I thought this was howbtobtune a carburetor. He keeps referring to something he talked about before. Ot as if everyone knows the basics of an old sholl Holley. For the love of God. Just show us how to tune the damn Carb.
Based on the venerable Autolite 4100. Annular discharge secondary ventures are a Autolite feature. Have a 1965 vintage 4100 with a 1.12 main venture on my Galaxie and it runs superb. If the Sumitt carburetor runs like a original Autolite, so it's a great carburetor. Still have to see one installed to say for sure.
My only criticism is the video seems less about "tuning tips" and more about describing what is the street & strip carburetor. I've got one on a 318 Dodge, all stock except for Comp Cams "high energy" 268H cam & double valve springs. My problem is I am located in Calgary, Alberta, Canada which is at 3,500 ft above sea level. The choke & idle all adjusted easily enough, but it runs very rich & tends to stall a lot until it warms up. That's why I'm looking for a real "tuning tips" video. I mean, I have the DVD and the book it came with. I guess my first problem is sourcing some different size jets, maybe some springs & maybe a different power valve. Suggestions much appreciated.
+Grunchy, There are many tuning videos and books out there for Holley carburetors, and many of the basics will apply to our carburetor. As for the tuning parts specifically, of course you can call us and get those! We also have a tech line available for you to call for more assistance if you would like.1-330-630-0240.
Kinda pisses me off that he's literally pointing at the accelerator pumps while saying power valves. Thanks for the tuning tips as well. Really got down to the nitty gritty of the.... Sales pitch!?.. FFS summit. This is B.S. and you know it. I have real tuning questions for your 750 dp and they are not even remotely answered here.
Whole lot of talking to say only a couple helpful things. How many times did he tell us there’s no metering plates and it’s a one piece body? You can see that by looking at the carb as it’s sitting on the car.
Summit drinking game video, "bad boy" two drinks, "Puppie and "Okay" one drink....I like the design of the carb from Summit. Autolight carb basic design with a single top but uses Holley style Accel pumps, pump cams, Jets and center hung floats adjustable from the outside. Also they moved the idle enrichment screws to the sides at an angle. so easier to adjust. Love the Autolight style removable dogleg style boosters. Should be a great performing carb.
I have a summit 750 double pumper on a 350 that has less than 10 inches of vacuum at idle at 750. It idles great after changing the front idle jets to 55's. It also seems to cruse fine. However it does not switch into main jet at all smoothly , unless you hammer it . I did not understand if I change the front idle jets do I need to change the rear idle jets? Is that still the idle circuit?
Has there been any talk yet about the leaking throttle shaft seal? I have two of these carbs and both have been replace by summit because there is no way to fix it one it starts leaking vacuum. The first carb lasted about two years and the second one leaked right out of the box. I commend summit for replacing them but if they start leaking again I'm back to square one. They are very easy to tune.
Summit Racing I am confused on how to install the Throttle Valve Corrector part #SUM-700202 I have a 1986 chevrolet monte carlo ss and I installed one of your pro packs (carb and manifold pack) and I had to buy part ## SUM-M 08080 I installed that no problem but I would love to see a video how to install the Throttle Valve corrector. I am so confused on that
Hay It's 2020 you are so out of date isn't funny sadly I've been buying from you company for 30 plus years cause it was a race car parts store gotta say here in 2020 I'm very Disappointed in your company
My issues are , increasing accel pump to 50cc and changing accel pump cam, no clearance , also how cna you change squirts to aloow better tuning , on Foot brake drag racing?
Hi Mike Neal, The internal vacuum source for the vacuum secondary’s is sourced from the primaries. Once the primary throttle bores are wide open under load there is a sufficient amount of vacuum to pull on top of the secondary diaphragm to open the secondary.
Hi summit just wanted to ask if I can use the Summit racing 750 cfm vacuum secondaries carburetor in a chevy 350 High performance engine with one of your solid flat tapped circle track cams part number (CT-109) And will I have enough vacuum for the brakes? Thanks Summit
Hi Husam Abdulzahra, That camshaft would not be recommended for street type applications with Power Brakes as it will have very little vacuum. The Summit carburetors have plenty of tuning parts available that you can use to tune it for your application!
