| Slant Six Forum https://slantsix.org/forum/ |
|
| HEI conversion? https://slantsix.org/forum/viewtopic.php?t=21048 |
Page 1 of 1 |
| Author: | JohnnyDees [ Sun Dec 10, 2006 4:23 pm ] |
| Post subject: | HEI conversion? |
Has anyone succesfully converted to HEI using a 7 pin module? I tried to fire mine up today for the first time with no luck. I grounded it well used heat sink compound and tried all the wiring combinations(still no luck). I did start looking thru some old posts and one said a 4 pin can stand alone while a 7 pin needs an ECM to work is this true? 
|
|
| Author: | Rick [ Wed Dec 13, 2006 8:02 am ] |
| Post subject: | |
I used a 7 pin hei module and its been working great for a couple of years now. If you got your HEI module from the junk yard that may be your problem. I guess they go bad after sitting for a long period after being used. I tried two from the junk yard and was almost convinced that the problem was in my wiring before I bought a new one. Dont take any chances with your ground. The thing grounds from the hold down screws so I looped a wire , with the appropriate terminals between the hold down screws, then to a drilled and tapped hole in the aluminum heat sink, then to the engine block. I dont have any kind of ECM on my truck. It was a lean burn ignition and I disconnected the wiring harness from the lean burn computer and then wired in the HEI system and used a vacuum advance distributor. I bought my HEI module from Autozone and its fine but if you want the best go to GM. About 15 years ago an uncle of mine had an HEI distributor in a camaro drag car and bought an accel or mallory ( I dont remember which) HEI module and was wiping it off and the company logo came off and it to reveal the GM logo underneath. He was a touch irate over this.The GM units supposedly have a longer dwell but I dont think you would ever tell from driving it on the street. I just hope my Autozone unit lasts a long time. |
|
| Author: | JohnnyDees [ Wed Dec 13, 2006 7:30 pm ] |
| Post subject: | |
Thanks for the reply. So on you're system the 3 extra pins are unused right. |
|
| Author: | Rick [ Wed Dec 13, 2006 10:22 pm ] |
| Post subject: | |
Yep, I'm not using all the pins. I am eventually going to build a long rod 225 and wanted to run fuel injection so I got the seven pin HEI module but the money is a little hard to find right now to do the engine. I've got an early seventies block , a head with the factory oversized valves and an early model Dutra casting to use for dual exhaust. My truck has 10.5x31 tires with 3.55 rear gears and an overdrive manual transmission. Its been a couple of years since I ran long wires from the coil to my dwell-tach meter in the cab and took it on the highway but , if I remember right, it was only turning about 2200 rpm at 70 mph. I'm going to be real careful about what cam I get so I get all the cam I can use but I dont want to get a cam that is too much. I'm going to call comp cams and see what they say thier cams will do in this application but I may go with a stock cam. Its not a race truck and I would like to get decent gas mileage but still have the power to tow something if I had too. |
|
| Author: | mrbillohnooo [ Wed Dec 13, 2006 11:23 pm ] |
| Post subject: | |
I am running a 4 pin hei Module , works great! I agree that salvage yard units must go bad after sitting, because I had a new in the box gm unit that had been sitting on a shelf in my garage for 15 plus years and it did not work. I used a unit from o'reillys... I am running a big valve head, erson 270 cam, 2 1/4 exaust with a flowmaster copy muffler, super six 2bbl setup right now in my 1/2 ton shortbed 2 wd truck ('84), and it turns 2150 rpm at 70 mph. It knocks down 20 plus mpg. I have an 833 od four speed, soon changing to either a t-5 5speed, possibly a t-56! Good luck on your project! Bill Oh yeah, the power is waaaay improved over stock! |
|
| Author: | JohnnyDees [ Thu Dec 14, 2006 5:36 am ] |
| Post subject: | |
Thanks for the help guys. I tried all 3 of my junkyard units and the third one (of course) worked. The wiring was fine from the beginning. Fuel injection just keeps getting closer all the time. |
|
| Author: | Rick [ Thu Dec 14, 2006 7:55 am ] |
| Post subject: | |
My trucks an '85 1/2 ton, short bed , slant six. I have a np or nv2500 trnsmission that I think I can make work with a some modifications. I'm glad to hear that 20 mph is possible. I was hoping to get that when I'm done instead of the miserable 13-14 that I'm getting now. The truck has over 200,000 miles on it and its pretty tired. To give an idea how tired-I can get it up to about 75mph with no problem but sometimes when I try to pass a semi, I cant. I can get up to the cab of the semi but some semi's are pushing so much air off the front and around them that I cant get through it. Its embarrassing. I get stuck beside them till we hit a place going downhill then I can usually pass. The engine is tired. Check out the progressive carbs at www.stoveboltengineco.com . They have new and rebuilt carbs for less then a hundred bucks. They might work better than that bbd 2bbl. |
|
| Author: | Chewie [ Thu Dec 14, 2006 8:06 am ] |
| Post subject: | Hei |
I used a Petronix kit in my stock distributor and did away with all the other stuff other than a coil. it works great. |
|
| Author: | mrbillohnooo [ Fri Dec 15, 2006 9:37 pm ] |
| Post subject: | Mpg |
I sure know the feelin of bein' unable to pass a semi. Mine did the same thing before the head and cam change. The super six setup helped a bunch. I found that the rpm's need to be above 2200 to pass one at hiway speed, before the cam swap anyway. Since the swap, it does real sweet in 3rd gear up till about 75 mph, about 3750 rpm, and ya can pass a semi in a serious cross and headwind even! Fourth gear is great in no wind passing anything...25 to 30 mph winds are the norm here in west Texas!...and when it's windy.....anyway, sorry to get so off topic. The Hei Ign thing has worked very well for me. I used a Ford e-core coil. btw, I drove from Amarillo to Oklahoma city ,240 miles from my driveway to the station I stopped at to fill up...9.4 gallons filled it up....no wind that day. (to speak of) I was averaging about 75 mph too...2200 rpm.... Thanks, and good luck with your truck project! |
|
| Page 1 of 1 | All times are UTC-07:00 |
| Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/ |
|