Later Model 318 and Weak Valves???

My '98 Dodge 1500 is ailing a bit this week.
Runs smooth enough on the flats but under any sort of load it stutters, shakes and pings badly.
It's got a new distributor cap/rotor and correct
spec plugs. I always run some injector/fuel system cleaner through it every 3K miles when changing oil and filter.
My long time mechanics think perhaps loose timing chain or worn distributor (the vehicle has 145K miles on it), although I'm leaning more toward some sort of vacum and spark advance problem.
However the mechanic told me a sticking valve might also be the problem. He said later model 318's (and 360's too) seem to have more than their share of this problem. He'd been to some "mechanics conventions" and on various mechanic's technical groups and said others had noted this as well.
Has anyone else heard this? He did say the 318 was over-all a great engine, but that those manufactured in its later years of production seemed to have a lot of valve problems.
BTW, I finally got a "check engine" light to come on yesterday so there should be some computer help in diagnosing the problem next week.
Any comments from AADT welcomed.
SMH
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

How is the fuel filter?

The problem you are leaning towards (spark advance problem) could be caused by the problem your mechanic suggested. By 98, IIRC, vacuum advance was a thing of the past.

Ok, so its a possibility, but the mere suggestion doesn't mean diagnostic work has proven it.

I haven't heard this, others may have. I'd still lean towards the timing chain/gears being worn, which has been a "problem" at 145K since 318's started manufacture in 1968.

That would be helpful.
--
Max

"There are four boxes to be used in defense of liberty:
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I don't know if the 98's 318, has the common plenum gasket problem. But it sounds like mine did before I replaced it. If the 98's 318 don't share the plenum design problem as my 96 - 318, then I haven't a clue. DMSO

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Having changed out a failed plenum gasket on a friend's '98 318, I can assure you that they do :)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
DMSO wrote:

The infamous 318/360 plenum gasket was indeed largely the culprit.
Coolant was leaking into the No's 6 and 8 cylinders causing misfiring and probably contributing towards valve sticking.
Although the truck largely runs well now, with the leak fixed, the mechanics say they've observed valve problems on Dodge 318s associated with weak oil pumps, and suggest I may want to simply replace the engine.
These are pretty good guys that I've had a long relationship with so I know they're not just trying to generate contributions towards their boat payments.
However, they also don't seem especially enthralled with Dodges and I think they may be thinking too harshly of my beast.
I've thrown in some Mystery Oil and may try some other "snake oil, tuneup in a can" type additives, but my thinking right now is I'll just opt to rebuild the heads at some point soon and hope the oil pump stays together and does its thing.
Runs pretty good right now, but power has definitely fallen off and cylinder compression, while good when cold, falls off on a couple cylinders when warmed up.
I think I'd look into a new vehicle before dropping in a new or rebuilt engine. An 8 year old pickup truck with 150K miles and a stick shift isn't a big demand item these days anyways. It will be off to the auction at trade-in time almost certainly.
Cost me $100 to fill up this morning!!
SMH
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

How did you make out with the rain?
Roy

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Roy wrote:

The CT River is as high as I've seen it in quite some time, but no flooding to speak of. Rainiest May on record I believe.
I think you guys got lots more out in the eastern part of the state than we did.
It's been largely dark and cool with rain threatening for almost a couple weeks now, but we don't end up actually getting that much rain.
Is your area staying above flood level?
SMH
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Roy
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I have heard about the valves. The thing to do is run a compression test that will tell you alot about the valves. Also the intake gaskets do go bad, causes vaccum leaks & an engine that pings. Check the converter too. Chrysler has had more than it's share of bad converters lately too
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.