At no time do the instructions state if the "idle restrictors" are idle fuel or idle air restrictors. If this were made clear a basic understanding of their purpose would be more clear. Also I am disturbed by the looseness of the idle mixture screws as they thread into the carb. This creates a calibration issue because of the ability of vacuum to bypass the threads. Also why aren't accelerator pump linkage levers and new idle mixture screws available separately for these carbs? They are different in design, although similar in appearance, than those offered separately in your catalog for the Holley carbs? The accelerator pump linkage arm on my carb didn't want to ride on the nylon accelerator pump cam properly and I wanted a new one. Also, over time the throttle mix screws may develop a groove in them if overtightened and need replacing. In my case, I was trying to source new mix screws to see if there may be a better fit than the originals. The thread size is different from the mix screws available separately for the Holley 4150 and 4160 style carbs.
+William Charles, Your concerns about the “Idle feed restrictors” are covered here on the instruction sheet that accompanies the assortment kit SUM-M08041. As for the other parts you mention, while our carburetor may share some of the same tuning and replacement parts as a typical Holley, they do not share all. Feel free to give our tech line a call and we can help you find what you need. 1-330-630-0240
Summit Racing Thanks for taking the time to respond to my questions. You all are a great group of folks and I will continue to do business with you. If it wasn't for some of your in house brands, I'd have a tough time enjoying my favorite hobby. The carb that you offer with 600 CFM and Vacuum Secondaries has worked well with my Ford 5.0 Liter with Ford Racing's B303 camshaft.
Very good so far.I have a Summit Racing 600cfm Vac Sec on my '65 Cutlass 330V8.Tuning for best vacuum didn't work for me as the engine produces under 8" of Vacuum and I don't see any changes to the vacuum when tuning.I have ended up leaning out the idle mixture screws as far as possible and stop just before I hear any change in the engine's idle.It's apparently well known that these engines have low vacuum ex factory and when you put a warm cam in them it gets worse.Was it a bad idea to put a vac sec carb on an engine that has vacuum issues like this? Also, can you tell me where I can find more video in regard to tuning Summit's own carbs? Thanks
Norm Salisbury, There are two types of vacuum that can be checked at the carburetor. One is manifold vacuum and the other is known by a few names; ported-timed or venturi. The manifold vacuum signal is produced by the motor and is used most times for power brakes and the modulator on an automatic transmission. Ported, timed or venturi (all the same) is created by the air rushing through the primary venturi of the carburetor. The vacuum pod that pulls the secondary open on your carburetor is operated by this type of vacuum signal. Therefore, as long as you have air rushing through the primary venturi when you are trying to get the secondary’s to open; the size of the camshaft and ignition timing will have little effect on the secondary opening. Now, there are other springs that can be purchased separately that will tailor the secondary opening to your driving habits! This spring is located inside the secondary diaphragm pod on top of the rubber diaphragm. As far as more video’s, any Holley video information can be used for information and applied to your carb, just make sure you purchase the correct tuning parts for the Summit carbs!
nice vid....i have a problem on my 97 mitsubishi lancer EL carburetor type. My engine runs like it is choking on something but it runs smooth again after i fully step on the gas...we did a carburetor cleaning already but its still the same what should I do next...tnx in advance..
Hi Kriston Lee Fuchigami, We have a few questions for you. Do you mind giving our tech department a call? 1-330-630-0240. We look forward to your call. Thanks for watching!
It is very easy to change the jets, squirters, etc. on those carbs. Please email our tech department with your application specifics, they can recommend a good starting point for you. help.summitracing.com/app/ask/
Summit Racing I just watched the DVD that came with carb. Looks like I take the top off, no gasket to worry about, and change jets. FYI,, Summit should do a TH-cam video on altitude tuning. There’s a video floating around saying Summit carb is a nightmare to change jets on
Hi Jesse, The carb stand displayed in this video are the Summit Racing Carburetor Work Stands; part number SUM-G1429. Here is the link: www.summitracing.com/search/product-line/summit-racing-carburetor-work-stands
I am glad to see that Summit picked up this carb casting. I had one from Holley, LOVED IT but if I nailed it hard, it had the dead spot and there were no way to change the pump shooter. I see that you have corrected that and have a whole line to support this casting. When finances are more available, I would love to put one back on. Leaning toward the 750 vac sec and I will order the larger shooter at the same time. Thanks again, from a future customer,
Sorry, I couldn't finish watching. Please watch your own video and count how many times you say "okay","all right", and "ah". Your message is lost in the overuse of these three words, not mention "puppy" and "bad boys". I would think Summit would have more quality control on their interface to customers. Try a little rehearsal time before turning on the video camera. A little practice before you convey your message will go a long ways with regard to keeping the customer's attention. Thanks.
