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Discussion Starter · #1 · (Edited)
HEI Distributor & Fuel Injection for 235

Hey,

I'm pretty sure I'm going to take the plunge and install fuel injection in my '55 that has a 235.

I've read, from peope who have done the coversion, that they use an HEI distributor from a Chev 250 6 cylinder engine. I found a new on ebay that says it's for a 194, 230, 250, and 292.

From what I read, I would have to fab up a mount to keep it in place.

Will this work? Does anyone see any issues tat I may run into?

Thanks
E
 

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HEI

Yes, it works, You'll need to compare the 235 unit to the 250 and make the shaft, cam gear same length and position as early dizzi. You'll need to grind off the collar from the late unit and slip on the bolt down portion from the 235 minus the vacuum can. Or you can purchase a modified HEI allready done if you want. check with Langdon's Stovebolt or Patrick's Antiques.
 

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How about a 4.O FI

Hey,

I'm pretty sure I'm going to take the plunge and install fuel injection in my '55 that has a 235.

I've read, from peope who have done the coversion, that they use an HEI distributor from a Chev 250 6 cylinder engine. I found a new on ebay that says it's for a 194, 230, 250, and 292.

From what I read, I would have to fab up a mount to keep it in place.

Will this work? Does anyone see any issues tat I may run into?

Thanks
E
A Jeep 4.0 has the same firing order. Could you modify that Fuel injection to work on a 235. There are tons of theses systems in the Junk yards.
 

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Port fuel injection can be done but its not as straight forward as doing a engine with non shared ports since the 235 has 2 intake ports siamesed together they tend to rob the fuel charge from each other.

Some solutions include installing a port divider (reduces airflow though) , moving the injectors back a ways from the port (requires manifold work or a custom manifold).

TBI injection is the easiest to implement , get a throttle body and computer off a 4.3L v6 a 2.8L v6 tbi & computer may work but the injectors might probably not flow quite enough and you will need to either bump up the fuel pressure or install larger injectors. Plan to have a chip burned to get the most
from it.

Another idea is to get one of the dual 1 barrel manifolds and use the v6 computer to drive 2 1bbl tbi units off a 2.5L 4 cylinder Pontiac also may need to install lower flow injectors ( gm tbi injectors come in at least 2 different types as long as they are the same exterior you can interchange them to get different flow rates.)

The hardest part of the TBI conversion is the adapter to the stock manifold
or you could use a clifford/offy 4bbl manifold and use a tbi to square bore adapter those are common. Or carve your own from aluminum or micarta.
Also EFI or TBI needs a steady 12volt supply so plan on a alternator conversion and make sure all your grounds are good

Regards, Robert
 

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Discussion Starter · #6 ·
Thanks for all the tips and heads up. To tell you the truth, I only know the basic concept of converting to fuel injection. And I think I'm using the terms wrong. When used "fuel injection" to include TBI. So, I really mean TBI on the 235.

Bear with me because I'm learning all of this as I'm going.

It sounds like the HEI is really not a big issue. It's just a matter of comparing it to the original and making it work.

Like Robert said... adapter the TBI to the stock intake is the most challenging part.

The guy who converted it on his truck said that the TBI and computer from a 2.8L engine ran the best. I think he had to flash the computer or solder a chip on it or something like that.

I also came across another guy who had an adapter made for his stock intake. I need to look for that thread again.

I'm all ears. Keep it coming.. :driver:

Thanks
E
 

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Discussion Starter · #7 ·
Oh yeah. My generator took a dump a couple of years back. So, I ended up converting it to an alternator. :cool:

E
 

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Actually tbi and multi port injection are both EFI systems :)

I did some checking , the 235 6 with a powerglide in a 55 is rated 136 hp.

Based on that the injector size calculators show 136 hp needs 80 lbs/hr flow total injector rate the 2.8 tbi has 2 , 33 lbs/hr for a total of 66 lbs/hr so its undersized unless you bump the fuel pressure up from 13 to 20 psi. on the other hand a tbi off a 305 chevy v8 has 2 , 40 lbs/hr injectors so use a tbi off a 305 if you dont want to monkey with the fuel pressure regulator and the computer off a TBI v6 the tps sensor and iac should be compatible.

for reference the 4.3l v6 tbi unit has 45 lbs/hr injectors so if you have hopped up the engine they will support 153 hp they are probably close enough that it would also work on a stock 235

the 350 tbi from a truck supply 55 lbs/hr each supports 187 hp
and the 350 from a police car 350 are 65 lbs/hr each supports 221 hp
the 454 tbi came with 80 ( 272 hp ) or 90 lbs for 306 hp
These specs are for pre 94 units they changed to a new injector type after that at least on the 454 units

Regards, Robert
 

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I found a place online that tells you how to do it, I think it was on Inliners.org. I will see if I can find it again. For how much it cost to replace the internals, seems you could buy one made for a 235.

Here is a new one under 100 bucks: http://www.cfrperformance.com/CHEVY_GM_INLINE_6_CYLINDER_50K_HEI_DISTRIBUTOR_p/hz-d6050.htm

Of course I see they are out of stock.

Stovebolt.com has lots of info: http://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=534537&page=1

Found the link to make a 250 hei work : http://www.stovebolt.com/techtips/hei_conversion.htm
 

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Discussion Starter · #10 ·
YOU GUYS ROCK!!

I know a lot more than I did a few days ago.. :tu

I just want to let you know that I'm reading every reply... a few times... because I really appreciate the replies and I'm learning all of this.

I think the 305 TBI would be the easiest for me.

Here's my contribution - - I found this site while surfing an off-roading website - http://www.binderplanet.com/forums/showthread.php?t=47254
It specific to IH engines... (??) I'm guessing Scout International. :dontknow:
But the info seems pertinent to most TBI conversions.

