idle & valve clearance

[JStoll]

hey folks I was working on the service truck today found #1 delivery valve on the pump a lil loose & leaking fuel I thought this would clear up a slight miss (or weak cylinder) at idle which seems to come & go I dident have time to adjust the valves but I did pull #1 rocker cover & the exhaust valve I easily slid a . 025 feeler guage under so if I have time tomorrow Ill get t them adjusted & see if it idles better it pulls like hell & seems to run well otherwise the miss is subtle the truck sat a long time before I got it & Ive only put like 50 miles on it since I wonder if one of the injectors is a lil flakey or varnished? I tried to do a cylinder balance test by cracking the injector lines open to kill each cylinder but the miss is so subtle that it was hard to tell which cylender was weak

Ill start with the valves I know they are WAY out

any ideas on the matter would be appreciated thanks again

JAK

 

[BushWakr - RIP]

JStoll,



Some of the obvious things to look at doing are, for example, running a good double dose of fuel additive thru the pump/injectors. You can us Howes Meaner Power Cleaner, it has pretty good detergent properties as I understand it. Stanadyne is also pretty good, and there are others to choose from as well.



The intermittent/subtle idle roughness can be an injector slightly out of tune/balance. In that case it may be a barely detectable thing... I've found that same thing with mine on occasion. I have driven it so much and paid such close attention to it's sounds that many wouldn't notice the little changes.

I have a poorer quality idle when running winter fuel grade like now.

Also, I've discovered that if the injector line is not very precisely matched to the top of the injector when it is secured in place, that it will have a miss with varying degree of severity.



The valves on these trucks don't really go far out of adjustment too often. Mostly it would be due to poor upkeep in my opinion.

Other than that you should not see a wide variation unless there is lifter problem, rocker problem, cam lobe problem, or pushrod issues.

The 'spec' for the valves is . 020 (twenty thou) exhaust and . 010 (then thou) intake.

You can set them a tad tighter, perhaps 19/9.



Start with a good double dose of additive and go from there, at least that is were I'd start.



bob.

 

[JStoll]

thanks bob I realy apriciate your input I had thought of that as well (fuel system cleaner) the first thing I did when I got the truck was change the oil & fuel filter. the truck realy needs to be driven. as I put this truck back together I see how neglected it was as well as some of the poor workmanship on behalf of the techs who have worked on it. as far as the miss goes I cranked it with the fuel shut off disconected & heard a balanced dip of each cylinder no obvious low comp (this is what I do with gas engines it works great if I hear uneven comp I do a real comp test) also its not puffin blowbye so I dont think its major

once again Im verry glad I found you folks & verry glad I bought the old dodge

this is a great resource & the people here are awesome

take care

JAK