Engine Timing 305

[gotyourgoat]

Well Sir that is a very strong vacuum signal...my first thought was vacuum ball.

I went out to my C20 for example and find a coveted triple nipple!
In THIS example -
It attaches to the vacuum ball and has the transmission vacuum modulator connected as well as the brake booster.

See attached photo.

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Hope this helps!

Hahaha triple nipple.

I'm not well.

 

[Rusty Nail]

Youre not well? Some jagoff wants to remake Total Recall.

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[Ricko1966]

Okay from your post I cannot tell what year truck you are working on.Trying to use factory timing specs for 1 year of engine, with a different distributor and carb isn't going to work out. I'd like to know the year of the truck,the engine the distributor number, distributor weight number and distributor cam number, and the number off the vac advance can.All Hei's are not the same. The timing specs will change depending on all of these variables.​

 

[Rusty Nail]

Youve been awfully quiet @Ricko1966

Stayin busy I hope.

 

[Ricko1966]

Way too busy.

 

[Rusty Nail]

Keep ya out of trouble.

 

[75gmck25]

With stock low compression heads you can definitely advance timing to 12 degrees BTDC, and maybe even as much as 16.

Do you have an adjustable timing light or a timing tape for the balancer? What you want to determine is total timing from the initial and mechanical advance. For example, if you rev the engine to about 3000 rpm you may find total timing to be about 28 degrees (8 initial and 20 mechanical). Most SBC’s can handle a total of about 34-36 degrees without any problem. This higher advance gives you more power.
You can also buy distributor recurve kits to adjust/limit total mechanical, and adjust the rpm where it comes in. For example, mine is all in by about 2200 rpm.

However, if you advance initial timing more, you also need to check your vacuum advance. First pull vacuum on the can and see how much it advances the timing. It may be anywhere from 15-22, but is probably about 20. This is the advance that gives you highway cruise gas mileage. However, if the total advance (initial + mechanical+ vacuum) goes too high ( more than about 54-56) you may get pinging during light throttle cruise acceleration. If that happens, you may have to move the initial back down a little to avoid pinging.

Bruce

 

[Vbb199]

Thanks.


There is no looking past this open manifold vacuum leak.
Plug this.
O.M.G. the horror! I bet she runs like ****.
(Nevermind what is intended to be there right now)
Getcha a piece of vacuum hose and run a screw in it big enough to seal it. Plug that hole.

Turn the distributor back to (about) where is was before you started messin with it and post the results.

First things first.

THEN-
We're gonna need a much wider angle view of the engine bay = more picks.

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This is gonna be #2. Your vacuum advance canister appears to be without vacuum signal.
Need more pix.

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I noticed that too lol

 

[tadslc]

Thanks! So I ended up rotating the Engine to #1 TDC and took the cap off of the rotor and it was pointing directly towards the front of the vehicle. To my best knowledge, I'm pretty sure it should be pointing towards cylinder 1? So I took the dizzy out and rotated it counterclockwise after turning the slot in the block a little back, and reinstalled it a little counterclockwise. After putting everything back together, and fine tuning it, I'm at 8 BTDC. As far as I know, or at least my owners manual, it says that's what factory spec is. Starts great, Idles great, runs good, shuts off fine, no dieseling. The only thing is, I don't feel like I'm getting as much power as I should. Should I go ahead and move it to 10 BTDC?

The rotor needs to be pointing at the #1 spark plug lead where ever that should be if it's really on TDC. My guess is someone took the distributor out at some point and perhaps reinstalled a tooth off. That's why you can't rotate enough to retard.

 

[Rusty Nail]

Umm you know any terminal on the cap can be #1..right..?. As long as you maintain the proper order, you can build to suit..make it easy on yourself.

1843
6572

See em on top of each other there?