Chrysler 400 engine lean burn

[bello78]

Hello, I did a lean burn conversion on 1978 Chrysler. The vacuum on distributor touches manifold when set at 8 degrees. It says to set timing at 5 degrees but was only able to go as far as 8 degrees. Anyone else have this problem?

 

[Mopars & Missiles]

Intermediate shaft gear can be moved a tooth or two to give you the adjustability that you need. Its probably in the wrong tooth now anyway, that's why you are hitting the manifold.

 

[Mopars & Missiles]

Typical alignment of the intermediate shaft with #1 TDC.

 

[66chargerpat]

I would shoot for 12 degrees btdc. IMO 5 degrees is to retarded.
It should be happier with more than only 5 degrees.

 

[bello78]

Intermediate shaft gear can be moved a tooth or two to give you the adjustability that you need. Its probably in the wrong tooth now anyway, that's why you are hitting the manifold.

Is it hard to remove?

 

[bello78]

I would shoot for 12 degrees btdc. IMO 5 degrees is to retarded.
It should be happier with more than only 5 degrees.

So it would run better at 12 degrees?

 

[Geoff 2]

Yes, much better at 12*. You don't need to move the dist. Move the high tension leads in the cap.

 

[Don Frelier]

Yes, much better at 12*. You don't need to move the dist. Move the high tension leads in the cap.

This is the easier solution.
Just note that moving them all one spot clockwise will yield a 40 degree advance.
So try and rotate the distributor counter Counterclockwise about 1/2 the distance between the terminals. (20 degrees back)
You should be pretty close at that point.
I agree with 12 or even 15 if it doesn't ping.

*** OOOps note edit above you need to rotate the distributor in the direction of travel to retard.

 

[qkcuda]

I think the lean burn unit controls the total timing, so if you add more initial it will run better and not over advance. Back in 1978 or so my buddy had a lean burn Volare wagon with the 318 4 barrel. He brought it to the track, and it would not run fast enough to make the bracket (18.50) so we started cranking in more initial timing. It kept going faster, so we kept adding initial timing until the starter was laboring turning it over. It ended up making the bracket. My foggy memory says we may have picked up half a second.

 

[bello78]

Yes, much better at 12*. You don't need to move the dist. Move the high tension leads in the cap.

What do you mean,n

 

[Geoff 2]

To bello.

[1] Remove plug leads.
[2] Rotate engine with a wrench to 10* BTDC [ not critical ] mark on dampener.
[3] Remove dist.
[4] Using a torch shining through the dist hole, look at the int & exh lifter positions for the front cyl on the left hand bank [ #1 cyl ]. The two lifters will either be on the base circle of the cam.....or......both could be lifted slightly on the cam lobes. If on the BC, it means the engine is at #1 cyl firing position; if lifters are elevated, it means #6 cyl is firing. Make a note.
[5] Replace dist & rotate/position it in a convenient location. Remove dist cap. Make sure rotor tip is pointing/lined up with segment in the cap. Rotate dist slightly if needed to line up.
[6] Fine tuning dist position. Dist SHAFT rotation is CCW. The spark occurs as the trailing edge of the reluctor tip just passes the pick up. Rotate dist body to get this, may already be correct. Tighten dist clamp.
[6] Note which tower on the cap is lined up with the rotor tip. Going back to [4], if both lifters were on the BC, then this tower is #1 cyl. If lifters were elevated, that tower will be #6 cyl.
[7] Install leads in firing order going CCW. If the tower was #6, install #6 lead there, then install leads CCW 5-7-2-1-8-5-3.

Engine should start & final timing adjusted.

 

[bello78]

I would shoot for 12 degrees btdc. IMO 5 degrees is to retarded.
It should be happier with more than only 5 degrees.

So I should try setting initial timing at 12 degrees first?

 

[66chargerpat]

Yes, it should be fine to start at 12 degrees advance at idle.