The Stovebolt Site Forums The Shop Area Engine Shop Slight Stutter

Good Morning all, sorry somewhat of a long windy post.

I have been working on getting the ole girl ready since about last summer, (52 Chevy 3600, 235 Motor 58-62 series by casting numbers) I pulled the head, took it to the machine shop, replaced a few burnt valves, had the shop go through and just check out clean and replace. This was deemed necessary after a valve was stuck and bent a push rod or two. I reinstalled the head, I also checked the cylinders for a lip or ridge, it seemed ok to me, and cylinder walls were pretty smooth not much or any scoring at all. I installed new pushrods, I had checked the lifters they didn’t show much signs of wear and tear. Put in a pertronix points replacement module, and the 40,000 volt 3 Ohm coil. new wires, new cap, rotor, new plugs gapped heavy for a fat spark. And recently replaced the Rochester with Tom Langdon’s Holley Weber.
I still have a slight stutter on acceleration or a miss if you will. I replaced the carb, because the Rochester was pretty leaky, and also I ran the engine a bit excessive out of the old gas tank before I resealed it. I figured it was gunked up pretty good. When I put the new carb on the truck ran pretty good, but alas still has a bit of stutter or miss.
I have adjusted and readjusted the valves per the manual, and am pretty sure they are ok, when I hook up the vacuum and I am getting 17" water column. Very low fluctuation in the gauge reading. The needle bounce between 17 and 19
My last ditch effort to rid the truck of the stutter is a rebuilt distributor, the old one shows some signs of wear, and is a bit loose and sloppy, I will swap my pertronix over and install when it comes in. I just ordered today from Jim Carters to try and take advantage of the stove bolt discount.
I guess in general besides a compression test, and I missing something? I know that’s pretty vast and vague.
I guess I just need a laundry list of things to check and double check. I am more than likely looking over something very simple. Any suggestions would be highly appreciated.

Thanks
Birge

Birge,

It sounds like you pulled the radiator cap and drove a new truck under it!

Describe the stutter or miss. Where do you feel it...steering wheel, seat of your pants, where!

When do you feel it? Under slight load. Can you duplicate it at will.

With all you have done to the engine, It almost sounds like you are feeling a bum u-joint, motor mount or some drivetrain phenomenon.

Stuart

Well, I should have specified that its defiantly engine related, may just be bad timing as if you recall some months back helping me with that. Nevertheless the stutter comes at about mid throttle range kind of a pop, pop cough stutter. I can pretty much produce at will, I really thought it was a carburetion issue either starving for gas, or too much. I think the new dizzy may help me a lot and will also probably cause me to have to go back to square one and retime everything again. The stutter is just that hesitation , it can be felt while your driving but just really as a stutter not really any u-joint or drive train that I can tell, and since I can produce this at idle while sitting, I almost have to think it’s a timing, carb, or vacuum issue?

Hi Birge;
Sounds like you've tried all the usual culprits. I'm wondering about your plug gap though, "gapped heavy for a fat spark" could be your problem if it's too wide. I'd go back to original settings and try it. Also, when you get your new dizzy, after setting the timing initially with a light, I'd advance it until you just begin to hear a "ping" under heavy load. Each engine seems to have it's own sweet spot on this. My '54 235 now has about 10-12 degrees initial advance with vacuum advance disconnected, and checked at idle with a light.

We've been to your fair city, we ate a couple of times at a BIG cafeteria style restaurant. Excellent!

Good luck with your 'bolt.

I,d take a hard look at the plugs. Slow speed & idle while testing can build up some black soot on them & cause that. Also check each one for cracks & loose pocelin. You can crack one putting them in or handling. If not experiment with the timing like the other bolters said.

Thanks for the input guys, yeah I am not sure but I read when I put the pertronix in here that I could get by with a big gap, I forget how big. I will check it out when the new dizzy comes in . Ahh Waldo you must be thinking of Roseners Homestyle Buffet, pretty good stuff.

Thanks I keep all informed



Birge