1971 C10 Starter/Timing/Transmission Issue

[68 P.O.S.]

My fault, I forgot to mention the article shows a Holley. It's the same concept tho. I can't see the transfer slots in your pics (they're in the bores of your crusty primary throttle blades). Check out post #10 from 454HO in this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=435769. You can see the vertical transition slots at the tip of the throttle blades. They look rectangular in his pic and they need to be a square. You don't have to get them perfectly squared with a feeler gauge, your eyecrometer (haha) is enough. Your idle adjustment screw moves the throttle blades, as you noted, and that is how you square the transfer slots. Your fast idle screw doesn't affect the transfer slots, it's function is to set your choke rpm (1500 rpm stock) when warming up the engine.

[GreyGhost85]

Originally Posted by 68 P.O.S.

My fault, I forgot to mention the article shows a Holley. It's the same concept tho. I can't see the transfer slots in your pics (they're in the bores of your crusty primary throttle blades). Check out post #10 from 454HO in this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=435769. You can see the vertical transition slots at the tip of the throttle blades. They look rectangular in his pic and they need to be a square. You don't have to get them perfectly squared with a feeler gauge, your eyecrometer (haha) is enough. Your idle adjustment screw moves the throttle blades, as you noted, and that is how you square the transfer slots. Your fast idle screw doesn't affect the transfer slots, it's function is to set your choke rpm (1500 rpm stock) when warming up the engine.

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[68 P.O.S.]

Yes, those are the transition slots. Once squared, don't adjust the idle screw anymore. Put the carb back on, connect vac advance to the full manifold vac port on carb, and see where your idle rpm is at. Remember how I said your engine rpms go up and down as you adjust timing? Since your slots are now correct, turn your distributor to set your idle rpms to 750. Then you should be in business.

[GreyGhost85]

Originally Posted by 68 P.O.S.

Yes, those are the transition slots. Once squared, don't adjust the idle screw anymore. Put the carb back on, connect vac advance to the full manifold vac port on carb, and see where your idle rpm is at. Remember how I said your engine rpms go up and down as you adjust timing? Since your slots are now correct, turn your distributor to set your idle rpms to 750. Then you should be in business.

Ok awesome, I’ve adjusted the screw to the point where it is literally as square as it can get and the screw is barely in lol. That vertical slot was pretty long and I had to back that screw out significantly but you see from the pictures that it is square as I can get it.
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[68 P.O.S.]

Excellent, looks good! Making good progress

[GreyGhost85]

Originally Posted by 68 P.O.S.

Excellent, looks good! Making good progress

Ok so with tdc on point, the transfer slots squared , set timing to 8, attached vac advance timing stayed at 8, haven’t tested at higher rpm because of rain, the rpms are at 900-1000 ish, waaay better than 1400, I set idles screw all the way in snug, the backed out 1 1/2 turns for both sides. Still stalls in reverse but haven’t had a chance to fine tune idle screws for max vacuum and mixture.
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[GreyGhost85]

Update... from smooth idle to now the truck barely wants to run, give it gas and it wants to die and it is hesitating bad. Disconnected vacuum advance and nothing changed timing wise. With it connected nothing changed as well. I feel like it has been one step forward, 20 steps backwards with this thing.
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[GreyGhost85]

So the distributor vacuum advance screw was fully seated backed off 5 turns or so and raised the rpms, the timing advanced as expected. My next though as it was suggested on here fuel pressure regulator. Would symptoms of a flooded carb cause symptoms of hesitation at wide open throttle? I’m thinking of trying to obtain rubber gaskets and ditching the paper ones. Timing and idle has been corrected, just to figure out this weird reverse issue.
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[68 P.O.S.]

You’re getting there lol. Is this the new distributor you posted the pic of? 5 turns out is in the ballpark. After you got the vac canister working, did you check to see how many degrees of vac advance and mechanical advance the distributor is giving you? Need to know those numbers so you can set it up right as well.

