AgTalk Home
AgTalk Home
Search Forums | Classifieds (162) | Skins | Language
You are logged in as a guest. ( logon | register )

Before you put an HEI distributor in a 366/427 ..
View previous thread :: View next thread
   Forums List -> Machinery TalkMessage format
 
Mike SE IL
Posted 10/14/2009 09:15 (#884038)
Subject: Before you put an HEI distributor in a 366/427 ..



West Union, Illinois

Before you put an HEI distributor in a 366/427 flip it over and look closely at the oil pump drive.

We didn't.

We have an old 10-wheeler, 1975 Chevy C-70 tag axle with a 366 and 5x2. It was needing a tune up.   We decided since we we were going to put cap, rotor, points, wires and plugs in it why not go a little farther and replace the old distributor with an HEI and see if it helped performance.  Son in law went to the local O'Reilly's and told them what we had and what we wanted to do. "Got just what you need right here. Now be sure and compare the length to be sure it fits"

He brought it home, compared the length, it was identical.  Put it on, started right up.  Built up air pressure, drove down the road to see how it worked ... and about 100 yards down the road the motor just stopped. No noise, no warning, just stopped. And it wouldn't even crank over. Fortunately a neighbor came along and helped him drag it back to the shed before the air bled off. Like most of us he was listening to the engine and didn't notice what the oil pressure gauge was reading.  We got to thinking about it and pulled the distributor out.  The gear on the bottom is identical on the outside.  Inside the end .. the oil pump drive ... it was made different. It didn't have the little cross on it


Did you know the oil pump has to be replaced when you replace the distributor on a 366 with an HEI?

First thing Monday morning we stopped by our local mechanic's and told him what happened.  He got this funny smile and asked if we dropped the pan and replaced the oil pump?

Talking to a few local "Chevy guys" nobody else we talked with knew that.  Guys at O'Reilly's admitted they didn't know it.  Their book said it would work.

Pondered on it and called the O'Reilly's manager.  He talked with is manager who said their part worked just like it should, it was our fault for not making sure it was the right part.

Should have caught it? The guys selling us the part didn't know it.  The instructions don't mention it (see http://www.msdignition.com/instructions/Products/Distributors/8362.... ).  With one exception all the Chevy gearheads I've talked to didn't know it.

But I guess I will get to pay for the repair.

My next decision is do I put that much money into a 35 year old tandem with body cancer or scrap it and put that money into a newer used truck?

Top of the page Bottom of the page
wilddog
Posted 10/14/2009 09:19 (#884044 - in reply to #884038)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Thanks for your post, I've been thinking about doing the same thing and you might have saved me a motor!
Top of the page Bottom of the page
WTW
Posted 10/14/2009 09:25 (#884055 - in reply to #884038)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Winkler, Manitoba Canada
We did that swap years ago. Fortunately I was warned about the oil pump drive. I think we just took the gear off the old distributor and put it on the HEI. Never changed the oil pump drive otherwise. Tough decision you have on your hands now.

Edited by WTW 10/14/2009 16:19
Top of the page Bottom of the page
Bristol Hillbilly
Posted 10/14/2009 09:39 (#884077 - in reply to #884055)
Subject: Re: Before you put an HEI distributor in a 366/427 ..



Palestine, IL 62451
Petronix makes kits to convert to old distibutors to elctronic ignition. It might not be a true hei but I have put them on all 4 of my older trucks(74 and older). Now I will say that I did have to remove on and go back to points due to some issues. All in all I have been happy. In most cases I did not even have to pull the dist.
Top of the page Bottom of the page
Mad Max Perf
Posted 10/14/2009 09:44 (#884083 - in reply to #884077)
Subject: Re: Before you put an HEI distributor in a 366/427 ..



North Western Alberta
Yeah, you can just order the aftermarket distributor for it, and then press the old gear off the old points distributor, and press it onto the new one. This is one of my planned mods for my ole 366. Im tired of replacing points and condensers, and them floating when you are really revin' the old girl! Hahah.
Top of the page Bottom of the page
plowboy
Posted 10/14/2009 09:55 (#884096 - in reply to #884038)
Subject: RE: Before you put an HEI distributor in a 366/427 ..



Brazilton KS

If the new one does not have the pin, what DOES it have to drive a pump?

 

I thought everything GM BB or SB used a pin across there to drive the oil pump??

Top of the page Bottom of the page
jakencks
Posted 10/14/2009 10:18 (#884120 - in reply to #884096)
Subject: RE: Before you put an HEI distributor in a 366/427 ..



