New Carburetor Choice Advice Wanted Chevy 454

ClydesdaleKevin · March 27, 2012, 11:41 AM

Hey all you experts in here. I would like your advice on what to do about my carburetor. I'm far from an expert, and not very good with carburetors, so I figured I'd ask the guys who REALLY know what they are doing...lol!

Here are my choices for our 89 Holiday Rambler, with a 454.

Option 1: I could remove the Rochester Quadrajet that is on here now, and bring it down to my mechanics here in Arizona and let them rebuild it. They were the ones that managed to cobble together a decent working carburetor for the Itasca out of two bad ones. Would cost about 200 bucks or less...but I might have to drive the RV to them at the end of the show if it needs tweaking. This would also ensure that its the RIGHT carburetor, and I wouldn't have to worry about linkage adapters, modifying linkages, the wrong jets, etc.

Option 2: I could buy a rebuilt Rochester Quadrajet from Summit Racing...rebuilt by Edelbrock...(I will never buy a rebuild from Holley again after the last nightmare we had on the Itasca!). Cost is around 450.00 bucks. It would be a fresh rebuild from Edelbrock. But I worry about the compatability, like metering rods and jets being the same, and it having the same linkage...and what the heck is a "divorced choke"? Mine has an electric choke...don't know what a divorced choke is, but that is what most of the Edelbrock Quadrajet rebuilds are listed as having.

Option 3: I could buy a brand new Edlebrock 1411 carburetor, a base plate adapter, the calibration kit that has springs and metering rods etc. for different applications (And try to figure out what will work best...did I mention I'm not very good with carburetors?), the linkage adapter, and a new air cleaner and housing (which doesn't have a snorkel). If I decide to remove the AIR system, it would also mean getting 2 crankcase breather filters to plug up the holes in the valve covers where the hoses plug in. Cost, around 500 bucks.

I'm guessing these are about my only options, but are there more options you can think of?

I'm starting to lean towards letting my mechanics rebuild the carburetor that is currently on the RV, since it has, until recently, worked great and given us good performance and gas mileage. It would also more or less rule out the carburetor as the culprit in the bad running no power issue we are having. Then if its something else...bad fuel line, dying fuel pump, bad distributor or bound up centrifugal advance or bad vacuum advance, then I wouldn't have wasted 500 bucks on something that wasn't the problem in the first place, and the carburetor would be freshly rebuilt and that isn't a waste of money at all, even if the carburetor isn't the problem.

I'm pretty sure...80% sure....that it is the carburetor. It always had a flat spot right before the secondaries would open, and then after Carolina this year, it got worse and worse, to the point that I had to fiddle with the choke dashpot just to get any power, which disabled the choke and now requires I hold my foot on the gas peddle and feather the accelerator to keep it running until it smooths out. Once it warms up it runs fine at idle and low speeds...but give it the gas, and it bogs and sputters. We didn't even tow the Jeep much with it once we got out here to Arizona. It barely had enough power to make it up the hills on its own! Maybe dirt is clogging something up, or maybe some diaphram went bad, like the accelerator pump?

For anyone reading this not familiar with what the problem isn't, and what we've recently done: New plugs, wires, cap, coil, and rotor. New fuel filters, both inline, and in the carburetor. I checked the EGR valve with a vacuum pump, and it works like its supposed to. I also checked the vacuum advance on the distributor, and it works like its supposed to. I put in a new ignition control module, and made sure the centrifugal advance was free to move, and it is. I checked manifold vacuum, and at idle it is where it is supposed to be, around 15...and when the accelerator is depressed, it drops down to around 6...the needle bobs a bit, but its not the best vacuum guage that I own.

So what do you think, folks? What would you do? I trust my mechanics, so I'm really leaning towards that route, but would like your opinions, since you guys are way better mechanics than I.

Kev

TommyM · March 27, 2012, 01:05 PM

I'm a QJ fan. It's hard to beat the power/reliability/economy combination. The combination of small primaries and huge vacuum secondaries is economical when you keep your foot out of it, and responsive power when it's time to hit it. The metering system, once it's initially set up well for your engine, never needs adjustment.