Please explain the hesitation in more detail please. When it happens, how it acts when it happens, any noises, smelling fuel…any details to further explain it. Getting the Edelbrock 1487 calibration kit will likely tune the hesitation out. It could be the accelerator pump or step-up springs. Which hole is your accelerator pump connected to? It should be in the middle hole to start with and only 13/32" of the pump rod should be exposed above the top plate of the carb. I looked at your carb pics, but can’t really tell. Your step-up springs should be roughly half the rating of your vacuum level. After you set the timing and the carb IMS, what is your vacuum level now? Check out this video from Jegs on tuning the carb: https://www.youtube.com/watch?v=wR_AfQjyT-A Check your fuel filter also and make sure it's good.

Getting a pressure regulator is still a good idea for this carb since we don’t know what the fuel pressure is. Geezer#99 is correct in saying “Sometimes your fuel pump will be fine at idle without a regulator, but with increased rpm the fuel pressure will rise up enough to overcome the needle/seat. You can look in the carb to test this at idle and higher rpm.” This is why I went with the Edelbrock fuel pump myself. I didn’t want to mess with a regulator.

Now for the tranny issue, I don’t know much about them at all, so someone else is gonna have to chime in on this one.

[GreyGhost85]

Originally Posted by 68 P.O.S.

You’re getting there lol. Is this the new distributor you posted the pic of? 5 turns out is in the ballpark. After you got the vac canister working, did you check to see how many degrees of vac advance and mechanical advance the distributor is giving you? Need to know those numbers so you can set it up right as well.

Yea so after 5 turns out I was able to acquire some type of advance at these RPMS.base timing set to 10 degrees, 0 advance at idle (800 RPM), at 1500RPM advance was at 15 degrees. my scale and balancer max out at this measurement. I could use gun to get additional measurements but need to wait for friend to come help. But reving to higher levels, I can clearly see the advance now as opposed to before. Will try to follow up with more advanced records.

Please explain the hesitation in more detail please. When it happens, how it acts when it happens, any noises, smelling fuel…any details to further explain it. Getting the Edelbrock 1487 calibration kit will likely tune the hesitation out. It could be the accelerator pump or step-up springs. Which hole is your accelerator pump connected to? It should be in the middle hole to start with. I looked at your carb pics, but can’t really tell. Your step-up springs should be roughly half the rating of your vacuum level. After you set the timing and the carb IMS, what is your vacuum level now? Check out this video from Jegs on tuning the carb: https://www.youtube.com/watch?v=wR_AfQjyT-A Check your fuel filter also and make sure it's good.

I let the truck run for the longest it has ever run yesterday for roughly 30 minutes and Iturned it off and tried turning it back on. It stumbled into a roughly start then idled properly. when you hit the accelerator, engine almost stalls then picks up the power. No gas smell.
It is just hesitating under strong WOT taps if you hold wot there is a possibility that it could die. NOW i let the engine cool for about 30 minutes or so and bam starts run like normal, then turn it off and turn it back on same thing, hesitation under heavy load. Now i will note that if i move the throttle back slowly, it will increase rpm accordingly and then stutter or hesitate at higher rpms 4000. Like this morning, cold start, bam fires up i can WOT and full response you can hear it really pull. As soon as it it warmed, sputtering and hesitation. I backed my IMS screws out 1 and 1/4 th and it is a lot better. Waiting on a new vacuum gauge from amazon.

Getting a pressure regulator is still a good idea for this carb since we don’t know what the fuel pressure is. Geezer#99 is correct in saying “Sometimes your fuel pump will be fine at idle without a regulator, but with increased rpm the fuel pressure will rise up enough to overcome the needle/seat. You can look in the carb to test this at idle and higher rpm.” This is why I went with the Edelbrock fuel pump myself. I didn’t want to mess with a regulator.

Regulator is on the way. I'm not sure if the carb was flooding or the fuel boil issue is back causing the rumbling start after warm and hesitation.

Now for the tranny issue, I don’t know much about them at all, so someone else is gonna have to chime in on this one.

IMPORTANT NOTE**** I for the life of me cannot get the base and spacer gaskets to seal properly torque criss cross pattern 15ft/lbs space and carb. Spray starting fluid at base, and get a response almost everywhere except sides of base and spacer. Brand new gaskets same thing. I ordered some slightly thicker gaskets and have a lot of spare gaskets.
Is there a trick to sealing these paper gaskets? i know rtv is a nono, grease? double the gaskets up? I really think the vacuum leak maybe causing everything. I'm just no sure how to get that perfect seal without some type of sealant around the edge.

