Some advice? Maybe?

[GotToGo]

Hi guys,

After my rebuild the truck is running well. Good acceleration and great mpgs. But I have a small vibration mostly noticeable at idle (but I think its there throughout the rpm range). I noticed it right after the rebuild but it smoothed out after driving a few miles so I thought I thought I was ok. Well its still there and I thought maybe there might be some ideas here.

Basically everything was replaced except the alternator and water pump. The water pump felt nice and tight so I kept it. I mention this because there is another small issue, the coolant temp runs up a little too high before the tstat opens and it cools back down. About 3/4 up on the gauge. Now, it did do that before the rebuild but it didn't go that high. I thought it was a sticky tstat so I replaced it during the rebuild. The new one was a 195 and I think the old one was 185. So you might be thinking "well, that all sounds about right then".

But is it possible that the "sticky" behavior is from the old water pump? As well as the vibration?

I don't want to replace the water pump if its fine but I will if this is a plausible solution.

What do you guys think?

Or is the new crank just a little unbalanced? I did NOT have the engine balanced. And I have checked the balance shafts. They are for certain correct.

It has about 700 miles on it and its on its 3rd oil change.

[jamesw]

is it an automatic ?
driveshaft maybe?
a loose universal joint would cause vibration threw the truck even at idle.
loose motor mount?
i would start by putting a wrench on everything just for grins and giggles.

[ragragtimetime]

re-check tension of timing belt?....now that it's "broken in" would be nice to see what the tension is with a quality timing belt tensioner gauge.:shrug:

[royster]

Also, check your transmission mount. It is likely pretty old and possibly cracked. For my 2nd gen truck it was only $15-ish. And it made a huge difference in eliminating vibration. Check RockAuto for prices.

[royster]

It has about 700 miles on it and its on its 3rd oil change.

It's time to re-torque the head.

[GotToGo]

Excellent stuff guys! Thanks!

Its a stick, and I already went through it with a wrench. The motor mounts are new but I'll check them again.

I was planning on driveline and suspension next anyway.

[GotToGo]

Timing belt might be a good idea but I can't afford a tool like that. I'll check it though.

I'll also check the transfer mount and retorque the head.

Thanks again guys.

[85Ram50]

If you did nothing to the driveshaft could it be the center pivot?

edit now that I think of it that would not affect it at idle.:/

[GotToGo]

I don't know what you mean by center pivot anyway.

[GotToGo]

Also, check your transmission mount. It is likely pretty old and possibly cracked. For my 2nd gen truck it was only $15-ish. And it made a huge difference in eliminating vibration. Check RockAuto for prices.

Found it!

[85Ram50]

I don't know what you mean by center pivot anyway.

The bearing in the middle of the drive shaft

[GotToGo]

That's what I figured. But mine is a one piece.

[GotToGo]

Got out and retorqued the head bolts. There were a couple that needed it. It seems to be a tad bit quieter but didn't help the vibration.

I also put my finger on the timing belt while the front cover was off. It did seem a little loose to me. That will be next.

[royster]

Let me just say "kudos" for the re-torque - it IS a bit of a pain, but that extra effort helps assure an enduring reliability, and possibly avoid a blown head gasket. The fact that you found a couple loose bolts justifies this extra step, donchathink ?

[GotToGo]

Absolutely!

I had already retorqued after the breakin. But thanks for suggesting it again.

[GotToGo]

Got into the timing belt today. It was loose but that wasn't causing the vibration.

[jamesw]

is there any way for you to take a vid and post it to youtube? maybe if we can hear it it might help narrow it down

[GotToGo]

I'll see what I can do. But there isn't anything to hear. Its a "feel" kinda thang. :)

I'll get back to you.

[GotToGo]

Here's a short clip. It should have video but I suck at cameras.

https://drive.google.com/open?id=12GSBF0q3_anOUMKVhM_Bgfs4YhKSlykx

[jamesw]

what are the rpm running @?
sounds a bit fast to me i run mine @ around 900-950 in park.
almost sounds like there might be a vacuum sucking.
have you done a vacuum test?
maybe some of the other guys can hear something just spit balling here.
if that is a glass of water sitting there i really didn't see a whole lot of vibration i know it,s hard to tell from a video but it does help thanks for the effort.

[GotToGo]

So the video did work! Cool.
Its a manual and idles at about 850.
I don't hear the sucking noise. Maybe its just from the video, but I'll look into it.
Yes, that's a glass a water. You have to look very closely to see the vibration. As I said, its not a big vibration. Just enough to be annoying.

[GotToGo]

I finally got back to the Dodge and did a vacuum test today.

Steady at 46.

At this point I think I'm going to just keep driving it. Maybe its getting a little better, maybe I'm just getting used to it. :)

[tortron]

Big screwdriver. Pointy end on the engine, handle end up to your ear. Have a listen around the engine and you should locate it

[GotToGo]

Yeah, I've done that.

[GotToGo]

Carburetor?

After deciding I would just live with the vibration, I moved on to other things. The reman carb hasn't been exactly right since I put it on 10 or more years ago (carbs aren't my thing). So I decided to pull it and do the checks and adjustments in the manual. When I took out the 4 main bolts one of them wasn't tight (right rear). It wasn't loose, but it wasn't tight either. I did the checks and adjustments and torqued the bolts, three times.

Vibration went down by 50%. Good ear James, I never heard it.

Its definitely in an acceptable range now. Thanks everybody!

[jamesw]

Carburetor?

After deciding I would just live with the vibration, I moved on to other things. The reman carb hasn't been exactly right since I put it on 10 or more years ago (carbs aren't my thing). So I decided to pull it and do the checks and adjustments in the manual. When I took out the 4 main bolts one of them wasn't tight (right rear). It wasn't loose, but it wasn't tight either. I did the checks and adjustments and torqued the bolts, three times.

Vibration went down by 50%. Good ear James, I never heard it.

Its definitely in an acceptable range now. Thanks everybody!
thank you sir just got lucky lol

[Mits187]

Is it possible that one of the balance shafts was misaligned during the timing belt install thus creating a slight vibration??

[geezer101]

There's always a small vibration - it's an engine after all. And there will be 2 or 3 rpm bands where the vibration will be noticeable. Unless it feels like your legs are getting a massage or the engine is running like a 3 legged donkey it is 'normal'. You will know if a balance shaft is out - it is horrid.

[GotToGo]

Yes, been there, done that. I know its not the shafts. But this isn't normal either. It wasn't there before.

Anyway, its minimal now.