Crate engine swap advise please?

[73 C10]

You need a limiter that will limit the pull the vacuum can rod. The one you call a top limiter will keep you in an advanced state of some sort. Not good.

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I don't think that's true. You set the limiter. Then you set base with no vac. So when used normally, when your vac drops (hit the limiter), you drop to base. Vac builds, and timing advances to whatever the stroke permits. It just takes more vac to get it started.

 

[350runner]

Oh grasshopper... Listen this whole top and bottom thing is going askew. The only sort of limit apparatus you need is one that limits the pull of the can rod into the can. This will give you the same effect you are talking about. Is that the kind you currently have installed?

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[73 C10]

So you have the top limiter correct?

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I have the Crane type in the link.

I don't no if it's more common, but it's definitely easier to find, and refered to more when searching the net.

 

[350runner]

Ok, that will limit the amount of timing provided. That's fine if you use it to limit the amount of rod stroke back into the can.

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[73 C10]

Ok, that will limit the amount of timing provided. That's fine if you use it to limit the amount of rod stroke back into the can.

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Yeah it will limit, but I think it would be best if the pull pin could remain in the same start position, and pull the pin into the limiter.

I may try installing it on the other mounting screw on the other end of the stroke and see if it will interfer correctly there.

I have it installed how Crane suggests.

 

[350runner]

Read this thread please...
http://www.nastyz28.com/forum/showthread.php?t=284420

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[73 C10]

Also, because of useing a limiter I think some diaphragm spring adjustment is nececary.

And the adjustment makes more sense if the limiter were limiting the top of the stroke.

 

[350runner]

You have the wrong limiter and it is causing your ignition too stay in an advanced state. Please read that thread in the link that I posted.

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[73 C10]

Read this thread please...
http://www.nastyz28.com/forum/showthread.php?t=284420

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Yep. That's what I think it should be. Thanks. Now I know where to add a screw to make the Crane work at the other end.

 

[350runner]

Here is an awesome guys email. His name is Dave Ray. He builds small body hei distributors. He has this crane limiter down packed in an email he will send the directions on " how to" use the crane limiter correctly. All you have to do is ask it's free instructions and while your there ask him anything else you have questions about.
[email protected]
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[73 C10]

You have the wrong limiter and it is causing your ignition too stay in an advanced state. Please read that thread in the link that I posted.

Sent from the dust in front of you!

If you have to drop more vac with out the limiter, I would think you would have a better chance of staying in an advanced state.

A lot of vacuum hose volume probably wouldn't help this.

I wouldn't expect to see vac drop to 5". I don't think it does on my gauge in the cab. Therefore it would still be in an advanced state.

This seams to to be normal stock.

With the Crane in the bottom, limiting to 15*, vac only needs to drop to 10" to get to base timing. More likely I think.

 

[73 C10]

Here is an awesome guys email. His name is Dave Ray. He builds small body hei distributors. He has this crane limiter down packed in an email he will send the directions on " how to" use the crane limiter correctly. All you have to do is ask it's free instructions and while your there ask him anything else you have questions about.
[email protected]
Sent from the dust in front of you!

Yeah. I just read an artical by this guy. Thanks. I seams like he agrees.

Post #9

http://www.chevelles.com/forums/showthread.php?t=390643

 

[350runner]

When the vac can rod retracts into the can it is advancing the timing. With the limiter acting as a stop on the side crane is suggesting the timing will always stay in an advanced state with or without the vacuum can connected to a vacuum source. It just the nature of the beast. When you lose vacuum your losing the amount of advance the distributor is seeing which is how it's designed.

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[rich weyand]

This is very important to get correct. Play with it with your vacuum pump and gauge until you get it correct. If you are holding VA in all the time, you will never be able to tune the engine properly.

Remember the spec for the stock AR23 can: 5-7 7.5 @ 11-12.5

- starts pulling in between 5" and 7" vacuum.

- 7.5 camshaft degrees (15 crankshaft degrees) total, all in.

- all in by 11" to 12.5" of vacuum.

(Or for $20 you could just buy a stock AR23 (VC1853) can and not worry about all the adjustment, limiters, etc. http://www.napaonline.com/Catalog/C...cuum-Advance-Control/_/R-ECHVC1853_0168354142)

 

[350runner]

Another note... I find small blocks like the vacuum advance to pull down to 5" of vacuum(the least amount a performance can will pull to). I feel it is because this is when the engine has the most load on it before the trans down shifts and removes some of the load on the engine and puts the cam higher in its power range. While driving before the down shift is where the engine could use the extra timing from the vac can the most as the rich A/f ratio is at its richest state and will tolerate the the total plus vacuum advance you have your dizzy set for.

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