Whoa, back up...you need an EGR to kill the detonation???

[243]

I don't want to confuse the issue with Paul's post so I'll ask here:

The EGR is used to lower combustion chamber temperatures to lower emissions, correct?

The Wagoneers are engineered lean to reduce emissions, correct?

The air pump and injection tubes are used to reduce emissions, correct?

The CTO's, retarded timing, and other devices are used to keep the motor running while the above devices cripple the performance while lowere emissions, correct?

If I am running an aftermarket manifold, aftermarket carb, no air pump or injection tubes, no cat, ect ect ect...I don't need and EGR period, correct?

Detonation is caused by to much ignition timing or to much compression, correct?

I see a number of people who are stating the EGR and other componenets of the original emission system are needed for the Wagoneer to run right...I am disagreeing if a guy is running an aftermarket carb and intake, sans oem emission controls.

I am not stating the above as fact because I am not 100% sure. Somebody clarify all these issues before I go buy a new egr, air pump, injection tubes and whatnot to make my 1406 and Holley carb combo quit detonating...

...I had planned to back the static timing down from 14deg btc to 12deg btc which would have been a lot cheaper :D

[SpruceMoose]

check out my sig to see what i am running. no egr, no air pump, distributor connected to ported vacuum on throttle body, no ctos, no pinging, regular gas, lots of power!

[Lindel]

Right now, on my 79, I only have the PCV hooked up and operating, no other emissions. Runs great, and the only time it suffers from detonation is in the heat of summer, air on, and going up a hill. I could back the timing off, just a hair, and probably increase my mileage by a tenth or two.

[Lindel]

BTW, I'm running the Edelbrock intake, and 1406 carb, best lean idle.

I avg 13.5 city/hwy combined with this setup, and make tons more hp than with the stock 2150, with the same, or comparable mileage. Combine this with the truck being a WT, and that's phenominal, and actually comparable to most modern day SUV's.

I'll be installing a Summit Racing AMC cam and lifters this fall, since I've been able to put the Chero back into semi-retirement (I got a 2000 Ford Focus as a daily driver), and can also fix floorboards, etc. on it.

[JeepFreak]

Pinging can be a combintation of too much timing and to little fuel. Mine actually pinged a little with 14 degrees initial timing so instead of backing the timing off I re-jetted the carb to deliver more fuel under a heavy load. No more pinging and I still get the off the line benifit from the 14 degree's of initial timing.

[Bob Barry]

<BLOCKQUOTE>quote:</font><HR>Originally posted by 243:
If I am running an aftermarket manifold, aftermarket carb, no air pump or injection tubes, no cat, ect ect ect...I don't need and EGR period, correct?
[snip]
I see a number of people who are stating the EGR and other componenets of the original emission system are needed for the Wagoneer to run right...I am disagreeing if a guy is running an aftermarket carb and intake, sans oem emission controls.<HR></BLOCKQUOTE>

You are 100% correct sir! smile.gif

The trouble comes in when a truck with a carb calibrated for use with an EGR valve is run without the EGR valve connected. The oxygen that would otherwise be displaced by the inert exhaust gasses is introduced into the cylinders without the accompanying fuel, which causes the engine to run lean, run hotter, and ping when the EGR is disconnected.

With your non-EGR carb, the carburetor is providing sufficient fuel for that extra air, so no lean running, no hot running, no pinging (due to lack of EGR).

I'd say you just have to back off a few degrees until it starts pinging. Don't forget, though; it's not just initial timing, but mechanical and vacuum advance that can push your timing curve over the edge into detonation range. You may find that backing off the amount or rate of vacuum advance, or even the rate of mechanical advance, is the cure for your pinging.

My Toronado's 455 runs a 10.25:1 (nominal) compression ratio, and would ping under part-throttle acceleration, but by backing off the total amount of vacuum advance by about 4º-6º I was able to run the stock 8ºBTDC timing setting and one step looser mechanical advance springs without pinging on 93 octane gas. Interestingly, the exact same engine in my Cutlass exhibits no part-throttle ping with the stock vacuum advance, but it does start rattling at the top end of each gear due to the vacuum-advance creeping in before it shifts.

I believe the vacuum-advance units on our distributors is adjustable through the vacuum nipple, and I recall seeing the adjustment procedure somewhere, but I can't recall where.

[JeepFreak]

Bobs right on with the vacuum advance being adjustable. Just use an allen wrench and you are good to go. I'm not sure which way does what on them though.

[243]

It was pinging pretty bad on the way home this afternoon...at cruising rpm, even "light" throttle would cause it to rattle.

