Replace or rebuild carburator

[The_Handier_Man1]

From: 77surveyor  (Original Message)
Sent: 1/19/2004 9:52 PM

440-3 the acellerator pump fell apart from sitting rebuild kit is $115 auto zone has one allready rebuilt for $186 which is the way im going to go ...should i keep my core and switch the jets to the rebuilt one of just go with the over the counter ... mine is the thermoquad the listing with auto zone is for a standred 440



From: Liv42dayOK
Sent: 1/19/2004 10:52 PM

If you know what you're doing with carbs, it certainly makes sense to go with the already re-built one.  But, there may be other issues with that rebuild that you woun't find out until you've already bought it; when it's too late.  From all the advice I've gotten, get a new one altoghther.  I, as will numerous others, recommend the Edelbrock Performer 750 cfm carb with Dodge throttle adapter.  It should be about $100 more than what you're looking to spend now but, it's a waaay better carb than the Thermoquad.  Much more power and reliability.  If you can splurge at some point for the matching dual-plane performer intake, you'll add 80 - 100 hp with just those two upgrades.

I had a quadrajet that the PO replaced the Thermoquad with.  Both had the same problems:  the accelerator pump and, the floats had deteriorated.  I noticed the difference with the Edelbrock immediately.  Want more advice?  Do a message search on carb upgrades and read the testimonies. - Sob



From: 77surveyor
Sent: 1/20/2004 12:20 AM

Thanks i did the search and got way sidetracked reading the posts , i guess ill go for the edelbrock carb for now and do the intake with a edelbrock r/v camshaft later in the summer to many things to finish all at once for the checkbook Richard



From: Liv42dayOK
Sent: 1/20/2004 11:50 AM

I understan completely,  as I'm sure the vast majority of us do who've purchased a "restorable" Winnebago, the dollar tally on the "to do" lists is a lot bigger than the last balance entry in the checkbook.  Day-by-day, piece-by-piece, slowly I turned, step-by-step, inch-by-inch,... oops, digressing into old comedy movies! - Sob



From: denison
Sent: 1/20/2004 12:37 PM

But my advice is freee.........
Personally I think Carter carbs can work as well as any of the others, unless it has a badly worn throttle shaft bore - I think all of the designs worked well in their youth. Getting a new OEM carb may be $unfeasible$, getting a suitable rebuilt carb can be risky. If the autozone rebuilt listing is for a passenger car or pickup truck application, then maybe the jets or other internals might be different for the carb on a 440-3 in a motorhome. I dislike running my engine too lean - and warping or cracking an exhaust manifold!
I like having extras; I would keep the old carb and rebuild it myself, and I would look for another carb to buy.
I have two 72 Winnies with identical 413 engines. Both work fine with either carb - one is a Carter thermoquad, the other a Holley 750. Both have already and in the future will need periodic rebuilding -new gaskets and cleaning- due to ageing, not because they are ‘worn out’. I have had good luck with rebuilding carburetors, after ruining a few in my youth. denison



From: 77surveyor
Sent: 1/20/2004 7:02 PM

I like that word free , ive rebuilt tons of quadrajets but on the thermoquad the accelerator pump has a disk holding it in place it seems to be a pressed in deal i was thinking of useing a dent puller to take it out ... but then theres the issue of the little somthing that fell out in the grass and i couldnt find must of been a check ball ... have you ever removed the accelerator pump ?

thanks Richard



From: denison
Sent: 1/20/2004 7:25 PM

Ive not removed the accel pump from a thermoquad that I can recall, but Im glad to have the info. I have dropped my share of check-balls into the grass. To find them I slide around the magnet from an old large scale hifi speaker. Im glad they arent non-magnetic. denison 



From: dave76Chieftain
Sent: 1/20/2004 8:43 PM

Been through so much since I got my rig last summer but, I do not recall that rebuilding my Thermoquad was that difficult.  Read all that I could find about it and just took my time.  Biggest thing to watch is not disturbing the primary mettering rod adjustment or at least making sure you can put it back where it was.  Affects fuel/air mixture in the RPM ranges that your going to be using the most.  I have had to play around with mine because I didn't.

Here are some websites discussing the thermoquad
A From Dodge themselves:
http://www.imperialclub.com/Repair/Lit/Master/290/intro.htm

http://www.offroadexchange.com/projects/CrtRbld.htm
http://anusf.anu.edu.au/~jgs900/thermoquad.html

and most likely the best person/source of Thermoquad info/parts
http://thermoquads.com/

All I can say is that I am happy with mine at the moment.

