spyke

hey im looking for the easiest directions i can get on how to change a points distributor and replace it with a HEI distributor without messing up my timing. on a 1970 oldsmobile cutlass

Chesrown 67 OAI

Biggest thing to watch is that the HEI will clear your intake manifold runner. Not sure about a 70 -- and you didnt say if 350 or 455 but a large diameter HEI will NOT clear the 66-67 400 intake runner!

To answer your question? You first have to do the wiring for the HEI and then you install it with rotor in same position as the one you removed, then timing is a matter of simple adjustment with a timing light! If youre not sure you can do it yourself -- get a friend over to help!

oldcutlass

You need to have a full 12v supply to the HEI when the key is on, do not use the resistor wire or ballast resistor. You may have to hook up the wire from the starter "I" terminal also. You will also need a different set of plug wires for an HEI.

What I normally do is bump the engine around to TDC with timing mark lined up at 0, and the rotor pointing to #1 on the cap. Then mark the distributor position with a scribe or a marker at the bottom of the housing and engine block.

Reinstall with everything pointing to the same position as the old distributor. Then I replace the wires from the old cap with the new wires following the same firing sequence.

bigD

i just recently did this to my cutlass, pretty simple process. the biggest thing to me was replacing the power feed for the distributor, not so much doing it but doing it right! what i did was use an extension with a flex socket to remove the engine harness plug from the firewall then i sorted out the wiring to be sure i had the right wire then used a pair of pliers to pull the wire out the back of the plug. i then build a wire to replace it, installed it in the plug and siliconed it to keep it weatherproof and then reinstalled the plug and ran the wire to the distributor and connected it.
to me that is the best way to do it in regards to reliability. you can't really run off the starter as the R terminal is only hot during the start mode, ie, starter engaged.
using the hei eliminates the R terminal connection, you'll only have 1 wire going to the distributor. the R connection at the starter simply provides a full 12v when the engine is cranking over, when the key is in the run position it is de-energized. due to replacing the power feed wire to the distributor the hei gets a full 12v all the time. i should have mentioned earlier that the wire that feeds the points distributor is a resistance wire.
it's not a difficult job from the technical aspect but it is tight working in around the power brake booster... having the hood hinge in the way doesn't make it any easier but it's not that big of a deal.

as previously noted you will need different plug wires and plugs then its a simple matter of setting the base timing and going for a drive...

btw, the base timing is 20 btdc with an hei. it has less mechanical advance than the points distributor so it runs a higher initial setting. you will need to either get a timing tab for a newer hei engine or mark your damper...

Allan R

Plug wires = yes. Why plugs? HEI should work just fine with same plugs and gap. Could gap them to .050 or .060 if he HEI puts out enough spark. My plugs are same as stock Dist and gap is the same too. Runs just fine now. I know the later model (80's) HEI plug gaps were all the way up to .080 depending on brand.

spyke

ok i have got a lot of good advice from everyone who replied to my question but don t think im crazy for asking this again,lets say i wake up and pull the dist. cap off ok? wich ever way the rotor is pointing im gonna make a mark so that i will kn ow where to set the new one. once i have set the new one in on the mark i made im gonna tie a strong enough wire into the pink wire in the plug going into my ignition switch and run it through the fire wall and attach it to the slot on the dist. marked (BATT). then im gonna put a new cap on and put my wires on according to the wires on the old cap right please correct me if im wrong but if i put the new wires on in the same slots like the old cap i wont be crossing the wires right? then i can slightly tightend down on the clamp crank the car and adjust idling buy turning the dist. base clockwise right? and by doing it this way when i crank it, it should start right up huh?

spyke

oh yeah its got a 350 rocket in it not the 455 all original the air conditioning still blows super cold with a 2 barrell carb it also has 41,287 original miles the car hasnt been driven since 1981 i just dont like the idea of haveing to always set the points and worrying about weather or not the coil is about to go bad i am familiar with the regular HEI but never had a car with points never really had an oldsmobile always had a chevy

oldcutlass

Spyke, its an engine, the only real difference between an Olds and a Chevy is the distributors turn in the opposite direction and the firing order is different. The same rules of wrenching apply. Like I said earlier, bump it around until your timing mark is aligned on "0" with #1 cylinder at TDC, and the rotor pointing to the #1 wire on the cap. Then do your swap.

If you put it all back together with everything pointing at the same things, it will start right up and all you will have to do is reset your timing, double check your carb tune, reset your idle speed and go for a drive.

Octania

When did Chevy adopt an alternate firing order?

Pretty sure they are all alike.
Fords APPEAR different because their cylinder numbering differs... if you renumber a Ford's cylinders per GM method, the firing order is the same.

