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Pete. (l33t FS)
Pete. (l33t FS) MegaDork
3/25/23 4:34 p.m.

One thing to note is that Holley terminology can be misleading.  The "idle" circuit is more of a low speed circuit that boost fueling before the booster gets fuel moving.  The idle mixture screw merely releases air and fuel emulsion from that circuit to below the throttle plates.

A lot of tip in stumbles are really just a lean idle circuit.  People bandage over it with big accelerator pump cams and squirters, but the real fix is in redrilling the idle jets, which are a fixed part of the metering block in Holleys.  Better aftermarket carbs have replaceable jets for the idle feed restrictions, but if you don't want to buy a set of aftermarket metering blocks, ONCE YOU HAVE THE IGNITION WORKING OKAY you can get a pin vise and small drill set and carefully open those up.

What you will probably find is that tip-in and low speed drivability get much improved, and the idle mixture screws get more responsive instead of needing to be 3 turns out...

4cylndrfury
4cylndrfury MegaDork
9/11/23 3:29 p.m.

So, its been a while without an update. I know this is a pretty lousy build thread, but I promise I am still lurking. I'm really trying to get thru the summer months without downtime for the Monte, so occasions for turning wrenches have been few and far between. But I am learning a lot and trying to educate myself.

I did make some progress however since my last post. When I first got her, she had a notable wobble in the water pulley, so assuming the bearing was toast, I decided to replace the pump in April - fun fact, there are 2 different colors of "Chevy Orange" engine paint at Advance Auto Parts...ask me how I know. Note the 50 years of dirt and grime on the frame, suspension etc- this will be relevant in the near future

SInce I had the front of the engine apart anyway, I decided to dive headfirst down the project-creep rabbit hole and took the opportunity to clean the aforementioned half-century's worth of South Carolina grime out off the fram and out of the engine bay. Aaaand, since it was gonna be so clean, I decided to brush on POR-15 wherever I could reach (which, without the worlds largest fan shroud in the way, turns out to be quite a lot of places). For those that dont know, POR-15 is a rust encapsulating material that goes on like paint, but if you do all the prep, the way the instructions say, and apply it correctly and in a low humidity environment, its bulletproof. and far superior to paint. Part of the prep is applying an acidic etching agent that turns everything white (the white stuff is something like phosphorous or potasium or one of the elements - this is what the encapsulator bonds with to adhere to the metal).  First you clean with degreaser, then you apply the etching agent liberally with a spray bottle:

It looks grimy above, but its actually very clean and nearly raw metal. After the prep, you end up with the white stuff I mentioned:

From there, after donning a good quality respirator (cuz the fumes are super noxious) and a paint suit (because POR-15 bonds to skin like ticks to a deer's ass), you just use 827 disposable chip brushes to apply the stuff all over the place. It actually flows relatively well off a brush, but I suggest buying many small cans of the stuff vs 1 big one. The big can is good for a large job like a floor pan or a naked frame, where youre going to do a large area at once. But the stuff has a short-ish pot life, and if you open the can, it will need to be tossed once you complete the task. Just the air inside  partially used and then closed can will cause it to continue to cure. Ive heard tale that using plastic wrap on top of the surface of unused POR-15 might help prolong a in-use can, but I wouldnt count on it lasting more than a few days that way. The smaller cans allow you to do a smaller project without tossing a bunch of the stuff. Anyway, the results were better than I expected.

All in all it was about 2 days of prep (mostly cleaning, only about 2 hours if that was the etching process - spray, wait 15 min, spray, wait 15 min repeat x4) and another day of application. Then 2 days to cure. I couldnt be happier with the results. It just looks like paint, but I can rest easy knowing that at least the front frame and suspension will last a long while. The rest of the frame (that I can get to without going body-off) will get its turn this coming winter. If you look closely at this shot, you can see the front frame and the upper A-arms poking thru

 

Also of note, I decided to have the TH350 automatic rebuilt in April as well - it was leaking from every place it could leak. Now it shifts super firmly...no shift kit, and a stock converter, just now with super crisp shifts. No pics, but imagine a hot-tanked and now very clean automatic transmission that otherwise is not exciting in any possible way.

Now, back to the carb...

I watched a lot of Uncle Tony (great suggestions from the forum, thanks!) and started with basics - getting float, idle, and mixes close to right. Pete was right above, the jets are probably too restrictive because it takes a lot of mix screw to make small impacts to the carbs behavior. I bought a vacuum gauge and will be working to fine tune things vs just "that sounds better" this winter.  With that said, earlier in the year, I replaced the accelerator pump squirt nozzle, going up one size. I also added what may be the same equivalent  muscle car snake oil as Warm air Intakes are to the tuner crowd - a Thompson performance Powerblast Plate. This is a little brass plate, bent on a brake, that sits under the squirter nozzle and is supposed to atomize the spray by spreading it off the cut edge of the brass plate versus the nozzle just acting like a squirt gun aimed down the gullet of the carb. IDK if it works, but Im still of the opinion that I have significantly more carb than I need, so this is probably super unnecessary anyway.  Between the new nozzle and the plate I was maybe $45 in, so it was worth it to try a potential cheap fix.

