Carburator, Ignition & Exhaust upgrades

Oz · November 24, 2008, 10:02 PM

Sent: 11/4/2003 9:26 PM

Well, we enjoyed a great year with our the new Winne-Beast. We got to go places and meet some terrific people. We were lucky that the PO's lack of maintenance and just the plain age of her didn't come out in-full until the last event of our season and not before next year's start. So... it's time to get down to the nitty-gritty. I am going to be doing some first time critical repairs and upgrades in order to get the ol' girl on the road to real road worthiness. I have 3 things I need some help with: '74 RM350, Indian, 440-3

1. I need a new carb ASAP to get her home. I know several of you have upgraded to Edelbrock. Can anyone tell me what model or CFM I need and if there is a consideration to be made when installing on the original cast iron intake. Also, any collateral items I need to know along with this like: linkage, jetting, or other complications. I have no choke so I will have to install a choke cable unless the suggested carb works off vacuum or something (and, most of the vacuum tubes and a lot of other EGR and God-knows-what-the-heck-that-went-to's have been cut).

2. I want to upgrade my ignition system. I heard that Jacobs is as good as MSD but a little less expensive. Anyone know? Also I want the whole package including the distributor. What do I need? What type/brand of plug/distributor wires should I get? What brand/part # plugs and is there a diffence in gapping?

3. I need to replace my exhaust. Is it better to go with dual or a single 3"? Is there a company that makes dual exhaust conversions or would I have to have it custom made?

I have a lot more to do but, like replacing the fried battery/alt cables, dropping, cleaning, and lining the gas tanks, repairing the fuel delivery system and the water tanks, replacing the starter and alternator... all that before I get to the minor things like fixing the roof and the other 2,389 items. For now, I want to make the apropriate upgrades to improve performance and economy and I need your help.

Now remember, I'm in mechanincs 101 here so, keep it simple for me. Thanks, -Sob

From: Jim83Itasca
Sent: 11/5/2003 11:16 AM

Hi Mark
Since i'm not a expert on the 440 engine lets see if i can sorta point out some directions based on what has been completed on a "chebby 454"
# 1 I would get it home with the original carb cuz modifying (different carb) is/can be a PITA. The Edelbrock is a square bore carb and yours "might" be a spread bore and that will require a adaptor plate + new linkage hookups.
Smog laws will determine which carb can be installed.
Here in Kalifornia the komrades dictate a Edelbrock "1400" 600 cfm which is smog legal.
# 2 On the ignition i have installed the "Jacobs complete with the hill climb module" with just mixed results power wise over a stock chebby HEI.
The man to talk with is a true guru in the racing circuit and his name is "Dave Ray" (562)699-6949.
web site http://www.davessmallbodyheis.com and e-mail addy is sparkman451@earthlink.net.
I would rather use his products cuz if you break down due to ignition problems anyone can purchase the parts over the counter (napa/autozone etc) instead of waiting on Jacobs/msd till they send out a part.
Ignition wire wise i use "borg warner select" from pep boys $39.95 and so far it has been perfect (another Dave recomendation).
# 3 If you already have duals on it just keep them and toss on some "Thorley" headers with gobs of torque increases along with 2 1/2 pipe.
Single pipe your 3" size is correct and of course mufflers is your choice BUT keep the noise level down (no flow masters).
A good "gear head" muffler shop would be the place to look for so look around for some hot cars and ask the folk's.
My fingers are worn out sooo i hope this will point you in the right direction & good luck.

