Engine vibration

Barber31

Barber31

Well-known member
Just when things were going good and I could just jump in and go this new problem starts. I took her out for a drive and I think I accidentally over revved the engine pretty high in nuetral when I was switching gears and after that engine ran rough and the car started chugging along. Kinda like intermittent power I suppose. When parked the engine has a slight intermittent vibration. But no backfiring or smoke or nothing. So what's your guys best guess?
 
if you feel its not running on all 4 take a piece of wire with 2 alligator clips and a screwdriver. connect one end to the screwdriver shaft and the other clip to a head nut. holding the handle touch each lead to the plugs and see if they are all canceling. this will lead you to what cylinder is not firing. then you can ck that plug or do a leak down test on that particular one.....
also make sure your basic settings are good, timing//point gap
 
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Barber31,

I would pull my spark plugs, see if is burning evenly, also take a look at your points.

Maybe flush the carburetor, only do one at a time.

Darryl in Fairbanks
 
Did you dislodge some carbon from on top the piston, and is now in the spark plug gap. Check your spark plugs!
 
it sounds like you have a valve problem caused by over revving engine, run a compression check, all clyinders should read all most the same
 
Dog:cool: here, GEEZ! Why duz folks jump to the conclusion thet he "BROKE" his motor, GEEZE, go easy on the guy, 'til we find out more facts, GEEZ! Buster T.:cool:
 
Bill your right, he may not have hurt any thing, but he did say his problems started after maybe over reving the engine, when that happens the first thing that comes to mind is valve damage
 
ford3 said:
Bill your right, he may not have hurt any thing, but he did say his problems started after maybe over reving the engine, when that happens the first thing that comes to mind is valve damage
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Yo, Buddy, Dog:cool: again, My gess is thet he's got a chunk uf KARBON, ur a COCKROACH, lodged in his spark plug gap:eek: I know about BUGS, I jist stalked a big FLY, jumped WAY up & ATE thet dude!! Buster T.:cool:
 

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I have seen simular to this with street driven car at the drag stripe normally loose carbon deposit s on the valves
dump a cap of oil(30ml) in each cylinder and run for 5 minutes and repeat add some oil down the carburettor if down draft
ps they all think they have killed there engine
 
I don't suspect some high revs briefly will do harm. You would have spent a lifetime looking at dead cars. I worked for a mechanic as a kid, he'd run 'em so fast (static) I'd back away.
If he wanted to purge a carb he'd run it till the engine screamed and put his hand over the carb. Never lost an engine but as a youngin' it was scarey to hear those motors hitting over 7000+ rpm. I thought he was crazy. In most cases it sucked any crap out of the carb. BTW he would hold them there for a while and listen, not just up and down.
 
I did pull the plugs after and they seemed fairly good. Not wet and not overly sooty. No debris between electrode. I can check the points and timing tomorrow but how would I flush the carb as Darrylkmc stated? I've never heard of that process. Also, where do y'all reccomend to get a fitting to check the compression and leak own test? Since our plugs are pretty big did y'all order them from a catalog or would a local parts house have an adapter?
 
Barber31.

Have you tried running your engine since you examined the plugs?

What color where the plugs - White - Black

The Carburetor has a single bolt that holds the bottom on, it is possible that there is contamination in the bowl of the carb.

Darryl in Fairbanks
 
Yes. I have run the engine since. When i pulled the plugs to examine it was the second drive after it started acting funny. I wanted to see if the problem went away before I checked anything else. But like I said, they were blackish.
 
I would bring each piston to TDC on the firing stroke, then put air pressure to that cylinder and listen at the carb intake, exhaust pipe, and oil fill to see if you hear air escaping. Short the plugs first as Mitch said to try to pinpoint the bad cylinder.

You might have a piece of carbon stuck under a valve.
 
Now I'm asking a question and looking for some thoughts. Way back in the 60's spraying water into the carb was a common fix to break up carbon. There was even an accessory that would do it for you.
In small towns were cars rarely got up to temp it was a real problem.

I have never read here or elsewhere that this is a practice.
Is it just frowned upon? Is it ineffective on low compression engines?

If the OP has a carbon problem as suggested is this a bad practice?
 
I thought pulling the head and scraping the carbon off the tops of the pistons and the head was done back in the day. Before fuel injected motors the auto shop instructor did suggest pouring in different concoctions to lube the top end and loosen the carbon. In this part of the woods I don't know if other guys put water in the intake as a preventative but I have tried it on several. out of time motors and bad carbs were the root cause. Regularly getting the motor warmed up should help, especially in the colder states IMHO.
Bob
 
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