Dave
78 26' Chieftian w/440-3



From: Colin
Sent: 1/20/2004 11:46 PM

I went with the Edelbrock carb. and it works great. I haven't even touched it since I installed it. But I have always wondered if I should have gotten the larger model. The salesman at NAPA sold me the 650cfm. Should I have bought the 750cfm? (I live in Denver.)

C.



From: Colin
Sent: 1/21/2004 10:45 AM

I should have added to my post about carb size that my engine is a 413 on a D-22 chassis.

C.



From: KEVSWS6
Sent: 1/21/2004 3:04 PM

Colin,
The 650 you run is perfect. 750 is overkill. I run a 750 Holley cause it was laying around and the stock ones throttle shaft was worn way out. Maybe Denison can help here also but the stock unit on mine was a Holley 650 or there abouts if I remember correctly.



From: KEVSWS6
Sent: 1/21/2004 3:12 PM

Denison,
What model Holley you running? Secondary jets or metering plate? Jets and plate size? I'm at sea level here and run 68 & 70 primary jets and a fat secondary plate (cant remember the number) cause I was to cheap to buy another. It causes a slight hesitation when the secondaries open.



From: Liv42dayOK
Sent: 1/22/2004 9:36 AM

The recommendations I've seen seen to be 650cfm for a 318 and 750cfm for a 440.  The 413 is grouped with the 440 so, the 750 would be the good match but, that's not to say the 650 is too little at all.; it's just fine.  The 750 seems to be deemed the best performance match.  800 cfm is also available as a direct Thermaquad replacement but, this has been rated as overkill for our applications and costs over $600! - Sob



From: Dave-Pam1
Sent: 1/22/2004 11:11 AM

You can also re-jet your Eldebrock, its easy to do and only costs about $20.00. You can make it a 700 or 750.
David



From: denison
Sent: 1/22/2004 3:21 PM

KEVSWS6; You asked what my Holley carb was. Its a model 4150, 750 cfm. It has center pivot floats, mechanical secondaries, and a manual choke. I presume it isnt the original. I have no reason to assume it doesnt have the jets it was made with; main jets of 122-70 and secondary jets of 122-80, according to the tech pages at the www. holley. com website. By the way, there is a cfm calculation equation on that Holley web site.
I didn't look at the jet sizes when I had it apart years ago, but will look when I clean it this spring. When warm it is misfiring at the first part of the throttle opening. There is a picture of the top of my engine with the carb in my album, Denisons D22T, which is on page 8 of the picture section now.
denison



From: Discoverer
Sent: 1/22/2004 3:39 PM

Sunken floats ARE a problem with the "plastic" floats on a TQ. Just replace them with hollow brass floats !! ....now as far as the Eddy carb being better than a TQ .......I do not agree. Maybe better than a malfunctioning TQ but not one that is operating properly. And YES - I have done a few rebuilds on a TQ .........and I even offer a new and improved secondary air valve adjusting tool !! 



From: dave76Chieftain
Sent: 1/22/2004 4:11 PM

Re:
.........and I even offer a new and improved secondary air valve adjusting tool !!

Care to provide more details?  Only one I have ever heard about is the one contained on the 3rd link I provided above.

Dave



From: HeavyHaulTrucker
Sent: 10/9/2004 9:28 PM

Dave76Chieftan wrote:
"Been through so much since I got my rig last summer but, I do not recall that rebuilding my Thermoquad was that difficult.  Read all that I could find about it and just took my time.  Biggest thing to watch is not disturbing the primary mettering rod adjustment or at least making sure you can put it back where it was.  Affects fuel/air mixture in the RPM ranges that your going to be using the most.  I have had to play around with mine because I didn't."

I have to agree with you there -- I just rebuilt mine on my dinette table in an Auto Zone parking lot this afternoon.  It took me two hours, and cost under $25.00 -- which is why I am questioning the post by 77surveyor that started this thread (not the poster, just the cost quoted for the rebuild kit).  My rebuild kit was from Auto Zone; it cost $18.99 and did not come with floats -- they were $3.99 each, but one of my floats was re-useable so I only used one new one.

Since the rebuild kit is so cheap, I plan to stick with my ThermoQuad for a long time to come -- most Hollys cost around $50.00 to rebuild by the time it is all said & done.  Besides, you can get a thermoquad from a junk yard for $10.00 or less -- but not a Holly!

John