Cliff's Quadrajet Parts and Rebuild Kits
General Category => Quadrajet Carb Talk and Tips => Topic started by: Hotrodssnova on May 31, 2017, 04:38:41 PM
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I tried to post about this carb back when the site crashed and, here I am again. Bought a marine 350 from pan to carb, completely rebuilt now.
Specs:
9.1:1 compression
Stock dual plane intake
Cam is a .470 lift on 110 lobe centers
Duration is 275 intake/ 285 exhaust
At 0.050. 221 intake/ 231 exhaust
Exhaust will be 15/8" headers thru mufflers
Gearing is 3.56 front and rear with 31" tires
This is going in a 81 jeep cj5 with a 4 speed manual transmission
I was thinking a stock rebuild on the carb should work good. I read here that cliff dropped one on his ventura, and ran perfectly.
Thoughts?
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(http://farm5.staticflickr.com/4217/34895575052_8322387428_h.jpg)
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Won't exactly be a stock rebuild but if you buy your parts from Cliff, he'll guide you thru what needs to be done to the carb to make it work right with your combo.
With that cam, one thing's for sure, the idle system will need to get addressed. You'll need to remove the idle tubes for sure.
Frank.
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Thanks, Frank. I haven't opened the carb yet. Might tackle that tomorrow.
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After a ton of reading here, how can I tell if this is a reman carb or original? I still haven't had the time to take it apart yet.
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I believe it's a reman unit as per the date code. Kind of hard to decipher the date code but it looks like the 97th day of 1987 for a 1979 Qjet. Is there any sticker on it or what is left of one? It uses torx screws as well. Wasn't that used on reman or wasn't used until the early-to-mid 80s? Or were they ALWAYS phillips head?
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No stickers or resudue of one. No play in the shafts and no marks on the torx screws either. I guess I will have to open it up and see what's in it.
Really need to get some of those tiny bits like in the book to measure and drill with.
The engine won't get put in the jeep till fall, so I have some time.
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There are a few drawbacks using a Marine carb in an automotive application. They lack vacuum ports for the distributor, and are set up for a Marine application.
Marine engines are heavily loaded most of their lives, so require a LOT more fuel than an automotive engine.
You can add a vacuum port for the distributor, and recalibrate for the engine you've built. Going to need a good bit of idle fuel as that cam is pretty "hefty" for 350cid at that compression ratio, and tight LSA, so it's going to have a "weak" signal at idle speed.
We can help out with everything you need to build the carb and set it up for what you are doing, no problem there.....Cliff
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Thanks, Cliff. I will be giving you a call after vacation. You are 100% correct about the vacuum ports. Looks like a simple fix on that. Still rereading your book. There's a ton of info to absorb.
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It's quite easy to add a manifold vacuum port, but a bit more difficult if you want ported distributor vacuum as the source location must be very precisely located above the throttle plates to it's adding nothing at idle but all in with the slightest movement of the throttle right off idle.....Cliff
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I'm back with more questions. I recently acquired a different cab for my project.
This carb has the following:
17059253 3228 BZA
K hanger with 'CH' rods
40K on the primary rods
73 on the jets
Would this be a better carb for what i have listed above? I know for sure it will need the shaft kit and the rebuild kit. It has the nytro float.
Thanks
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Light years better than the Marine unit.
Someone has been in that carb however, as none of the metering rods being used are correct for it, or even close for what you are doing.
The later carb will convert easily to electric choke, has the later APT system, bigger cfm and overall a much better unit everyplace.....Cliff
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Thanks, Cliff. I guess I will need a starting point for the rods and jets for this setup. Been years since i tuned a carb, and it was holleys back then.
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Found these specs here I believe from Ethan:
17059253 Primary Jets .073", 55P Primary Metering Rods, "K" Secondary Hanger, and CV Secondary Metering Rods.
So the jets are good to go for this carb, but i will need to get the proper rods. I'll check my parts bin and see what I have.
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Found these specs here I believe from Ethan:
17059253 Primary Jets .073", 55P Primary Metering Rods, "K" Secondary Hanger, and CV Secondary Metering Rods.
So the jets are good to go for this carb, but i will need to get the proper rods. I'll check my parts bin and see what I have.
Those are the correct stock specs bud as, Cliff, mentioned.
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I would replace them with new jets, and new metering rods. I quit using used jets decades ago, pretty rare to find a set that will not be worn some from the metering rods sliding in them for many years.
It will need different metering rods as well than the stock ones. I've built hundreds of those here and we use a lot of those for our custom electric choke front inlet units. They are a bit too lean on the primary side so we use a different jet/rod combo in them with perfect results.....Cliff
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I will build it to the recipe #2, I forgot it listed the rod sizes.
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I got the idle tubes out. The restriction measures out to .051. Now this is where I need some help. I have been all over the book and can't figure out where the idle down channel is.
Also, the small end of the idle tube that is necked down, is that what I want to enlarge? #2 is calling for an idle tube of .037 to .038.
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It's the restriction to the outside of the idle tube, about a 1/4 inch away. It's recessed a bit.
(http://st.hotrod.com/uploads/sites/21/2006/12/0702_hppp_09z-rochester_carburetor_tuning-drilling_diameter.jpg)
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Thank you for the picture. I was assuming that was it, but, you know.
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Update time
I got the carb all back together and the sbc dropped in the jeep. Firs start didn't go so well. The top plate was warped and let fuel seep up between the primary bores. I took the carb back apart, checked the float level first (it was good) then checked top plate. It was quite obvious it was warped when I held the flat edge on it. Took all the tubes and butterflies off and went to town. With a flat 1/4"steel plate as a base, i put a full sheet of 150 grit sandpaper and sanded it down to a perfect flat surface.
Cleaned it up and reassembled. Started up after it cleared up the extra fuel. Got the cam broke in, and started to tune. Nozzles were dripping. Opened up the mixture jets 7 turns and it stopped. Noticed that I still had fuel showing up around the pump rod on the top of the carb.
Logged on here, found that the stock aftermarket fuel pumps could pump too much pressure, blowing the needle off the seat. Got a fuel pressure guage and it showed 11 psi!
Installed a fuel pressure regulator, dropped it to 5 psi, and the fuel stopped seeping.
I am now at the point of tuning the apt and locking everything down.
Thanks for all the help!
And thanks go to Cliff for his book and parts!
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Now those are good news ! It's at that moment that it gets rewarding, seeing that all the work pays off.
You should NEVER let your guard down. Never assume anything. Check and double check EVERYTHING. That way when a problem arises, it will be a lot easier to pinpoint.
Like Cliff says: I like old stuff...it does what it's supposed to do.
Frank.
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Good news, glad you got things sorted out.....Cliff