GMCforum: GMCnet » [GMCnet] Injection versus Carbs

Home » Public Forums » GMCnet » [GMCnet] Injection versus Carbs

Show: Today's Messages :: Polls :: Message Navigator

Re: [GMCnet] Injection versus Carbs [message #74215 is a reply to message #74212]

Wed, 17 February 2010 22:01

mlincoln

Messages: 107
Registered: August 2006
Location: Salt Lake City

Karma:

Senior Member

Now that's what I've been looking for...do you have any pictures of this modification, Gary? Do you know if this works on the quadrajets fitted to the 403s?

I need to get my carburetor rebuilt...I wonder if this fellow Dick Patterson can do what you describe.

Best, Mike
Born a Buckeye, but went to U of Mich, normally living in Utah
1978 Royale

On Feb 17, 2010, at 10:46 PM, Kosier wrote:

> Mike,
>
> On the late Q-Jets, there is an adjustable part throttle screw,
> which regulates the height of the primary needles in the jet.
> Directly above it is an aluminum plug. Knock the plug out and
> tap the hole for 3/8" thread. put a short socket head
> set-screw in it. Take a fairly long 5/16" bolt, cut the threads
> off and slot the end. To change the mixture, you have to
> stop, raise the engine lid, remove the bonnet from the carb,
> remove the set screw and adjust the APT screw. Not as easy
> as leaning the mixture on a plane, but you can't pull the plane
> to the side of the road and shut it off. Works for me!
>
> Gary Kosier
> 77EII & 77PB
> Newark, Ohio
>
> ----- Origial Message -----
> From: "Michael Lincoln" <mlincoln1@gmail.com>
> To: <gmclist@temp.gmcnet.org>
> Sent: Wednesday, February 17, 2010 8:31 PM
> Subject: Re: [GMCnet] Injection versus Carbs
>
>
>> Has anyone tried a carb (a fixed carb, not an
>> altitude-adjusting one) that has been specifically leaned for
>> altitude? Does it detonate (too lean) at sea level? I'm
>> thinking that one of the experienced tinkerers might know.
>>
>> In airplane flying in the Rockies one leans to peak rpm (fixed
>> pitch prop), then richens to make the exhaust gas temp 50-100
>> degrees cooler for takeoff. There's a big difference in power:
>> running full rich (firewalled mixture control) compared to
>> optimally leaned makes a huge difference in a high
>> density-altitude situation. In the Utah mountains I once
>> foolishly filled up a Cessna 152 (a little underpowered
>> straight-tailed 152 from the 1950's) with avgas the night
>> before, and then took off the next day. My friend and I flew
>> the plane in ground effect for three miles to the edge of Bryce
>> Canyon (airport was 9000 MSL), in order to throw ourselves off
>> the edge and get some altitude beneath us. If I hadn't leaned
>> for altitude I'm sure we would never have even gotten into
>> ground effect. (By the time we got to the Grand Canyon 45 min
>> later, I had thermaled to 14,500 feet, and LA Center didn't
>> believe our type aircraft--an 89 hp 152--given our
>> altitude-encoding transponder rea
>> ding, but that's what rising air will do for you).
>>
>> Therefore I suspect an optimal air *mass* to fuel mixture might
>> make a significant difference in the GMC too. But, without the
>> manual mixture control, it may be that the altered air/fuel
>> volumetric mixture of the "mountain carb", when running at low
>> altitude with the air mass much greater, would result in a too
>> lean situation, with unacceptable detonation or at least higher
>> cylinder head/EGT and wear in the valve train.
>>
>> Has anyone tried it?
>>
>> Mike
>>
>>
>> On Feb 17, 2010, at 6:57 PM, Ken Henderson wrote:
>>
>>> Mike,
>>>
>>> Larry W. must be off line while travelling or he'd have chimed
>>> in: He got
>>> all excited about an altitude compensated Quadrajet he came
>>> across. He
>>> spent a lot of time and his expertise on getting it working --
>>> for a while.
>>> From what I recall of what he told me, it worked great as long
>>> as he kept
>>> working on it. As if the QJ's not complicated enough, imagine
>>> what those
>>> extra bellows, jets, needles, etc., would add. I don't
>>> remember whether
>>> he's running it right now -- I don't think so -- but I do know
>>> he's planning
>>> on port injecting his Cad 500 ASAP.
>>>
>>> Ken H.
>>> Americus, GA
>>> '76 X-Birchaven
>>> www.gmcwipersetc.com
>>>
>>>
>>> On Wed, Feb 17, 2010 at 6:34 PM, Matt Colie
>>> <mcolie@chartermi.net> wrote:
>>>
>>>>
>>>>
>>>> mlincoln wrote on Mon, 15 February 2010 16:31
>>>>> Does anyone have actual experience with "splitting the
>>>>> difference" in the
>>>> Quadrajet enrichment to suit a MSL of 4500 to 5000 feet? I
>>>> was once told
>>>> that some old Detroit iron came with a "high altitude option"
>>>> (possibly a
>>>> re-metered carb?). A shop in ...
>>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> List Information and Subscription Options:
>>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>> _______________________________________________
>> GMCnet mailing list
>> List Information and Subscription Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist

Mike

Report message to a moderator

[Message index]

		[GMCnet] Injection versus Carbs By: Richard Lister on Mon, 08 February 2010 10:01
		Re: [GMCnet] Injection versus Carbs By: Mr ERFisher on Mon, 08 February 2010 10:10
		Re: [GMCnet] Injection versus Carbs By: GeorgeRud on Mon, 08 February 2010 10:17
		Re: [GMCnet] Injection versus Carbs By: Ron on Mon, 08 February 2010 11:08
		Re: [GMCnet] Injection versus Carbs By: Matt Colie on Mon, 08 February 2010 11:14
		Re: [GMCnet] Injection versus Carbs By: Steven Ferguson on Mon, 08 February 2010 12:25
		Re: [GMCnet] Injection versus Carbs By: k2gkk on Mon, 08 February 2010 12:35
		Re: [GMCnet] Injection versus Carbs By: Mr ERFisher on Mon, 08 February 2010 12:46
		Re: [GMCnet] Injection versus Carbs By: Steven Ferguson on Mon, 08 February 2010 18:31
		Re: [GMCnet] Injection versus Carbs By: Larry on Mon, 08 February 2010 22:00
		Re: [GMCnet] Injection versus Carbs By: Steven Ferguson on Tue, 09 February 2010 07:19
		Re: [GMCnet] Injection versus Carbs By: bill schurman on Mon, 08 February 2010 13:11
		Re: [GMCnet] Injection versus Carbs By: Ron on Mon, 08 February 2010 14:31
		Re: [GMCnet] Injection versus Carbs By: Ken Burton on Tue, 09 February 2010 02:11
		Re: [GMCnet] Injection versus Carbs By: Jim Bounds on Tue, 09 February 2010 06:40
		Re: [GMCnet] Injection versus Carbs By: tgeiger on Tue, 09 February 2010 09:51
		Re: [GMCnet] Injection versus Carbs By: Jim Bounds on Wed, 10 February 2010 07:57
		Re: [GMCnet] Injection versus Carbs By: Jim Galbavy on Mon, 08 February 2010 15:30
		Re: [GMCnet] Injection versus Carbs By: USAussie on Mon, 08 February 2010 16:23
		Re: [GMCnet] Injection versus Carbs By: Larry C on Thu, 18 February 2010 09:06
		Re: [GMCnet] Injection versus Carbs By: Jim Bounds on Thu, 18 February 2010 11:17
		Re: [GMCnet] Injection versus Carbs By: Gary Worobec on Thu, 18 February 2010 11:33
		Re: [GMCnet] Injection versus Carbs By: Chr$ on Mon, 08 February 2010 16:48
		Re: [GMCnet] Injection versus Carbs By: Chr$ on Mon, 08 February 2010 16:49
		Re: [GMCnet] Injection versus Carbs By: k2gkk on Mon, 08 February 2010 18:12
		Re: [GMCnet] Injection versus Carbs By: Rick Williams on Mon, 08 February 2010 18:45
		Re: [GMCnet] Injection versus Carbs By: David L Greenberg on Mon, 08 February 2010 19:55
		Re: [GMCnet] Injection versus Carbs By: George Beckman on Mon, 08 February 2010 20:14
		Re: [GMCnet] Injection versus Carbs By: Matt Colie on Tue, 09 February 2010 13:25
		Re: [GMCnet] Injection versus Carbs By: Richard Lister on Tue, 09 February 2010 14:36
		Re: [GMCnet] Injection versus Carbs By: George Beckman on Tue, 09 February 2010 20:50
		Re: [GMCnet] Injection versus Carbs By: GeorgeRud on Tue, 09 February 2010 15:04
		Re: [GMCnet] Injection versus Carbs By: Jim Galbavy on Tue, 09 February 2010 15:54
		Re: [GMCnet] Injection versus Carbs By: Jim Galbavy on Tue, 09 February 2010 17:03
		Re: [GMCnet] Injection versus Carbs By: Jim Bounds on Wed, 10 February 2010 05:41
		Re: [GMCnet] Injection versus Carbs By: klassic kampers on Tue, 09 February 2010 17:34
		Re: [GMCnet] Injection versus Carbs By: Bob de Kruyff on Tue, 09 February 2010 18:35
		Re: [GMCnet] Injection versus Carbs By: Sandra Price on Wed, 10 February 2010 11:18
		Re: [GMCnet] Injection versus Carbs By: tgeiger on Wed, 10 February 2010 14:37
		Re: [GMCnet] Injection versus Carbs By: ljdavick on Wed, 10 February 2010 14:45
		Re: [GMCnet] Injection versus Carbs By: Jim Bounds on Sat, 13 February 2010 08:20
		Re: [GMCnet] Injection versus Carbs By: Bill Freeman on Sat, 13 February 2010 09:01
		Re: [GMCnet] Injection versus Carbs By: emerystora on Sat, 13 February 2010 09:47