Jim

From: mightybooboo
Sent: 11/5/2003 2:10 PM

# 1 I would get it home with the original carb cuz modifying (different carb) is/can be a PITA. The Edelbrock is a square bore carb and yours "might" be a spread bore and that will require a adaptor plate + new linkage hookups.
Smog laws will determine which carb can be installed.
Here in Kalifornia the komrades dictate a Edelbrock "1400" 600 cfm which is smog

SOB,thats the carb i have,they had to do a small linkage weld to make it work,it has an electric choke,looks like a bolt on re:manifold,I didnt install,shop did.It works well,but not as powerful on full accelleration as EO carb was.
BooBoo

From: daved27c
Sent: 11/5/2003 9:12 PM

Mark;
I think the "Magic" carb will work on your rig. You should probably check what CFM that carb is. I think if you take it to a parts store, they should be able to tell you. As far as the linkage, on the drivers side is the throttle linkage, transmission kick down and the cruise control.( I can't remember if you have cruise or not). These should be pretty strait foward. The vacuum lines looked like they would hook right up. The only question is the choke. The original had some sort of non working electric choke. A manual choke is pretty simple. When you pull the lever on the dash, the choke closes. When you push it in, the choke opens. I hope this helps. I don't know anything about Ign stuff, and Obviously mine needs exhaust work too.

Dave

From: Sea Hag
Sent: 11/6/2003 9:40 AM

Mark if your rig was manufactured after Jan. 1 1973 it already has electronic ignition system , don't let the vacume advance fool you , it did me on my 76 d23c 440 3 I was suprized by the lack of breakerpoints . the modual and ballast resistor are mounted on a plate on top of the bell housing a llittle hard to see . I found replacements on a display shelf at a local Farm and Fleet store I got the ignition modual ,ballast resistor . and a voltage regulator and replaced them all for safe measure and kept the old for back up . they didn't cost much I'm pretty sure well under $50.00 for all three . -- I would stick to the original model carb if at all posible ( these engines are much like the legendary 440 HP magnum but biult different it is a Truck deignated engine and built accordingly your not going to get any better ET by changing carb brands ) I don't have the manual for 74 only up to 73 then 76 - they used a holley or carter thermoquad on 440 3 if thats what you have 440 was an option on 73 RM350 318 was standard eventually replaced by a 360 . If it is 440 3 your plus are Champion BL 9Y or RBL 9Y gap .035 if you cross over watch the thread length . --- My chief was converted to 2 1/4 " Dual exhausts before I got it the pipes sections used look off the shelf with a section for a catalitic converter for later models and a perfict mirror image . If you have a good local exhaust shop with a RV lift ( Chain stores arn't always better ) you should get an estimate it may not be as much as you think . I like to do as much myself as I can but Ive found exhaust systems arn't worth it - I can't buy parts for what the shop will the complete job do it for --- Sea Hag

From: Sea Hag
Sent: 11/6/2003 9:52 AM

Sorrry , Fat finger sydrome -sounded like oby waun - I ment to say I can't buy the parts for what the muffler shop will do the complete job for .--- Sea Hag

From: Liv42dayOK
Sent: 11/6/2003 9:41 PM

Yeah, I did find that ballast resister hiding under that other thing on the back of the motor. It was one of the first things I checked when I lost all power.

The Winne-Beast has the 440-3. The original carb was a thermaquad and this had me in quite the quandry while I was trying to figure out why the manual showed a totally different type of accelerator pump than the one on my carb. I finally called the PO and he enlightened me to the fact that he had replaced the TQ with a quadrajet! Myster solved. However, I have no reference on this carb. I am thinking of getting a 600 cfm Edelbrock which, of course, opens up another set of hurdles involving the linkage, the fuel hook-up, etc.

She also has the electronic ignition. I've been looking at upgrades but, what I am finding is that most of these ignition systems, carbs, manifolds, blah blah blah, are only beneficial at RPMs that the 440 will never see so, they have very limited benefit for the expense. I will be contacting a few of the manufacturers to see what they have available for low rpm, high torque usage.

I did contact an exhaust place in town and they said they could custom make an exhaust. All I had to do was bring it in. I haven't gotten that far yet and, with the cost that I've seen in catalogs for other exhaust systems for RVs, I wanted to be thoroughly anesthesized for the shock of hearing the price on a custom made one. The good thing is, I've talked to a number of people that had custom exhausts made and, they aren't as bad as I was expecting.