Wondering the same thing. Did a conversion 10+ years ago and don't remember changing gear and dam sure didn't change out pump. Used a donor distributor off salvage vehicle, though.
Top of the page Bottom of the page
Mike SE IL
Posted 10/14/2009 10:28 (#884131 - in reply to #884096)
Subject: RE: Before you put an HEI distributor in a 366/427 ..



West Union, Illinois
plowboy - If the new one does not have the pin, what DOES it have to drive a pump?
I don't know ... ours didn't have it!  I'll try to remember to grab the camera and take some pictures
Top of the page Bottom of the page
Pat H
Posted 10/14/2009 10:45 (#884156 - in reply to #884131)
Subject: RE: Before you put an HEI distributor in a 366/427 ..


cropsey, il 61731
Mike,

Now is the time to make this a real project and stick a 8.2 DD or 7.3 PS diesel in it (higher reving diesels might come close to working with the gas gearing). Then of course you might as well get new doors and do some body work then you might as well and might as well - you get the idea. However, a used engine might not be so bad on $ - may have to buy the whole rusty truck to get it though.

Thanks for the post,

Pat

PS: Another option:



(chevy engine.jpg)



Attachments
----------------
Attachments chevy engine.jpg (15KB - 1279 downloads)
Top of the page Bottom of the page
plowboy
Posted 10/14/2009 14:22 (#884363 - in reply to #884131)
Subject: RE: Before you put an HEI distributor in a 366/427 ..



Brazilton KS

Obviously the problem lies with not knowing about it ahead of time, but looking back, couldn't you just change the gear (or probably the colalr below the gear) rather then changing the oil pump?

 

I know for certain that there are HEI distributers with the pin type drive on them, because I've seen them apart.  I started to wonder if it's a tall deck vs passenger thing, but since your old one was evidentally in a tall deck engine, it would seem that's not it.  I'm guessing it's a model year issue?

Top of the page Bottom of the page
nwks baler
Posted 10/14/2009 10:54 (#884172 - in reply to #884038)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Kansas
You do not have to change the oil pump, only the gear on the end of the distributer. The small block truck engine is the way. I have remanafactured several of those over the years because people didn't know about the oil pump drive shaft being different on the trucks and did the same thing you did.

I am sure most people in the parts house would not know about this.
Top of the page Bottom of the page
Rich
Posted 10/14/2009 12:35 (#884273 - in reply to #884038)
Subject: Now wait a second, you fellars that are saying change the gear on the distributer shaft........



Kansas
Why?

That cannot be the culprit that kept the oil pump from spinning and working. If it was the culprit, the distributer wouldn't of spun and the truck wouldn't of fired.

I'm not following the logic why changing the gear has anything to do with his dilemma.
Top of the page Bottom of the page
scott nelsen
Posted 10/14/2009 12:52 (#884288 - in reply to #884273)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Leeds, North Dakota
cam turns distributor in turn distributor turns oil pump, i don't remember i thought all gm's used roll pin to turn oil pump, but i do recall some shafts had a hex shaft to drive oil pump, scott
Top of the page Bottom of the page
mac4440
Posted 10/14/2009 13:06 (#884299 - in reply to #884288)
Subject: Re: Before you put an HEI distributor in a 366/427 ..



It's been years since I worked on a big block in a pick-up, but seems like the oil pump drive was a hex shaft, and the dist. shaft fit over that? Not sure, I might be thinking of something else.
Top of the page Bottom of the page
scott nelsen
Posted 10/14/2009 13:16 (#884309 - in reply to #884299)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Leeds, North Dakota
i will look have a couple big blocks, scott
Top of the page Bottom of the page
notillgleaner
Posted 10/14/2009 13:24 (#884315 - in reply to #884288)
Subject: Re: Before you put an HEI distributor in a 366/427 ..



Central Kansas
scott's got it right.  Some have a hex shaft.  I did the swap on a small block truck motor.  I think it's because it's on truck that makes the difference.  The 350 Chevy was the same way.
Top of the page Bottom of the page
Rich
Posted 10/14/2009 13:49 (#884333 - in reply to #884288)
Subject: Re: Before you put an HEI distributor in a 366/427 ..



Kansas
your only strengthening my point.

Why would changing the gear have anything do do with the oil pump?

It wouldn't. Nada, nothing, ziltch, zero.