The only difference I have seen in looking over 1950s thru 1990s V8s is that for some reason the 1950s Olds V8s interchange like 4 and 7 with respect to the ubiquitous 18436572 firing order. [i.e. 18736542]

Beware the Chevy reverse rotation distributor. For some reason they thought it was more clever to spin it CW viewed from above. If the distributor has vacuun advance you can discern the direction of rotation by looking at how the vacuum canister enters the distributor- follow it into the distributor and go around the distributor shaft, and that's your direction of rotation.

oldcutlass

Ford changed their firing order in the 80's, I found this out the hard way. As I really have never looked at Gm, or all the other manufacturers firing orders, and went by my motors manuals, I never realized or put 2+2 together, they are all the same (with the exception of some early years)!

Hmmph, I learned somefin new today!

Intragration

I think Cadillac was the only GM brand with an alternate firing order. The reason for different plugs is that the HEI allows for a longer spark length. If you use the same plugs and regap them, the electrode won't be quite parallel to the tip. I converted my '70 455 to HEI, and I used the same plugs recommended for a '75-'76 HEI 455.

As for orientation, and for illustration only, it technically doesn't matter which way the rotor is pointing, as long as it has the same orientation to the firing order as the old one, e.g. you could theoretically point the rotor 180* off from where it was, as long as you also move the #1 wire 180* too, it would still work. The ideal way to make sure it's right is to get cylinder #1 to TCD by removing the spark plug, bumping the motor until you get a strong puff of air from the hole, and then setting the timing mark to zero. Then just make sure that the new rotor is pointing to the terminal that you wire as #1, and you're set. There are I believe 17 teeth on the distributor gear, so the rotor could be pointing in 17 possible directions. You'll need to make sure that you have enough physical space around the distributor to turn it a little in each direction, to set timing. If the vacuum canister bumps the intake before you can reach your desired timing, you'll need to move forward or backward a tooth, to give you a little more adjustment room.

Having said all this, the points don't require constant attention. I have another '70 motor with points and it runs quite reliably and rarely requires tuning.

MDchanic

+1.

I've never had a problem with points.

I have had an HEI module go, though - it was only through luck that it happened in the driveway and didn't strand me.

- Eric

spyke

so just listening to you guys makes me wonder should i or shouldnt i pull my point distributor out? which would be better? because if changing it is gonna take away from my performance then i'll keep it the way it is and just buy me an after market coil and distributor cap and wires. hey just out of curiosity are oldsmobiles high running motors because mine runs 180 degrees on a good day but when the the weather is like 90 degrees out my car is almost running 200 is that normal or should i run an electric fan along with the clutch fan maybe im just picking at things huh? so should i keep the point or go with the HEI?

MDchanic

I wouldn't change parts that are working perfectly well. It's asking for trouble.

As for the temps, there are two or three "overheating" threads running here right now, and countless others from years past.

My opinion (worth what you pay for it) is that the temperature should stay right where the thermostat sets it unless something very unusual is going on, like towing a trailer up a mountain on a 100° day. If it goes up under "normal" driving conditions, then something is wrong somewhere.

- Eric

Allan R

I did that and I'm still kicking myself for doing it. Hindsight is 20/20. If it was me all over again? The stock distributor would be staying.

Intragration

You certainly wouldn't hurt your performance by going with HEI, but you're not going to help it much either. On a low-mile original motor, I'd definitely leave it alone. Same goes for the cooling system. Give it a good flush, make sure the radiator is clean inside and out, and don't worry about it. I have a car with a 195* thermostat that gets up as high as 220 on a hot day sitting still in bumper-to-bumper traffic. The rest of the time, it's between 200 and 205. That's good enough for me.

spyke

Wow 220? and its not boiling over or anything it doesnt have the valves rattling? well i guess you right because i was told that oldsmobile motors do run high in temp like that but mine has never reached that high at the most 195-almost 200 but i do need an overflow bucket because i dont have one i had to make one so since i have more water than anti-freeze should i flush it then add more anti-freeze than water someone told that the water boils faster and its easier to cool the anti-freeze than it is to cool the water. i havent checked the heater core it may need flushing out because its not leaking or anything

MDchanic

WOW! People do spread some wild rumors, don't they?

The fact is that water has a higher specific heat (Cp = 1.000) than ethylene glycol [antifreeze] (Cp varies with temperature), which means that a gallon of water will accept more heat before its temperature goes up 1° than a gallon of ethylene glycol will, and will shed more heat before its temperature goes back down. This means that a given amount of water will be able to move more heat from the engine to the air than the same amount of antifreeze.