This will definitely be a difficult selection process for me. I don't want to blow what cash I have saved up on expensive stuff that isn't right. I think I will stay with a lot of stock items. As Denison put it, "It worked 30 years ago." There may be some room for improvement but, if what was original is good, then that's what I need.

Thanks for the info - Sob

From: Liv42dayOK
Sent: 11/6/2003 10:02 PM

Thanks for the info and links, Jim

I did run into the carb change PITA already. The most appropriate being the same Edelbrock 1400, 600 cfm and, yup it would require the adapter which only complicates the linkage problem further. It has a quadrajet on it now that the PO put on (which came off a Chevy). It fits flush, the linkage isn't a perfect match but, it didn't require any modification to make it work. Problem is, I don't know what year it is, how old, if the bore is worn, if it's fixable, the cfm, or anything. But, I do know, other than the accelerator pump being inop, the darn engine purred before the carb cleaner was applied. I want to get it home and see if I can rebuild it. Problem is, I can't tow it (no room to maneuver it into my yard) and it's throwing waaay too much fuel to attempt to drive it home in traffic (even though it's only about 2 miles away, it's all in town driving) So, I really don't know what my least expensive options are. I guess I could let the guy see if it's rebuildable and let him do it. I can then go onto the other stuff. I'll bet the sluggishness is a combo of the age of all the stuff involved. She's run regularly her whole life and that's good. Now, it's time to give her the attention she's needed to get her back to young again. Sob

From: Liv42dayOK
Sent: 11/6/2003 11:30 PM

I found a new Edelbrock quadrajet replacement for thermoquad applications. It's a direct replacement. Electric choke. This has 795 cfm. I looked in the manual and cannot find what the cfm on the original thermoquad was. Does anyone know the cfm of the original? - Sob

From: Sea Hag
Sent: 11/7/2003 9:43 AM

I Looked it my chassis manual also ,the old and new ,with all the spec. you would think it would be in the I can give you model # but if you have a MH Chassis manual you already have what I do . Another rig I own a share of has a 440-3 with a holley replacement I think it is a 750 CFM but not sure . Make sure your cross over carb is for a truck 440-3 ( heavy service ) not a car 440 they are not the same design . --This may sound obvios and you may have already done this . I noticed you said that it ran fine before you cleaned the carb with spay carb cleaner . Have you replaced the plugs after you cleaned the carb. Carb cleaner sometimes fouls them . I would replace the plugs cap and rotor if you haven't already done so , before I'd takel the carb. and maybe that thing ( the ignition modual ) that the balast resistor was hidding under . esppecially if your trying to get it home . --- Mine had sat for a long time I thougt the carb was also suspect once I got it running but after burning up old fuel it's much better . Mine has the california emmision system ( even though it was originally purchased in Pioria ,IL. ) that of course has been butchered - I'm taking my manual to a mechanic freind and he's going to help me sort it out - so may be I can help you with that when I'm done . ----Just some thought on getting your rig home sao you can takel the rest there --- Sea Hag

From: denison
Sent: 11/7/2003 10:44 AM

I think if the new carb bolts onto the manifold, the linkage connects, and the butterflies operate without intefereing with the manifold openings, then its a perfect size. If a motorhome doesn't need a large capacity carb for its 440, what does? denison

From: Liv42dayOK
Sent: 11/7/2003 11:01 AM

Sea Hag,

I was about certain that the plugs had fouled but, the tow driver that came the next day said it started right up. The guy at the shop I had it taken to was also able to start it but, after a couple of minutes of running it, the carb started dumping gas again. I'm going to call him today and see if he can do anything to make it possible to get it home. I found a carb that is an Edelbrock quadrajet replacement for thermoquad applications but, eeek $600 (it's also 795 cfm)! Twice the price of the Edelbrocks that will work with modification. It doesn't matter if I have to do the modification, I just want to be sure it is the right carb the first time around. I have this aching feeling that I'm not going to get out of this without dumping more cash into the carb than the carb is dumpig gas on the manifold! When I talked to a couple mortorheads at work who have knowledge on low end torque motors, they were saying that 600 cfm is the max I'd want to use. The website that Jim referred me to had a formula to calculate cfm need: cid times max rpm divided by 3,456. This would bring the cfm for the carb around 600.