I don't think there's any reason to prefer a factory-rebuilt unit as compared to a local rebuild, as long as the locals really know how to set one up. It's important that your local guys can bush the throttle shaft if needed (if it leaks). Not everybody can do that.

Divorced choke is a class 3 felony in most states.

Okay, actually, a divorced choke is one that is not mounted directly on the carb. Yours electric choke is NOT divorced.

Tommy

Wantawinnie · March 27, 2012, 01:39 PM

I had the Quadrajet rebuilt locally for my '77 Pontiac T/A 400 and couldn't be happier with how it runs. Starts good after sitting long periods of time, has power, and gets decent mileage.

HandyDan · March 27, 2012, 02:03 PM

Well, I'm certainly no expert so don't take what I say as the way to go, but I can tell you what I did. When I bought my motorhome it was running terrible. Backfiring through the carb, no power at times and lots of power at other times. I also had the dual fuel system with propane. The propane system doesn't affect the carburetor, just the delivery system so the carb for dual fuel isn't any different than straight gas. When I took it to the truck center to have it worked on they suggested a new carburetor and they tried to find another Quadrajet. However, they couldn't seem to find one for a motorhome so they ordered an Edelbrock Performa 1406 four barrel with the adapter plate and electric choke. The old Quad had a "climatic" choke. I ran the Edelbrock on our yearly trek to the Ozarks and it ran okay but just didn't have the power I was hoping for. The 1406 is a 600cfm where the Quad is a 750cfm. Any little hill caused it to slow down more than I would like. The truck center gave me back my old Quadrajet and I started looking around for some way to rebuild it. I couldn't find anyone local that I trusted and my local mechanic didn't want to take it on, so I sent it off to a place in Florida that specializes in QJs. They even advertised on their website that they did motorhome carbs. It came back in two weeks looking like a new carb. My local mechanic installed it and got it running nice. I ordered an electric choke for it since all the "climatic" stuff had been removed by the truck center. I can say that it has more power with the Quad than the Edelbrock and it has a completely different sound than the Edelbrock. The Edel would squeal when lots of power was required, the Quad just roars. I'm much happier with the Quadrajet.
However, if you look at the working parts of the two carbs, the Quad has twice the moving parts of the Edel. It is a much more complicated carb. Maybe if they had installed a Performa 1411 instead of the 1406 I might have been happier, but for now, I satisfied with the Quadrajet.

Elandan2 · March 27, 2012, 04:01 PM

Hey Kev, Like you I am no expert on carburetors (even have trouble spelling it!), but your description sounds similar to what I experienced with my 440. It ended up being the exhaust valves in #3 and #5 cylinders burning. They burnt because as the vavles recessed into the head, the hydraulic lash adjusters ran out of travel and would hold the valve open ever so slightly. Ran perfect at idle and low speed, but low vacuum at higher speeds and no power. Although I believe that the 454 has pressed in hardened seats rather than induction hardened like the Dodges, it might be prudent to do a compression test and find out if you have a problem there.

Also, it isn't too likely that it would be the accelerator pump, that is only used at low speeds to squirt an extra bit of fuel into the primaries. Rick

Elandan2 · March 27, 2012, 04:02 PM

I forgot to add, that it isn't too likely that it would be the accelerator pump, that is only used at low speeds to squirt an extra bit of fuel into the primaries.

tiinytina · March 27, 2012, 07:30 PM

We put the Edelbrock quad on Gone right after we got her since the previous carb was actually warped and bleeding gas over the engine (gotta love POs).... Have been happy with it no issues..power is good, mileage 7.4 avg. Never tried a Rochester so can't comment. I have, um, rebuilt 2 carbs (boyfriends cars

), not overly difficult just tedious and both worked fine after I put them all back together...

