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Mel, Lars, and others: I have received my new pull-off from Cliff's High Performance and it behaves the same as the old one. If anything it might be just a tiny bit faster. It takes well under one second to extend when vacuum is released. If you don't mind, please check the following video clip to verify that this pull-off is defective, since it takes nowhere near two seconds to extend. Thank you again for the help, I really want to get this fixed.
I didn't have a helper available so please excuse the quality of the video as I had to do it one handed
If I can find my super tiny drill bit index I can make a restrictor, but I'm not sure where it is since I moved. I don't have anything on hand to measure the hole in the vacuum pull off (I don't have a wire type plug gap gauge) but it looks to me like the hole is about 1/32nd or a little bigger which makes it over 50% larger than the .018" Lars specified. I'm going to see if I can find that drill index to make a restrictor.
Update: No luck so far finding the super tiny drill index, but I figure it doesn't have to be super precise to start. Assuming I don't find the super tiny drill index I'm going to find whatever bit of wire (maybe a bread tie) I think will get me in the ballpark and heat it to make a restrictor.
I just realized, I can 3D print restrictors with the resin printer! I'm going to make 3 different sizes to test, I'll report back with the results.
Last edited by Trip Rodriguez; Apr 21, 2023 at 04:21 PM.
Those are way too big. Hole needs to be down in the .018" range.
They look bigger than they are in the photo. To the naked eye you can't even tell they have holes in them without looking very closely in intense light. The one with the smallest hole is .018 as per your instructions, and it resulted in the retract time being about 2 seconds as you said it should.
Here is proof in case you are unconvinced about the size being correct, this is that smallest one from the post above next to a .020 plug gap gauge. It's incredible what you can do with a good resin printer.
Last edited by Trip Rodriguez; Apr 23, 2023 at 01:05 AM.
It's hard to get a grasp on how small they are in a flash photo. To the naked eye you can't even tell they have holes in them without looking very closely in intense light. The one with the smallest hole is .018, and it resulted in a retract time of about 2 seconds as you said it should be.
Here is proof in case you are unconvinced, this is that smallest one above next to a .020 plug gap gauge. It's incredible what you can do with a good resin printer.
Not on the car, no. I'll almost certainly get to test drive it later this week when the roads are dry.
Also I need to send a message to Cliff's about the pull-off they sold me being incorrect. It's the same as the old one and the opening is far, far bigger than .018" I'd sure like a refund since the part they sent is incorrect but I'm not optimistic. Hopefully they'll surprise me.
From: At my Bar drinking and wrenching in Lafayette Colorado
It's not necessarily "incorrect." Just because a part is "correct" doesn't mean it might not need "tuning" to operate its best on your particular application. That's what working on these cars is all about. Try out the restrictor and see how the engine/car behaves. If it still falls flat, you know you have other issues. The pulloffs used on the L82 carbs were quick-release. The L48 carbs had a slow release. You gotta' play with it and see what your engine combo wants.
Lars
If it still falls flat, you know you have other issues. The pulloffs used on the L82 carbs were quick-release. The L48 carbs had a slow release. You gotta' play with it and see what your engine combo wants.
Lars
I understand, thank you Lars. This seems very promising, and I'm hoping to find the problem solved when I test it but won't be shocked if it's not. I'll be checking the secondary spring setting while I'm at it. I'll also likely swap to jets two sizes up once this testing is complete, and after testing with the Adjustable Part Throttle kit set as rich as it will go.
You mentioned you printed the part. Make sure you printed it from a filament that is impervious to both gasoline and ethanol. Most are not. While this area should not have direct fuel exposure, this is a carburetor you are working on after all.
You mentioned you printed the part. Make sure you printed it from a filament that is impervious to both gasoline and ethanol. Most are not. While this area should not have direct fuel exposure, this is a carburetor you are working on after all.
Thanks Kossuth, it's not filament printed it's resin printed. The part gets washed in a sonic bath of Isopropyl Alcohol, and then UV cured, so it's a whole lot different from the type of 3D printing you're referring to. It's highly unlikely to ever encounter gasoline embedded as it is in the middle of this piece of vacuum hose but it's a good idea to test it anyway.
One thing that came to mind when I read your post was a sticking EGR valve. Your problem sounds suspiciously like one I had with my '79 back when I still had an EGR.
One thing that came to mind when I read your post was a sticking EGR valve. Your problem sounds suspiciously like one I had with my '79 back when I still had an EGR.
My EGR is gone too, headers and block off plate. Thanks for checking though!
The weather here went back to cold and very wet so I haven't had the car out of the garage yet to test the pull-off fix.
Hey guys, I finally got to do my first quick test drive (the weather has been terrible) and my first impression is that adding the .018 vacuum line restrictor to the vacuum pull-off hose did indeed solve the problem.
It's a little too early for me to 100% say it's solved as I only drove the car maybe five miles but so far so good.
Many thank you's to Lars and the others who helped me solve this.
