shaking at idle
 

today while I was reworking my cylinder head, I found #5 and #6 exhaust valve only holding 10 Hg, so I reworked the seats and they are back to 25 Hg.

here are some pics of my rebuild

the pictures with the exhaust valve out, that is after I reworked it (on a peterson 25 guide and seat machine)

the picture with the piston, this was the worst of them(just alot of carbon build up)

here is before and after pics

when you say shaking at idle are you talking about like sitting at a stop light and all of the sudden your truck starts to shake a little? cus i have that problem every now and then some times worse then others

Good work Cummins Guy, very nice! :tu:

If the idle rpms drop too far these baby's will shake like a stripper needing to make a rent payment.:rocking:Rocky

I have that same weird shake when i come to a stop at a light..... sometimes its worse than others also. Its got me confused.

so is it something that i should look into and maybe turn up the idle a bit? or is it just something that wont really make a difference other then stopping a little bit of shaking every now and then? thanks
Tanner

What's your timing set at? If you increase the timing it will shake the engine a bit more. Although not sporadically... Is your KSB cycling on and off?

mine did the same thing. almost like a nasty lope sometimes. especially after getting into it hard for a long shot. i some things i thought of are maybe timing, possible air in fuel issue, or idle too low. i turned the pump up some more to bring my idle up 100 rpm and it seems to be doing better now. i just havent had time to look into messing with my timing yet since its advance 1/8" to the head.

Its probably a injector with a bad pop... Clean and pop test your injectors...

the shake is almost like a bad lope, when Im running down the road (highway), it went away and then when I get off the highway and come to a stop it shacks( just a little, even when I rev up the engine to 900 rpm it shakes, anything after 900 it goes away) and when I start to take off it has a little more shake to it, but when the truck is up in rpms it goes away.

the valve were not that bad, they were reading something like, 10 hg all I did was use my quickway to clean the seat and installed new valves.

it wasnt that bad of a shake, it just that I go down the road with the radio off and listen to every little noise, I guess you can say, I'm finding reasons to rebuild or replace something (lol)

snoot, I thought the same thing, so I replaced my injectors with oem replacments (still did it) said the heck with it and bought 5 x 14 from SDX (BRICE @ BBD TOOK CARE OF ME) when I put those in, it seem to be gone, took if for a drive (highway about an hour) the shake was back, after the SDX injectors went in, it would only do it after the truck was at running temps, so I pulled the head and found #5 and #6 burnt, have not put the truck together yet, it will be runnning in 3 weeks, I will post results, but I did replace pistons and rings as well so if they were also the blame to the warmup shake, as I call it, not sure. I also decked the head .001 with my new play toy (VULCON STORM 85B)

here is more pics, almost done. just a few other little things that I have to do.


I did find that my fuel pump gear had a hair line crack.

if you look at my first pic(at top of page), you can see that tiny little bowls in the piston.

so what exactly do you mean when you are talking about "10Hg" and "25Hg"?

vacuum, you want your valves too absolute pressure, or very close.

Hg = inches in mercury

oh ok. so how do you test that?

here is a cheap one, mine came with with my machine.
Pistol Grip Vacuum Tester Kit with 4.75" Vacuum Plate | Item #DVC-2011. | Goodson Tools & Supplies for Engine Builders

I buy alot of my tools from goodson, if you are loking for good tools, I would also look at MSC tools, and kwick way by iron tite

I did get the truck up and running as well, the shake is gone, the engine is really smooth and not as load as it was, so I would have to say that the shaking was from the the valves, the only thing that I can say why( when it was cold, the valves were seated better, then when I got it to running temps, it would leak around the seats)

but I also trued the bores to .00005, installed premium rings, had the crank, rods and pistons balanced, decked my head which also trued to .0005, put a 3 angle on the seats (when I took the valves out, I noticed that there was only 2 angles, just the throat and seat, no top angle at all) I have a 3 peice manifold installed with new hx40 (laggy on the bottom end)
I also had my balancer re-balanced, put in a 24v oil pump (just has more gpm's then the old one) 24v water pump (more gpm's as well) new cam (ground to my specs)new tappets, push rods, and bee hive valve springs (didnt really need them but what the heck)and a new clutch velair ceramic (took some time to get used to the clutch letting almost all the way out intill it engaged)oh, and I put in the marine cooling nozzles, they are just longer and direct the oil a little better and helps cool it better

the only thing that I dont like, when I put the foot down, she can smoke just like a freight train, the only thing that I did to the pump was put in a denny 2 pin, no adjustment to the pump(because the pump that was sopposed to go on was tweaked and done, but my guy who did the pump messed up the timing, no big deal, but I just put on another pump and will have him tweak the one on the truck)

wow you got a lot of work done too it. i bet it runs really good now. someday i wanna go through my motor but not for quite a while. although ill probly check into the valves though. what size are your injectors? my hx40 isnt really that laggy. after running my truck on the dyno it seems like my hx40 is at its limit. it doest hold the power like a bigger one should.

my injectors are SDX 5 x 14