If the gear is doing it's job and the cam is turning the distributer, it would equally be turning the oil pump. That gear has nothing to do with the dilemma at hand.
Top of the page Bottom of the page
plowboy
Posted 10/14/2009 14:14 (#884357 - in reply to #884333)
Subject: Re: Before you put an HEI distributor in a 366/427 ..



Brazilton KS
Rich, how is it going to turn the oil pump if it does not have the pin through it???? The pin is what turns the tangs on the pump. 




(OIL-PUMP.jpg)



Attachments
----------------
Attachments OIL-PUMP.jpg (19KB - 1270 downloads)
Top of the page Bottom of the page
Rich
Posted 10/14/2009 23:25 (#885127 - in reply to #884357)
Subject: Re: Before you put an HEI distributor in a 366/427 ..



Kansas
That is true. And the gear turns the distributer shaft drove off the cam.

So what you need is the correct end. Not the GEAR!

GEAR.......the helical toothed part that drives off the cam.

What are you talking about?
Top of the page Bottom of the page
WTW
Posted 10/14/2009 23:41 (#885156 - in reply to #885127)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Winkler, Manitoba Canada
In this case the gear and the end are one and the same.
Top of the page Bottom of the page
Rich
Posted 10/14/2009 23:48 (#885168 - in reply to #885156)
Subject: Re: Before you put an HEI distributor in a 366/427 ..



Kansas
That would explain the misunderstanding
Top of the page Bottom of the page
junior
Posted 10/14/2009 17:24 (#884519 - in reply to #884333)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


thumb of Michigan
Rich,
The gear on the old distributor had a roll pin down low to drive the oil pump. Roll pins are Sh1te for shock loads.....say some -10f 15/40. So about 1974 some brainy engineer came up with the idea that the distributor shaft itself could actually drive the pump. The shaft has a flat ground on the end. It looks like the oil pump drive shaft where you put the plastic collar. When I was apprenticing about 1991 I learned why it was important to check oil pump engagement. If engagement wasn't enough we would press the shaft out more in the oil pump.
Top of the page Bottom of the page
Mike SE IL
Posted 10/14/2009 16:55 (#884494 - in reply to #884288)
Subject: Re: Before you put an HEI distributor in a 366/427 ..



West Union, Illinois

scottnelsen - cam turns distributor in turn distributor turns oil pump, i don't remember i thought all gm's used roll pin to turn oil pump, but i do recall some shafts had a hex shaft to drive oil pump, scott
Scott's right. Most people thought all GM's had that roll pin to drive the oil pump.  BUT 366's or at least some 366's and 427's apparently are different. I got it backwards.  The photo I posted is what most GM's and the new distributor that we tried to use look like.  I didn't pull the one in the 366 but it doesn't have the cross, it is open centered with flats on each side like might fit a hex shaft or a shaft that has been ground flat on 2 sides.

I think our solution is going to be moving the bed to a differnt chassis this winter.  

Top of the page Bottom of the page
Indianajones
Posted 10/14/2009 17:38 (#884537 - in reply to #884494)
Subject: Re: Before you put an HEI distributor in a 366/427 ..



The "pin" in the pic everyone is refering to is actually the end of the distributor shaft that is ground flat to drive the pump. I talked to a couple old school chevy guys today and neither have heard of a different style oil pump drive for any big block chevy engine.
I am wondering if they built the distributor wrong when it was rebuilt.
If I get a chance, I will pull the dist from the 454 I have on the shelf and check it.
INDY
Top of the page Bottom of the page
pknoeber
Posted 10/14/2009 13:18 (#884312 - in reply to #884273)
Subject: RE: Now wait a second, you fellars that are saying change the gear on the distributer shaft........


SW KS, near Dodge City
I think the pic shows the old distributor. I would bet the new one is hollow and does not have the pin in it that powers the oil pump. I'm not much of a mechanic though, so I might be wrong.
Top of the page Bottom of the page
OHKen
Posted 10/14/2009 13:58 (#884340 - in reply to #884312)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Ohio
Mike if the bed is good in this economy maybe you could find a newer truck/tractor and update. Sorry about your luck,once in a while things like this slip thru the cracks. The description of body cancer tells me to say addios.
Top of the page Bottom of the page
OHKen
Posted 10/14/2009 14:07 (#884352 - in reply to #884340)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Ohio
Mike reread your post it's a single axle with a cheater -----say goodbye . A newer truck/tractor with a live tandem would give you the option of pulling a big gravity wagon.
Top of the page Bottom of the page
Old Pokey
Posted 10/14/2009 15:27 (#884440 - in reply to #884038)
Subject: RE: Before you put an HEI distributor in a 366/427 ..