I did  have someone suggest that it may be my power-valve in the carb - apparently, these can get bent and become sticky after a lean condition carb backfire. The valve could also be over/undersized to the engine . A mismatch could contribute to an off-idle stumble if youre making too much vacuum (which I could be given its a 2 barrel engine with stock exhaust manifolds and cam, while wearing a moderately sized 4 barrel carb) and the valve isnt opening at the right time/rate. More to come - again, i dont want to have downtime in the summer, so a carb rebuild will be coming in the winter months. A vacuum test will help determine which valve that I should be using, so we shall see. 

Lastly, have a few other maybe-projects planned for the off season - new headers, new front swaybar mounts and end links, install a rear swaybar with tubular rear control arms, and maybe a rear disc brake conversion. Im also earily suspicious that i have bad piston rings/cylinder bores. On the freeway cruisng at 60, when you let off the gas to coast, she'll produce a not-inconsiderable puff of blue smoke. She has a real drinking problem - probably consumes about a quarter quart of dinosaur juice every 2-3 times i take her out. Between that and her declining oil pressure at idle after she warms up tells me we probably need to get a good look inside. Probably gonna get a scope and go in thru the spark plug holes/do a compression test. 

Regardless, onward and upward. The summer isnt over yet and Im still having more fun per dollar than anyone has any right to. The Monte found her way to several shows and cruise-ins this summer (and hopefully more to come). She gets a ton of attention everywhere, though no hardware yet. Every time I have her out, someone stops to tell me about the sweet Monte that their uncle had or the one they sold after high school that they wish desperately to have back...its regular as clockwork. So here are some obligatory pics from this summer (nevermind the silly effects, i was playing with pic editing apps...) 

Thanks for allowing me to rant and ramble. Any and all ideas or feedback are welcome. 

4cylndrfury
4cylndrfury MegaDork
9/11/23 5:27 p.m.

Hoping the mods can move this to the Build Threads section and retitle the thread to something like "Gold Dust - a 1st Gen Monte Carlo thread".

 

Please and thanks!

danvan
danvan Reader
9/11/23 5:53 p.m.

In reply to 4cylndrfury :

Start with the ignition system toss the Chinese distributor and get a MSD ready to run IMHO most carb problems are ignition problems.

As for the Holly I have been running them for 50 years and they are very good 

danvan
danvan Reader
9/11/23 6:14 p.m.

Note to self look at the date of the post you comment on

4cylndrfury
4cylndrfury MegaDork
9/12/23 7:54 a.m.
danvan said:

Note to self look at the date of the post you comment on

its all good - this is a project that will probably never be "finished", and Carb stuffs are at the center of my attention at the moment

HotNotch
HotNotch New Reader
9/12/23 8:48 a.m.

Cool thread, and sweet car.  The timing of me seeing this thread is perfect because I've been fighting a tip in stumble / miss on my Holley Street Avenger equipped 460 in my Lincoln.  Looks like I'll be watching some Uncle Tony on Youtube

anger_enginering
anger_enginering New Reader
9/12/23 8:49 a.m.

I know Uncle Tony was suggested in the past, and I do watch his videos, I have found Thunderhead289 to be the best on Carb tuning I have found on the tube. He has run a lawnmower carb on a car.. if you can believe that.. 

Beautiful car.. thou personally not a fan of the wheels. To me it takes away from the overall "look".. 

Do you plan to keep it stock-ish or go more restomod?

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
9/12/23 11:40 a.m.

IDK how i missed this the first time around.  beautiful car!  i greatly prefer the slick top look vs the vinyl top on this body.  my first car (back in 1984) was a '72, equipped very much like yours.  PS PB AC AM/FM, red with white vinyl top and black cloth bench.  i'll get another someday.

shawng and others have given the wisdom of the ages re: thorough cleaning and verification of correct components in the carb. then begin tuning from a known baseline.

i would not install headers unless you're also bumping up the compression and stabbing a big cam in it. "+20hp" is meaningless in the context of a 1972 Monte when it is measured at 6000 rpm. ;-)

i'm looking forward to following along!

 

4cylndrfury
4cylndrfury MegaDork
9/12/23 11:48 a.m.
anger_enginering said:

Beautiful car.. thou personally not a fan of the wheels. To me it takes away from the overall "look".. 

Do you plan to keep it stock-ish or go more restomod?

