Sputtering

Engines, Transmissions, running gear, etc.

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Re: Sputtering

Postby Drummerskey » Sat May 28, 2016 6:16 pm

I saw where they would go in your picture but I couldn't remove the base of the air filter or it would drop my hex bar. A hole would have to be drilled for it to work.

She always seems like she is on the edge of running so perfectly but not quite right. Like I am running on 93% of the car's real potential.
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Re: Sputtering

Postby Mark Reid » Fri Jun 03, 2016 9:12 am

Drummer, Give me a call. I went through this process years ago and resolved all issues (an none of it had to do with filters or lines or dirty jets) Will do a write up about my process and experiences soon but do not have time to do it at the moment. 8322516600. Ask for Mark Reid. Thanks.
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Re: Sputtering

Postby Mark Reid » Fri Jun 03, 2016 9:14 am

Or give me your number and I'll call you. Thanks.
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Re: Sputtering

Postby RVosari » Sat Jun 04, 2016 5:47 am

So...the solution in 30 seconds...was it a problem with the wrong advance curve on your distributor Mark [8D]

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Re: Sputtering

Postby Drummerskey » Sat Jun 04, 2016 6:36 am

I'll likely call at some point this weekend. Thanks Mark
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Re: Sputtering

Postby Mark Reid » Sun Jun 05, 2016 5:05 am

Went through a couple years of chasing down multiple little things. Many of the things mentioned already (and some of those ended up being problematic). When I bought my car (with 3,000 miles on it) I had crappy burned out intake gaskets (assuming from back fires), leaking exhaust gaskets, etc. Completely rebuilt and blueprinted a killer motor, custom exhaust, custom cut Phenolic intake separators, external oil cooler, ceramic coated piston and combustion chambers, etc - No detail spared (you get the picture). After putting it all back together, obviously, many problems were gone but then I spent many months syncing and re-syncing carbs. Popping and sneezing problems. Seems like I could get it synced while cool but then gave me problems while warm - or get is synced at low rpm but not high or the inverse. Went through the proper process over and over. Long story short, I started examining the complete throttle linkage setup and determined that there were a combination of things that added up to just enough "play" in the system between left and right side to make it impossible to stay in sync (and it doesn't take much). These were my findings that were problematic:

a) ball-end cross linkage had wear and caused some play
b) further, the wear zones changed as the engine grows with heat at different rate than cross linkage.
c) cross linkage bar was to flexible causing a disproportional down force due to the offset of the throttle cable mounting point (at least that was my observation).

Dumped the setup and fabbed my own cross bar linkage setup. Nothing fancy but high quality parts and tight tolerances. The result: I have not had to sync a carb in 8 years. Runs like a top hot or cold, humid or dry, high rpm or low.

Not saying this is your problem but you've eliminated a lot of other common causes (as did I). Might be worth inspecting the system. Any play in the system can mess up the geometry between left and right under varying conditions just enough to cause popping and sneezing.
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Re: Sputtering

Postby Mark Reid » Sun Jun 05, 2016 7:17 am

Here are a few before and after pictures over the years (including my current aluminum interior, leather, seats, rear brakes, etc. project). I think there is a pic of the throttle linkage setup I made (like I said, nothing fancy but it works).

https://www.flickr.com/gp/17316178@N02/q54S9N
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Re: Sputtering

Postby Mark Reid » Tue Jun 07, 2016 4:00 am

Forgot to mention. As you can see in the pic, the design allows for a) horizontal adjustment of the bar to slightly preload to accommodate expansion when warm but more importantly b) left/right vertical adjustment to fine tune and sync the length of the throttle linkage rods and ensure angular geometry is good between left and right. Also, tested a a few different cross bar materials. Only challenge is making sure crossbar is drilled and threaded very straight. Since I did not have precise enough tools, I used pre-drilled, reverse thread turnbuckle hex bars and high quality rod ends.
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Re: Sputtering

Postby Mark Reid » Wed Jun 08, 2016 11:16 am

May have had some bad permissions on the photos. Sorry if so. All public now.
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Re: Sputtering

Postby Drummerskey » Wed Sep 07, 2016 12:41 pm

So....................Need some suggestions and reviving this thread since I am having issues again. As an update, she was running pretty well for a while but on the last drive, sputtering happened again. Now, it is on acceleration only and once I hit higher rpms, it's fine but she is doing it every time I accelerate and then it stops. Gear changes, taking off at the light and it sounds like it is missing a cylinder occasionally (could just be more stutter). It's pretty bad sputtering right now. I have been getting more popping than previously as well.

I am having a mechanic (a new one) do a tune-up. He already plans to adjust the valves, sync the carbs again, check the timing according to Larry's recommendation, do the fuel pump and change the valve cover gaskets.

I did find some loose screws over the weekend, before I took it for a drive. The valve covers bolts were loose and the header bolts were loose as well. They weren't about to fall off but loose enough. I was wondering if any of you had other possible causes I could have him look at. I was thinking points, spark plugs, possibly spark plug wires and if he felt froggy, replace the manifold gaskets and exhaust gaskets.


I shouldn't have to have the carbs synced 3 times in a year, right?
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Re: Sputtering

Postby Larry Jowdy » Wed Sep 07, 2016 1:07 pm

2 things to check. First is the idle jets. Second is a poss. Exh or intake leak
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Re: Sputtering

Postby Drummerskey » Wed Sep 07, 2016 3:54 pm

Thanks Larry.....I am thinking exhaust leak but hoping it isn't. Those bolts at the headers were lose and I am wondering if the gaskets are crap. I cleaned the idle jets twice in the past month but really didn't see anything either time.
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Re: Sputtering

Postby Drummerskey » Tue Sep 20, 2016 2:34 pm

Had lots o' issues to be fixed but only one unresolved. All of the ones that were fixed seems to have really helped.

My spark plugs were loose enough to untwist by hand and low quality ones. The disk on my distributor wasn't seated properly, I had a gas leak under the gas tank, my valves needed adjustment and one of my rockers were cracked but not broken......voila, sputtering :)

I did switch over to an electric fuel pump, changed out fuel lines and replaced the spark plugs. She is running so much better
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