[trssho]

<BLOCKQUOTE>quote:</font><HR>Originally posted by 243:
It was pinging pretty bad on the way home this afternoon...at cruising rpm, even "light" throttle would cause it to rattle.<HR></BLOCKQUOTE>

I am running a similiar setup on my Jeep (see sig) The first thing you need to is go out with a wrench, loosen your distibutor, and start backing off timing until tje ping goes away. That is exactly what I did, and mine runs great with plenty of power and no driveability problems. I have no idea where my base timing is right now, and I really do not care. Also I have by vac advance disconnected. Someone is going to say I should hook it back up, but no, I wont. I would argue that I have one of the quickest smoothest running Jeeps on the forum, so I dont think I'll change it.

So give it a shot, and if it doesnt work, put it back.
Good luck with the ping, Andy

[reddog]

<BLOCKQUOTE>quote:</font><HR>Originally posted by trssho:


Also I have by vac advance disconnected. Someone is going to say I should hook it back up, but no, I wont. I would argue that I have one of the quickest smoothest running Jeeps on the forum, so I dont think I'll change it.
Good luck with the ping, Andy<HR></BLOCKQUOTE>


I won't argue with success but have you tried running it with the advance connected??

Kerry

[243]

OK, I didn't have time to buy a timing light tonight so I'll have to move it a little without a light.

Which direction retards the timing?

[reddog]

<BLOCKQUOTE>quote:</font><HR>Originally posted by 243:
OK, I didn't have time to buy a timing light tonight so I'll have to move it a little without a light.

Which direction retards the timing?<HR></BLOCKQUOTE>

Turning the distributor clockwise (I think :D)

Kerry

[ September 06, 2001: Message edited by: reddog ]

[nograin]

As you decrease initial advance, rpms will drop!

Back it the hell off and preserve you're motor!

Then when you get the opportunity. Diconnect the vac advance, and plug the souce vacuum line. Run it in high gear up hill, with a/c on or what ever thats close to heavy load conditions. Increase the advance until it just pings under these conditions. Back off 2-3 degrees from the just ping and you should be set not to ping under real worst case. Reconnect the Manifold vac advance. If you get any ping - especially at part throttle, back off the vacuum advance (if its adjustable) and/or make sure the power valve is high enough and large enough.

Like if you're running a 6.5 powervalve, and you need a 10.5. I chased that ping for years before I discovered that was my problem. Power valve should open at about 1/2 of you highway cruise vaccum reading IIRC.

[KWK 1]

I've been reading this thread and I have a ? On my '77 I have what I believe to be a Motocraft 4350 and right behind it is the egr valve. Well I have nothing hooked up to the valve(p.o) I have the pinging noise, sounds like it is coming from the rockers, could this be caused from that not being hooked up. And where does it hook up to?

[Bob Barry]

<BLOCKQUOTE>quote:</font><HR>Originally posted by KWK 1:
I've been reading this thread and I have a ? On my '77 I have what I believe to be a Motocraft 4350 and right behind it is the egr valve. Well I have nothing hooked up to the valve(p.o) I have the pinging noise, sounds like it is coming from the rockers, could this be caused from that not being hooked up. And where does it hook up to?<HR></BLOCKQUOTE>

A 4350 would be the stock 4-bbl for that truck, and since it is an emissions-calibrated carb, it would run lean without the EGR hooked up and ping like you describe.

It should be hooked up to the ported vacuum advance nipple on the front passenger side of the carb, but running through the yellow CTO switch that is screwed into the front water passage on the intake manifold, next to the oil-filler tube (so it doesn't kick-in until the engine has warmed up).

[KWK 1]

Thank you Bob , sun comes up in a few hours I will be out there messing with it.

[trssho]

What's the status 243?

[243]

trssho~

I started retarding the timing, a little at a time until it quit pinging. I heard a little bit after idling in traffic caused the temp to go up on Friday.

Counter clockwise - Advances

I don't know if it would have anything to do with pinging, but I found that two sparkplugs were loose.

I pulled a couple of plugs and they are gray, next step will be to add some fuel and see if the plug color turns tan.

243

[Snakeyes_Tx]

Ping ping ping?? What the heck is PING?? I have had 4 360's in 2 FSJ's and I've never encountered this PING thing everyone here always talks about? Can I ride along with one of you ping monsters and hear it?? :D

The only thing I've had that I've never been able to beat is a little miss every now and then at idle.

[Stuka]

BTW: EGR RAISES the temp inside the cumbusstion chamber by dumbping raw exhuast fumes into the intake under the carb in order to burn up more of the gases. This unfortunately causes you to loose power. But it will allow you to burn cheap gas with out pinging as much.

And yes after you block off the EGR you need to richen up the mixture...if you dont you will run super lean and possibly crack a piston.