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TECH: better late than never, easy 235 hei conversion

Discussion in 'The Hokey Ass Message Board' started by 55 dude, Jun 16, 2007.

  1. dudes!, i missed tech week because i was off at a car show. this is nothing new only the pic's are :D . anyone that has points knows the pain of being broken down because the points or condenser took a dump. here is a easy conversion that is cheap also. here we go hit the local pull-a-part (self service yard) an find a 250 chevy HEI usually under $50 bucks making sure it's of non-computer variety simply put it has to have a vacuum advance. all you are going to do is remove the mounting flange and use the slightly modified 235 hold down mounted about 1/4"-3/8" further up on 250 HEI dizzy drop in dizzy hook up one wire (12 volts) to BAT teminal on cap, the other terminal is marked TACH pretty easy to figure out what that one is for :rolleyes: . i will post pic's and try not to confuse anyone. please excuse some pic's are a little dark. please pm me with any questions so stay cool and feedback please:D :D

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  2. ok! it's been 5 days has anyone built a dizzy yet for their 235? feedback and pic's please. my tech ego needs some feedback:D :D
  3. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    Good tech! An add-on, applicable to almost all HEI swaps: All or almost all HEI's came on cars with EGR systems. EGR cars need WAY more vacuum advance at part throttle than cars without, and so most conversions will ping like crazy on minor hills unless you get on or back way off the throttle.
    Advance in degrees is stamped on the shank of most vac cans, it'll be around 20 on these things. While at the junkyard, steal a can from a big Chevy truck (V8 is same fit) and check shank--it'll be not much more than half the advance. Use it. Done.
    Aftermarket performance cans, NAPA cans oodered for heavy truck use also usually good.
    Moroso HEI V8 advance tuning kit for V8 fits well--try it with middle and lightest springs to find engine's happy point.
  4. squirrel
    Joined: Sep 23, 2004
    Posts: 46,844


    Looks good! also remember to keep a spare HEI module in the glovebox, anyone that has hei knows the pain of being broken down because the module took a dump.

  5. brokenspoke
    Joined: Jul 26, 2005
    Posts: 2,882


    Speaking of Module...last year on my way to a cruise my sbc with a HEI started acting up. It started with a miss every now and then and progressively got worse and with in 30 miles it would back fire and die..I could wait a few and it started again for a few seconds and die again..I just replaced boy the coil and module..been running good since..Which do you think the problem was ??Coil or module??
    Joined: Nov 22, 2005
    Posts: 7,591

    from SIDNEY, NY

    On that subject, the time to make sure that the module screws still move is at home in your driveway. Nothing's more sickening than trying to change your module along the road and snapping the seized screws off when trying to remove them.
  7. flatheadpete
    Joined: Oct 29, 2003
    Posts: 9,867

    from Burton, MI

    I bought new I6 HEI for about a hundy. Changed the gear on it and put it in my AMC 6 banger. Idiot proof hook up is only the beginning of an HEI. It could be mayor of Reliable City and they're readily available.
  8. patgizz
    Joined: Jun 14, 2007
    Posts: 86

    from cleveland

    awesome tech. what year 235 did you do this to?

    the only reason i ask - i am not sure if all distributors are the same, but i know the 55-62 oil pump is different so not sure if the pump drive on the dist is the same.

    i need to do this to my '54 235 engine, i have a strong dislike of points and would give up some of the "traditional" look with the hood up for the beautiful reliability/1 wire install/compactness(ie - no external coil) of the HEI.
    Joined: Nov 22, 2005
    Posts: 7,591

    from SIDNEY, NY

    The only point of contention that you need to be aware of is that the 1937-53 and '54 standard shift drive gear is a different material than the '54 PG and '55-'62 all gear. If you run an H.E.I. in the early engines, you need to install the gear from your original distributor on it. The early engines had steel camshafts, and will chew up the later gear that was intended for use on cast iron camshafts.
  10. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    The things are insanely durable in my experience...
    Their only normal deterioration point is the central area at the coil secondary, which slowly erodes at cap, rotor, and eventually the coil, requiring replacement at maybe 200,000 just to be prudent...
    That being said, they seem to keep cranking even with highly advanced burnout at that are. I have seen them with the whole center area of cap scorched and eroded, center of rotor turned to charcoal from continual fire-through, and whole advance trashed by advaced electrical erosion...on running engines without overt signs of missing. Still, toss in a new rotor every ten years just to be safe...
    I picked up a couple of modules, a complete cap/coil assembly from a car that had had a recent tune, and even the mag pickup bits from the junkyard, and a smashed housing that I made into an oil pump rimer for almost nothing, and feel utterly secure with the things.
    My conversion moment?? When they came out, like every other rodder I said "Aaah, black box, can't fixxem on the road like points", and ignored them. Then, a friend got me to help him with his: At 230,000 miles, he was worried that nothing in his ignition had failed, so he bought all the parts. After we replaced everything, he had a static signal on his radio, and the old parts, all perfect, went back in...that got me thinking!
    On the road, it's barely more expensive to keep a spare module thaan spare points under the seat, anyhow...and who ever fixes points rather than replacing them?
  11. squirrel
    Joined: Sep 23, 2004
    Posts: 46,844


    Today I drove my son's truck to Bisbee, it's at least 20 miles each way. the truck has a rebuilt 235 with the stock points distributor, with all new parts in it. Ran like a champ....made it back home just fine....I was quite impressed.

