318 camshaft timing question

[gliderider06]

I have a stock 1988 roller cam 318 that I rebuilt some 30,000 miles ago. Stock cam, lifters etc. Dingle ball hone rebuild and freshened up #302 heads. Cast 4bbl intake, Holley 390cfm and a MSD ignition. Runs great, get 14mpg in my Ramcharger with 3.21 gears.
The question is that this dude is loud. I just switched from the dual exhaust to the factory single 2-1/2" exhaust and catalytic converter. I thought that the duals were the reason why it is loud, but not the case. It's loud at the engine especially for a stock Ramcharger.
Another issue I have is It needs 93 octane or the thing will ping like crazy. I have the ignition timing at 10*, total 32 and with vacuum like 50ish. I'm using the med-heavy springs in the MSD distributor and the factory advance stop in the MSD. It doesn't matter what I do timing/distributor wise, it still does this.
Now, i used a stock single link timing set, but I do not remember the brand (I rebuilt it 5 years ago) but it has me wondering if it is off and it has the cam really advanced and causing me to have high cylinder pressure, in turn causing the pinging and such. Every year the dude also fails emission testing with high hydrocarbon and Co2 with my EGR hooked up.
Any thoughts on something I may be missing?
Thanks!
Paul

 

[RustyRatRod]

Regarding the emission testing, you can probably pass if you retard the intitial timing. Have you run a compression test to confirm high cylinder pressure? That would be my next step before possibly digging into anything.

 

[gliderider06]

Regarding the emission testing, you can probably pass if you retard the intitial timing. Have you run a compression test to confirm high cylinder pressure? That would be my next step before possibly digging into anything.

I retard the ignition timing way back, pull vacuum hoses and dump a bunch of guaranteed to pass bottles in the tank in order to pass.
No, I hadn't done a compression test on it. I will this weekend though.

 

[MV8]

For the ping, is the trans kicking down?
For less emission at the tail pipe, less initial timing, higher idle, leaner idle, test egr with vacuum applied for rpm drop at idle, air pump working, cat working, loosen exhaust clamps, rubbing alcohol.

 

[gliderider06]

For the ping, is the trans kicking down?
For less emission at the tail pipe, less initial timing, higher idle, leaner idle, test egr with vacuum applied for rpm drop at idle, air pump working, cat working, loosen exhaust clamps, rubbing alcohol.

Yes, the trans kicks down. It pings with or without it kicking down. As far as the exhaust goes, it had dual cats on it, now with the stock single exhaust it only has one. (Haven't taken through inspection yet with the stock exhaust since I just installed it last weekend). EGR is hooked up and functioning properly. No airpump. Was seized up when I bought the truck and never fixed it.
I have tried 3 different distributors, and best results are with the MSD since I can change springs and limit bushings. I'm using Champion RN11YC plugs. 8.5mm MSD plug wires and blaster 2 coil.
The current 390 Holley has a 10.5pv, 55 jets and a 28 squirter.
I had used in the past an Edelbrock 1406, 600 Holley and a 650 spreadbore Holley all producing the same results in the pinging department. The 390 gives me better MPGs and throttle response.

 

[mygasser]

have you checked that the tdc mark on the damper is actually tdc? if it was mine i'd retard it til it stopped pinging and call it done. but then i've never used a timing light.... ever, for tuning.

 

[RustyRatRod]

Does it ping on hard throttle, part throttle, both?

 

[gliderider06]

Does it ping on hard throttle, part throttle, both?

Half to full throttle it pings. When it kicks down pretty bad. Wide open in 3rd it pings. I generally drive it fairly light throttle to keep it from pinging and help on milage.

 

[RustyRatRod]

Half to full throttle it pings. When it kicks down pretty bad. Wide open in 3rd it pings. I generally drive it fairly light throttle to keep it from pinging and help on milage.

I believe you will find the cylinder pressure high. Simple solution. A larger camshaft. I wouldn't jump the gun, though. Do the compression test first.

 

[TT5.9mag]

Initial timing and total timing have very little to do with when and why it’ll ping. You need to work on the shape of the curve. Specifically around peak torque where it will most likely rattle. The vacuum advance may be a little too early also which can influence the rattle. Step 1. Is always to verify your timing marks on the balancer.

 

[plumkrazee70]

Following

 

[RustyRatRod]

I just now back read. You have a Holley 390 on a roller cam 318 and it's pinging. Might be a tad lean.

 

[George Jets]

Holley 390 cfm is not giving the 318 enough fuel, needs at least 600 cfm.

You are getting pre-ignition because there is nothing in the chamber to burn.


'89 318 Roller, 1406 600 cfm Edelbrock, Mopar HEI conversion Distributor with 60,000 volt E-Coil.
No Ping, No Ping... just go, go, go.....


* * * * *

 

[gliderider06]

Holley 390 cfm is not giving the 318 enough fuel, needs at least 600 cfm.

You are getting pre-ignition because there is nothing in the chamber to burn.


'89 318 Roller, 1406 600 cfm Edelbrock, Mopar HEI conversion Distributor with 60,000 volt E-Coil.
No Ping, No Ping... just go, go, go.....