I also dont love the wheels, but SWMBO does, and so, there we are. Personally, Id like something more akin to Torque Thrust or Cragars. Ive also seen some US Mag wheels that look pretty sweet and appear to be modernized versions of throwback styles - I like the Bandit

and the Roadster

Regarding the future as a restomod or more of a classic, Im leaning to a little of both. I am not going EFI, (though Sniper kits look to be very high quality and easy to install, so that is tempting given the headaches the carb is giving me). But I want to do tubular suspension with coilovers, and rear discs like I mentioned. Im not opposed to swapping the rear end with an updated IRS setup, but I know that would be some real cutting and fab work, and I struggle with that given how original the steel is.

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
9/12/23 12:04 p.m.

Regarding the future as a restomod or more of a classic, Im leaning to a little of both. I am not going EFI, (though Sniper kits look to be very high quality and easy to install, so that is tempting given the headaches the carb is giving me). But I want to do tubular suspension with coilovers, and rear discs like I mentioned. Im not opposed to swapping the rear end with an updated IRS setup, but I know that would be some real cutting and fab work, and I struggle with that given how original the steel is.

in my experience, the move to EFI will bring you more driving enjoyment than all that other stuff.  but it's all cool, there's no doubt about that.

4cylndrfury
4cylndrfury MegaDork
9/12/23 12:49 p.m.
AngryCorvair (Forum Supporter) said:

IDK how i missed this the first time around.  beautiful car!  i greatly prefer the slick top look vs the vinyl top on this body.  my first car (back in 1984) was a '72, equipped very much like yours.  PS PB AC AM/FM, red with white vinyl top and black cloth bench.  i'll get another someday.

shawng and others have given the wisdom of the ages re: thorough cleaning and verification of correct components in the carb. then begin tuning from a known baseline.

i would not install headers unless you're also bumping up the compression and stabbing a big cam in it. "+20hp" is meaningless in the context of a 1972 Monte when it is measured at 6000 rpm. ;-)

i'm looking forward to following along!

Awesome ride! I do prefer the hard top vs vinyl (mostly just because Ive seen so many vinyl tops that a rust breeding grounds). I have seen some 2-tone hard tops with white paint that look a lot like yours though and I really like that look! 

And, Ive been looking at mild street-cam options that would pair well with headers. That may end up being part of the winter plans. Bumping compression may be a longer-term plan, but is on the wish list!

4cylndrfury
4cylndrfury MegaDork
9/12/23 12:59 p.m.
AngryCorvair (Forum Supporter) said:

in my experience, the move to EFI will bring you more driving enjoyment than all that other stuff.  but it's all cool, there's no doubt about that.

Yeah, but then what will i do when the EMPs go off and the zombie apocalypse befalls us?

jokes aside, SWMBO's Father has a classic A-body that he just swapped to a crate 350 with Edelbrock EFI, and he says he cant tell a difference between it and a modern car from a driving feel  perspective. Youre probably right about a dollars per enjoyment ratio. And I am certain it would be more suited to longer distance drives...so far I havent gone more than about 45 min from home, mostly because I dont like the idea of relying on this car for anything further than where I can ask for assistance if she takes a dump.

But mainly, I just like the idea driving a beautiful classic with tech from before my time - there's something about that sentiment that brings me a bit of joy in the experience...sounds corny I know, but there it is.

Recon1342
Recon1342 SuperDork
9/12/23 11:44 p.m.

In reply to 4cylndrfury :

Takes guts to tackle a carburetor in this day and age. I've been working on carburetted engines for 25 years, and there's something satisfying about getting a perfect tune set up. That being said, EFI is pretty much impossible to beat in a daily driver.

pres589 (djronnebaum)
pres589 (djronnebaum) UltimaDork
9/13/23 12:04 a.m.

I think if I had a car like this was burning oil like this, I wouldn't change anything besides the parts needed to make it run right, and then rebuild to address wear + add performance after the bugs are shaken out.  I know that means the carb might need some changes to address added fuel requirements, but that should be easier when the carb is in a known good state vs. now when it sounds questionable.  Have you done a compression test?  It sounds like there might be a cylinder or two that really aren't contributing anything useful.

There was an earlier comment about ignition issues looking like carb issues and I think that's kind of how a lot of these things work out.  I'm wondering how the advance is coming in on this thing and if everything is working 100% on the ignition side of the coin currently. 

I wonder what the current wheels on the car would look like if the black (or seemingly black) painted center areas were painted a lighter color, like a gray. 

4cylndrfury
4cylndrfury MegaDork
9/13/23 4:30 p.m.
pres589 (djronnebaum) said:

I think if I had a car like this was burning oil like this, I wouldn't change anything besides the parts needed to make it run right, and then rebuild to address wear + add performance after the bugs are shaken out.  I know that means the carb might need some changes to address added fuel requirements, but that should be easier when the carb is in a known good state vs. now when it sounds questionable.  Have you done a compression test?  It sounds like there might be a cylinder or two that really aren't contributing anything useful.

