1971 C10 Starter/Timing/Transmission Issue

[GreyGhost85]

Good Afternoon All.

I'm kind of at a point with my restoration where it is almost road worthy and would appreciate any insight anyone has to give. This may be long winded but I try to do as much research as possible before asking questions.
1971 C10 with 1985 305 and TH350C, no major modifications. Once started idles great.

Problems:
1. SBC 305/ TH350C starts here an there. I can start it after sitting for a couple of hours but I can never start it right after it has been running for 20 minutes or so. I have heard of heatsoak from exhaust and placed heatshielding around the starter. I can start it while jumping it from my other vehicle no problems. I have changed all battery cables, cleaned all grounds, replaced ground strap, added an additional ground strap, used some jumper cable to connect the ground of battery to starter bolt. One time i hit the starter with a hammer and it fired up lol and then 20 secs later, no start. When I describe no start it is like, the engine turns over very slow. Sometimes it will start slow then go fast and fire right up. Sometimes it will turn slow and then bam start up. Most of the time, it will start slow and then die all the way down to clicks or short turns. When I jump it, bam turns like it never has before and starts right up. Volts read 11.9-12V and 13.89 when it is running. Battery is brand new, 600 CCA at 0 degrees and 750 CCA at 32.

2. TH350C Stalls in reverse. Had to rebuild the transmission last week because it had 0 gears. Fluid is filled to correct level. During rebuild I noticed vacuum modulator valve was taken out or missing so i replaced it and put a new one in during the rebuild. I added the Transgo 1-2 shift kit, all check balls are in place, all valve body bolts torqued to spec, the whole 9. I have attached pictures of my vacuum set up. 1406 Carb, vacuum advanced port connected to dizzy, pcv valve connected, trans valve on carb plugged. Intake manifold vacuum port to th350c modulator. Th350C lockup plug disconnected. Kickdown cable plugged with delete kit. When truck is on stands, all gears function properly. When on ground, D, D1, D2 all function, the engine drops rpms and i can drive. When put in reverse, the engine rpms drop and then stalls. Torque converter is stock and new. I have checked for vacuum leaks and there do not appear to be any.

The only things not replaced are the distributor and the starter (which was sold over as just replaced upon purchase of my project). Could Timing be an issue here? I read that timing could cause slow cranking and problems when put in reverse because of higher engine load required to go backwards? Like if i don't brake while putting it in reverse it will literally squeak tires and try to zoom. With the vacuum advance disconnected shouldn't the engine idle properly? It idles super high with it disconnected and reverse stalls still.

The truck idles like a champ and just purs smoothly, is there a possibility that not enough fuel flow is getting there for the reverse gear causing it to stall. I swear it acts like it wants to start backing up and then it just stalls. I can feel the load of the engine shift and engage but then it just dies.

Attached is a pic of the harmonic balancer, is the little line grove the factory TDC mark? Or do i have to manually find TDC and mark it.

Again sorry for the long winded details, I try to do as much research as possible before asking. I appreciate any insight.

[68 P.O.S.]

1. It is possible you need a new starter. Having to hit it is one sign of that. I don’t recall the exact year off the top of my head, but 70’s Vette starters are hi torque and mount right up. Another issue is you say you can’t start it after running for 20 mins or so….that sounds like the classic Edelbrock carb boil symptoms to me. You need a heat insulating gasket to cure that, and from your pics, you don’t have one. An Edelbrock 8723 may work for you.

2. I’m not sure what’s going on with the reverse issue, but your tranny sounds good to go to me. What I do see is you need to switch your vac advance hose to the other port next to the PCV port.

Yes, timing very well may be your issue. Timing is your engine’s baseline, if it’s not set correctly, none of your adjustments on anything else will be correct. I shouldn’t say none, but you get the idea. Timing is always first and foremost. To start off, set your initial timing in the 12-14 degree area (with the vac advance disconnected and plugged), plug the vac advance back in to the port I mentioned (your idle speed will jump up once reconnected), set your idle speed to 600 rpm in gear (should work out to 750 in park), and test it out to see how the engine likes it.

[lil hoodlum]

Sounds like to me a weak battery, however you mentioned replacing it with a new one.

I used to have problems with the reman starters from autozone and the like for a long time, until I had it a starter rebuilt from a local business. Have not had any more issues with starters close to 10 years now.

DC Starter Service Inc.

1909 Glenwood Lane
Denton, Texas 76209
(940) 484-6691

Not sure how far Denton is from your location.


I also second getting an insulating gasket/ non heat conducting base for your edelbrock carb. I had to do the same for my edelbrock carb on my old motor.

[GreyGhost85]

Originally Posted by 68 P.O.S.