I would not recommend going without the carb snorkel.. we tried that with a "naked" KN filter assembly.. all was good until cold weather and mileage dropped to 3.2..... cold and damp make 454's very unhappy.... when there is no recirc from exhaust pumping back into carb... There are a bunch of hoses on the snorkel running hither and yon, ours much happier with all connected again.

AIR system is useless... only issue is that the drivers side is a bear to fully remove...My mechanic friend simply disconnected it at first but when we put in BANKS took remaining parts out to get to the manifold and you will have to put all new belts on which need to be "eyeballed"... for size.... double check and retighten after about 50 miles.. nice to have it work in and not have breaks as the belts powers the steering and hydroboost for brakes... eeeks.

tina

ClydesdaleKevin · March 27, 2012, 11:23 PM

So far all your posts are still inclining me to let my mechanics rebuild it. I'm sure I don't have bad exhaust valves...compression is still even and good across the board. Just the fact that I could adjust the dashpot and get enough power back to keep on rolling, even though it essentially disabled the choke, makes me pretty sure its the carburetor. And the fact that is started as a small flat spot, and just got bigger and bigger over time.

Although the simplicity of a Edelbrock appeals to me, and the 1411 is a 750 cfm made for a balance of fuel economy and power, I think I'm more inclined to get a rebuilt Quad than a 1411, provided it was a rebuild by Edelbrock, and NOT Holley...lol! That last one was one heck of bad rebuild! Even I could have done it better!

My mechanics, Kurt and Jerry, are older guys, in their 50s, and they know carburetors. They fix all kinds of vehicles, but their personal vehicles are all classic cars and trucks and jeeps, with carbs and lot of modifications.

I'm planning on taking the carburetor out in the morning, and bringing it to the shop...but I still want to hear from Dave. Dave? Are you reading this? Your advice to me has always been solid and reliable, and if you have read this post and are keeping up with it, I would really value your opinion.

I know, you'd fix it yourself, and have it running perfect in 10 minutes, while juggling flaming cantelopes and cracking whips at wild tigers...lmao! But assuming you weren't a carburetor guy with all the skills to fix it yourself, what do you think my best options are, Dave?

Thanks to everyone! I love this group and all of the members here! You make my life as a gypsy SO easy!

Kev

DaveVA78Chieftain · March 28, 2012, 09:41 AM

Kevin,
I will try and find some time to put together some feed back. Real busy at work plus I have been working on My Chieftain and the wifes van (Have to clear check engine light so I can get it inspected). Honestly, this is one of those subjects where you love um or hate um. All the options have their plus and minus though GM used the Quadrajet for decades so to me that says something in and of itself. Additionally, you already have a solid record with the mechanics abilities. Just don't accept a franken carb like you had before.

Off and running to contractors facilty,
Dave

ClydesdaleKevin · March 28, 2012, 11:14 AM

Sounds like a plan has formed...I love it when a plan comes together! Okay...so this morning, after my workers get here and I get them started, I'll remove the carb and take it over to my mechanics. They really know their stuff, so we should be good to go, or at least it will rule out the carburetor with a minimal expense.

Kev

Froggy1936 · March 28, 2012, 01:46 PM

Hi Kev. My Personal opinion is you cannot beat a Quadrajet if you have to have a caburetor (They cannot compete with Fuel Injection) I have rebuilt 4 or 5 Quadrajets over time. But i highly reccomend How to rebuild and modify Rochester Quadrajet By Cliff Ruggles This book has every biy of info that there is on QJ $24.95 @ www.cartechbooks.com ISBN 978-1-932494-18-1 Item SA113 All the tricks & secrets to repairing anything that can go wrong are in there Frank

HandyDan · March 28, 2012, 03:29 PM

Take every precaution not to drop anything down the hole when you take it out. That could be bad.

ClydesdaleKevin · March 28, 2012, 10:30 PM

LOL Dan! I was very careful, took a lot of digital photos before I removed anything, especially of the vacuum line routing, and stuffed clean rags down the intake manifold so dirt, dust, dog hair, and whatever that damn mouse brings around don't get down in the manifold.