nice video, I have the 600cfm vacuum secondary on my 86 camaro. Im running into a problem. I have called into summit and was no help, so hoping you can help. Ill start by saying this engine was in our truck with the same carb(witch was removed,so i bought another one the same) but now im blowing a lot of blackish smoke from raw fuel and when adjusting air fuel mixture there is NO change all the way in or out. Ive had this carb for about 2-3years before installing just because the build took longer then expected. now the engine itself with this new carb has less then 50 miles on it. I said that info because its out of summits warranty. Any ideas? thanks for your time.
Dan F, Three things that come to mind right away, make sure that your fuel pressure is no higher than 7psi. Don’t assume, get a gauge if you don’t have one! Also, make sure that the float level on both front and rear bowls are is no higher than the bottom of the sight glass. Then, remove the power valve and make sure the diaphragm has not dried out and cracked (due to storage) causing improper operation; replace if necessary!
I thought this was howbtobtune a carburetor. He keeps referring to something he talked about before. Ot as if everyone knows the basics of an old sholl Holley. For the love of God. Just show us how to tune the damn Carb.
Based on the venerable Autolite 4100. Annular discharge secondary ventures are a Autolite feature. Have a 1965 vintage 4100 with a 1.12 main venture on my Galaxie and it runs superb. If the Sumitt carburetor runs like a original Autolite, so it's a great carburetor. Still have to see one installed to say for sure.
My only criticism is the video seems less about "tuning tips" and more about describing what is the street & strip carburetor.
I've got one on a 318 Dodge, all stock except for Comp Cams "high energy" 268H cam & double valve springs.
My problem is I am located in Calgary, Alberta, Canada which is at 3,500 ft above sea level.
The choke & idle all adjusted easily enough, but it runs very rich & tends to stall a lot until it warms up.
That's why I'm looking for a real "tuning tips" video. I mean, I have the DVD and the book it came with.
I guess my first problem is sourcing some different size jets, maybe some springs & maybe a different power valve.
Suggestions much appreciated.
+Grunchy,
There are many tuning videos and books out there for Holley carburetors, and many of the basics will apply to our carburetor. As for the tuning parts specifically, of course you can call us and get those! We also have a tech line available for you to call for more assistance if you would like.1-330-630-0240.
Have you ever thought about Fuel injection ?
Kinda pisses me off that he's literally pointing at the accelerator pumps while saying power valves. Thanks for the tuning tips as well. Really got down to the nitty gritty of the.... Sales pitch!?.. FFS summit. This is B.S. and you know it. I have real tuning questions for your 750 dp and they are not even remotely answered here.
Great presentation!
Thanks for watching
I had to turn it off after the third "puppy" reference
+Fairlane351C Summit could have edited it a little better. Still could, for that matter.
I ordered one of these puppies yesterday
NOT a "how to tune" video. But a lot of useless babbling.
I’ve got two of these puppies, a 500 and a 600.
Good carbs.🤘
Whole lot of talking to say only a couple helpful things. How many times did he tell us there’s no metering plates and it’s a one piece body? You can see that by looking at the carb as it’s sitting on the car.
Summit drinking game video, "bad boy" two drinks, "Puppie and "Okay" one drink....I like the design of the carb from Summit. Autolight carb basic design with a single top but uses Holley style Accel pumps, pump cams, Jets and center hung floats adjustable from the outside. Also they moved the idle enrichment screws to the sides at an angle. so easier to adjust. Love the Autolight style removable dogleg style boosters. Should be a great performing carb.
Yes Why don`t Norm show us how to set the float level..Like do you turn the adjustment down to increase the level or OUT to increase the level ???
THATS EXACTLY WHAT I CLICKED ON THIS VID FOR
I have a summit 750 double pumper on a 350 that has less than 10 inches of vacuum at idle at 750. It idles great after changing the front idle jets to 55's. It also seems to cruse fine. However it does not switch into main jet at all smoothly , unless you hammer it . I did not understand if I change the front idle jets do I need to change the rear idle jets? Is that still the idle circuit?
where do the check ball go
Has there been any talk yet about the leaking throttle shaft seal? I have two of these carbs and both have been replace by summit because there is no way to fix it one it starts leaking vacuum. The first carb lasted about two years and the second one leaked right out of the box. I commend summit for replacing them but if they start leaking again I'm back to square one. They are very easy to tune.
