ESC need someone that knows more about ESC system than I do

[SirRobyn0]

Reading through this again, there is part of the ESC you have wrong, or it is different than my 1982 305 system. I looked at vacuum diagrams posted for the 1984 305 and they have the same vacuum to the distributor as my 305.

The vacuum advance uses what is called trapped vacuum spark. It only traps and holds vacuum to the advance when the engine is stone cold. The vacuum is sourced from both manifold and ported and held by a check valve. It uses the strongest vacuum. As the engine warms, the thermal vacuum switch now connects the vacuum past the check valve. I believe to just ported vacuum. (need to check that, can't remember) There is a cindered iron bleed on the thermal switch that allows the trapped vacuum to bleed off if the engine stalls when cold.

The ESC has no electrical control to the vacuum system that goes to the distributor advance. The ESC delays the spark timing electrically 4* when triggered. Another 4* if still triggered. Yes the ESC does see engine vacuum, and uses that to control the spark timing too, electrically, not by changing the vacuum to the distributor.

Ok thanks. I have not re-read all if the tread, though I have been meaning to so I'm not 100% sure of what I have said before.

I am aware of the original vacuum routing however the PO had pretty much stripped it all off before I got it so stuff like the check valve and bleed off are gone. When the vacuum advance was hooked up and my plan is to run it to ported because that's basically the closest option I have. The PO also installed an Edelbrock carb, so I don't have the exact same connections a Q-jet would have, but of course there is ported and manifold.

I could not remember how much timing the ESC was capable of pulling so thank you for mentioning that.

I've got to get the EGR functioning and the knock sensor and see where I'm at at that point. I'm going to pull the carb and attempt to clean the passages but suspect that it will end in failure and the manifold will need to come off or possibly be replaced. There are some Edelbrock performers with EGR used on E-bay for about $150, and I will think about that possibility for a bit.

 

[AuroraGirl]

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If you do get one of these make sure to get the phenolic spacer so you can keep the edelbrock from heat soaking so bad. they also sell a heat shield in addition to the spacer which Im not sure how much radiant heat it blocks but under the spacer i imagine thats better than nothing(Or just not in contact with the carb)

 

[AuroraGirl]

Well I stuck the ESC distributor back in on my lunch. Nothing more to report yet, I got the truck running but did not have the time to time it. So I will time it tonight before I go home and hopefully I'll be back to where I was. The mechanical advance is clearly not in the best of shape in the ESC distributor, it moves okish. I've seen it move when revving the engine during the timing procedure so I'll have to do something about that in the long term as well. Right now job one is getting it back to where it was, #2 will be getting the ESC system functioning and then I'll decide what to do about the advance in the distributor. Part of me is thinking that I might try swapping parts from the non-ESC dist in IF they appear the same, but for now getting the ESC system functioning is more important.

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I hope your distributor takes the bushings kind and not the older kind? This is MSD kit for electronically controlled(5to 7 pin modules, ESC)

MSD Ignition 8428 MSD Advance Kits | Summit Racing

Free Shipping - MSD Advance Kits with qualifying orders of $109. Shop Distributor Advance Kits at Summit Racing.

www.summitracing.com

 

[SirRobyn0]

@Turbo4whl I guess I should have said this in my prior post, but with the PO having stripped all the vac hoses, all of the bleeds switches ect are gone. The EGR is simply hooked to ported vacuum, I've done that on other engines with good results, though sometimes it'll give some cold run issues. Distributor will get plugged into ported when the ESC is fixed and while not the factory arrangement hopefully it'll be close enough to function well enough for power, economy and ping resistance. We'll see that's the plan for now, but I'm open to input.

 

[SirRobyn0]

@AuroraGirl I've already got a phenolic spacer between the adaptor and carburetor as I thought I was having some percolation issues at one time that turned out to be to much fuel pressure and to high of a float level.

IDK, if my distributor has bushings, but I would think so given the year. I should pick up one of those kits even though I do not need to tune it, I should have those bushings on hand for when the time comes.

 

[AuroraGirl]

@AuroraGirl I've already got a phenolic spacer between the adaptor and carburetor as I thought I was having some percolation issues at one time that turned out to be to much fuel pressure and to high of a float level.

IDK, if my distributor has bushings, but I would think so given the year. I should pick up one of those kits even though I do not need to tune it, I should have those bushings on hand for when the time comes.

The top half of the distributor has to be the kind that takes them. If you’ve seen the pic of hei that I have, I think one of my 4 or so were the kind. The one In my engine does not. That requires used parts or top of one that does. I’m on ipad rn so I don’t have a pic on hand

 

[SirRobyn0]

The top half of the distributor has to be the kind that takes them. If you’ve seen the pic of hei that I have, I think one of my 4 or so were the kind. The one In my engine does not. That requires used parts or top of one that does. I’m on ipad rn so I don’t have a pic on hand

Yes, I think I remember it, but not the specifics, but it's no problem.