1. It is possible you need a new starter. Having to hit it is one sign of that. I don’t recall the exact year off the top of my head, but 70’s Vette starters are hi torque and mount right up. Another issue is you say you can’t start it after running for 20 mins or so….that sounds like the classic Edelbrock carb boil symptoms to me. You need a heat insulating gasket to cure that, and from your pics, you don’t have one. An Edelbrock 8723 may work for you.

2. I’m not sure what’s going on with the reverse issue, but your tranny sounds good to go to me. What I do see is you need to switch your vac advance hose to the other port next to the PCV port.

Yes, timing very well may be your issue. Timing is your engine’s baseline, if it’s not set correctly, none of your adjustments on anything else will be correct. I shouldn’t say none, but you get the idea. Timing is always first and foremost. To start off, set your initial timing in the 12-14 degree area (with the vac advance disconnected and plugged), plug the vac advance back in to the port I mentioned (your idle speed will jump up once reconnected), set your idle speed to 600 rpm in gear (should work out to 750 in park), and test it out to see how the engine likes it.

Thanks for the insight. I have attached a couple more pics of the carb. I think I’m going to purchase a new starter, distributor, carb gasket and timing light to see if I can reset things a bit. I may try to recalibrate the carb as well. Also considering changing the mechanical fuel pump out as well. I have an electric pump pushing through the mechanical one only for quick and easy starts. There is a gasket on the carb that’s very beat up as you can see in the picture.
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[GreyGhost85]

Originally Posted by lil hoodlum

Sounds like to me a weak battery, however you mentioned replacing it with a new one.

I used to have problems with the reman starters from autozone and the like for a long time, until I had it a starter rebuilt from a local business. Have not had any more issues with starters close to 10 years now.

DC Starter Service Inc.

1909 Glenwood Lane
Denton, Texas 76209
(940) 484-6691


I also second getting an insulating gasket/ non heat conducting base for your edelbrock carb. I had to do the same for my edelbrock carb on my old motor.

Yea I’m going to get the gasket and see if that helps
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[GreyGhost85]

Originally Posted by 68 P.O.S.

1. It is possible you need a new starter. Having to hit it is one sign of that. I don’t recall the exact year off the top of my head, but 70’s Vette starters are hi torque and mount right up. Another issue is you say you can’t start it after running for 20 mins or so….that sounds like the classic Edelbrock carb boil symptoms to me. You need a heat insulating gasket to cure that, and from your pics, you don’t have one. An Edelbrock 8723 may work for you.

2. I’m not sure what’s going on with the reverse issue, but your tranny sounds good to go to me. What I do see is you need to switch your vac advance hose to the other port next to the PCV port.

Yes, timing very well may be your issue. Timing is your engine’s baseline, if it’s not set correctly, none of your adjustments on anything else will be correct. I shouldn’t say none, but you get the idea. Timing is always first and foremost. To start off, set your initial timing in the 12-14 degree area (with the vac advance disconnected and plugged), plug the vac advance back in to the port I mentioned (your idle speed will jump up once reconnected), set your idle speed to 600 rpm in gear (should work out to 750 in park), and test it out to see how the engine likes it.

So after looking, there is a spacer on the carb already. Can I just purchase a new gasket set??? Or am I stuck replacing the spacer and gaskets?
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[GreyGhost85]

Originally Posted by GreyGhost85

So after looking, there is a spacer on the carb already. Can I just purchase a new gasket set??? Or am I stuck replacing the spacer and gaskets?
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[68 P.O.S.]

You're welcome, just trying to pass on some of the lessons I've learned. This thread has the starter info I was talking about: http://67-72chevytrucks.com/vboard/s...d.php?t=554106

Why a new distributor, is there something wrong with it? We can get into setting that up correctly too.

Oh, nice. One less thing to buy haha. I couldn't see it in the pic. No need to buy a new spacer, just a new gasket for each side of the spacer and you'll be set.

For the timing light, get an adjustable dialback light. I recommend getting one that displays rpms as well. It makes setting total timing and adjusting the carb idle properly easier. Do you have a vacuum gauge? You'll need one for setting the carb idle as well. Getting a carb cal kit is a great idea. The one you need is the Edelbrock 1487.

For the fuel pump, get the Edelbrock 1721. It's more expensive than a stock replacement, but it puts out the correct pressure for the carb so it won't flood....which they are known for doing. Otherwise you'll need to slap a pressure regulator on there.

[geezer#99]

Look closer!
It’s not a heat spacer, it’s an adaptor!

[68 P.O.S.]

You're right, hard to see on my phone. I thought it was an Edelbrock painted orange. That changes things. Any idea which heat spacer he would need?

