jensenracing77

my 62 Jetfire is to be sat at 10 degrees with the vacuum advance unhooked. i got that with no problem. now, with the vacuum advance hooked up and a 17 inch vacuum i should be at 10.5 to 13 degrees. i have 30. the jetfire with hydramatic transmission has the vacuum advance hook direct to manifold vacuum (not sure why). i can't see any way to adjust the vacuum advance? where do i go from here? i would rather not just unhook the vacuum advance but don't know how to fix this. i have no experience with the vacuum advance other than unhooking them. any help or ideas would be great.

HonestDave

Interesting problem. I go through this all the time with my various projects. Just did it with my 80 Trans Am. Always end up on the internet checking to see correct hook up. I would bet your vacuum advance should be coming off a metered port on the front of the carb, driver's side. Probably part way up so you don't get full vacuum at idle. They often get changed over the years, so it's likely wrong the way you have it. Just check on Google, or whatever, and if you don't find your car, try another 62 GM with similar carb. I have to check constantly, as I play with so many cars, my old brain just won't retain the knowledge any more. If that fails, take the carb to your rebuild guy and ask him to point the correct port out for you.
Good luck.

jensenracing77

the 62/63 Jetfire is the only model of it's kind. it is Turbocharged with a 1 bbl side draft carburetor. the Oldsmobile Manual shows that all Jetfire with a automatic transmission is to be hooked to the intake vacuum. when it builds boost it will retard the advance back to 10 degrees.

brown7373

I'm no expert on a 62 vacuum advance, but it is probably similar to later versions. There are different canisters that look the same but have different advance characteristics, depending on the application.

compedgemarine

I dont have any direct knowledge on the turbo motors but I will take a stab at it. you say you should have 10.5 to 13 degrees. is that from the service manual? if so then most likely the setup is not actually a vacuum advace but a boost referenced retard to prevent detonation. what I mean is that it is hooked to manifold vacuum and is designed to work opposite what you are used to. under vacuum it would pull it a tiny amount but under boost it would push and take out timing. it is possible that someone replaced the canister with the wrong one and the one for the turbo motor is specific to that motor.

MDchanic

I have no specific knowledge of these rare birds either, but this is the first thing I thought: Are you certain that your advance can is the right one. They all look the same.

I'd recommend mapping out the behavior of your can at various vacuum levels, and see if it corresponds to what the manual specifies at any point in its curve.
If it doesn't you've probably got the wrong one.


- Eric

HonestDave

Maybe the 10.5 - 13 dgrees is vacuum pod advance, and you should be adding that to your initial distributor setting of 10 degrees, for a total of 20.5 - 23 degrees. Maybe you aren't that far off. Some cars run at a total of 30 - 35 degrees (I believe).

Sugar Bear

I have no experience at all with this motor but have a couple of questions.

Wouldn't building boost decrease intake vacuum and the make the vacuum advance no longer advance the timing, putting it back to the base setting of 10 degrees? Does this distributor also have mechanical advance?

DeltaPace77

Maybe, a quick explanation of what vacuum and advance is all about. Engine vacuum is greatest when cruising with the carb throttle plates nearly closed. You've got all those pistons trying to pull air against almost no intake opening. You want some initial timing advance for better power, and the dizzy adds more mechanical advance, about 2000 rpm, and about 35 degrees on most cars. When highway cruising at light throtte, the dizzy advance canister can add another 20 degrees for better fuel milage. Once you put your foot in it, opening the carb throttle plates wide, vacuum drops way down, with only dizzy mechanical, and intial advance still being in the picture. Since your car's a turbo, may vary the equation a bit. The turbo's only gonna give boost when the carb plates are open at higher rpms. Hence, when their lots of exhaust gases moving to spin the impellar. Doesn't do much of anything at light throttle plate highway cruising. If anything, adds exhaust system back pressure.

HonestDave

Actually, I was thinking about the distributor weights added to the initial timing, not "vacuum pod". My brain is adled. Didn't mean to confuse, but I wouldn't be surprised if your timing is almost right where it should be.

I threw my timing light out years (decades) ago. No matter what I set it to from a book, I always ended up changing it. Now I ballpark it to begin with, and then keep advancing it (engine warm) until the pinging starts. Then I back it off a hair. Too far advanced and it pings and is hard to turn over when it's hot. Too far retarded and it backfires and has less power. I just pick a comfortable spot somewhere in that zone. My cars always run great and pass emisions tests when I'm done. Never worked on a 62 turbo car, though. Had two 62 Starfires and worked on an 80 Turbo Trans Am, but they aren't quite the same.