  Hopefully Jon Hagen will be along and set the record straight. Smile
Top of the page Bottom of the page
Jon Hagen
Posted 10/14/2009 18:01 (#884564 - in reply to #884440)
Subject: RE: Before you put an HEI distributor in a 366/427 ..(PICS)



Hagen Brothers farms,Goodrich ND
Old Pokey - 10/15/2009 14:27

  Hopefully Jon Hagen will be along and set the record straight. Smile




LOL, OK , for what it's worth, this is what I have seen for chevy big block distributors and oil pump drives to the late 80's. If they changed the drive after the late 80's I would not know about that as I have not been inside one of them.

The bottom end of the distributor shaft is ground down to the shape of a large flat blade screw driver. This flat paddle shaped end of the distributor shaft is what fits in the slotted end of the oil pump drive shaft and makes it turn. The distributor gear has a long hollow bottom that allows the oil pump shaft to slip inside it and keeps the oil pump shaft slot centered over the paddle shaped end of the distributor shaft.
All the pin through the distributor gear and shaft does is to drive the distributor shaft.

The joint between the bottom of the oil pump drive shaft and oil pump is another screwdriver and slot arrangment. The screwdriver like end of the shaft fits in the slot in the oil pump shaft, with a plastic or metal sleeve surrounds it to keep the joint in mesh.

Where you can get into trouble swapping distributors on big block chevys, is if you try to use a low deck car or light pickup distributor in a tall deck engine like a medium truck 366-427. The medium truck 366-427 actually has a cylinder block that is about 3/8-1/2 inch taller from crank center line to the deck surface so they could use taller 4 ring pistons for longer life. With the deck being taller, the heads and intake manifold sit higher than they would on a passenger car or pickup low deck block.

It takes a longer distributor to sit on that taller intake manifold and still reach deep enough into the engine to properly mesh with the camshaft gear and drive the oil pump shaft.
A distributor made for a small block or low deck big block, will not work in a tall deck medium truck 366-427.

EDIT: I did not realize until I reread the original post that it was an aftermarket distributor and not a GM medium truck HEI that was installed.
I suspect that part number is intended for smallblock or low deck big block car /pickup engines. The parts guy did instruct to compare distributor length, but the instruction sheet should have stated and parts guy known that this distributor was NOT intended for a tall deck truck / marine BB engine.

The difference in length is small enough that it is not easy to spot.
The easiest way is to place the two distributors shaft to shaft. If they are the same length, placing the distributor gear on one distributor against the mounting flange of the other, will allow the other gear and flange to also just touch.

EDIT 2 : did a little google searching and find this

"MSD 8362 MSD Street Fire distributor, a Chevrolet HEI small block and big block distributor."

If it fits a smallblock, it is not the one for a tall deck BB engine.

Another fix may be to get a salvage yard engine. Thousands of good running 366 engines out there for as little as $300.



Edited by Jon Hagen 10/14/2009 19:02




(GM distributor shaft.jpg)



(chevy distributor gear..jpg)



(chevy distributor gear and pump drive..jpg)



(chevy oil pump drive shaft.jpg)



(chevy oil pump..jpg)



Attachments
----------------
Attachments GM distributor shaft.jpg (29KB - 1798 downloads)
Attachments chevy distributor gear..jpg (2KB - 1814 downloads)
Attachments chevy distributor gear and pump drive..jpg (2KB - 1985 downloads)
Attachments chevy oil pump drive shaft.jpg (1KB - 1771 downloads)
Attachments chevy oil pump..jpg (1KB - 1795 downloads)
Top of the page Bottom of the page
nwks baler
Posted 10/14/2009 20:15 (#884733 - in reply to #884564)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Kansas
The distributor on a short deck and a tall deck big block chevy are the same length. All that needed to be done on the truck in question is take the cam drive gear from the old distributor and install it on the new distributor and it would have been fine.

There are two different oil pump drive shafts for a big block chevy. Melling part number IS77B( which is what was on the truck ) and IS77A (which would have been on a short deck at that time.

GM also did the same thing with the small block 350 during that same era. Melling part number IS55F for the large trucks and IS55G for the rest.
If you don't change the gear on small block distributor it will have no oil pressure.

While the block on the tall deck is taller than the short deck you will find that the intake manifolds will not interchange which is how GM kept the distance from the distributor to the oil pump the same.