Here are pics comparing the distributor that ca1955belair posted and one from ebay that I'm thinking about buying.
From CFR Performance ................................................. From Ebay


It looks like the main difference would be that gear that turns the shaft. I'm assuming that that engages with cam shaft or something. :dontknow: It looks like the collar on the ebay one extends farther down. I don't know if that's an issue or not.

I'm going to ask that guy on ebay how long he's gong to sell those distributors at that price. I think it's $62 plus $10 with shipping. Maybe I'll make a trip down the junk yard within the next week or so... I've heard that they sell those distributors for about $40 and that they are easy to come by.


BTW - what the heck is a "dizzy?" I've seen this word a couple of times and it always seems to come from someone who know's their way around engine, technically at least..

THANKs
E
 

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A dizzy is a distributor. People use short term and slang for many car terms. Although I will not do a 6 EFI conversion I am interested in technical aspects of your conversion. There is a guy at our shows that has an HEI in his early 60's Nova, Merry Christmas.
 

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Discussion Starter · #12 ·
I went to a few junk yards last week and found only 1 straight 6. It had an external coil, so I passed it up. I should have pulled the hold down clamp thingy. There were a ton of V6s and V8s.

It's kind of funny. I found a lot of 5.8L V8s and only two 5.0L V8s. Someone already pulled the TBI from one and the other had a little bit of melted plastic on the injections. I couldn't tell why, but I passed that too.

So, I bought this thing...



It arrived yesterday.

I read and read, and re-read threads and how tos. Then I measured and measured, and re-measured. It looks like the hardest part is finding a split collar clamp and making a hold down clamp.

I'll probably tinker with it on the day after Christmas. I'll post more pics too..

E
 

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Discussion Starter · #14 ·
I finally had time to work on this over the last couple days.

It started right up on the first crank.

I think I read somewhere that the ballist resister thingy needs to be by-passed when converting to HEI.


I'll try to get some pictures up later on today.

E
 

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Thanks, I want to do that to mine, I believe it will help mine run alot better since mine has the original in it, who knows how worn out it is.
 

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Discussion Starter · #16 ·
I just realized that the hard drive that crashed on my had all my pictures on it. :1zhelp: So, I'll do my best with the pics that I do have.

It took about 30 minutes to shave off the collar from the new HEI. (You can see it in the pictures above.) I used an angle grinder, bench grinder, course & fine files, and sand paper. It needs to be exactly flush with the rest of the shaft or else it won't slide in. (No pics)

I bought this split collar from Ace Hardware - $9. OUCH.. I couldn't find a split collar off the shelf anywhere else. And made this bracket out of 1/8" steel.


.

.


I welded it up.

Here's a test fit.




Here is the final distributor hold down bracket. I had to enlarge the hole for the bolt because I didn't drill it exactly where it should have been.



It was actually pretty easy to do. I spent more time thinking about it than I did working on it. If I were to do it over again, I would find a hinge collar that was shorter because I don't have much room back there with the dip stick and the hot wire on the starter in the way.

I set the timing by ear and it's just ok right now. I need to find out if I'm supposed to by the voltage ballast resister thingy. There's also bad gas still in the tank. So, I'll work on those things before I try to set the timing.

Oh, I also picked up a 1/8" street fitting with a barbed end and replaced the hard vacuum line. The fitting attaches to the carb and I just ran a rubber vacuum to the vacuum advance.

If anyone wants to see pics if anything else, just let me know..

All-in-all it was pretty easy to do.

E
 

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Just remove the resistor the HEI needs a full 12v to work so it should be hooked to and igniton switched on source.


I looked really hard at adding TBI to my 235.

Really pretty easy. You just need a single TBI unit off a 2.5L and upgrade the injector or better yet get a 4.3L twin TBI and make a adapter plate to the manifold. Its a little larger but will work.

Also since you have TBI you can run the ignition control as well.

Here's some info on the TBI http://67-72chevytrucks.com/vboard/showthread.php?t=337554
 

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Discussion Starter · #18 · (Edited)
Just remove the resistor the HEI needs a full 12v to work so it should be hooked to and igniton switched on source.


I looked really hard at adding TBI to my 235.

Really pretty easy. You just need a single TBI unit off a 2.5L and upgrade the injector or better yet get a 4.3L twin TBI and make a adapter plate to the manifold. Its a little larger but will work.

Also since you have TBI you can run the ignition control as well.

Here's some info on the TBI http://67-72chevytrucks.com/vboard/showthread.php?t=337554
I bypassed the resistor today.

It starts a heck of a lot quicker than it did before with points.

In Park or Neutral, it shakes a tiny bit at idle, but revs quite SMOOTHLY. However, I don't have any power under load. I can take off slowly, but if I give it gas or hit about 30mph, it will cut out. hmmmm.

Next I'm going to gap the plugs to .45 to see how it does (I've read that it can be gapped to .60, but I don't know if that's sound advice.). Then I'll swap out the wires to a later year that can with a stock HEI.


If I get the suspension done by the end of the month, then I think the TBI conversion will be my summer project. :cool:
 

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I would guess if you had power before you put this in, that the power loss is due to the timing being off. You may have to elongate the hold down hole so you can move it some more to get the correct timing. Nothing will rob power more than the timing being off. I doubt gaping the plugs larger will help the power much, but it should help it over all some as the fuel will be burnt more completly. Good luck, I'm watching this link closely as I may do this to my 57 also.
 

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Easy way to set timing is to connect a vacuum gauge then rotate your dizzy to get the highest vac reading. Just loosen your split collar to rotate.

Also Langdon's Stovebolt.com says you want to use a #10 ga wire from ign sw to the HEI as this will draw more current than original dist.
 
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