My '85 MGM, "Maisa"

[Tiggie]

Ford seals were still available from the dealer up until a couple years ago. Seems they are discontinued now. Plus the potential shipping issue - not sure it's worth it. https://www.rearcounter.com/E1AZ-907...rts331824.html

[Arquemann]

What about putting some RTV schmoo in there along with the seal after you clean things up real nice? Oh, is your gas tank up there nice & tight? Perhaps it's shifting around and slowly ruining the seal?

I did that when the previous seal started weeping the first time, worked for about a year. Also learned that almost none of the RTV silicones sold here are fuel resistant. Had to find myself a tube of Athesil, most sellers of Reinzosil had conveniently stopped stocking it around the same time.
Tank should be in place properly, doesn't look like anyone's ever even touched the straps. And I've bashed my knees, elbows and head plenty of times on it to confidently say it's atleast not loose.

Tiggie Yeh, I'd guess a Dennis Carpenter repop isn't any better than a Dorman or Spectra.

[Arquemann]

Maisa got her big tits on!



I did friday's cruise night without the center caps, just to make sure the snugged wheel bearings weren't getting warm and lug nuts weren't getting loose on the freshly powder coated wheels.
On saturday I retorqued the wheels and spent about 45 mins cleaning up the caps, then off to a cruise night. A bit of hammering on the worst dents, some headlight restoration compound on the emblems and metal polish on the stainless. They're not great, inside lips are mangled, the red on the emblems is disappearing and the caps kinda need to be oriented in a certain way so they fit tight.

New tires drive great, tire noise is reduced, ride is smoother (one of the old tires wasn't quite round). Passenger seat still has the jitters at 60-80, but my ass isn't vibrating anymore.
Speedo error is down to about 4-ish kmh too low at 100kmh. I shouldn't be triggering speed cameras anymore if I match the speed limit on the speedo.

[87gtVIC]

looks so damn good.

[sly]

looks so damn good.

QFT

[Tynnerstroem]

What a great look for the car! Wonderful.

[Arquemann]

Today I decided to pull off the magic ziptie (the one keeping the secondaries shut). We went to get dad's Grand Prix from storage, so I drove there with the magic ziptie in place, to see the baseline under todays conditions. Then for the drive home I took the ziptie off.

Idle leaned out, in gear it went from about 13.5 to ~14.2, it naturally leaned out the decel aswell and brought back the herky jerky. This would probably indicate that the secondaries are flowing less air with them ziptied shut (I didn't even pull the ziptie that tight). The flow through the secondaries should pull fuel at idle too, but (contrary to a lot of people) the idle fuel comes from the front bowls and shares the passage to the venturis.

Very light throttle also seems a bit leaner, but I didn't feel any ill effects. I was seeing AFRs more in the 16s compared to the usual 15s. Today was a warm and muggy day, so symptoms might appear on colder days. This could probably be another symptom of the butterflies being slightly more open, as with such light throttle input I'm barely into the transition circuit.

On the flip side, light and medium acceleration look to be richer than before. Usually in those scenarios the AFRs were around high 13s up to about 14.0, but afterwards I'm seeing a lot more low 13s and the acceleration feels softer and the engine sounds less laboured. Strikingly similar to how things felt last fall after the base plate swap.
It just doesn't make a bit of sense, considering the vacuum secondaries should not be opening at such mild loads, therefore the secondary transition circuit should not be in play. And if the secondaries are flowing more air for some reason, it should reduce the vacuum signal on the primaries and run leaner...

And the actual problem: when getting deep into the throttle (ie where the secondaries should be opening), things gradually go leaner and leaner until I lift off the throttle so I don't hurt things. Still not magically fixed. As if the secondaries are opening really slowly, but without adding fuel. I tried carefully opening the secondaries at idle by hand, the engine died almost immediately. No lean cough, no surge, no bog, almost like snuffing it out with a rag or just switching off the key. Weird.


I guess I'll tear apart the secondary side, I'll have to go through every single possibility before my noggin lets me buy an Edelbrock in peace.
A friend of mine is most likely upgrading to a Terminator X on his Camaro, and he could sell his slightly used Sniper 2. It would obv. be cheaper than a new one, and feel better than buying a used one from someone that has fought with it until giving up. No idea on the timeline though.

