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HEI swap ...need help

L

LKJR

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ok guys, I just swapped in an HEI unit out of an 81 model. put on new plugwires, and I lined up the rotor with the old one when I replaced it. well now I'm not getting any fire, it rolls over and I've turned it a hundred times it seems like, but all I ever get is backfire through the carb or gas blowing out of the carb. I hooked the yellow wire up to the connector on the HEI unit. Am I missing something. HELP.
 
If you're getting backfire and popping thru the carb chances are that you either have the distributor 180 degrees out or at least off a few teeth. When you took out the old one did you mark where the rotor was pointing and aim the new one at the same spot or just drop it in?
 
you are probably off one wire. rotate all your wires one spot over to the right (counter clockwise). there is a different starting point for the #1 between points and hei. also you need to put a stronger wire on the coil side. the stock wire isnt big enough. put a bigger fron the fuse box.

hope it helps

nathan
 
[ QUOTE ]
I lined up the rotor with the old one when I replaced it.

[/ QUOTE ]

yes I put the hei rotor in the same spot the points was at, I tried rotating the wires counter clockwise already, I'll try the bigger wire trick tommorrow.
 
if its backfiring im 90 % sure that its off on the starting point. as long as the rotor is pointing at the #1 wire when you start cranking on it, and the order is right. it ought to fire off. mine gave me hell for like 3 days. /forums/images/graemlins/mad.gif i swapped em every direction. i thought it was one spot over it might have been 2. i know i tried both. good luck.

nathan /forums/images/graemlins/grin.gif
 
If it is the original engine, you are probably one cylinder off in the firing order, in 74 (i think) GM changed the firing order by one cylinder. I had the same problem in my blazer, but it was because the previous owner swaped in a 305 and retained the points distibutor, I didn't bother to mark the distributor position and when I put it where it should have been for a 72, it was off by 1 cylinder. This was of course in my younger, less informed days. Now I know better, but only from experience.
 
is there a way to test this HEI unit somehow? I've got the rotor lined up and I've got an 8 gauge wire going straight from a 12 volt source to the BAT terminal on the HEI unit. I"m at a loss, I heard something from someone about when it sounds like it's trying to roll over on itself to do something but I don't remember what. I'm getting that much.
 
Was the moter turned at all once you removed the points distrubitor..if so just turn the engine with a breaker bar on the damper tell your sure it's on the compresion stroke then 0 it out on the damper and pointer...then remove the cap on the HEI point it to the 1 cylinder in the cap and drop it in..that will give you a exactly TDC...put all the plugs back in and wires and start the engine it will be running a TDC then advance it to you desire...Also keep in mind that running spark plugs with points are gapped about .035...you may need to gap them more or buy a plug that was for a HEI most I think are around .045..
 
When I did my hei swap, I had almost the same problems. I eventually pulled the dist, pulled the #1 plug, & turned the motor until it made compression on #1. Then I started all over & dropped the dist in with the rotor pointed at #1.

I got all confused at first because the manual shows that the #1 on the dist is in a different location for hei & non hei. Since I was totally confused & it wasn't starting it made sense to just start all over.
 
dosen't it make two rotations to every time it fires one for compression and one for exhaust? how do I know which one I"m on if that is the case?
 
Remove the driver's side valve cover, roll the engine over by hand, [with a 1/2" drive ratchet,with the dampner bolt] watch the rocker's on #1 cyl, driver's side, front, watch as the exhaust close's, and as the intake move's down, and back up, now watch the degree mark's on the dampner, slowly roll it up till about 10 degree's before TDC, then set the rotor to #1 cyl. on the dist cap.

Reinstall valve cover, and fire it up, then set timing with a light. /forums/images/graemlins/eek.gif
 
[ QUOTE ]
If it is the original engine, you are probably one cylinder off in the firing order, in 74 (i think) GM changed the firing order by one cylinder. I had the same problem in my blazer, but it was because the previous owner swaped in a 305 and retained the points distibutor, I didn't bother to mark the distributor position and when I put it where it should have been for a 72, it was off by 1 cylinder. This was of course in my younger, less informed days. Now I know better, but only from experience.

[/ QUOTE ]

?????????????????????????????
 
You don't even need to take the valve covers off...If you got the plugs out just put your finger over the number 1 cylinder and you will be able to feel compresion when it's on the compression stroke....easy as that...
 
FINALLY!!!!!!!!!

it ended up being a combination of things. 1 I got some bad info on firing order, I had the order right but I had my odd / even cylinders backwards. Also the distributer was 180 off I lined up with the notch on the dampner but it was on the wrong cycle. so all is well, I still need to find where it's supposed to be at with the timing but I think I'm gonna replace my plugs first just to make sure there isn't anything in the way like that to keep it from running right. it still acts like it's stumbling a little when it idles. and it takes a bit to start.
 
Any Chevy V8, No1 cyl. on driver's side front.
Firing Order, 1 8 4 3 6 5 7 2
Distributor rotation, Clockwise, to advance, turn counter clockwise, to retard turn clockwise.

Probably around 8* before will get it running. /forums/images/graemlins/eek.gif
 
Problems with stumbling yet? I don't think this would be the problem, but is there a chance that the valves are set too tight?
 
running a new wire to the HEI unit from the ignition, where should I run it from? accessory? does that have full power during cranking?
 
you should have two links on you fuse box. One is hot all the time. the other is hot with the key on and the one you want to connect to. By the way I did this to a 71 2wd I had. one problem I had was I kept plowing the control module. keep 1 or 2 with you just in case. it was no fun breaking down when you on the road and no autoparts nearby.
 
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