Pulling the motor
#1761
I actually found an idle screw tool I must have bought years ago. They were way outta whack. One was almost closed and the other was open close to four turns. I don't know if it will help but I turned them both out 2.5 turns. I'll test it tomorrow if the rain holds off.
What's the downside of eliminating the choke pull off? I've read that's a no no.
#1764
My old carb only had the front pull off and it ran just fine.
There's also a lever of some sort against the secondary butterfly shaft. Looks like it keeps them from opening under certain conditions but I don't see it actuated by anything. My old carb didn't have that either. Can it go as well?
There's also a lever of some sort against the secondary butterfly shaft. Looks like it keeps them from opening under certain conditions but I don't see it actuated by anything. My old carb didn't have that either. Can it go as well?
#1767
Because GM was in the habbit of installing "unnecessary" parts on cars to increase production cost and reduce profit...
On most Qjets, the FRONT "pulloff" actually controls the seconday air valves. It has an internal restriction in the nipple that limits air valve opening speed. It is really a dashpot.
The REAR "pulloff" actually is the choke pulloff for the choke plate. It helps open the choke plate more quickly.
Sorry, but not correct. Qjets used one of two secondary lockout features. On most Oldsmobile Qjets, the secondary lockout is an "L"-shaped lever that is operated directly from a rod off the choke housing. It is labeled "Air Valve Lockout" in this drawing.
Note the little tab sticking out just above the leading edge of the secondary air valve in this photo. THAT is the secondary lockout on most Olds carbs. FYI, also note that the front vacuum diaphragm is connected to the secondary air valves, not the choke.
On most Chevy Qjets and on the 1980s Olds Qjets, the secondary lockout is actually on the secondary throttle shaft at the bottom of the carb, just rearward of the choke housing.
On most Qjets, the FRONT "pulloff" actually controls the seconday air valves. It has an internal restriction in the nipple that limits air valve opening speed. It is really a dashpot.
The REAR "pulloff" actually is the choke pulloff for the choke plate. It helps open the choke plate more quickly.
Note the little tab sticking out just above the leading edge of the secondary air valve in this photo. THAT is the secondary lockout on most Olds carbs. FYI, also note that the front vacuum diaphragm is connected to the secondary air valves, not the choke.
On most Chevy Qjets and on the 1980s Olds Qjets, the secondary lockout is actually on the secondary throttle shaft at the bottom of the carb, just rearward of the choke housing.
#1768
Oh DAMN this is TWICE now I busted Joe P being incorrect.
"note that the front vacuum diaphragm is connected to the secondary air valves, not the choke."
In the above photo, notice the zigzag bend in the secondary air valve link to dashpot. It bumps against a tang on the choke parts and does indeed serve as the choke pulloff. Bend tang to adjust.
The pulloff diaphragm/ dashpot serves both purposes on that carb.
"note that the front vacuum diaphragm is connected to the secondary air valves, not the choke."
In the above photo, notice the zigzag bend in the secondary air valve link to dashpot. It bumps against a tang on the choke parts and does indeed serve as the choke pulloff. Bend tang to adjust.
The pulloff diaphragm/ dashpot serves both purposes on that carb.
Last edited by Octania; July 12th, 2016 at 09:33 AM.
#1769
Oh DAMN this is TWICE now I busted Joe P being incorrect.
"note that the front vacuum diaphragm is connected to the secondary air valves, not the choke."
In the above photo, notice the zigzag bend in the secondary air valve link to dashpot. It bumps against a tang on the choke parts and does indeed serve as the choke pulloff. Bend tang to adjust.
The pulloff diaphragm/ dashpot serves both purposes on that carb.
"note that the front vacuum diaphragm is connected to the secondary air valves, not the choke."
In the above photo, notice the zigzag bend in the secondary air valve link to dashpot. It bumps against a tang on the choke parts and does indeed serve as the choke pulloff. Bend tang to adjust.
