 Measuring Carb air draw, Weird Reaction at #1 |
|
|
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
|
  |
| Allan |
 Dec 18 2005, 01:10 PM
Post
#1
|
|
Teenerless Weenie  Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California  |
While measuring the air flow on my carbs the motor would want to die when we put the meter on the stack feeding the #1 cylinder. All the others were fine.
Any ideas??? |
   |
 
|
| ArtechnikA |
Dec 18 2005, 01:15 PM
Post
#2
|
|
rich herzog Group: Members Posts: 7,390 Joined: 4-April 03 From: Salted Roads, PA Member No.: 513 Region Association: None |
are you using a SynchroMeter? contemporary UniSyn's seem to be junk...
sounds like all the others have their idle air bleeds opened up a lot. at least one should always be closed all the way - sounds like it's your #1. can't speculate further without knowing what kind of induction you've got ... |
|
|
|
| Dr. Roger |
Dec 18 2005, 01:17 PM
Post
#3
|
||
|
A bat out of hell. Group: Members Posts: 3,944 Joined: 31-January 05 From: Hercules, California Member No.: 3,533 Region Association: Northern California |
when you say air flow, do you mean vacuum? (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) |
||
|
|
|
||
| Allan |
Dec 18 2005, 01:21 PM
Post
#4
|
||
|
Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
What the carbs are sucking in. All the air flow valves were open around 1/2 - 3/4 turn. |
||
|
|
|
||
| ArtechnikA |
Dec 18 2005, 01:27 PM
Post
#5
|
||
|
rich herzog Group: Members Posts: 7,390 Joined: 4-April 03 From: Salted Roads, PA Member No.: 513 Region Association: None |
well, that's just wrong. one school of thought says there's no real reason to use any of the air bleeds - you're just building in a vacuum leak on purpose. if one cylinder breathes better, so be it... so step one - close ALL the idle air bleeds and get a Synchrometer. check for a bent butterfly shaft. there's a proper sequence for dialing in Webers and MFI (i assume you've got one or the other...) and starting in the middle trying to chase symptoms just leaves you chasing your tail and frustrated. |
||
|
|
|
||
| Dr. Roger |
Dec 18 2005, 01:53 PM
Post
#6
|
|
A bat out of hell. Group: Members Posts: 3,944 Joined: 31-January 05 From: Hercules, California Member No.: 3,533 Region Association: Northern California |
sounds like a vacuum leak at the vacuum access point.
the only reason i know to have air running past the butterfly is to tone down a radical cam. radical cam = less vacuum. less vacuum =less air/fuel at idle. some guys drill a very small hole or two in their butterflies. i do not suggest you do this. most likely the butterflies are worn and metering ways gummed up a bit. are they old/worn carbs? my last carb was setup that way buy it was old and needed a rebuild. i got a new weber and she runs like a top. upon furthur inspection ans speaking with the PO, i found air and fuel metering was fine but the butterflies were not sealing very well and PO has jetted up on the transition circuit trying to get it to idle right. |
|
|
|
| SLITS |
Dec 18 2005, 02:02 PM
Post
#7
|
|
"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None  |
He just traded (yesterday) his 46s for a set of 40 IDA3C on the 2.7 Kotex motor.
|
|
|
|
| Allan |
Dec 18 2005, 02:12 PM
Post
#8
|
|
Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
Is this the kind of syncrometer to get?
Attached image(s) 
|
|
|
|
| SLITS |
Dec 18 2005, 02:16 PM
Post
#9
|
|
"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
If your ears are good, a rubber hose works too!
|
|
|
|
| SLITS |
Dec 18 2005, 02:40 PM
Post
#10
|
|
"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
You know Allan, being your friend, I can't stand to see you suffer this way.....
So, Just bring that unreliable, nasty 2.7 down to the shop and I'll swap in a sweet running '73.5 2.4 CIS motor...no leaks, starts and idles smooth, altitude compensation..... And I won't charge you anything for the swap.... Killer deal....................... (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) |
|
|
|
| Allan |
Dec 18 2005, 03:18 PM
Post
#11
|
||
|
Teenerless Weenie Group: Members Posts: 8,373 Joined: 5-July 04 From: Western Mesopotamia Member No.: 2,304 Region Association: Southern California |
When can I come down???? (IMG:http://www.914world.com/bbs2/html/emoticons/w00t.gif) |
||
|
|
|
||
| SLITS |
Dec 18 2005, 05:13 PM
Post
#12
|
|
"This Utah shit is HARSH!" Group: Benefactors Posts: 13,602 Joined: 22-February 04 From: SoCal Mountains ... Member No.: 1,696 Region Association: None |
As soon as you can get a trailer....I wouldn't want you to tempt fate with that unreliable 2.7.
(IMG:http://www.914world.com/bbs2/html/emoticons/driving.gif) |
|
|
|
|
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:
|
Lo-Fi Version | Time is now: 23rd May 2024 - 02:30 AM |
Invision Power Board
v9.1.4 © 2024 IPS, Inc.