OK, here's where the techno-geniuses have a chance to pontificate upon their expertise...

- Sob

From: Liv42dayOK
Sent: 11/7/2003 11:19 AM

I like that way of thinking, Dave. It's simple. What's not simple has been finiding a carb that fits the bill. The closest is the Edelbrock quadrajet for themrmoquad applications but, $600 is waaaay out there. I think I may have to go with the Edelbrock 750 cfm with linkage modifications for @$300 unless I can find a source that has one that is a thermoquad replacement that's cheaper (which I doubt). The quandry being, in order to get the Winnie home, either I have to pay for a new carb to be installed or, pay to have the current one taken apart and repaired enough to make it home. If that can be done then, the one I have can possibly be rebuilt. But, I have no idea of the model it is except that it came off a Chevy and no idea of the cfm (it could be underpowered for the motor and part of the lack of umph I've been having) or it could just need that rebuild to perform a lot better! Lawdy be! Decisions, Decisions... - Sob

From: Dave-Pam1
Sent: 11/7/2003 11:38 AM

Don't put too small of a carb on your 440, I had an old carb guy look at my thermoquad and he said it was 650cfm. He told me to try a 600cfm Eldelbrock but if the plugs started to look white when I checked them it was running too lean, now I'm rejetting it to a 750cfm which I should have boughten in the first place. It is easy to rejet though...
David

From: Liv42dayOK
Sent: 11/7/2003 11:40 AM

Ok, so it's good to go with the 750 cfm. Good, this opens up more possibilities and I won't be choking the engine of its potential. Thanks Dave

- Sob

From: Jim83Itasca
Sent: 11/7/2003 11:59 AM

Let's go back to the drawing board !
If the carb ran ok/so-so before it might be something as simple as "dirt" plugging up one of the circuits.
Instead of throwing money & time into carb replacements i would find a (GOOD) carb person and hand it to him for a complete rebuild.
(case in point) is my carter 625 cfm got some dirt in the idle circuit and just barely ran and thats with one of them (glass junk) filters in line. Now it has a much better inline filter & end of problems.
I would call up the muffler shop and i'll just bet he knows a decent carb person.
Removing & replacing for you should be easy and remember to get the base gasket from the carb person.
Another thing i do with base gaskets is use "copper spray" silicon for leak insurance & high temp copper silicon in the tube will work as well.

Jim

From: Sea Hag
Sent: 11/7/2003 2:12 PM

There is a post on engine boad that says he has a 750 cfm Holley on a 440 - I don't see my southwind very often so I can't confirm - it does run nice with it on there installed by PO but I'm $ure he paid for it . I'm glad to see you are getting closser to home and getting it running good enough to get it the rest of the way there would be my priority , the labor rate is much cheaper . - I agree with Jim on back up a few steps . if it ran good before carb cleaning fluid ? Carbs don't usually just stop working that quickly . the deposits removed by cleaner flow through the whole system and sometimes relodge somewhere else . If you have a EGR - (My 76 Chief does , it eas to the left of the carb on the intake manifold ) take it out and clean it there is a process in the manual . - My carb may indeed need some work but I'm going to replace all the Plugs ,wires ,ect.- Straiten out my vaume/emmishion system first to make it right berfore I go into the carb . ---- The dual exuast on my chief sound very nice Quiet inside - Nice rumble from behind at least at Idle - never been behind it on the road . It seams the way to go when you get that far - no idea on cost PO fliped bill before I got it --- Hope you get it safe at home soon ----- A question for Jim is that 625 cmf the original carter the Thermo Quad ? if so which model ?- it would be nice to know the CMF on mine --- Sea Hag