The pulloff diaphragm/ dashpot serves both purposes on that carb.
#1770
My front pull off does both, secondary was tied into the choke linkage. I thought he meant the lock out tab you had pictured. I went off what Cliff Ruggles suggested. He said, as long as the primary pull off can control both, eliminate the secondary pull off. GM did a lot of weird things, probably had a reason. I am pushing the performance of this Cutlass way beyond GM's smogger specs. Emissions was their main concern followed by good drivability and performance was barely thought of.
Last edited by olds 307 and 403; July 12th, 2016 at 11:52 AM.
#1771
All good info. Thanks for the pics, Joe.
So here's where I think I am now:
1. I advanced the initial timing until it was hard to start and then backed it off (I'm waiting on a dial-back timing light to come from HF). It helped immensely with the acceleration.
2. I had the choke adjusted way too rich. It was different than my last carb (I think) and I didn't notice.
3. I adjusted the air door as best I can and the bog is much better.
4. It still has a slight bog and slower than ideal acceleration off idle (i'm sure the air door is too tight)
5. It also has a stumble at high RPM.
(a) I think, and my mechanic buddy agrees, it's running lean either from the float incorrectly adjusted or it needs jetting. I had my buddy drive it too.
(b) When I ordered the carb from an eBay builder I needed to specify my horsepower. So I guessed. I told him 250 hp. I may have underestimated. Or overestimated but it's not running rich.
6. The only simple thing I haven't tried, because I can be a doofus, is replacing the gas filter. I plumbed in a large, high-flow, clear filter before the fuel pump. It looks clean and full of gasoline so I haven't bothered yet.
Man, this thing wants to run strong. There's just a little something holding it back. I'll find it eventually.
So here's where I think I am now:
1. I advanced the initial timing until it was hard to start and then backed it off (I'm waiting on a dial-back timing light to come from HF). It helped immensely with the acceleration.
2. I had the choke adjusted way too rich. It was different than my last carb (I think) and I didn't notice.
3. I adjusted the air door as best I can and the bog is much better.
4. It still has a slight bog and slower than ideal acceleration off idle (i'm sure the air door is too tight)
5. It also has a stumble at high RPM.
(a) I think, and my mechanic buddy agrees, it's running lean either from the float incorrectly adjusted or it needs jetting. I had my buddy drive it too.
(b) When I ordered the carb from an eBay builder I needed to specify my horsepower. So I guessed. I told him 250 hp. I may have underestimated. Or overestimated but it's not running rich.
6. The only simple thing I haven't tried, because I can be a doofus, is replacing the gas filter. I plumbed in a large, high-flow, clear filter before the fuel pump. It looks clean and full of gasoline so I haven't bothered yet.
Man, this thing wants to run strong. There's just a little something holding it back. I'll find it eventually.
Last edited by Macadoo; July 12th, 2016 at 01:25 PM.
#1773
Okay, you talked me into it, lol. I don't know why I haven't done it up to this point. Just don't feel like getting covered in gas maybe. Well, that and I just removed and cleaned my tank last summer before the trip to Niagara so I figure it's probably fine.
#1774
Joe this the same as my carb with the secondary pull off removed. Notice the air door is linked directly to that pull off only.
Last edited by olds 307 and 403; July 12th, 2016 at 06:49 PM.
#1776
I can see it just fine. I will take a pic of mine on friday. I need to do an oil change, check plugs, adjust the air door looser and check slick's tire pressure for the 1/8 mile this weekend. Is this any better?
https://www.google.ca/imgres?imgurl=...act=mrc&uact=8
https://www.google.ca/imgres?imgurl=...act=mrc&uact=8
Last edited by olds 307 and 403; July 12th, 2016 at 07:27 PM.
#1777
It looks like the carb I swapped out for this eighties-something unit.
The pictures look pretty small to me too, 307. I suppose it depends on the looker's screen resolution.