Hi there Norm and team ..just wanted to know if I should use that thick gasket supplied with my weiand dual plane manifold
Summit Racing I am confused on how to install the Throttle Valve Corrector part #SUM-700202 I have a 1986 chevrolet monte carlo ss and I installed one of your pro packs (carb and manifold pack) and I had to buy part ## SUM-M 08080 I installed that no problem but I would love to see a video how to install the Throttle Valve corrector. I am so confused on that
Hay It's 2020 you are so out of date isn't funny sadly I've been buying from you company for 30 plus years cause it was a race car parts store gotta say here in 2020 I'm very Disappointed in your company
Hi Karl, this is an older video. We appreciate your business for the last 30 years.
My issues are , increasing accel pump to 50cc and changing accel pump cam, no clearance , also how cna you change squirts to aloow better tuning , on Foot brake drag racing?
I have a 750 electric choke model and am having issues with too much fuel when switching between gears. Any suggestions?
Its on a 472 ci ford big block. Stock cam, heads an edelbrock street intake.
Where does the steel ball go ?
Front or rear spray nozzle? & which hole?
@summitracing will the 750 carry enough cfm for a 454 at 5200’ elevation? If not are there any plans for a larger model?
What are the cam specs, what vehicle is it in, and what is the vehicle mainly used for?
Great video and education. Thanks for sharing.
as far as the base gasket, what if you want to keep your carb base split right to left
you forgot about the different accelerator pump cams.
Where does vacumn come from on the secondaries...is it internal ? Or is behind the electric choke towards the bottom...
Hi Mike Neal,
The internal vacuum source for the vacuum secondary’s is sourced from the primaries. Once the primary throttle bores are wide open under load there is a sufficient amount of vacuum to pull on top of the secondary diaphragm to open the secondary.
Hi summit just wanted to ask if I can use the Summit racing 750 cfm vacuum secondaries carburetor in a chevy 350 High performance engine with one of your solid flat tapped circle track cams part number (CT-109) And will I have enough vacuum for the brakes? Thanks Summit
Hi Husam Abdulzahra,
That camshaft would not be recommended for street type applications with Power Brakes as it will have very little vacuum. The Summit carburetors have plenty of tuning parts available that you can use to tune it for your application!
At no time do the instructions state if the "idle restrictors" are idle fuel or idle air restrictors. If this were made clear a basic understanding of their purpose would be more clear. Also I am disturbed by the looseness of the idle mixture screws as they thread into the carb. This creates a calibration issue because of the ability of vacuum to bypass the threads. Also why aren't accelerator pump linkage levers and new idle mixture screws available separately for these carbs? They are different in design, although similar in appearance, than those offered separately in your catalog for the Holley carbs? The accelerator pump linkage arm on my carb didn't want to ride on the nylon accelerator pump cam properly and I wanted a new one. Also, over time the throttle mix screws may develop a groove in them if overtightened and need replacing. In my case, I was trying to source new mix screws to see if there may be a better fit than the originals. The thread size is different from the mix screws available separately for the Holley 4150 and 4160 style carbs.
+William Charles,
Your concerns about the “Idle feed restrictors” are covered here on the instruction sheet that accompanies the assortment kit SUM-M08041. As for the other parts you mention, while our carburetor may share some of the same tuning and replacement parts as a typical Holley, they do not share all. Feel free to give our tech line a call and we can help you find what you need. 1-330-630-0240
Summit Racing Thanks for taking the time to respond to my questions. You all are a great group of folks and I will continue to do business with you. If it wasn't for some of your in house brands, I'd have a tough time enjoying my favorite hobby. The carb that you offer with 600 CFM and Vacuum Secondaries has worked well with my Ford 5.0 Liter with Ford Racing's B303 camshaft.
What video shows how to connect electronic choke
Mediocre...very mediocre.
Very good so far.I have a Summit Racing 600cfm Vac Sec on my '65 Cutlass 330V8.Tuning for best vacuum didn't work for me as the engine produces under 8" of Vacuum and I don't see any changes to the vacuum when tuning.I have ended up leaning out the idle mixture screws as far as possible and stop just before I hear any change in the engine's idle.It's apparently well known that these engines have low vacuum ex factory and when you put a warm cam in them it gets worse.Was it a bad idea to put a vac sec carb on an engine that has vacuum issues like this?