After I got my workers settled in and did a little routering on armatures so they could sand them, I came back into the RV and carefully removed the carburetor, as noted above.

I then drove it over to my mechanics, Kurt and Jerry. Kurt wasn't there...he recently had open heart surgery to repair a leaky heart valve...congenital condition, so he's home and bored to tears...he can't wait to get back to work! Jerry WAS there, however, and we talked about the carburetor, which I brought to him in a box.

He looked it over, and announced a good prognosis. Apparently, even though our RV is an 89 with just over 100k on the engine, no one has ever rebuilt the carburetor. All original. The rivets are still in place on the choke, as from the factory. The metal plugs are also in place, that cover the mixture screws, as from the factory. He said that would make it a much more successful rebuild, since no one else ever messed with it. They have the capability to replace the bushings, but since we've never had fuel seeping out of them, and they felt tight to him, and because it "only" has 100k on the engine, he said chances are the bushings would be just fine, since no one ever messed with it before or did a bad or sloppy rebuild.

Then he told me he was having one of his "guys" rebuild it. I was skeptical...Kurt and Jerry are the ones I had rebuild the last frankencarb. He laughed and pointed to this older biker looking dude in the garage. The guy's name is Steve, and he's about 60 years old...and a Chevy guy who's been working on Quads and other carbs for over 40 years. He said Steve has forgotten more about carburetor than he himself knew about them. He trusts Steve, and that's good enough for me!

We did discuss other options, but we still came to the same conclusion. A factory rebuilt Quadrajet rebuilt by Edelbrock...not Holley (he agrees after seeing the last rebuild they did)...might not have the right jets, springs, or metering rods, and would still have to be set up and tweaked by someone who knows what they are doing. A new Edelbrock 1411 is a good choice, but 600 bucks plus by the time all the adapters are bought and its set up by someone who knows what they are doing. By rebuilding my apparently very solid core of a carburetor, he's convinced that is my best option, since its already set up for my engine, and gave me good performance until recently.

The estimated cost is going to be somewhere between 250.00 and 300 bucks...but that means all new parts including the float...and also includes the final tweaking and tuning...in other words, they'll rebuild it and give it back to me. I'll reinstall it, and then after the faire closes this weekend, I'll drive the RV to their shop on an appointed morning, and they will do the final adjustments on the mixture, idle, choke, etc....and test drive it and make sure its perfect.

He's also going to check my work from the tune up and check and adjust if necessary the engine timing, all included in the price he quoted me.

I might go ahead and let them take out the AIR system, and put new belts on that fit...he said it wouldn't add a heck of a lot to the cost and could be done the same day, so we might very well go that route.

So its a done deal, and hopefully soon The Nautilus will be back up and running better than before! Patti already has plans on what to do while they are working on the RV...Since we have to take the dogs with us in the Jeep somewhere, she wants to take them to the groomers for baths...lol! Barnabas will NOT be happy about that, but Sheba will! The kitty is going to be babysat by our nextdoor neighbor friends, Robert and Leah, the folks who own the 77 Cheiftain with the diesel conversion and the trailer toad. Sammy and their two cats have become best friends.

I'm really hoping its just the carburetor and nothing else, but at least its good and honest mechanics doing the job. They'll be able to troubleshoot and isolate any other problem we might have and then we are good to go with no worries...SWEET!

Kev

DaveVA78Chieftain · March 28, 2012, 11:02 PM

Look at it this way, the problems you have had do not sound that serious. The steps you are taking will not only get to the root of the problem you will have dependable mechanics looking it over and getting it set up correctly. In the long run you should be ahead of the game.

Dave

Wantawinnie · March 29, 2012, 12:03 AM

I would like to see some pics of that trailer towing diesel Winnie bad boy.

BTW: Do you know if it is a Cummins diesel or something else?

ClydesdaleKevin · April 03, 2012, 11:32 PM

Yay! They finished the carburetor rebuild today!