The pictures look pretty small to me too, 307. I suppose it depends on the looker's screen resolution.
#1778
The second link you can see where the secondary pull off is missing. Mine was linked to the back of the choke linkage. I will show a close up, either way it runs better, probably because the rear pull off was leaking.
#1779
If no link rod at all is connected to your secondary air valve, then there is no dashpot to control the speed of its opening. If you counter that with more spring wrap, your top end will suffer though the bog in transition may improve [less bog].
So, just a thought, why not hook up all the carefully engineered links that control how things work and see how that goes? Adjust them per the CSM or carb kit instructions. Set the spring wrap correctly [tapping housing as you go, to allow the SAV to move little by little as the spring is adjusted].
So, just a thought, why not hook up all the carefully engineered links that control how things work and see how that goes? Adjust them per the CSM or carb kit instructions. Set the spring wrap correctly [tapping housing as you go, to allow the SAV to move little by little as the spring is adjusted].
#1780
If no link rod at all is connected to your secondary air valve, then there is no dashpot to control the speed of its opening. If you counter that with more spring wrap, your top end will suffer though the bog in transition may improve [less bog].
So, just a thought, why not hook up all the carefully engineered links that control how things work and see how that goes? Adjust them per the CSM or carb kit instructions. Set the spring wrap correctly [tapping housing as you go, to allow the SAV to move little by little as the spring is adjusted].
So, just a thought, why not hook up all the carefully engineered links that control how things work and see how that goes? Adjust them per the CSM or carb kit instructions. Set the spring wrap correctly [tapping housing as you go, to allow the SAV to move little by little as the spring is adjusted].
I haven't removed anything. Both dashpots are there and hooked up. I was playing with the adjustment screw on the air valve dashpot. I think I see what it's supposed to do but I'm just guessing. I don't have a CSM for this carb, it's a mid-eighties. I've been looking online and youtube but some of these folks are..........well, they aren't as versed in Quadrajets as they think. "Wow, it must be really warm out. Did you see how the choke cracked right open when I started it?"
I replaced the fuel filter and low and behold it did help the high RPM/acceleration stuttering (I guess it was a little dirty, even after just 5k miles), but didn't help the off the line bog. Went back at that air door "spring wrap"? for most the afternoon. I thought I had it at one point but no, still bogging. Seems to get worse the warmer the engine gets.
I also discovered the fast idle screw was all the way out, which explains why I had no fast idle.
So I think I'm off the miss-adjusted float/under jetted idea. That was more about the high RPM stumble. It's got to be the relationship between the spring and the dashpot.
#1781
If no link rod at all is connected to your secondary air valve, then there is no dashpot to control the speed of its opening. If you counter that with more spring wrap, your top end will suffer though the bog in transition may improve [less bog].
So, just a thought, why not hook up all the carefully engineered links that control how things work and see how that goes? Adjust them per the CSM or carb kit instructions. Set the spring wrap correctly [tapping housing as you go, to allow the SAV to move little by little as the spring is adjusted].
So, just a thought, why not hook up all the carefully engineered links that control how things work and see how that goes? Adjust them per the CSM or carb kit instructions. Set the spring wrap correctly [tapping housing as you go, to allow the SAV to move little by little as the spring is adjusted].
#1783
That's it I'm saying it. Invest in a holley lol. I haven't messed with a q jet ever lol. Edelbrock and holleys over that last 10 years have worked reliably. Not saying the q jet is bad but the holley is simpler.
#1784
Holley float adjustment: loosen lock nut, turn screw, tighten lock nut. Pffft, you call that wrenching? Haha.
Although it's not as bad as the guy in the internet that wrote an article about how to adjust the secondary air valve on the QJ. It's easy, just start by removing the air horn! Aye carrumba!
Although it's not as bad as the guy in the internet that wrote an article about how to adjust the secondary air valve on the QJ. It's easy, just start by removing the air horn! Aye carrumba!
