Sorry Gary, some how missed what you guy were saying here my bad. For TDC this works as long as the stop is stable and can'r bend or flex. The tape deal should work also. How well do the idle mixture screws respond? As you turn them in will the rpm get lower and then die or does it not move to much?
When the origanal intital timing was set to 16 and 18* there was no rpm loss or gain when screws were adjusted. When you turned the screws in one side at a time it would just start running rough but rpm really stayed the same. The other day however when I changed the intital timing to 22* (the mechanical was still 18* I had to readjust the idle rpm back down to 800 and when I adjusted the mixture screws in to where it would run rough I had rpm loss when as I turned them back out the rpm would increase. The engine seems to be responding to the timing increase. I will not be able to run the car today with the 14* in the distributor, sleet to rain most of the day hear.
When you advance the timing it raises the idle so you lower the rpm by adjusting the idle screw down which in turn closes the throttle plates more inturn it starts to try and use the idle curcuit hence why you start to get responce out of the idle mixture screws. Too much cam/motor for that carb, can it be fixed? Maybe some what, is it the right carb for your combo? No.
They will foul if they are too cold. I know at the race track. I had NGK UR6 and it run like a nitrous engine but soon after it started popping and the plugs were black so I went to 5's If it stumbles when you floor it it is usually the carb. I have never liked Eldebrock because Buick needs 800 Quad or bigger. But just like my 1050 Dominator I had to change the accelerator pump cams to make it pump fast enough to feed the stomp of the throttle plates opening. Did you dial in the cam on the build? That is a must with a bigger cam than stock on any engine no matter what make or size. You can take the timing cover off and the valve cover off on number 1, which is drivers side, plus you need to take the intake off and put a solid lifter on the intake lobe so your reading are correct and set a dial indicator on the push tube and check .050 before and after top lift in the direction of rotation and see if it dead on or close with in 2 degrees of the intake centerline on your cam card. But the stumble is usually the carb not shooting enough gas when you punch the throttle. I have lost lots of races because of stumble and the Buick needs a good pump shot to get off the line.
I think he should fix the carb problem before pointing at the cam shaft. Fix what you know is a problem and in this case its the carb. Put 15* int in it and set the idle, then pull the carb off flip it up side down and look at the throttle plate position in relation to the transfer slots then move on to the next thing if your not happy. 1 thing at a time.
If 44's and 43's are colder than 45's (the lower the # colder the plug) Is the UR5 the same heat range as the R45T?
But still if you have the oem spec 45 and the cam is in the right spot the carb makes it hesitate when you stomp it even if the cam is a little off.
I believe he is using the Edelbrock equivalent of the Carter AFB. I used this carburetor years ago on a Buick 350. I could never get it to transition seamlessly into the secondaries. It uses a counter weighted air valve, so there is no way to adjust it, unless you grind on the counterweight to make it lighter. Carter also made an AVS carburetor, and that has an adjustable air valve like a Q-jet. Personally, I would never use either of those carburetors. Either Holley, or Q-jet, or EFI as I will eventually do.
When Fred Catlin met me he said take that 850 Holley off of there and he gave me a Quad and he was right but after wanting to go faster I bought a used Dominator and still had to change the cams on the pump shaft to keep from hesitation.
Thanks for the insight on the Edelbrock secondaries. As soon as I figure out what Holley and what cfm "is correct" and will work with the single plane SP1 intake I'm going to get it and at the very least I will have a better product with more adjustability and hopefully at least eliminate another posibility. As far as the plugs go, if the UR-5 foul out I will get the R44T
Its been awhile since I messed around with an ebrock carb,but if I recall correctly the way to make the secondaries open faster or slower is by changing the spring that is under the 2 slide plates on the top of the carb. If it opens to fast you will need heavier springs,if they open to slow you need lighter springs. I think the silver spring is the heaviest one you can use,this is the one I had to use with the cam I had,I think it was 20+ hg of vacuum.(a stock roller cam) I hope this helps,GL. Derek
No the UR6 fouled but I was using 98 jets all around and it was cold out with the SP1 wit 4" of spacer. When I switched to the Kenne Bell Cool Runner and a 2" spacer I had to go down on the jets. so for stock 70 pistons I would go 44 if you are close to 0 deck.
Derek, I believe he has the Carter AFB type carburetor clone made by Edelbrock. The plates on top, on each side, cover the power piston, spring, and primary rods. Changing the springs just affects the enrichment rate or timing. The secondaries have fixed jets, and a counter weighted air valve. Looks like this, http://static.summitracing.com/global/images/prod/mediumlarge/EDL-1406_ml.jpg
Deluxe what kind of ignition you have? I run UR-6'S with 10-7 comp. with a MSD my plugs are fine.The boys are on the money with the carb not right for your cam.I went crazy with a new built would not idle had timing up 22 before it ran. The cam was custom grind 509-519 235-242 on a 108 I then locked timing out at 35* with a start retard. Like Chris says look at the plates mine were open 3/8.I got a Cliff Ruggles maxed out Q-jet 850cfm with all the idle circuits done hit the key it was at 1300 turned down to 900 for a nice idle.When weather gets better I'm going to see if it will run with timming back at 20* and 14*That carb is too small for that build see if you can get a good q-jet to try or holley you will see the difference.