They were quite pleased with themselves, and I got to talk to the mechanic who is going to be working on the rig on Thursday...he's the one that rebuilt the carb and is going to do the fine tuning and timing and all that. Now he knows what I have done so far, and what needs to be checked, etc.

So...it came out so pretty, I had to post pictures!

Horray for great mechanics! They were also quite happy it was a virgin carburetor...no one else had ever messed with it before...lol!

I'll be driving the RV down to the shop at 7am Thursday morning and parking it in front of the bay they told be to park it in front of, and then waiting for them to open at 9am. They said that if I don't get there that early, we'll never be able to get the RV in once all the other customers start pouring in.

Or neighbors at the campground are going to watch the cat, and we are going to take the dogs in the Jeep down to the groomers and just hang out with them until the RV is done.

SWEET!

Kev

ClydesdaleKevin · April 04, 2012, 02:10 PM

So I installed the carburetor with a new base gasket, hooked up the fuel line and vacuum lines, and turned the key to let the electric fuel pump fill the bowl...and to check for any fuel leaks. No leaks, so before starting it, I put the aircleaner housing back on and hooked up all those lines.

Turned the key...VROOOOM! Started right up! Yay! And sounded really smooth too! Let it warm up, and then went to kick the throttle down...nope. It kicked down a little, but is idling at 1800 rpm...WAY too high to safely bring it to the mechanics tomorrow.

So I called the mechanics, and the guy who rebuilt it tried to walk me through a quick fix on the phone, but I couldn't figure it out. I did manage to get the idle to drop down to 800 by pushing on the lever in between the choke housing and the carb body, but as soon as you hit the accelerator pedal again, it hops right back up to 1800...oi vey!

The mechanic said he'll try to stop by on his lunch break...I can't find the set screw he's talking about under the choke body that will supposedly clear it up. If he can't make it down here, he said I could let it warm up tomorrow morning, and then zip tie that kickdown lever in the down position just to get it to the shop, which appears to be the game plan now if he can't make it down here.

Anyhow, it appears to be a successful rebuild, but we just have to get that idle down to drive it to the mechanics for the final tune up.

Kev

DaveVA78Chieftain · April 04, 2012, 04:08 PM

Da-Ja-Voo:
http://www.tocmp.com/manuals/Carbs/Rochester/QJet/1973/pdf/1973%20manual%20complete.pdf

Late 4MC Carb version
Choke description: PDF page 19 (Fig 24)
Choke Install to body: PDF page 31
Choke Adj: PDF pages 36-37; Fig's 5 & 6

Dave

ClydesdaleKevin · April 04, 2012, 11:03 PM

So after packing down my whole workshop and porch, and rolling in the awning, and dumping the tanks and checking all the fluids and air pressures, it was around 6pm. Still an hour of daylight, so I took the dogs out, and decided to see if a zip tie really would work to keep the idle down.

So I started the rig, and it was only idling at 1100 rpm this time...even after warm up though. So this time when I kicked down those levers with my finger, the idle dropped NICE and low, purring like a kitten. I hit the gas, and back up to 1100. Okay, push it back down again...around 600 rpm, nice and smooth. I threaded a zip tie under the dashpot linkage, around one of the choke body screws, around the levers, and back...and zipped it so it couldn't move. Awesome! The zip tie doesn't touch anything hot so it won't melt before we get there, and it doesn't interfere with anything else. I hit the gas, and man it sounds great! And it stayed at a low idle.

Looks like its going to be a nice easy time to get out of here in the morning! I cut off the zip tie so the choke will work in the morning...still gets down to the very low 50s here at night...and have one at the ready on top of my tool box, right next to the engine.

It will probably run crappy on the way there, but its pretty flat with gentle hills all the way to the shop...8 miles. I'm saying it will probably run crappy because I'm sure those levers have some purpose...they all seem tied in together with the choke and even the secondary linkage. So we'll just take it nice and easy, nice and slow, and get there by around 7am.

Outstanding!

I love it when a plan comes together!