[geezer#99]

The adaptor works but not as well as a true heat spacer.
Just need two different gaskets. A spreadbore and a square bore.

[geezer#99]

On second thought after rereading the original post maybe it is a square bore heat spacer used on a spreadbore intake and the op has a bad vacuum leak.
He’d need to pop the carb off and post more pics of the spacer and intake to be sure.

[68 P.O.S.]

I had that thought bouncing around in my head too. Yes, he'll have to pop it off to see.

[GreyGhost85]

Originally Posted by geezer#99

On second thought after rereading the original post maybe it is a square bore heat spacer used on a spreadbore intake and the op has a bad vacuum leak.
He’d need to pop the carb off and post more pics of the spacer and intake to be sure.

I plan on doing that soon, I took it for it’s first test drive since I don’t know how long it has been sitting and it shifts through all gears so tranny appears to be good. Still stalls but tries in reverse.

I just ordered a new distributor, heat gasket, base gasket, timining light, and some other project stuff.

Is the calibration kit and fuel pump regulator necessary if it is running and idling well? Attached are the parts. They should be here Sunday via amazon and I’ll take the carb off this weekend to show better pictures. Threw a pic of the front cab in there without the bed. I’ll be cutting and welding the bedsides and doing a wood bed.
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[geezer#99]

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.

[GreyGhost85]

Originally Posted by geezer#99

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.

Ok guys, took carb and spacer out. There was a crack in the carb mounting gasket, kind of flimsy rubber gasket, and the spacer gasket looks like death. But when spraying starter fluid around base, I didn’t get a response at all. Ganna grab a vacuum gauge when assembly time comes around again.

Should I just spray the carb down with carb cleaner or should I disassemble and clean ?

The last attachment appear to be a temp sensor tap, I cannot loosen that fitting for anything, it had a cap over it but I need to figure out how to use that existing tap somehow or find a way to remove that plug without breaking the intake manifold
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[Steeveedee]

Lots to cover here, but I'll just address the battery, since it hasn't been talked about. A fully charged battery is 12.6 Volts; 12 Volts isn't far from dead. Charge it up so that when you check the voltage it is 12.6V. Your charging voltage looks OK. I'm not going to interject anything on the carb or distributor work.

[GreyGhost85]

Originally Posted by geezer#99

On second thought after rereading the original post maybe it is a square bore heat spacer used on a spreadbore intake and the op has a bad vacuum leak.
He’d need to pop the carb off and post more pics of the spacer and intake to be sure.

It appears that the spacer is a spreadbore to square bore. Could I use the edelbrock 9266 still even though it has the center divider? I have to figure out where to get that spreadbore gasket.
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[geezer#99]

That’s an adaptor.
You’ll need a spreadbore and squarebore gasket to reseal it.
Leave the carb alone for now.
Nothing to be gained pulling it apart.
That tap you talk about is for the heater hose to your heater core. Surprised it hasn’t leaked like that with a cap on it. To remove it you need to apply a bunch of localized heat to it.
Do you plan on hooking up your heater core?

[geezer#99]

Originally Posted by GreyGhost85

It appears that the spacer is a spreadbore to square bore. Could I use the edelbrock 9266 still even though it has the center divider? I have to figure out where to get that spreadbore gasket.
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Parts store should have a gasket.
You can use that 9266.
Not ideal but it’ll work.

[GreyGhost85]

Originally Posted by geezer#99

Parts store should have a gasket.
You can use that 9266.
Not ideal but it’ll work.

Only problem it cuts off some of the holes... I will try to obtain the correct spacer base gasket
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[Pro299]

And that "tap" you refer to in your last picture is for a heater hose. Over the years these have sometimes been changed around but commonly you'll have this one and a return going into the radiator just below the cap.

[GreyGhost85]

Originally Posted by Pro299

And that "tap" you refer to in your last picture is for a heater hose. Over the years these have sometimes been changed around but commonly you'll have this one and a return going into the radiator just below the cap.

Completely removed heater core as it was capped upon purchase, I was just looking for an easy place to place a water temp gauge. But if it’s goingnto be that much work to remove that tap, I will just leave it capped for now. Going to get vintage or universal a/c set up
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[geezer#99]

Originally Posted by GreyGhost85

Only problem it cuts off some of the holes... I will try to obtain the correct spacer base gasket
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Of course it does!
I thought you were gonna use it where you’re supposed to use it.
Under the carb between the carb and the adaptor.

[GreyGhost85]

Originally Posted by geezer#99

Of course it does!
I thought you were gonna use it where you’re supposed to use it.
Under the carb between the carb and the adaptor.

I purchased the thicker rubber one to go under carb to prevent heat soak. Problem is I ordered before taking the spacer off lol...
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