Big cam and A/C - ClassicOldsmobile.com


Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old July 30th, 2017, 02:40 PM   #1
Registered User
Thread Starter
 
Join Date: Jul 2013
Posts: 44
Big cam and A/C

I have a 350 with a jm 3-4 cam in it (230-238 522-542) and was going to run air on it for a trip coming up.I have 3;08 gears with a edge 3600 stall.Will it work?
a70oldscutlass is offline   Reply With Quote
Old August 3rd, 2017, 02:14 PM   #2
Telecom Guru
 
Join Date: Aug 2009
Location: Oklahoma City, OK
Posts: 172
Gear ratio sounds fine for running the compressor. What's your highway cruise RPM? The main thing, with that cam, will be having enough vacuum to run the vent actuators. If the air comes out the right vents when you're at cruising RPM, it will be fine. If your idle is lumpy you might have to raise the idle RPM a bit to keep it from stalling. Or you can manually turn off the A/C when sitting at a stoplight.
jslabotsky is offline   Reply With Quote
Old August 3rd, 2017, 04:26 PM   #3
Registered User
 
stevengerard's Avatar
 
Join Date: Jul 2008
Location: Chi-town
Posts: 4,024
I have Rhoad's lifters in my W30 as I have a bunch of vacuum operated accessories. They help - though next time around I'll probably go with a more modern cam design
stevengerard is offline   Reply With Quote
Old August 3rd, 2017, 07:52 PM   #4
Registered User
 
Join Date: May 2011
Location: Cochrane Alberta Canada
Posts: 3,227
My 2 cents

Quote:
Originally Posted by a70oldscutlass View Post
I have a 350 with a jm 3-4 cam in it (230-238 522-542) and was going to run air on it for a trip coming up.I have 3;08 gears with a edge 3600 stall.Will it work?
Your drive line is poorly matched. That gear doesn't go with that cam and converter in my opinion.
oldsmobiledave is offline   Reply With Quote
Old August 4th, 2017, 08:55 AM   #5
Registered User
 
Join Date: Nov 2008
Location: Central Fl
Posts: 4,480
Quote:
Originally Posted by oldsmobiledave View Post
Your drive line is poorly matched. That gear doesn't go with that cam and converter in my opinion.

X2. No mention of compression ratio either.
cutlassefi is offline   Reply With Quote
Old August 11th, 2017, 03:30 AM   #6
Registered User
 
midnightleadfoot's Avatar
 
Join Date: May 2017
Posts: 279
You will have problems, that rear gear will have the rpm lower than the cam power-band, adding the load of a/c it will most likely fart, cough/etc
Don't expect it to idle, without stalling with the a/c on ,or you with one foot on gas and one on brake at lights..
I had a/c on a 355 with a 292 cam but I had 411 gears, and two idler pulleys to help keep the belt on..
midnightleadfoot is offline   Reply With Quote
Old August 18th, 2017, 09:01 PM   #7
Registered User
 
Join Date: Mar 2014
Posts: 238
He never mentioned the true diameter of his tires, or how far the trip is, or how fast he would be going. In fact too little info period.
Firewalker is offline   Reply With Quote
Old August 19th, 2017, 11:27 AM   #8
Gary
 
VC455's Avatar
 
Join Date: Feb 2014
Location: Gillespie County Texas
Posts: 283
To solve the potential stalling problem, add the electric solenoid used to cut the throttle opening at shutoff on 70s Cutlass models.

If you power the solenoid from the air conditioning clutch relay, it will advance the throttle however much you want whenever you start the A/C. This will keep the engine from stalling and could even provide adequate vacuum to operate the diverter doors.
VC455 is offline   Reply With Quote
Old August 19th, 2017, 01:00 PM   #9
Registered User
 
Join Date: Mar 2014
Posts: 238
Quote:
Originally Posted by VC455 View Post
To solve the potential stalling problem, add the electric solenoid used to cut the throttle opening at shutoff on 70s Cutlass models.

If you power the solenoid from the air conditioning clutch relay, it will advance the throttle however much you want whenever you start the A/C. This will keep the engine from stalling and could even provide adequate vacuum to operate the diverter doors.
Those electric solenoids are handy for a lot things, when you get even more creative that just using them as anti dieseling devices when you kill the motor. Good idea you have, especially with him having that high of a converter stall.
Firewalker is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Brand C big block, REALLY BIG block Octania General Discussion 2 April 7th, 2016 02:51 PM
idling down new engine with big cam Octania Big Blocks 8 July 10th, 2015 09:21 AM
455 Question: To cam or not to cam Uncle Hulka Big Blocks 11 March 12th, 2014 03:41 PM
big Thumpr cam for oldsmobile hydraulic roller for sale Scott Hamel Parts For Sale 2 August 16th, 2013 07:46 AM
Im sick of these Big Pro Touring Bully Builders with their big wallets. Kidcutty Small Blocks 15 March 10th, 2010 06:08 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -7. The time now is 11:44 PM.


All content Copyright 2017 by Internet Brands, Inc.