Best of luck to you.

droldsmorland

You need to customize your advance curve. Where it was 50 years ago isn’t where it should be on today’s gas. Do you have the factory suggested settings?
Start with the base timing which it sounds like you have. Most street drive Oldsmobile’s (naturally aspirated) like 10-12* at curb idle
Next you should have another 10-12* come in from the vac advance can at curb idle.
The mechanical weights are closed at this point.
Next, the weights should bring in the remaining advance for a total of somewhere around 34-40* at about 2800 -3000 rpms…The suggested total advance setting is dependent on the compression ratio, octane of the gas your using and your driving habits. I usually take it out on the road at this point and see if the engine likes the settings under load. Keep the distributor loose and make the final adjustment on the road at op temps. There is way more science to it but I won’t bore you.
You say you’re getting 30* when you plug in the can? It sounds like the weights are opening to early or hung up. What do the springs and weights look like under the rotor? They should be rust free and move freely. The springs may be weak?
I'm not familiar with that 215 turbo engine but I can’t see it being that far off the above. Being as its all aluminum you'd think it would like even more advance which is the general rule when tuning an engine with aluminum heads.
.5-3* of advance in a canister is not much. Unless that’s a spec for that engine?
Get an adjustable travel (not rate) advance can. If you can’t find one for that application get a full travel can and fabricate or source a stepped stopper. Some kits have this in it.
It sounds like the weights are hung open or opening at low RPMs which is why you’re getting 30* at idle.
I usually run all distributor vac cans off direct intake vacuum. Ported is generally found on newer pollution controlled cars. Again there’s more science to this too and other reasons for ported vacuum signals but I won’t bore you with that here. Try the above and see what’s up and how it reacts to the above suggested curve. Let us know how you make out.

compedgemarine

drolds, that is all great advise except that this is a turbo motor. when you boost a motor you have to start pulling timing out as the boost goes up. that is why I questioned if the canister is there to take timing out rather than add it. turbo motors started to really make power with the addition of computors as you could better control the timing under every condition but this is a 1962 where they had to make do with the avalible technology. about the only way to remove timing in the higher rpm with boost is with a canister that would move the points plate opposite when boost is present. just a guess though on my part, I have worked on lots of turbo and supercharged race engines but not a 62 olds turbo.

HonestDave

I like compedgemarine's and MDchanic's suggestions. Wouldn't be surprised if someone swapped in the wrong distributor and/or vacuum advance can. So many years for people to be trying things. Might even be the wrong weights and springs, assuming the turbo engine even came with them !!

jensenracing77

a little more information. i think for one i was reading the manual wrong. i think it means that the 10.5 to 13 for the vacuum advance is on top of the 10 initial timing. that would put it at 23 degrees with initial and vacuum advance. i have 30.

i took it for a drive the way it is now and at 40 MPH and under it will stay at 190 degrees but if i get much faster than that the temps goes up to 200. i would then slow down and it would cool right back to 190. my theory is that the mechanical advance, vacuum advance and initial timing is to much? i need to see if i can come up with a new vacuum advancer that only advances 10.5 to 13.

any more thoughts?

HonestDave

My thoughts are thus: When my cars have been running too hot it's usually when I have them too far retarded. As I increase the advance, usually they run more efficiently with more power and a little cooler.

However....the last car I had that was doing exactly what yours is doing (getting hotter at higher speed, and cooling when I slowed down) turned out to have a plugged up radiator. I'd hit 50 on the highway and the gauge would start to go way up. I'd bring it down to 40 and the gauge would come back into normal territory. I bought a rad for $15 off a guy, and the problem was gone. Maybe you have more than one issue to play with. Always fun to solve them, but sometimes it's one small step at a time.
At least you have a unique car to fuss over.
Chow for now.

jensenracing77

the radiator is a 4 core that was just gone through. i am sure that i have two issues and likely more but would like to get the timing fixed first.

oldcutlass

Does yours still have the water injection tank in it? From what I've read over the years that they were really sensitive as far as valve adjustments, and timing. I tried to find some tuneup info today and could not come up with any spec's.

MDchanic

You've got it right, but the wrong way .

Retarded timing causes overheating, advanced timing cools the engine.

I wish I knew more about these things - fully mechanical tubo motors - they're fascinating.

- Eric

droldsmorland

Well I did a little homework on this 215hp animal and it is all by itself. The compression is rather high on this engine 10.25:1! That’s up there for a hair-dried V8 That’s why the OP questions the 30* at idle in the first place. Something’s definitely not right. 30* at idle this thing shouldn’t run to well if at all. If it does run it would be popping out the exhaust for sure. Jensenracing does it run at 30*???