You could also change the oil pump drive shaft to the proper distributor gear.
Top of the page Bottom of the page
5230
Posted 10/14/2009 20:35 (#884784 - in reply to #884733)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


sw wi
''While the block on the tall deck is taller than the short deck you will find that the intake manifolds will not interchange which is how GM kept the distance from the distributor to the oil pump the same.''

The intake will not interchange because the heads are farther apart because of the tall deck height, you can buy the spacers from after market to put low deck intakes on tall deck motors. Sure would have been easier if they would have stuck with one design!!!
Top of the page Bottom of the page
Jon Hagen
Posted 10/14/2009 20:40 (#884789 - in reply to #884733)
Subject: Re: Before you put an HEI distributor in a 366/427 ..



Hagen Brothers farms,Goodrich ND
nwks baler - 10/15/2009 19:15

The distributor on a short deck and a tall deck big block chevy are the same length. All that needed to be done on the truck in question is take the cam drive gear from the old distributor and install it on the new distributor and it would have been fine.

There are two different oil pump drive shafts for a big block chevy. Melling part number IS77B( which is what was on the truck ) and IS77A (which would have been on a short deck at that time.

GM also did the same thing with the small block 350 during that same era. Melling part number IS55F for the large trucks and IS55G for the rest.
If you don't change the gear on small block distributor it will have no oil pressure.

While the block on the tall deck is taller than the short deck you will find that the intake manifolds will not interchange which is how GM kept the distance from the distributor to the oil pump the same.

You could also change the oil pump drive shaft to the proper distributor gear.



I disagree, the stock small block / low deck BB distributor is NOT the same length as the tall deck distributor, as shown in this link. Note the warning not to use this distributor in a tall deck engine.
http://www.yearone.com/serverfiles/fbshopmain2.asp?pid=1919N&hid=Q1...

The distributor shaft drives the oil pump, not the distributor gear, so how would changing the gear get the distributor and oil pump shaft to connect ?
You might be able to adapt a short distributor with a custom gear that mounts the distributor gear lower on the shaft so it has the right mesh with the camshaft gear, and use a custom longer oil pump drive shaft, but you can't do it with stock 1975 parts.

Also this comment from Wikipedia " Unfortunately, the raised deck design complicated the use of the block in racing applications, as standard intake manifolds required spacers for proper fit. Distributors with adjustable collars that allowed adjustments to the length of the distributor shaft also had to be used with 366 and 427 truck blocks."

Edited by Jon Hagen 10/14/2009 20:58
Top of the page Bottom of the page
nwks baler
Posted 10/15/2009 08:58 (#885392 - in reply to #884789)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Kansas
I was wrong about the distributor gear, I went back and checked my records.

On the truck in question the HEI will work,but I was wrong on how. The distributor gear on the old distributor does in fact drive the oil pump, however the HEI distributor gear does not and is driven by the distributor shaft. You can move the old distributor gear to the HEI but(here is one place I was wrong) you must cut the flat tip off the end of the Hei distributor shaft, then install the old distributor gear using the same roll pin hole. I sold a lot of these setups years ago when these engines were popular for remanafacturing,(late 80s to early 90s) but it has been a while.

The other way it can done is to replace the oil pump with a (these are the pump and shaft for a short deck big block but will work in a tall deck big block whe using the HEI) Melling part #M77 or M77HV(high volume) oil pump and IS77 oil pump drive shaft. You can then install the HEI as is.

A reminder this same thing can happen to a 350 small block of that era in a large truck as it has a simaler oil pump drive shaft and distributor gear as the truck in question.

Sorry for the confusion I should have checked my records before using my memory which apparently isn't as good as it once was. haha
Top of the page Bottom of the page
scott nelsen
Posted 10/14/2009 22:19 (#885008 - in reply to #884564)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Leeds, North Dakota
what i'm thinking is when old distriburtor pulled plastic piece broke off oil pump dropping shaft into pan, jon might be right in different lenths shafts been to long , scott
Top of the page Bottom of the page
Ed Winkle
Posted 10/14/2009 20:54 (#884819 - in reply to #884038)
Subject: Re: Before you put an HEI distributor in a 366/427 ..


Martinsville, Ohio
Wow, that stinks Mike. No I didn't know and no one ever told too.

Right at harvest.

That really stinks.

How much do you sink in this when you have hundreds of thousands in the field.

Priority, it is all priority.

Tell them this is serious and I will get back with you.

Ed
Top of the page Bottom of the page
Jump to forum :
Search this forum
Printer friendly version
E-mail a link to this thread

(Delete cookies)