Kev

ClydesdaleKevin · April 05, 2012, 10:37 PM

Was up at 5:30am this morning...ick!...and we unhooked and drove the RV down to the mechanics. Its actually 14 miles to the mechanics. I took it easy with that zip tie in place, only driving about 40mph...but it was already running better than it has in a long time. A little hiccup right when I accelerated from a dead stop...but I figured the mechanics would clear that up.

So we drop the rig off and talk to the mechanics about the belts. We decided to play it by ear and see what condition both smog pumps were in before customizing or shortening the belts. Apparently, according to my mechanics, if everything is working correctly with an AIR system, it actually burns more of your fuel and burns it cleaner...making the RV actually run better and get slightly better fuel economy. Seems that some of the air it pumps also goes into the air intake.

We killed some time and then decided to drop by the mechanics and see what progress was being made...and they had the carburetor all dialed in and the RV road tested, and when we got there all the belts were off. Turns out the air pumps were working perfectly with smooth as silk bearings, so we took their advice and went with the stock belts...which their parts guy got wrong twice...so when we arrived, the belts were off and AT the part's place, so they could match them up perfectly.

They estimated that they would be done around 3pm, so we now had to kill 3 more hours...sucks being temporarily homeless...lol!

We went back at 3pm, and they were just finishing the belt install. Then when they started it again, it was idling too high again. So they brought out a meter, and started playing with the carb settings and choke setting...which meant another test drive, where I was the passenger. Runs AWESOME now! No hesitation, LOTS of power, smooth and sweet! Loud because of the headers...but I like that muscle car sound! Secondaries open when they are supposed to, and there are NO flat spots.

So now the final bill is tallied up...OUCH! 695.00 smackaroos! I guess there is a drawback to a shop that doesn't use the "book." Usually you make out and end up paying way less than the book says...sometimes it takes longer than the book says. But around 700 bucks for a carb rebuild and final tune, a vacuum leak check with a smoke machine, all FIVE new belts, and an RV that runs like a top is worth every penny of that to me!

One bad bit of news, although my mechanics say its not critical this year, since we only put about 6-7K on the RV a year...the timing chain is definately stretched, making an exact timing adjustment pretty difficult. It varies +-2 degrees because of the chain slack. They said we'd easily get another year out of it though the way we drive her, as it wasn't that bad, but they recommend a new timing chain next year....to the tune of probably around 800 bucks with the labor...removing the radiator in an RV and all that just to get to the timing cover. They charge 75 bucks an hour, so I can definitely see that as a fair price. Patti and I talked about it and will get it done next year...we are just glad its not so bad it has to be done now!

So we settled up the bill...I gave them 300 bucks in cash towards the final bill when I picked up the rebuilt carb...and now it was time for ME to drive the rig.

Oh yeah! Runs even better than when we got it! LOTS of power, no hesitation, very responsive throttle...and when you gas it, she moves! There are a couple of small hills on the way home, so I opened it up and VROOM! NO lack of power now! I'm SO glad it wasn't anything major! Oh yeah! She runs so SWEET now!

The mechanic called me shortly after I got back to camp and set camp back up, and asked me to make sure I start it in the morning while its cold to make sure the choke is working perfectly. He thinks it will, but wants to make sure, since the engine was warm when he did the final adjustments. If the choke works and she starts right up...and then kicks down when it warms up...we are good to go! I'll also check the belt tightness in the morning...and then every morning after each stop for the night, since they are new belts.

Close to 700 bucks spent in total, but it runs like a dream now! And that included all five new belts. I'm not going to complain about that!

Kev

ClydesdaleKevin · April 06, 2012, 12:03 PM

I turned the key early this morning, and the choke was definitely not closed all the way...so I marked where the mechanics set it, and slightly turned it, just enough so the butterfly was closed. VROOM! I then let it warm up...and it kicked right down to a very steady 700 rpm. Awesome! I only had to turn it maybe a millimeter or two, just enough to close the butterfly...SWEET!

Kev