S0 idle timing it calls for 6-14 BTDC I under stand this part to be able to start it easier.

Now advance timing. 400 calls for around 34 advance. So my question is ,

When you set it at 34 degrees at 3000 RPM with the vacuum hose still attached and then lock it down , I'm thinking then that the idle timing must not be between 6-14?

So why not give the timing at idle to be set at what it is when you lower the RPMS when you have just set the advance . ( sorry I suck at putting this into words )
I hope you understand what Im saying.

 

It's 34° total advance.. the combination of mechanical plus vacuum at the specified RPM.

If you're not getting whatever advance you're looking for then it's time to change the advance springs.

 

The vacuum advance can also be adjusted through the vacuum hose port with a 7/64 allen wrench. A good dial back light or a timing tape on the harmonic balancer with help you map your advance. Initial timing is only one third of the actual settings you make to fine tune the advance system and is barely a suggestion since it was determined when gas was formulated a lot different than it is now.

 

Is this even on a HEI dizzy? (allen wrench part)

So before i go out and do this, this is what I need to , turn the dial to 34 on timing light bring it up too 3000 rpm and move the dizzy until it reads TDC and then lock it down right?

If so , my question is , After I lock it down and bring it back down to idle and disconnect the timing advance hose will it read between 6- 14 degrees at idle or will it it be different?

 

Only Fords have it stock, you have to buy an aftermarket vacuum advance with that provision for the HEI to be adjustable.

 

That all depends on the condition of the distributor and how it's calibrated but Ideally, yes. Keep in mind there are a butt load of different weights and springs for an HEI and who knows what's in there.

 

So is this done with the vacuum hose connected or disconnected, thanks for your help

 

Misread your post, my reply is irrelevant now.

 

lol Np problem , But to answer your question , its a fresh built 400 I just did
With HEI (new)
I only ran it at 2000 rpm for 10 mins , I still need to finish breaking in the cam for another 20 mins

I still have the base timing set a 14 BTDC unil I have broke the cam in then I'll set total Timing

 

If you are checking "all in" you would keep the hose connected

 

On post #5 above, I was referring to Stock GM HEI. I don't know what the ones made for Ford use. If it's the $89 ebay chinese one I'm going to say it won't. If you have a good Davis Unified, I would guess it probably does have the vacuum adjustment.

 

The idle timing is not critical. Something north of 10 and less than 20 degrees is where it will end up. "Total timing" isn't really what it sounds like, vacuum advance is disconnected and plugged when this is set. If you spool the RPM up in neutral with vacuum advance connected there is no load on the engine and it will probably show 60 degrees BTDC and you'll think something is really wrong!

Spool engine up to get your 34 or 36 degrees (or whatever the spec is, whatever you can get away with, etc) and let the initial timing fall wherever it needs to, to get that. That's why it's not critical, the high end where it tops out is. Take some test drives and see what you think. Try advancing or retarding distributor slightly as required just short of any engine knock in hard acceleration. Engine modifications, altitude, fuel quality etc plays a role on what your engine will run at, each engine is a little different.

Then when you are satisfied with the mechanical part of the ignition curve, re-connect the vacuum advance and adjust the can only for part throttle operation, with the allen wrench. Vacuum advance is only really a factor at steady, part throttle conditions when engine loading is low. It will add better all around driveability, and the engine will run a lot cooler in the summertime. It also adds a few extra mpgs. Don't run without it.

 

Thank you , that makes what everyone is saying come together.


AWESOME thank you all !!

 

This is why we have our trusty hand held vacuum pump/gauge. There are stock specs for a distributor/engine for how much advance at what vacuum reading. While I am the first one to say the stock specs may be a little off with today's fuel, your stock engine is going to run pretty decent with those specs. Beyond that is just experimenting and tuning, comes only with you spending a lot of time with your rig and getting to know it. Especially if it's modified.

 

https://www.summitracing.com/parts/crn-99600-1

HEI adjustability. If you can't get it right with this kit, it can't be made right.