#1785
#1786
I just found this article. I'll read it tomorrow as it's a getting a little late.
http://members.shaw.ca/crussel/quadr...ing_Paper.html
http://members.shaw.ca/crussel/quadr...ing_Paper.html
#1787
You will see those letters on the metering rods near the top, they SHOULD read CV but who knows what might be in there. The CV or aftermarket Edelbrock CK rods, both .527" are a good starting point along with a G hanger. Most carbs I have owned had CV rods with I through M hangers. The lower the letter, the more it pulls the metering rods out, makes it richer.
#1790
I do all the wrenching at work. Messing with Can bus systems , air bags systems and fixing mangled steel. That takes all my thinking at home i go by the K.I.S.S rule lol. Hope you get it figures out mac. get that thing out on the track.
#1791
Lol, I get it. And as much as I love a good Q-jet, I'm leaning the Holley way for adjustability. The trouble is that I would need a $150 linkage kit for the AOD trans plus the price of the carb.
I'm going to call the guy that built this carb and see if he has a build sheet. I want to know what primary jets and metering rods he put in there.
I'm going to call the guy that built this carb and see if he has a build sheet. I want to know what primary jets and metering rods he put in there.
#1792
Okay, I talked to the builder and he said it's got #72 main jets but I've forgotten what he said about the rod size. He's going to send me an assortment of jets and rods to try. He offered to do it for me if I send it back but I'm not waiting for shipping from illinois to Cali and back! Lol.
He also thought that maybe the dashpot is pulling too soon and that a reducer on the vac line could help (which is what I thought that spring adjustment on the dashpot was for but what do I know?
He also thought that maybe the dashpot is pulling too soon and that a reducer on the vac line could help (which is what I thought that spring adjustment on the dashpot was for but what do I know?
#1793
U hanger is very lean, try the J hanger. Higher letter equals leaner, less the rods pull out of the secondary jets. Secondary rods and hangers interchange between all years.
#1794
Well on my last carb that ran very well, it has the J hanger and CV rods. This carb has the u hanger with CV rods. I'll just swap the hanger and see what that does. I'll take it from my original original carb. It's also a J hanger just really really dirty.
I guess I misunderstood what you meant by the letters. U being very lean I'm taking as good news
I guess I misunderstood what you meant by the letters. U being very lean I'm taking as good news
#1795
I laid a nice, black, long, two-wheel patch from a decent roll. I knew there was power there somewhere. Now, to deal with that torque converter.....
Thanks dude!
Last edited by Macadoo; July 16th, 2016 at 11:12 AM.
#1798
You, sir, are a steely-eyed rocket man! The "J" hanger did the trick. Geez, I've been at this for almost two weeks. Such a simple fix had I known about the hanger ratings.
I laid a nice, black, long, two-wheel patch from a decent roll. I knew there was power there somewhere. Now, to deal with that torque converter.....
Thanks dude!
I laid a nice, black, long, two-wheel patch from a decent roll. I knew there was power there somewhere. Now, to deal with that torque converter.....
Thanks dude!
Dam I miss this awesome thread !!!
Hope your doing Ok and your Olds is rumblin' along just fine.
Eric
#1799
Hey Eric. How are you my Canadian friend?
The work continues on the Olds, for sure. Now I'm teaching myself bodywork. I'm doing okay at it but I don't think I'll be quitting my day job, lol. I started picking at the small rust spots behind both rear wheels and uncovered a real mess. I ended up cutting out a lot more steel than in the pictures and a bunch from the outer wheelhouses. It's been a hard, but fun, learning experience.
The work continues on the Olds, for sure. Now I'm teaching myself bodywork. I'm doing okay at it but I don't think I'll be quitting my day job, lol. I started picking at the small rust spots behind both rear wheels and uncovered a real mess. I ended up cutting out a lot more steel than in the pictures and a bunch from the outer wheelhouses. It's been a hard, but fun, learning experience.