[rechinca]

Are you 100% sure your adapter plate is flat? May want to pull it and flat file it to make sure. Had one on the wife’s for doing a similar thing with new gaskets. I pulled it and was amazed how untrue it was. Solved a lot of my problems.

[GreyGhost85]

Originally Posted by rechinca

Are you 100% sure your adapter plate is flat? May want to pull it and flat file it to make sure. Had one on the wife’s for doing a similar thing with new gaskets. I pulled it and was amazed how untrue it was. Solved a lot of my problems.

So today, I literally took the carb off again with the adapter plate, used an 8 in straight edge with a .025 feeler guage. lightly sanded intake manifold with 600 grit, spacer and carb bottom as well. 2 Brand New gaskets (paper) same leak =/, took apart again tried using grease, same leak. Purchased a brand new spacer plate, well the only one available was auto zone those cheap spectere ones, same leak. Although with grease there was a noticeable difference in rpm. still waiting for vacuum gauge in the mail for readings. I really need a thicker gasket, thicker than the paper ones and preferably some type of synthetic rubber or something. Maybe i can make my own or something i dont know, these paper gaskets just aren't sealing. If there was some type of gasket sealer that i could use with a carb, that would do it. its only one spot at the front giving me problems.

[GreyGhost85]

Originally Posted by rechinca

Are you 100% sure your adapter plate is flat? May want to pull it and flat file it to make sure. Had one on the wife’s for doing a similar thing with new gaskets. I pulled it and was amazed how untrue it was. Solved a lot of my problems.

Took everything off again and the 100% new adapter wobbles on a flat surface. The old adapter plate, heavier, wobbles slightly. Who would have thought the adapter plate (new) would be that warped. So warped that I could slide a .02 feeler gauge under it almost everywhere. I so took the old adapter plate and sanded both sides smooth until a .0025 feeler gauge could not or barely not going under on both sides. Repeated for intake manifold and slightly for carb bottom. I lined the adapter plate to intake and checked with a .004 feeler gauge and to the bottom of carb with the same gauge. No gaskets were on and the feeler gauge could not make it through. I’m going to grab some brand new gaskets again and try once more. May even go to harbor frieght and pick up a vacuum gauge as well.
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[GreyGhost85]

Ok guys vacuum leak resolved yay!!!! I went and attempted to grab new gaskets and I saw a mr gasket adapter plate, and I think they are a pretty reputable company. I inspected the adapter plate, and hardwares with the kit and instead of strippable screws, it came with nice deep hex bolts to really promote a firm grip on the base plate, carb bolts were a little short but ultimately they still worked. Started truck up, sprayed starter fluid around base and no leaks. I tunes carb by rpms for the moment and will continue tuning once vacuum gauge arrives.
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[68 P.O.S.]

Nice, glad you got that figured out. Weird your other spacer was warped like that and wouldn't seal correctly. Is it running much better now? I bet you're happy with the progress hahaha. You're almost there!

[GreyGhost85]

Originally Posted by 68 P.O.S.

Nice, glad you got that figured out. Weird your other spacer was warped like that and wouldn't seal correctly. Is it running much better now? I bet you're happy with the progress hahaha. You're almost there!

Yea! You bet and thanks for helping too and everyone else that provided input. I’m a carb noob that was spoiled by electronic fuel injection lol. But yea it was weird that autozone’s spectres adapter was that warped out of the box. But that mrgasket kit looked too solid to pass up for 19.99. The vacuum gauge comes in today so I will see if I can adjust the ims screws for highest vac. I’ll pop the fuel regulator on as well when it arrives and see where were are then.
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[68 P.O.S.]

You're very welcome. Carbs aren't bad at all once you get the hang of it; Edelbrocks are very simple and work well when setup correctly, just like any other carb. Quickly on your way

[rechinca]

Great news. I had a feeling there was some issue of warpage there. Took me a couple of days on the one for the wife’s Ford. I even had to get a thicker almost 1/4” thick gasket under to help with fuel boiloff here. I could never find the leak until I did the same thing and flat filed the adapter and new gaskets. Now, does it move when you put it in reverse?