    I've only had 3 hei modules die on me, first was my fault doing a compression test using the key to crank it with all the plug wires off. other two gave hints they were going bad before they went all the way out.
  12. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    And points...they do need occasional replacing, but I've NEVER had to walk home or fix points on the road.
    One interesting old Nova desperately needed a tuneup, I could tell points were far enough closed that timing was way down...winter was coming on, no garage, rain, snow, ice, lazy...just kept on driving. When I finally got to the job in the spring, car still running quite adequately, I noticed points weren't visibly moving when I rotated distributor...spunnitover with the starter, and total point movement was the barest twitch the eye could detect. Still getting 18MPG and running entirely well enough...
    Old car points problems are usually either loose distributor bushings or breaker plate, and on at least Fords, really bad Chinese points from the restoration suppliers. Buy real points!
  13. squirrel
    Joined: Sep 23, 2004
    Posts: 46,844


    I guess you haven't owned many mopars? :)
  14. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    '63 Plymouth...for some reason, setting timing and points was VERY fiddly, it had to be exactly right and would always shift a bit when tightened...but once set, everything stayed happy forever.
    Pinged like crazy from new, figgering out how to static time it (timing light would have been like 30 years allowance...) and get it right made my Father very happy!
    Changed to electronic at around 300,000 miles when pivot on breaker plate disintegrated!
  15. If you take the ign module out of the distributor and move it to a cooler place like under the dash, it will last about 100 TIMES longer, will become an anti-theft device, and be very easy to change if it ever quits on you. It sure beats working under the hood in the rain if one goes out.

    I put TWO under the dash with a switch so I could fix it with a flip of the switch instead of getting out of the car, and I have NEVER had one fail since. Over 10 years now on the same module.

    Did you know you can put that same Chevy 6 HEI in an AMC or JEEP simply by changing the distributor gear? Use an older gear. The later gears had a larger I.D. I have sucessfully used quite a few factory 8 cyl gears when the 6 cyl gears ran out.

    I did that to my new 1981 Eagle long ago, and started selling them for several years before the bigger places took over that niche market I used to have. That "AMC" HEI knocked a few seconds off the 0-60 times of the family wagon.
  16. the 54' burb was the happy camper that recieved the "test"HEI yesterday and acted very good by firing right up. next victim is a 59' chevy truck that lost it's spark(bad condenser) i do like the remote module mount. my 87' chevy truck used to go through modules all the time. sometimes they will recover if allowed to cool down. i used to carry a can of butane lighter fluid hit it with a shot of butane wait a minute or 2 and it's like a cool splash of water on a 100 deg. day! butane is also great for the use in finding cracks in aluminum heads.
  17. back to the top for tech week
  18. RugBlaster
    Joined: Nov 12, 2006
    Posts: 563


    This points v. HEI debate..... I wonder why I don't just throw this new fangled computer brain in the trash and just start writing letters.

    I'm a HEI fan. It is astonishing how many performance problems can be traced to a dicked up ignition.

    Nice tech
    Last edited: Oct 25, 2009
  19. El Caballo
    Joined: Mar 3, 2001
    Posts: 5,896

    El Caballo

    Very good tech.
  20. Nubomb
    Joined: Jul 4, 2009
    Posts: 9


    Just performed the conversion on my daughter's boyfriend's 52 A.D. with a 235. Works like a champ, $60 pick-n-pull HEI (complete with like new wires, cap, and rotor), never started so easy. Thanks for the article 55 dude!
  21. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,754


    sounds like a great idea! Nice tech too!
  22. fastcar1953
    Joined: Oct 23, 2009
    Posts: 2,212


    btt for new members
  23. scrmkr
    Joined: Nov 19, 2011
    Posts: 16

    from memphis tn

    Are there any junkyard MINI hei's that will work in the 235? I've seen you can buy them pre-built but would like to save a few $$.
  24. fordcragar
    Joined: Dec 28, 2005
    Posts: 3,180

    from Yakima WA.

    Check with HAMB'r GMC BUBBA.
  25. If you follow the tech article you will have a cheap ignition upgrade that will work great! I have had tons of pm's about guys doing this and they say it works great for them. You can also contact gmcbubba because the dude knows his craft.
  26. silversink
    Joined: May 3, 2008
    Posts: 917


    you have my vote
  27. Indychus
    Joined: Jun 9, 2010
    Posts: 134

    from Irmo, SC

    I know this is an old thread, but i just did this on my '52 235 and it's a huge improvement over the points!

    Also, it should be mentioned that there are a couple of sellers on ebay right now having a price war, and you can pick up a brand new 250 HEI for $60 shipped. It looks to be a quality piece, and comes with the coil already in the cap.
  28. Good and cheap tech is always welcome here!
    Joined: Aug 7, 2009
    Posts: 2,069


    My 7 year old was doing that 3 years ago when he was 4

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