distributor hold-down could be loose & allowing the dizzy to backspin. Yes, what you propose certainly *could* be the cause but I'm an Occam's Razor kinda guy and tend to think that a lot of guys tend to twist it a bit too far looking for that snappy throttle response off-idle & then not being happy when it pings at speed. Everything's a trade-off and you have to balance throttle response against detonation. We haven't heard from the guy in close to 3wks so I'm assuming his problem went away after he timed it again. One way or another detonation problems usually come down to timing issues & it's a matter of finding out just WHY your timing isn't what it should be. $hit, maybe the engine is old & the timing chain jumped a tooth, doesn't happen often but I've seen it a couple times.

 

[Schroder's 84 Bronco]

Hey all I finally took my plugs out and they were dirtier than the ones I replaced. I just need to figure out why its running so rich, if any one could help me figure out how to lean out my carb. it would help tons.

 

[Broncobill78]

What type of carb & how old ?