Water does boil at a lower temperature than ethylene glycol, which is one of the reasons why pure water is seldom used in automotive cooling systems: even if the coolant is not boiling out of the radiator, if the coolant is boiling in the passages right next to the combustion chambers (like when you look into a pot that is just beginning to boil and there are small bubbles forming at the bottom), then the bubbles that are forming are not transferring heat well, and heat is not being drawn away from the heads, resulting in hot spots and warpage.

Water also facilitates corrosion inside the engine, especially between dissimilar metals, such as aluminum and iron.

The additives in antifreeze are designed to work best at a 50:50 ratio with water, so that is the ratio you should use. Using more water will improve heat transfer, but decrease boiling point. Using more anitfreeze will do the opposite.
With modern ethylene glycol antifreeze, you should use distilled water instead of tap water, as tap water has contaminants, especially chlorine (if on a town water system), which combines with the antifreeze to cause corrosion.

Here are two tables showing the changing specific heat and boiling points in water / ethylene glycol solutions
(credit to: engineeringtoolbox.com):


- Eric

spyke

So to make a long story short because honestly i didnt understand anything you said water is bad by itself because it causes corrosion and im guessing the anti-freeze is bad by itself so i would be better off just mixing it 50/50? when i think about it my car isnt really running that hot compared to the guy who said his car runs 220 in bumper to bumper traffic and 200-205 on a good day im just running 180on a good day and 190-195 on a hot day i was just curious why the radiator hose was getting so hard is that normal? htis is why i prefer a chevy motor over oldsmobile they dont run that high in temp. i was told to try a flex fan and do a better mixture of the anti-freeze and water and maybe just maybe that will drop my temp a lil and it may not raise to 195 on those hot days.

MDchanic

The engine will go to the temperature of the thermostat, and hopefully not much higher, whether Chevy, Olds, Ford, Dodge, Packard, DeSoto, Delage, or Auto Union.

The hose is supposed to be hard. If it's not, then you've got a leak in your cooling system. The coolant needs to be under pressure to raise the boiling point and cool the engine properly.

Mix your antifreeze 50:50. It will be better.

And flex fans are crap - use a properly-functioning fan clutch and you will never have a problem.

- Eric

Intragration

There's chorine and other things in city water, but well water is probably even worse with all the calcium, iron and other elements and minerals, which can build deposits. I agree, distilled is the way to go, and 50:50 with anti-freeze.

As for Chevy engines running cooler, I think it's all a matter of how your cooling system is working and the general condition of your engine. I have a friend with a poorly tuned Chevy 400 that he claims hits 240* at times. This is ridiculously high, even for a typically hot 400. He's not a serial exaggerator, but I also have never confirmed it for myself. It hasn't resulted in the radiator cap exploding off...but it's sure not a happy temperature.

I can attest that I've hit 215-220 on hot days in traffic without a problem, and it cools right down when the air starts flowing again. This is with a freshly built Chrysler 440 with a 195* thermostat, a clutch fan, a shroud and a 4-row radiator. My point was, if 195 is your absolute max, it's nothing to even come close to worrying about.

oldcutlass

The engine will go to whatever the temperature it will reach based on circumstances and how all of the equipment plays together, combined with outside air temperature and speed.

There are good flex fans on the market!

MDchanic

Well, that's pretty obvious, I would say.

I believe he wanted to know whether his engine is supposed to get that hot, and, no, it really isn't.

Yes, how hot it gets is the result of internal and environmental factors, but that's the point we're all trying to get across to him. The question is which factors are causing it in his case, and all we can do is make suggestions for him to check out.

- Eric

oldcutlass

My point is that the thermostat only regulates minimum operating temp. It does not set the max. It's going to go to whatever IT generates based on the above!

The jest of this major temperature conversation is based on the OP's statement that on a 90 deg day he runs 200 deg temps. That is normal! I don't see any issues with that.

MDchanic

Well... I agree and disagree.

So long as the engine is operating within it's design parameters (outside temperature less than about 110° F, antifreeze full and mixed 50:50, system cleans, unobstructed, and pressurized, and, if it's very hot out, car not idling more than 10-15 minutes), the thermostat should work to determine both lower and upper temperatures.

The engine supplies the heat to warm it up, but, if working properly, the cooling system will blow off however much heat is produced, so the thermostat will essentially settle in a part-open position (rather than a binary combination of open / closed, like an idle control valve does) which keeps it at it's temperature set point.
It will close slightly as the engine gets cooler, and open slightly as it gets warmer, thus maintaining it's set point, UNLESS there's something wrong with the system.

That engine should be able to sit within 5-10° of it's set point under normal operating conditions. If not, there's something wrong.

- Eric