Pull the cap and do some inspecting. Apply a vac source and see what the breaker plate to adv can actuator rod looks like. You shouldn’t see a ton of movement as it is supposed to only apply 3*. That was news to me never heard of a 3* can. There may be a “stop” that has fallen out allowing full travel hence 30*. Look around under the breaker plate for spare parts.
I’ll bet your going to have a hell if a time finding one NOS or otherwise. You may have to modify a standard canister with a stop. Unless you can put this one back toghther. I don’t think an adjustable can will go down to 3*. Call Summet or Jegs as I may be wrong and ask that Q. Or contact one of the major distributor suppliers and ask.

Taking a look into the 62-63 Motors Manual specs for the BOP 215s, nothing stands out as vastly different or out in left field for the distributor settings on the 215hp, 215ci one barrel Olds tubo engine. It’s a clock wise distributor in all 3 makes which should make interchange possible with any 215 Buick, Pontiac or Olds distributor. That’s good news as this might improve your chances of finding parts.
The spec says base is 10*, “full advance” is 12* at 2100RPM. The spec on the advance can is 5-7” of vac to start the plunger with max advance distributor degrees at vacuum is 13* at 16”
So the 10* initial and .5 to 3* on the can that jensenracing stated is right on spec. So why the 30* once the cans hooked up? It has to be something’s “up” with the can.

The distributor part number Motors lists is 1110975.

MDchanic

Gotta luv the old "Motor" manual collection .

- Eric

jensenracing77

thanks guys, i am going to call Mark at D&D today and see if he has a vacuum advance i could get or advice for me. i took it for another drive after the sun went low enough to cool off some and couldn't get it to get past 190 at any speed. i wonder if part of the temp issue will just be the nature of this beast? i am also running without a hood right now, not sure how or if the hood will affect the temps when installed.

it does have all the water injection and it is all rebuilt. i have not stepped on it hard enough yet to build any boost so it would not have used any of the injection yet.

oldcutlass

Ok, you made me do it, crawled up in the attic and dug out my old 65 Motors manual.

My manual says his dist stamp should be 1110975 but you can also have a 1111034.

Plugs should be set at .025 / Dwell @ 30*

You timing is as follows:

10* BTDC - Idle RPM 500 in drive.
Advance starts 2 deg @ 1000 rpm - distributor on engine crankshaft degrees!
You have 24* of mechanical advance all in @ 4200 RPM.
You have 24* - 26* of vacuum advance @ 17 in hg.


So if you have your timing set @ 10* with the advance can at manifold vacuum then you should see 34* at idle. If you run the engine up to 4300 RPM with vacuum connected, you would see 10* initial + 24* mechanical + 24* vacuum = 58*

They had a "Turbo Rocket Fluid Injection Tank" (½ distilled water, ½ methyl alcohol). This tank was necessary to prevent detonation.

Also the factory setting for max boost was 5 psi. I would think if your running more boost you would need to retard timing a bit.

Note - in the Motor's manual if you are looking at the dist. chart, it is in dist. degrees. On the car all rpm and degree values must be doubled for crankshaft degrees.

jensenracing77

thanks for looking all that up but i have the original Oldsmobile specs on the engine, i just can't get it to those specs.

Mark at D&D told me to not set the initial timing to 10, he said i should go 7. he also said that the vacuum advance is to much and that these has a bushing on the pin originally that like to fall off. i was looking for something like that last night. when i get home i will see if i can put something on it to limit the travel. he also said that he wouldn't hook it to manifold vacuum like the manual said to do. the problem with that is that the 1 bbl carb don't have a place to hook it for ported vacuum. i would really like to hook it up like it originally was but i guess i have to do what is going to work. i plan to just add the bushing to the advancer and put the hood on and see what that gives me for now.

oldcutlass

Were the spec's I gave you close to what you have? Is that the dist number you have on the car? If not, let me know the number and I can tell you the specs of the one you have.

As suggested above you can get an adjustable vacuum can. Some come with those limiter bushings. Just remember when you come of the idle circuit whether your vacuum is ported or manifold, the timing works the same either way. I don't think 10* initial is too much, but try what Mark says, you can always bump it up later.