From: LowellN
Sent: 11/7/2003 2:43 PM

Sob,
I really don't think that the carb cleaner was the culprit. When you ran the tank dry it picked up all of the "crap" that had settled on the bottom. Then when we decided to siphon the gas from the good tank and put it into the dry tank the hose more than likely picked up more sediment off the bottom of the other tank. I would almost bet my paycheck this is what caused the flooding. Also when the "winniebeast" stalled at the pump, I'll bet that it choked itself out by dumping too much fuel. Which would mean that it was already starting to clog. My winnie did the same exact thing last year. The accelerator pump was clogged, anong with the needle valves(

), and after I took the carb off and gave it a good cleaning and a new acc. pump diaphragm, it ran fine. It just picked up some dirt that somehow got around the filter. One little flake of rust will reek havoc on a carb. I would also check the float for signs of saturation (if foam) or a pinhole (ir brass), and check the float level. Another possibility might be a hairline crack in the carb body, so I was told when mine was acting up. Just thought I'd add my two cents. Might not be much, but then again it might help.

Lowell

From: dave76Chieftain
Sent: 11/7/2003 3:54 PM

1) Regarding the CFM question,
Clipped from:
The Thermo-Quad was available with two primary throttle bore sizes, 1-3/8" and 1-1/2". Flow ratings (CFM) vary depending on the source, but the TQs with the 1-3/8" bores are listed as 750-800 CFM and those with the 1-1/2" primary throttle bores are rated at 800-850 CFM. All TQs have the 2-1/4" diameter secondary throttle plates. The primary bore size depended
on application. In general, all 78 and later 318s and 360s and all 340s had the smaller bore. Earlier 360s varied depending on application, most 400s and all 440s had the large bore. The 9000 series have the small primary bore and were rated by Carter at 800 cfm. Later TQs (ie, Lean Burn and ESA applications, feedback systems) are quoted with less flow ratings, but
this is due to the control of the carburetion system, not the inherent flow capability of the basic carburetor. The internal metering is set for leaner running conditions for Lean Burn. Either bore size can be tuned to run well on most engine combinations. The smaller bore offers a slight increase throttle response but less overall flow. The different bore sizing, ie. speadbore, is an aspect that can lead to increased fuel economy while delivering similar wide open throttle (WOT) performance to an equivalent standard bore configuration. The adjustability of the TQ and the spreadbore configuration allows the use of a large CFM carburetor on
a small displacement engine.
By performing a web search for thermoquad, a whole lot of info can be found. T/S articles, parts (even the plastic fuel body), adjustment, overhaul, etc. are out there.

2) Back to basics
When trying to isolate a problem, many times you simply need to go back to the basics.
Even though the site is oriented toward the Chrysler Imperial, the http://www.imperialclub.com/Repair/Lit/Master/ web site contains a lot of general automotive mechanics info. The series (sadly, it's not all there) was produced by Chrysler for thier mechnanics. A lot of basic principles are covered as well as explanations for design improvements Chrysler made along the way. There is a very good/detailed themocarb article in 1972, several articles on basic brake principles of operation, AND detailed Chrysler electronic ignition information. Word of warning though, will take many days to crawl through the site. On the upside though, the comical illustrations Chrysler used in years gone by make the visit worthwhile by themselves. Additionally, the photos and illustrations are of very good quality. Far better than the digital version of the Dodge motor Home manual I bought. So, if you trying to remember the basics or just starting out, this is a good place to build your knowledge base from.

Dave
78 24' Cheiftain

From: mightybooboo
Sent: 11/7/2003 5:01 PM

Re: ignition module.FWIW,the Napa in Grants NM had a plug setup to thier PC on the desk.They plugged in my module and it failed 7 of 15 tests,miracle the thing could run.It failed idle test and assorted voltage tests,dwell angle test too.They even can print out the results if you want.Free test too!Bought a new module,cost was 50 dollars.Pretty nice of them,huh?
BooBoo

From: Liv42dayOK
Sent: 11/7/2003 7:54 PM

Was this an OEM or aftermarket ignition module? Did that cure your problems then? - Sob

From: mightybooboo
Sent: 11/7/2003 7:58 PM

Aftermarket module.Cant tell any difference,but it sure runs better at 1000 feet than 6600 feet,that much is for sure.I will do a story next week about the repairs we did,off for my 3 days of 12 shifts,later....
Boo

