HEI Installation Woes

Aside from grinding and all around just being a PITA...

Modified an even fire HEI for use with my 225cid. Ground three of the points down, installed an odd fire pickup and '75 vac advance. I think I might have a problem. When I align the odd points on the pickup to the 3 points on the shaft, the tip of the rotor does not point to the #1 contact on the cap. It's as if I'd have to add almost 10deg of vac advance to get them to line up. Did I do something wrong during the conversion?

 

I dont have any experience with HEI conversions but I have converted standard F-Head distributors to dual advance............Sounds like you need to rotate / reposition the breaker plate assembly.

 

It is common for the rotor to not index correctly with the cap, and is often modified on race cars. MSD sells and adjustable cap and rotor to correctly idex the parts they call Cap-Adapt.

Here is a link describing how rotor phasing is adjusted on a racing Jaguar.

Have you tried to start it yet? Obviously you need a pretty strong spark to jump the gap, and it does increase the likelihood of crossfire as well as increasing the rate of wear on the cap and rotor, but it should run unless the rotor gets too close to the next cylinder and you get crossfire.

http://books.google.com/books?id=ze...ts=mZVz8fXqaS&sig=CX86fOraLntiLTy-6LiS_r8wKIU

 

Haven't tried to start it yet. Still working on clearance issues. Second guessing my decision not to get the Pertronix right now.

That's the first thing I thought of, too. When I rotate around to where the other points theoretically would be, it is off by more than half a post. Even tried several combinations of 180 out/cutoff points, 180 out/remaining points, cap position, etc. I'm 99% sure I've got the right points cut off, and the right pickup, its just off by 10 deg or so. Appears that it will move into TDC with vac advanced, but it looks to me like it would have really rough miss at idle it's off so far.

 

Actually, if you count MOP's assistance, two of them. R)R)R)

(j/k Adam, much respect for both of you guys.)

Yup, musta posted it while I was typing, just got done reading it. Thanks. Parts going back onto the dining room table. I need to start a "cuss jar."

 

More clearance issues. Interference with the hold downs. I've got a narrow range of space here to leave myself room for initial timing. I can't start the motor right now. I can't remember if I spin the dist clockwise to advance initial, or counterclockwise. TIA.

 

When I put mine in the only way the distributor would clock is with the vacume advance pointing towards the drivers headlight. Makes it very close to the fan. As far a clocking the rotor. Just move the oil pump shaft with a long screwdriver until you can slide in the gear with the rotor pointing towards your number one. Hope this helps. Also read the posts on being 180 deg out. Good luck with it.

 

Yup. I'm at that point. I'm sitting at zero, vac advance toward the headlight. I'm assuming I need to go somewhere in the range of 5 to 8 BTDC once the engine is started. I can put it down on one tooth and not be able to move the dist clockwise due to intake clearance, or I can put it down on the next tooth and not be able to move it counter clockwise. I need to leave myself room, so when I pretend I'm standing on at the fender with the timing light running, from zero, which way do I rotate the cap to get to BTDC? Clockwise or counterclockwise? I just can't seem to remember at the moment.

 

standing at the drivers fender clockwise advances the timing. i just installed a new cam last week, it took me a few try's to get my hei where i wanted it, my vac canister is pointing just to the pass. side of center. very little movement of the oil pump drive shaft makes a big difference on how it will drop in for you. for the last 12 years i was taking a dremel tool and grinding my cap slightly for easier timing adjustment, but this time i ground my intake a little more.

 

HEI is installed and working well in the JEEP. Just a couple footnotes:

1) The 6cyl even fire coil dust cap will not fit the odd fire dist cap. Didn't really see any note about this in the writeups. Maybe I missed it. At first, I ground the ears off and just sort of "friction fit" it in among the plug wires. It held, but kind of cheesy. Was stumbling through the junkyard a couple days later and found out the stock 8cyl dust cap is the same as the 6cyl odd fire and fits the dist cap using the stock holes.

2) I was able to use the stock '75 Buick 231 vac advance module without problems. There must be more total advance in the HEI dist compared to the stock Delco unit. It took me a couple test runs, but finally realized I was getting a little too much advance at high RPM under load. I dialed down initial timing a couple degrees and bumped the idle back up, runs great.

3) I ended up pointing the vac advance forward and slightly toward the driver's side headlight. Clearance for the module was fine, but the vac hose was really close to the fan. I keep it out of harm's way but routing it across the top of the intake with the pass side plug wires, down under the base of the dist and then back up the other side.

4) The HEI in my JEEP replaced a good working Delco unit. I won't say that it is a night and day difference, but the HEI has definitely improved my high RPM performance, and smoothed out a little bit of a pass side sputter I had.

 

Clint,

What did you end up doing to get the rotor to line up? I am having the same problem with a converted EF to OF HEI, the rotor doesn't seem to line up with the plug wire posts without the advance.