As a side note because I did not say this earlier the heat issue is one of the things that I don't care for about the aluminum intakes. I'd kind of like to keep a cast iron manifold, but they don't make them anymore and even if they did I'd still have to run an adaptor unless edelbrock made one or I go back to Q-jet, which I have talked about, but with an aluminum Edelbrock manifold I could bolt either flavor of carburetor on. IDK, do you know on the Edelbrock performer manifolds if the mount is much higher than the factory manifold. My concern there is having to cut and raise my cable holder to match the carb height, as I have a 700R4 and the geometry has to be correct. I guess that wouldn't really be that big of a deal, it would just add a step. I would also plan to paint mine, just because I prefer it.

 

[AuroraGirl]

Yes, I think I remember it, but not the specifics, but it's no problem.

As a side note because I did not say this earlier the heat issue is one of the things that I don't care for about the aluminum intakes. I'd kind of like to keep a cast iron manifold, but they don't make them anymore and even if they did I'd still have to run an adaptor unless edelbrock made one or I go back to Q-jet, which I have talked about, but with an aluminum Edelbrock manifold I could bolt either flavor of carburetor on. IDK, do you know on the Edelbrock performer manifolds if the mount is much higher than the factory manifold. My concern there is having to cut and raise my cable holder to match the carb height, as I have a 700R4 and the geometry has to be correct. I guess that wouldn't really be that big of a deal, it would just add a step. I would also plan to paint mine, just because I prefer it.

edelbrock does make an adapter I actually have one. It’s also able to put a qjet on a square bore. But I hear that’s not very efficient use of a qjet.

sadly cast iron is too heavy to econimcally make and ship probably.

 

[Catbox]

If you need one, I have an older Edelbrock Performer Intake that I am not using.
I would do $100 shipped from Portland.
It is dirty and used looking, but I do not believe there is anything wrong with it.
I picked it up a couple of years ago and then never used it.
So it sits on a shelf in the garage.

I can get better pics this weekend if you are interested...

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[SirRobyn0]

If you need one, I have an older Edelbrock Performer Intake that I am not using.
I would do $100 shipped from Portland.
It is dirty and used looking, but I do not believe there is anything wrong with it.
I picked it up a couple of years ago and then never used it.
So it sits on a shelf in the garage.

I can get better pics this weekend if you are interested...

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Thanks, I might take you up on that, but I have to have an EGR manifold and I can't tell from the picture if that's an EGR port with a block off plate or for a choke stove. Thanks.

 

[TotalyHucked]

Best thing I did when my truck still had the 305 in it was getting rid of the ESC, dropping in a regular HEI dizzy in and getting rid of all the vacuum spaghetti. Made so much more power, better throttle response and better mileage. And my ESC worked properly (up until the ignition module died lol). IMHO it's not worth bothering with

 

[AuroraGirl]

Best thing I did when my truck still had the 305 in it was getting rid of the ESC, dropping in a regular HEI dizzy in and getting rid of all the vacuum spaghetti. Made so much more power, better throttle response and better mileage. And my ESC worked properly (up until the ignition module died lol). IMHO it's not worth bothering with

the mans on a mission beyond our comprehension but even if it wasnt for performance im sorta convinced he would do it for the science! of it. lol.

 

[AuroraGirl]

Yes, I think I remember it, but not the specifics, but it's no problem.

As a side note because I did not say this earlier the heat issue is one of the things that I don't care for about the aluminum intakes. I'd kind of like to keep a cast iron manifold, but they don't make them anymore and even if they did I'd still have to run an adaptor unless edelbrock made one or I go back to Q-jet, which I have talked about, but with an aluminum Edelbrock manifold I could bolt either flavor of carburetor on. IDK, do you know on the Edelbrock performer manifolds if the mount is much higher than the factory manifold. My concern there is having to cut and raise my cable holder to match the carb height, as I have a 700R4 and the geometry has to be correct. I guess that wouldn't really be that big of a deal, it would just add a step. I would also plan to paint mine, just because I prefer it.

I

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Based on just pure eyeballing it, it almost looks like yeah its lower. I dont have a spacer either on my carb. dont mind the bracket that was for the 2jet.

also sorry about that I didnt see your question about the throttle bracket when I last read your post lol.

 

[SirRobyn0]

Ok cool at least it's a very similar height. Thanks for that.

 

[SirRobyn0]

Best thing I did when my truck still had the 305 in it was getting rid of the ESC, dropping in a regular HEI dizzy in and getting rid of all the vacuum spaghetti. Made so much more power, better throttle response and better mileage. And my ESC worked properly (up until the ignition module died lol). IMHO it's not worth bothering with

Um, tried that, did not go well for me. I have a theory on way going to a standard HEI system works well for some people and not others. My very shortened condensed version on that is different cylinder head options from the factory and compression ratios.

the mans on a mission beyond our comprehension but even if it wasnt for performance im sorta convinced he would do it for the science! of it. lol.

LOL, you talking about me? Well it's a simple enough of a system really, two sensors, knock & tip in, one simple ESC computer, and the distributor. So it shouldn't be to bad if I can ever get the bad knock sensor out of the block lol.