I have never played with one of those 1V carbs.

jensenracing77

BINGO!!!! i just found my troubles, my heating issue is not related to timing. (at least it don't look like it) i was talking to Jim Noel (the guy that rebuilds the turbo systems) and from everything i was telling him he thought i may have a vacuum leak in the system somewhere. i had already checked every vacuum line and fittings and didn't think that was it. we decided that i should go out with some glass cleaner and start spraying everywhere. i found that the carburetor gasket is leaking. this explains my thoughts of my accelerator pump not working also. i still want to get a better handle on the timing but i need to fix this first. i will start pulling the carburetor tomorrow night. sounds easy to pull a 1 bbl side draft carb but this has a ton of things in the way. i am feeling much better now about things other than i have ran it lean since i started it. i am sure there isn't any harm done.

droldsmorland

Feels good to find problems and solve them. From what I understand there’s plenty of plumbing to remove.
Post the results of your repairs and more importantly when you make sense of the timing mystery too so it’s recorded somewhere. There just isn’t a lot of info available on these cars.

oldcutlass

X2^^^^^^

jensenracing77

well, i have the vacuum leak fixed and some other problems. i ended up having to rebuild my extra carburetor using the parts from my carb that Jim rebuilt. the surface that attaches to the throttle body was warped to bad to fix. Jim said that is very rare to have one warped and that he didn't think to check that. my extra carb was perfectly flat. now it runs great everywhere other than wide open. it is cutting out at wide open throttle, i think that is where my timing or points are giving me troubles. i am going to upgrade to a pertronix and install a new vacuum can before i do much else.

any advice on cutting out at WOT. my manual said i should have a 5K ohm resister at the coil but i don't, the book is saying that it is for higher RPM performance. could that be causing my trouble?

MDchanic

I have not heard of lack of a ballast resistor creating full-throttle performance issues, but I do agree that the problem could be in your ignition system.

I would go through it to be sure that everything is set up and working properly:
Plugs, wires, cap, rotor, points, condenser, coil.

A bad set of points, condenser, or coil, carbon-tracked rotor or cap, or leaking wires could cause this.

- Eric

oldcutlass

The ballast resistor is there to prevent premature wear of the points, it may have a resistor wire. Make sure your dwell is at 30*. Then double check your timing. Also make sure your throttle blade is opening up all the way at WOT.

droldsmorland

Another possible cause of WOT cut-out can be fuel starvation (lean). Does it come right back when you let off the throttle?

jensenracing77

i fell pretty sure it isn't starving. it don't completely fall on it's face and comes right back if you let off a little amount.

it has a full 12 volts at the coil. the Jetfire supplement manual says that the Jetfire coil has a higher resistance than standard coils and needs a .5 external resistor for proper ignition at higher engine RPMs. i don't have the original coil so i guess that wouldn't matter anyway. still have to order a vacuum can for the distributor but i don't think that is it either.

droldsmorland

“i fell pretty sure it isn't starving. it don't completely fall on its face and comes right back if you let off a little amount.”

That’s indicative of starvation. Try pulling the fuel filter see if it still does it. Verify the pumps putting out the spec'ed PSI. Has the gas tank "sock" been examined in the last many years?
It’s possible its ignition related too…but this is a simple test.

jensenracing77

when i had a car starve for fuel in the past it would fall on it's face and take a couple seconds to come back. this don't fall on it's face but more of just missing out till you let off a little. i guess you could be right but not sure. i know the sock and filter are both good. the Jetfire had a higher volume pump with a return line back to the tank for unused fuel and i think my pump is just a standard f85 pump but not sure. i have some ignition parts coming that i need to do anyway so i will get that done and see where i am after that.

droldsmorland

Ya it could very well be a bad dwell angle, bad point contacts, bad condenser, week coil etc...Have you checked the side to side play in the distributor upper bushing? A wobbley distributor will cause high RPM misfire. Open the hood at night and look for arcing on the cap and wires. Sometimes just a carbon tracked cap will do this too.
Keep us posted on the fix.

jensenracing77

i found that the coil was weak and also one plug wire was out of range to the others. i put a new coil and another new set of wires on and it runs great! after that i installed a Pertronix setup but not sure i really needed that. i can't believe how hard a stock 215 engine can pull. it's not like my Rallye 350 but it still pulls MUCH better than i thought it would. now if i can fix my rocket fluid leak it will be done.

MDchanic

- Eric

jensenracing77

you hit it pretty well, thanks.

MDchanic

We're all good at diagnosing problems that have stranded us once or twice .

This is the sort of thing that you can nail own with a SUN machine, if you can scrounge one up. They're kind of archeological artifacts now.

- Eric

jensenracing77

i know this is not the one you are talking about but i just scrapped this one.

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