LANGDON HEI SETTINGS - What do YOU use?

[Powerhouse]

I am curious to find out what anyone running the HEI from Langdon uses for timing settings.

His suggested settings:

- 10-18 deg BTDC with NO vacuum advance

- suggests ported vacuum only when running a mild cam

- suggest full vacuum for performance cam

I am running with no vac adv, around 10 BTDC. With vac can pointing to 5 O'clock.

ENGINE - 218

PISTONS - .030

HEAD - .050 milled

CARBS - Dual Carter Webers

INTAKE - (Moose) Dual Pipe Intake

Exhaust - Dual exhaust through a customized stocker (2 inch pipes back)

Edited January 9, 2013 by Powerhouse

[james curl]

I run the same distributor on my 235 Chevy I/6 and just use the vacuum gauge to find the highest reading and it is ported on the vacuum from a Holley 390 cfm carburetor. Something over 10 degrees at idle.

[martybose]

When it was last running (a long story I won't bore you with) I was running 4 degrees BTDC with manifold vacuum advance. My motor is a 230 with 9 to 1 compression, a mild cam, dual Carter-Webers and cast iron headers to full 2" dual exhausts. I played around with carb jetting and eventually came back to the original jets.

Marty

[Powerhouse]

I checked it out with a vacuum gauge.

got 22 highest vacuum at about 15 btdc. I have no line past 10 so I am just guessing. Sounded better, no occasional popping sounds from the tail...smoother running too. I hooked up the ported vac adv. Drove to work this morning, seems ok, I will remove the ported vac adv for the ride home.

I noticed a steady flicker on the vac gauge, I think a bit lean on the fuel mix. Slight white on the plugs.

[martybose]

I checked it out with a vacuum gauge.

got 22 highest vacuum at about 15 btdc. I have no line past 10 so I am just guessing. Sounded better, no occasional popping sounds from the tail...smoother running too. I hooked up the ported vac adv. Drove to work this morning, seems ok, I will remove the ported vac adv for the ride home.

I noticed a steady flicker on the vac gauge, I think a bit lean on the fuel mix. Slight white on the plugs.

You need to find a tuning hill. I've got one a couple of miles away that has a long fairly steep road going over it that I run up at about 50 MPH. I'll bet that you'll find yourself backing down the initial timing quite a bit after that!

Marty

[Powerhouse]

it kinda runs rough at any less advance...puting occasionally at idle...not as smooth. I was running at around 7 for a while...and that seemed better but still not so smooth at idle.

[martybose]

it kinda runs rough at any less advance...puting occasionally at idle...not as smooth. I was running at around 7 for a while...and that seemed better but still not so smooth at idle.

Unless you have a pretty radical cam installed I'd say it's time to check the basics.

(1) Make sure that the throttle plates and the linkage are synced up well; If one plate is more open than the other idling can get a little weird. Generally you want to disconnect the linkage and adjust the idle speed screw until they are the same (I used feeler gauges on the primary throttle plate clearance). Then make all adjustments to idle speed equally on both carbs. Reconnect and adjust the linkage, and make sure that it doesn't move one of the carb shafts first!

(2) Turn both idle mixture screws in all of the way (gently!!) and turn them back out 1-1/2 turns. Any further adjustments should be made equally to both idle jets.

My motor idles smooth as silk, and yours probably should too!

Marty

Edited November 10, 2010 by martybose
fat-fingered typo as usual!

[Powerhouse]

OK, so last night with the little time I had to mess around with the car I re-indexed the dizzy. The minor adjustment screw (mounts dizzy to block) was not easy to get to with the vac can in the way.

So I turned it down to where the can is pointing towards the bottom right, near dipstick. I readjusted via the main adjustment screw(screw with nut that olds clamp on dizzy) until it was right on. I tightened it and then moved to the minor adjustment screw.

WHAT A DIFFERENCE in sound! WHY, I have no idea...but it idles much better now. I set the timing to 10BTDC(as Langdon suggests), it sounded best there, it's the spot just before it makes the rpms highest, but only by a few. I tried with and without vacuum to see it's effect on timing, not a change I could see. SO I left it off(as Langdon suggests). I am not sure of the actual rpms, No tach and the old delco multi tester I have is not correct. Sounds like maybe 500 rpm.

I test drove it......! It was pretty amazing.

BY the way(Marty), I adjusted the carbs/links again last night to make sure they were OK. I used the sound method...length of hose to the primary barrel, and listened to what they were saying. I made sure they both sounded the same. I have one of those syncro things with the red plastic float thing...but it won't seal properly for me to get a reading. I did some minor adjusting to get the same pitch. I may mess with the mixture again tonight.

Edited November 10, 2010 by Powerhouse