From: Liv42dayOK
Sent: 11/7/2003 8:02 PM

Wow! Thanks for the link. I always love looking at ads, illustrations and such from back in the day. So, the Winne-Beast had a darn big carb, basically. I can see where the replacement carb (the quadrajet) that I have on there is most likely considerably less cfm if the size of the openings I see in there are any indication (as compared to pictures I've been looking at of high cfm carbs). Can't get good power from the big beast if she can't breath now, can you? Well, I can't bust for $600, 795 cfm replacement but, I think the 750 for $249 should be sufficient (I think I also saw an 800 cfm for not much more). - Sob

From: jipjob1
Sent: 11/7/2003 8:36 PM

This is just a stupid question? But what is wrong with the orginal carberator that Dodge put on the old 440 and by the time you pay 600 dollars for a carberator what difference will it make? You sure can go along way on 600 dollars if it only makes a mile or so on your gas comsumption.

From: jipjob1
Sent: 11/7/2003 8:40 PM

This is oft the given trail but I do have a question about Carberators? I have an old buick (1977) and it runs like a top. But in order to get it to start I haft to prime it with some gas (down the carberator), I checked out the fuel pump (OK) and also the filter to the carb (OK). Could this problem maybe the accelerator plunger? Any ideas? thanks jipjob

From: Im-still-Lefty
Sent: 11/7/2003 9:02 PM

Hi jip, To answer both questions, first, no there is nothing inherrently wrong with the original carb. from Dodge. The Thermoquad was a sound design with only a few engineering problems. they are prone to leaking,they are harder to rebuild, and the secondaries are bad about getting warped. There are a few better choices out there, the Holly is excellent, the Edlebrock is a little harder to fine tune but never leaks and has a lot of flexibility for tuning. Rochesters like to bog off idle, and love to drink gas but are rock-solid reliable. To answer your second question, A bad fuel pump diaphram will allow the fuel to siphon out of the fuel bowls after sitting overnight causing you to need to prime the carb. also a small leak in the fuel line will do the same, sometimes it will be so small it will allow air in but no fuel will leak out. inspect the fuel lines for minute cracks. the accelorator pump is for giving the engine a shot of extra gas during sudden loads, like when you go to pass someone and half-way around you see a car coming and you plant your foot to the floor. without it the carb would lean out when the secondaries fly open and the power would drop quite a bit. If you are having to manually prime the carb. I don't think the accelorator pump is the main problem as the engine should crank without it. let me know if you need more help than I can post here and I will try to work it out with you as best as I can. Lefty

From: Im-still-Lefty
Sent: 11/7/2003 9:10 PM

It is always nice to hear good things about NAPA !! lol, We also have the same tester at my store. It does a very thorough job as you said. From the price you stated, I assume it was an "Echlin" brand module. They are very well made. Most of Echlin's products are as good as OEM or better.I am glad you made out OK with the fires. Your Friend, Lefty

From: Im-still-Lefty
Sent: 11/7/2003 9:12 PM

The original Thermoquad on mine is listed as a 625cfm, Lefty

From: daved27c
Sent: 11/7/2003 11:16 PM

Mark;
Obvoiusly the best answer would have been NOT to let Lowell spray it down with the carb cleaner...........It was running before that. LOL I still think the Magic carb will work, but I am not a carb expert.

From: Liv42dayOK
Sent: 11/7/2003 11:52 PM

You know, Dave

I think the Magic Junkyard carb would work too but, I don't know what the heck it is, if it's any good, and it's missing a linkage. I just don't have the time or gumption to mess with it. Maybe when I have some leisure time, like.... 4 or 5 years from now ! - Sob

From: mightybooboo
Sent: 11/8/2003 12:16 PM

:Was this an OEM or aftermarket ignition module?I assume it was an "Echlin" brand module"

Youre right Lefty,thats the module!
Boo

Carburator, Ignition & Exhaust upgrades

Oz