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Laemmle
07-08-2007, 12:56 PM
In the 40 plus years I have had my Avanti I have often pondered if it really is required.......I am referring to what I call the hot idle compensator on my AFB arb......Carter calls it their 'thermostatic valve' illust. number "86" on page 35 of the Avanti parts manual.....1558449.

Years ago I remember the Studebaker service manager telling me that the part is more problem than it is worth...he would bend the bi-metallic piece so as to keep it down and not be effected by the heat...

When my car has been run for awhile the idle will slowly increase on-it's own to about 1000-1100 rpm...this up from the idle of apx 650-700 when cold......the only detriment I can see is that I am burning more fuel at this faster idle.....so gents, do I bend the valve as that Studebaker dealer guy told me almost 40 years ago...I wish I could prevent the idle increase when it gets hot. The car is 4 speed.

GTtim
07-08-2007, 11:13 PM
I'd be more inclined to think your problem is due to intake gasket leak or a problem of throttle adjustment at the bellcrank. Do you have both springs on the linkage? I've driven a lot in hot weather with AFB's and not noticed the problem that you speak of.

Tim K.
'64 R2 GT Hawk

Laemmle
07-09-2007, 10:21 AM
I have two springs on the linkage....I have never heard of fast idle when hot caused by intake leakage....this problem does not happen during the winter months.


quote:Originally posted by GTtim

I'd be more inclined to think your problem is due to intake gasket leak or a problem of throttle adjustment at the bellcrank. Do you have both springs on the linkage? I've driven a lot in hot weather with AFB's and not noticed the problem that you speak of.

Tim K.
'64 R2 GT Hawk

StudeRich
07-09-2007, 03:18 PM
Just spray WD40 on the intake runner flanges at the cyl. head, with it hot & running fast and see if it increases speed more.


StudeRich
Studebakers Northwest
Ferndale, WA

GTtim
07-09-2007, 05:45 PM
quote:Originally posted by Laemmle


I have two springs on the linkage....I have never heard of fast idle when hot caused by intake leakage....this problem does not happen during the winter months.


quote:Originally posted by GTtim

I'd be more inclined to think your problem is due to intake gasket leak or a problem of throttle adjustment at the bellcrank. Do you have both springs on the linkage? I've driven a lot in hot weather with AFB's and not noticed the problem that you speak of.

Tim K.
'64 R2 GT Hawk



My thinking was that with the engine getting hot, metal expanding, that it was causing a vacuum leak and much like leaving the vacuum advance tube off it would cause the idle speed to increase. Just a thought. Check to make sure the screw stop at the top of the bellcrank isn't bottoming out too soon. Good luck.

Tim K.
'64 R2 GT Hawk

bige
07-09-2007, 07:47 PM
I think you could do without the hot idle compensator. I tried to bend mine so it did not operate but I was never truly succesful. I built the Edelbrock/AFB Hybrid I run now because I could never get the car to idle and perform suitably when hot. I've never seen another AFB form any other brand with the Hot Idle Compensator, doesn't mean there aren't any but...

You could try tapping the hole and screwing a plug in there or use a rubber plug of some kind to see how it runs with it truly plugged up.

Check your heat riser and by all means block off the exhaust crossover. There are gaskets sold by vendors on this site that make it easy and pulling the intake is a cake walk on the Avanti. If you do pull the manifold I would get new hold down clamps or at least carefully insect the old ones. They fatigue and crack and will prevent proper torquing of the bolts.

ErnieR

http://i146.photobucket.com/albums/r241/AvantiR2/track.jpg

Laemmle
07-09-2007, 10:07 PM
Heat riser works as it should..is there a reason to defeat the exhaust crossover?



quote:Originally posted by bige

I think you could do without the hot idle compensator. I tried to bend mine so it did not operate but I was never truly succesful. I built the Edelbrock/AFB Hybrid I run now because I could never get the car to idle and perform suitably when hot. I've never seen another AFB form any other brand with the Hot Idle Compensator, doesn't mean there aren't any but...

You could try tapping the hole and screwing a plug in there or use a rubber plug of some kind to see how it runs with it truly plugged up.

Check your heat riser and by all means block off the exhaust crossover. There are gaskets sold by vendors on this site that make it easy and pulling the intake is a cake walk on the Avanti. If you do pull the manifold I would get new hold down clamps or at least carefully insect the old ones. They fatigue and crack and will prevent proper torquing of the bolts.

ErnieR

http://i146.photobucket.com/albums/r241/AvantiR2/track.jpg

bige
07-09-2007, 10:18 PM
My experience with the blocked crossover vs open is that warm weather driving is VASTLY improved, no more hesitation, hard start or stumble from a dead stop. I run my R2 without a choke plate and don't have any cold weather driving issues but an R1 may be a little more tempermental in the very cold because the supercharger heats the incoming air a little.

ErnieR

http://i146.photobucket.com/albums/r241/AvantiR2/track.jpg