* * * * *

Thanks, but it also pings with a 1406 Edelbrock, 650 Holley spreadbore, 600 Holley Vacuum secondary. The 390cfm gives me the best mpg and throttle response over anything else.
I'll bump it up a few jet sizes and see what that brings.
Thank you!

 

[Bewy]

318s came with smaller 2 bbls than a 390 Holley...& didn't ping...& weren't lean.

 

[TT5.9mag]

Carburetor size has nothing to do with pinging.

 

[George Jets]

"Another issue I have is It needs 93 octane or the thing will ping like crazy." ^^^

I run the Non-Ethanol in my roller 318, no ping...
A little more money but I don't want that ethanol crap sitting in the bowls of my edelbrock here in the salty humid air of Florida. That ethanol blend will pull moisture right out the air into the fuel.

Put ethanol out in an open air small can while working on a generator. The fuel in the can turned white after sitting open to the air after 1 hour. Yeah, it draws moisture.

______________________

Here is your N11YC Spark Plug

Here is the Plug I am running in the roller 318. GR4 V-Power, it burned clean white after switching to the Mopar HEI conversion and E-coil. Has more of the porcelain and electrode hanging out than your N11YC.

* * * * *

 

[Newbomb Turk]

We know your initial and total but where is the timing curve?

32 total doesn’t mean **** unless we know it’s 32 at 2500 or 32 at 8500.

Unhook the vacuum advance until you get the timing curve sorted out.

And when you do hook it up to ported vacuum. You do NOT need it hooked to manifold vacuum.

 

[TT5.9mag]

We know your initial and total but where is the timing curve?

32 total doesn’t mean **** unless we know it’s 32 at 2500 or 32 at 8500.

Unhook the vacuum advance until you get the timing curve sorted out.

And when you do hook it up to ported vacuum. You do NOT need it hooked to manifold vacuum.

Falls on deaf ears. Again. Said the same thing in post 10

 

[TT5.9mag]

"Another issue I have is It needs 93 octane or the thing will ping like crazy." ^^^

I run the Non-Ethanol in my roller 318, no ping...
A little more money but I don't want that ethanol crap sitting in the bowls of my edelbrock here in the salty humid air of Florida. That ethanol blend will pull moisture right out the air into the fuel.

Put ethanol out in an open air small can while working on a generator. The fuel in the can turned white after sitting open to the air after 1 hour. Yeah, it draws moisture.

______________________

Here is your N11YC Spark Plug

View attachment 1716372763

Here is the Plug I am running in the roller 318. GR4 V-Power, it burned clean white after switching to the Mopar HEI conversion and E-coil. Has more of the porcelain and electrode hanging out than your N11YC.

View attachment 1716372764






* * * * *

Instead of showing pictures that do nothing to help the guy, how about telling him your timing curve on your roller 318 that doesn’t ping.

 

[toolmanmike]

I have a stock 1988 roller cam 318 that I rebuilt some 30,000 miles ago. Stock cam, lifters etc. Dingle ball hone rebuild and freshened up #302 heads. Cast 4bbl intake, Holley 390cfm and a MSD ignition. Runs great, get 14mpg in my Ramcharger with 3.21 gears.
The question is that this dude is loud. I just switched from the dual exhaust to the factory single 2-1/2" exhaust and catalytic converter. I thought that the duals were the reason why it is loud, but not the case. It's loud at the engine especially for a stock Ramcharger.
Another issue I have is It needs 93 octane or the thing will ping like crazy. I have the ignition timing at 10*, total 32 and with vacuum like 50ish. I'm using the med-heavy springs in the MSD distributor and the factory advance stop in the MSD. It doesn't matter what I do timing/distributor wise, it still does this.
Now, i used a stock single link timing set, but I do not remember the brand (I rebuilt it 5 years ago) but it has me wondering if it is off and it has the cam really advanced and causing me to have high cylinder pressure, in turn causing the pinging and such. Every year the dude also fails emission testing with high hydrocarbon and Co2 with my EGR hooked up.
Any thoughts on something I may be missing?
Thanks!
Paul

Does your heat riser in the passenger manifold work? Is it stuck closed? That can cause problems you described.

 

[junkyardhero]

Holley 390 cfm is not giving the 318 enough fuel, needs at least 600 cfm.

total and utter malarkey

all the factory two barrels were under 400 cfm

in what world does a stock 318 need more than a 383 or 400?

it might be lean but that's a tuning issue, *not* a "this carb isn't big enough" issue.

 

[TT5.9mag]

Here’s the funny thing, if it had a 1050 dominator on it, it would probably run leaner than the 390. People need to think in terms of SIGNAL when talking about a carb.

 

[junkyardhero]

Here’s the funny thing, if it had a 1050 dominator on it, it would probably run leaner than the 390. People need to think in terms of SIGNAL when talking about a carb.

c'mon turbo mike! how do they fit that whole red, yellow and green thing in there?

you're pulling my leg again!

 

[Newbomb Turk]

Falls on deaf ears. Again. Said the same thing in post 10

I thought maybe my handsome good looks and charming manner would convince him to to reconsider his timing curve.

Obviously not.