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TOPIC: 1987 Ford Motorhome, 460 cu; Canada

1987 Ford Motorhome, 460 cu; Canada 24 Feb 2013 12:01 #1

  • GadgetmanSaskatchewan
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This fall, I wanted some experience with carbs. Being that I switched my Ford 150's bigblock 460's original Motorcraft (Holley) carb for a Rochester Quadrajet, which apparently can't accept the groove, I opted to experiment on my sister's and bro-in-law's 60,000km unit.

I replaced most of the vacuum lines,( as they were all due), blocked off the EGR, up-rooted the air pump, and did a road test with a low pressure pump and 2 gal. tank hooked up, before and after. There seemed to be no difference. They prior mileage was 10 mpg, and the after mileage seemed to be about 10.5 . A proper long trip check did not work out as the electric lift pump was faulty and was leaning out the carb, to the point that my Bro-in-law hooked in another electric pump just before the carb to get him home. I had my suspicions, and had given him the pump and hook-ups just in case. Apparently the two other in-tank pumps are going as well. It is now out of the shop, repaired and waiting.

So, I will continue with this project when the 2 or more feet of snow has disappeared. Now, question: how much do I re-size the jets (15 - 20%) and what do I look for and at for this type of carb re: further work with the groove?

Thanks!!

Luke

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1987 Ford Motorhome, 460 cu; Canada 25 Feb 2013 00:03 #2

  • Tracy Gallaway
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Luke Exactly what carb. is on the Ford in question? Original, replacement, 2V, 4V,...?

Pics would be Great!

Tracy G
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1987 Ford Motorhome, 460 cu; Canada 25 Feb 2013 08:33 #3

  • Ron
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Tracy asked one of the right questions. What type of carb is on this engine?

Also, you will find it important to check the intake manifold bolts. Simply re-torque them. If some need one or more full turns to be tight, then the gaskets are suspect and should be replaced.

Leaks in old intake gaskets are common and this is the only diagnostic for them of which I am aware.

The fact that mileage did not increase indicates either A) The Groove is not deep enough -or- B) A vacuum leak.

Personally, I wouldn't have done the EGR as it does provide some heat to assist in vaporization in these Carbs. The 460 (if it's like mine was) has a base for the connection to the EGR. If your intent is to block off that system completely, you will need to remove that plate and block the passages (JB Weld) or have a new base machined for the carb.

As to replacing the jets, you must first know what size you have. I would remove them (once you've checked the intake manifold) and see what they are. You'll need to call around to see if anyone has them in your area. Once you find someone, take your old ones in and get the next three sizes smaller. Try them in sequence until you have a power loss. That will be the 'Sweet Spot' for your carb tune.

Anyway, you're doing well! Glad to have you in Gadgetman Land!

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Last edit: by Ron.

1987 Ford Motorhome, 460 cu; Canada 25 Feb 2013 23:46 #4

  • Tracy Gallaway
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Luke Ron is right about the intake gaskets!

On the jets- If it's a Holley or an Edelbrock Performer/ Carter AFB then jets (and metering rods if applicable) are available.

If it's an OEM Motorcraft then not so readily available.

But there are a few tricks available for any Carb! ;)

Good idea to install an adjustable press. regulator in the fuel line near the carb, try setting at 2-3 pounds. Most stock pumps will have 5 or 6 lbs. pressure, this often overwhelms the inlet needle/seat and dumps excess fuel into the bowl(s).

I could say more, but I need to know just what carb you are working with.

Tracy G
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1987 Ford Motorhome, 460 cu; Canada 26 Feb 2013 00:48 #5

  • Tracy Gallaway
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Well I'll be.....

Learn something every day!

Correction: just did a search for Motorcraft carb jets:

http:http://www.allcarbs.com/detail.php?pid=159//







My search phrase in Google was: Motorcraft carb jets. I found all this and more in about 10 minutes...

Until now I didn't know replacement jets/ parts besides rebuild kits were this avail. for stock Motorcraft carbs. Motorcraft are on Fords, of course, also on many Jeep products up till fuel injection.

People confuse Motorcraft with Holley carbs the 2 bbl's do look somewhat alike. Personally I've had good results rebuilding them for Ford owners. I prefer the 2 bbl Motorcraft to the 4 bbl ones.

But Ford used Holley 4 bbl's built to OEM spec's a lot in the 80's on trucks, motorhomes, etc.

George Wiseman of Eagle-Research.com has good things to say about the Motorcraft 2 bbl's.

Seems at one time or another most every Carburetor manufacturer has made carb's for most every OEM, you'd be surprised...

Anyhow this greatly changes my view on Motorcraft carbs! :cheer:

Tracy G
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The following user(s) said Thank You: Ron, GadgetmanSaskatchewan

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Last edit: by Tracy Gallaway. Reason: more info.

1987 Ford Motorhome, 460 cu; Canada 12 Mar 2013 19:38 #6

  • deshear
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maybe a quarter inch alum spacer plate could have the groove cut in it--to use a quadra-junk carb --get Rons opinion

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1987 Ford Motorhome, 460 cu; Canada 12 Mar 2013 21:01 #7

  • GadgetmanSaskatchewan
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Hey thanks, Ron and Tracy,

I believe the carb is a Holly product, 4 barrel, but I will check that once the snow is gone, so I will continue this particular thread at that time, when I re-visit this beast!!

Luke

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1987 Ford Motorhome, 460 cu; Canada 14 Mar 2013 09:33 #8

  • Ron
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The Quadrajet is one that is going to require a special part be manufactured, attached via bonding agent to the bottom of the carb to allow room for The Groove.

The project is on the list, but given the lack of reliability of the Quadrajet, it is far better service in the long run to simply replace it with an Edelbrock. I have a 78 Chev P/U that I'm currently 'projecting' that is so equipped.

I will be videotaping all aspects of the process, and have been given free reign with. This is going to be "Total Engine Transformation - GADGETMAN STYLE" and will be available on GadgetmanGlobal when I'm done.

You'll see how I do it!

Ron

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