There was an earlier comment about ignition issues looking like carb issues and I think that's kind of how a lot of these things work out.  I'm wondering how the advance is coming in on this thing and if everything is working 100% on the ignition side of the coin currently. 

I wonder what the current wheels on the car would look like if the black (or seemingly black) painted center areas were painted a lighter color, like a gray. 

Agreed - im going to take a good look with a scope inside the cylinders, and likely will yank the motor and have it repaired as needed when it goes in for cam and headers.

Ive also been researching better quality distibutors, as it seems like an easy button, especially considering how much a problem unit can contribute to the issues im facing

wawazat
wawazat SuperDork
9/13/23 7:51 p.m.

I've been away from the forums due to personal stuff but I really do love the slick top Monte!  Not a fan of the wheels though.  Im also of a similar mind set/design focus on my '69 Cougar build-modern bits on a classic tub with little to no irreversible mods.  My car is also a base model with limited option.  Have fun and keep at it.  Classics deserve to be driven so people don't forget them!

Recon1342
Recon1342 SuperDork
9/13/23 10:36 p.m.
wawazat said:

  Classics deserve to be driven so people don't forget them!

This is why I would be a lousy collector. Original survivor with 500 miles on it in a rare 1 of 250 color scheme, and the factory only made 1500 total of that model?

I WILL DRIVE THE SNOT OUT OF IT!! 

4cylndrfury
4cylndrfury MegaDork
9/20/23 2:39 p.m.

Went to a car show at Caesars Creek lake in SW Ohio this past weekend. The show was the 2nd annual, held in honor of a fallen Oh Dept of Natural Resources officer and K9 handler., and the Dog Park theyre building in his memory. Took home a top 30 trophy (the sign was a christmas gift last year from SWMBO)

 

In other news, started in earnest to formulate the off-season plans

 

Small stuff:

  • New sway bar end links with urethane bushings
  • New cast valve covers
  • Fix the horn
  • Fix AC wiring/AC recharge/determine if AC will work

Medium Stuff:

  • Hood is going top come off so I can clean up/paint the firewall and paint the hood underside
  • New heater core (if you know anything about A-body cars, you know why this is under the Medium section)
  • Mid-length headers
  • street cam

Big Stuff

  • Piston Rings

Wishlist

  • Tubular rear control/trailing arms
  • Rear swaybar
  • Rear disc conversion
  • Serpentine setup

 

 

Dusterbd13-michael
Dusterbd13-michael MegaDork
9/20/23 2:50 p.m.

I would put the serpentine conversion prior to air conditioning as Serpentine will require a different AC compressor. I'd also suggest that you look at using the late 90s GMT 400 Vortec accessories and compressor for the upgraded alternator power steering pump and brackets. They come up pretty frequently down here for cheap if you want me to Source you a set

eastsideTim
eastsideTim UltimaDork
9/20/23 4:19 p.m.

Any chance you'll be at a either of the Milford cruise ins, or the Eastgate cruise in this weekend?

4cylndrfury
4cylndrfury MegaDork
9/21/23 8:26 a.m.

In reply to eastsideTim :

probably not this weekend - SWMBO bday is this weekend, and she already put up with many auto shenanigans last weekend (we were at Milford last week as well as the show).

With that said, the car came to us via the Milford cruise, so we do go a few fridays each month - its not far from my home and its usually an awesome time.

4cylndrfury
4cylndrfury MegaDork
9/21/23 8:28 a.m.

In reply to Dusterbd13-michael :

Thanks for the suggestion - the aftermarket prices are bananas! What constitutes cheap in your area? I havent begun to source that stuff from Cincy yards yet.

Dusterbd13-michael
Dusterbd13-michael MegaDork
9/21/23 8:41 a.m.

About $100 for everything including pullies, hardware, accessories, etc

pres589 (djronnebaum)
pres589 (djronnebaum) UltimaDork
9/21/23 9:29 a.m.

Engine pay would be easier to paint while engine is out and being rebuilt.  Do all at once and really get the bay cleaned before paint.  Pulling the hood is the start of that project anyway.  I like Duster's suggestion of going to a later accessory drive setup + A/C update all at once.

I'll make a really crazy suggestion; snag late GMT400 350 Vortec engine complete with accessories so you've got everything all at once and rebuild that.  Freshen the heads, get a matching Vortec-compatible carb intake (Edelbrock sells a Performer RPM Vortec for square-bore carbs, which sounds perfect), street cam and a new compatible distributor. Pull existing engine and bag it for the future.

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