		Re: [GMCnet] Injection versus Carbs By: Bill Freeman on Sat, 13 February 2010 15:47
		Re: [GMCnet] Injection versus Carbs By: Ron on Sat, 13 February 2010 16:14
		Re: [GMCnet] Injection versus Carbs By: Surbo on Sat, 13 February 2010 17:45
		Re: [GMCnet] Injection versus Carbs By: Ron on Sat, 13 February 2010 17:57
		Re: [GMCnet] Injection versus Carbs By: Bill Freeman on Mon, 15 February 2010 13:33
		Re: [GMCnet] Injection versus Carbs By: emerystora on Mon, 15 February 2010 13:42
		Re: [GMCnet] Injection versus Carbs By: Larry on Mon, 15 February 2010 14:40
		Re: [GMCnet] Injection versus Carbs By: mlincoln on Mon, 15 February 2010 15:31
		Re: [GMCnet] Injection versus Carbs By: Bill Freeman on Tue, 16 February 2010 07:49
		Re: [GMCnet] Injection versus Carbs By: Matt Colie on Wed, 17 February 2010 17:34
		Re: [GMCnet] Injection versus Carbs By: GMCWiperMan on Wed, 17 February 2010 17:57
		Re: [GMCnet] Injection versus Carbs By: mlincoln on Wed, 17 February 2010 19:31
		Re: [GMCnet] Injection versus Carbs By: Ken Burton on Wed, 17 February 2010 20:23
		Re: [GMCnet] Injection versus Carbs By: Kosier on Wed, 17 February 2010 21:46
		Re: [GMCnet] Injection versus Carbs By: mlincoln on Wed, 17 February 2010 22:01
		Re: [GMCnet] Injection versus Carbs By: Kosier on Wed, 17 February 2010 22:34
		Re: [GMCnet] Injection versus Carbs By: klassic kampers on Thu, 18 February 2010 14:22
		Re: [GMCnet] Injection versus Carbs By: Jim Bounds on Thu, 18 February 2010 09:09
		Re: [GMCnet] Injection versus Carbs By: Matt Colie on Thu, 18 February 2010 07:49
		Re: [GMCnet] Injection versus Carbs By: mlincoln on Thu, 18 February 2010 08:38
		Re: [GMCnet] Injection versus Carbs By: Kosier on Wed, 17 February 2010 20:57
		Re: [GMCnet] Injection versus Carbs By: Surbo on Mon, 15 February 2010 14:09
		Re: [GMCnet] Injection versus Carbs By: Jim Galbavy on Mon, 15 February 2010 14:38
		Re: [GMCnet] Injection versus Carbs By: Bill Freeman on Tue, 16 February 2010 07:38
		Re: [GMCnet] Injection versus Carbs By: Carleton Douglas[1] on Wed, 10 February 2010 14:53
		Re: [GMCnet] Injection versus Carbs By: jimk on Wed, 10 February 2010 22:18
		Re: [GMCnet] Injection versus Carbs By: Richard Lister on Tue, 16 February 2010 10:55
		Re: [GMCnet] Injection versus Carbs By: bryant374 on Tue, 16 February 2010 12:21
		Re: [GMCnet] Injection versus Carbs By: Bill Massey on Tue, 16 February 2010 13:24
		Re: [GMCnet] Injection versus Carbs By: psakw on Sat, 13 February 2010 21:58
		Re: [GMCnet] Injection versus Carbs By: emerystora on Sat, 13 February 2010 22:07
		Re: [GMCnet] Injection versus Carbs By: rallymaster on Thu, 18 February 2010 11:45
		Re: [GMCnet] Injection versus Carbs By: g.winger on Thu, 18 February 2010 14:11
		Re: [GMCnet] Injection versus Carbs By: Larry on Thu, 18 February 2010 15:08
		Re: [GMCnet] Injection versus Carbs By: wally on Thu, 18 February 2010 15:33
		Re: [GMCnet] Injection versus Carbs By: Larry on Fri, 19 February 2010 13:44
		Re: [GMCnet] Injection versus Carbs By: wally on Fri, 19 February 2010 14:44
		Re: [GMCnet] Injection versus Carbs By: Larry on Fri, 19 February 2010 19:05
		Re: [GMCnet] Injection versus Carbs By: GMCWiperMan on Fri, 19 February 2010 19:23
		Re: [GMCnet] Injection versus Carbs By: Keith V on Sat, 20 February 2010 10:12
		Re: [GMCnet] Injection versus Carbs By: GMC_LES on Sat, 20 February 2010 16:45
		Re: [GMCnet] Injection versus Carbs By: WD0AFQ on Sat, 20 February 2010 17:35

Previous Topic:	[GMCnet] Combination Valve Wire
Next Topic:	[GMCnet] smog/vent?

Goto Forum:

-=] Back to Top [=-

Current Time: Sun May 12 14:21:38 CDT 2024

Total time taken to generate the page: 0.01113 seconds