Also, can you tell me where I can find more video in regard to tuning Summit's own carbs? Thanks
Norm Salisbury,
There are two types of vacuum that can be checked at the carburetor. One is manifold vacuum and the other is known by a few names; ported-timed or venturi. The manifold vacuum signal is produced by the motor and is used most times for power brakes and the modulator on an automatic transmission. Ported, timed or venturi (all the same) is created by the air rushing through the primary venturi of the carburetor. The vacuum pod that pulls the secondary open on your carburetor is operated by this type of vacuum signal.
Therefore, as long as you have air rushing through the primary venturi when you are trying to get the secondary’s to open; the size of the camshaft and ignition timing will have little effect on the secondary opening. Now, there are other springs that can be purchased separately that will tailor the secondary opening to your driving habits! This spring is located inside the secondary diaphragm pod on top of the rubber diaphragm.
As far as more video’s, any Holley video information can be used for information and applied to your carb, just make sure you purchase the correct tuning parts for the Summit carbs!
Summit Racing Thanks very much for your reply.BTW kudos to whoever put the installation and tuning instructions, most helpful.
So with the tuning instructions did you actual fix it or are you being just nice....
nice vid....i have a problem on my 97 mitsubishi lancer EL carburetor type. My engine runs like it is choking on something but it runs smooth again after i fully step on the gas...we did a carburetor cleaning already but its still the same what should I do next...tnx in advance..
Hi Kriston Lee Fuchigami,
We have a few questions for you. Do you mind giving our tech department a call? 1-330-630-0240.
We look forward to your call. Thanks for watching!
Okay!
How easy is this carb to tune for high elevation?
It is very easy to change the jets, squirters, etc. on those carbs. Please email our tech department with your application specifics, they can recommend a good starting point for you. help.summitracing.com/app/ask/
Summit Racing I just watched the DVD that came with carb. Looks like I take the top off, no gasket to worry about, and change jets. FYI,, Summit should do a TH-cam video on altitude tuning. There’s a video floating around saying Summit carb is a nightmare to change jets on
what is the part # on them carb stands?
Hi Jesse,
The carb stand displayed in this video are the Summit Racing Carburetor Work Stands; part number SUM-G1429. Here is the link: www.summitracing.com/search/product-line/summit-racing-carburetor-work-stands
Thank you.
I am glad to see that Summit picked up this carb casting. I had one from Holley, LOVED IT but if I nailed it hard, it had the dead spot and there were no way to change the pump shooter. I see that you have corrected that and have a whole line to support this casting. When finances are more available, I would love to put one back on. Leaning toward the 750 vac sec and I will order the larger shooter at the same time. Thanks again, from a future customer,
Sorry, I couldn't finish watching. Please watch your own video and count how many times you say "okay","all right", and "ah". Your message is lost in the overuse of these three words, not mention "puppy" and "bad boys". I would think Summit would have more quality control on their interface to customers. Try a little rehearsal time before turning on the video camera. A little practice before you convey your message will go a long ways with regard to keeping the customer's attention. Thanks.
+Brian Craft ,
Thank you for your feedback. We work really hard at improving our video skills. Thanks for watching!
nice video, I have the 600cfm vacuum secondary on my 86 camaro. Im running into a problem. I have called into summit and was no help, so hoping you can help. Ill start by saying this engine was in our truck with the same carb(witch was removed,so i bought another one the same) but now im blowing a lot of blackish smoke from raw fuel and when adjusting air fuel mixture there is NO change all the way in or out. Ive had this carb for about 2-3years before installing just because the build took longer then expected. now the engine itself with this new carb has less then 50 miles on it. I said that info because its out of summits warranty. Any ideas? thanks for your time.
Dan F sorry will add when this same model carb was in the truck it ran great!!
Dan F,
Three things that come to mind right away, make sure that your fuel pressure is no higher than 7psi. Don’t assume, get a gauge if you don’t have one! Also, make sure that the float level on both front and rear bowls are is no higher than the bottom of the sight glass. Then, remove the power valve and make sure the diaphragm has not dried out and cracked (due to storage) causing improper operation; replace if necessary!