Or I could just keep going with half of a Holley. But FFS is it hard to leave things running fine when they're not right.

[gadget73]

What actually shuts the secondaries on these? Spring wrapped around the throttle shaft I'm guessing? Any chance thats weak or not wound tight enough to make it actually do it's job?

[Arquemann]

What actually shuts the secondaries on these? Spring wrapped around the throttle shaft I'm guessing? Any chance thats weak or not wound tight enough to make it actually do it's job?

Just the vacuum dashpot spring and engine vacuum holding them shut. The dashpot springs are changeable to adjust the opening speed of the secondaries, they can't be too stiff or compressed or the secondaries won't open correctly.

[Arquemann]

Dunno if to laugh or cry, this shit is just beyond fucked

Couldn't be arsed to remove the carb again, so I tore apart the secondary side of the carb with the thing still on the car, flushed out all the passages and slapped it back together. I broke my own rule of only doing one thing at a time, but I replaced the secondary jets with ones a few sizes larger. Mainly did it so I could see them coming to action on the AFRs.

First thing I noticed, the lean idle decided to fix itself, which is neat, considering I did not touch a single thing that would (or should) affect the idle in any way. Idled ridiculously well even from a quite cold engine.

And the thing still goes uncomfortably lean, but it happens before the secondaries open. If I floor it and keep pushing it despite getting leaner, I can eventually hear the secondaries roar open and things go rich. The AFRs seem to get leaner faster and earlier depending on how far the pedal is buried. Below like half throttle its not an issue at all.
But the problem shouldn't be the primaries either, as I didn't have this issue with the secondaries tied shut. But if its the secondaries hanging open, they should also flow fuel, especially now that everything is cleaned out and stuff.

[gadget73]

sure its not the power valve failing to work? That would make things lean out until the vacuum dropped enough to open the secondary up. Though I don't understand why wiring the secondary shut would have any effect if that were the case.

seems like the secondary blades are opening but fuel isn't flowing for whatever reason. I don't know Holley carbs at all so no idea what would cause that. Unless its just a way too soft spring allowing the blades to open but not enough vacuum to actually pull fuel through the back?

[Arquemann]

sure its not the power valve failing to work? That would make things lean out until the vacuum dropped enough to open the secondary up. Though I don't understand why wiring the secondary shut would have any effect if that were the case.

seems like the secondary blades are opening but fuel isn't flowing for whatever reason. I don't know Holley carbs at all so no idea what would cause that. Unless its just a way too soft spring allowing the blades to open but not enough vacuum to actually pull fuel through the back?

The vacuum secondaries don't open based on manifold vacuum, they open based on air flow at the primary venturis, above the throttle blades.
The power valve works off of manifold vacuum (as you probably know), mine's supposed to be open at 7.5 inHg and below, and it seems to do so.

If the secondaries were opening early for some reason, it would drop the manifold vacuum and make the power valve open sooner. Though if the secondaries aren't flowing fuel for some reason, the power valve definitely wouldn't be able to compensate. But I can hear the secondaries open and see the extra fuel eventually.
I've had a lighter secondary spring in to diagnose the secondaries coming in, but I did try things out with the stiffer factory calibration spring. No change, other than it staying leaner for longer as the secondaries take longer to open.

This shit is fucking stupid, I'm geniunely out of ideas. Guess I'll just blame the wrong base plate and wire the secondaries shut.
I've got better things to do, like a ticking sound to fix, its coming from under the engine bay, I hope its just an exhaust leak.

[Tiggie]

I'm just here to say the turbines are a win. Good luck with the carb issues. I think I might turn off the Air/Fuel gauge and run it.

[DerekTheGreat]

I'm just here to say the turbines are a win. Good luck with the carb issues. I think I might turn off the Air/Fuel gauge and run it.

This. Thank you for saying it.

[Arquemann]

I'm just here to say the turbines are a win. Good luck with the carb issues. I think I might turn off the Air/Fuel gauge and run it.

This. Thank you for saying it.

Do you want your engine going way lean when hard on the throttle? I don't.
When I say its lean at high rpm its like 15:1 and above. It's unhealthy, especially considering the cylinder distribution of a carb.