BritishV8 Forum

General Category => Engine, Transmission, & Rear Axle assy. => Topic started by: 88v8 on July 28, 2023, 09:52:15 AM

Title: Tightening torque, hunting idle
Post by: 88v8 on July 28, 2023, 09:52:15 AM
Edelbrock 4bbl, manual choke....

The Rover V8 is still not running right since it came back all fouled up with ethanol and I cleaned it up  (http://forum.britishv8.org/read.php?6,71712).

At first it seemed OK hot and cold, but now it's still fine when hot, but not at all when cold. Started up this morning, air temp around 67F and the idle was hunting up and down between 1200 and 700rpm, or 1200 and stall, without me even touching the throttle.
Any idea what's going on?

If it's this bad in summer, it's going to be even worse in winter.

Another thing... tightening the carb onto the manifold I can't find a torque spec. The Edelbrock manual says 'snug' but one person's snug is another person's slack, that's why torque wrenches were invented....
I tightened the hold-down nuts to 60 in lb, is that enough?

Ivor
Title: Re: Tightening torque, hunting idle
Post by: DiDueColpi on July 28, 2023, 04:02:13 PM
The Holley spec is 60 to 80 in. lbs. I would suspect the Edelbrock to be the same.
The hunting idle  is generally a lean problem. Possibly some debris still in a transfer port or idle jet?
Title: Re: Tightening torque, hunting idle
Post by: MGBV8 on July 28, 2023, 04:45:21 PM
I just snug them up by feel.
Title: Re: Tightening torque, hunting idle
Post by: 88v8 on July 29, 2023, 03:01:18 PM
Snug by feel, yes but you might be Charles Atlas lol

I was afraid there might still be carp in there. Got fed up with the thought of stripping and cleaning it again, so I just bought a 1901 AVS to put on there. I can swap the tune.
It has an autochoke. Never had an autochoke, complexification, hmm we'll have to see how that goes.
Title: Re: Tightening torque, hunting idle
Post by: MGBV8 on July 29, 2023, 09:17:25 PM
No one will mistake me for Charles Atlas, Ivor.  :)

Snug up by feel, mechanic tight based the size of the fastener, etc.

I didn't have torque wrench for a long time.  Generally only reach for it for the serious stuff,  head bolts & such.
Title: Re: Tightening torque, hunting idle
Post by: Spitfire 350 on July 29, 2023, 10:46:19 PM
Carburetors are tough to torque down because you seldom have a straight path to the bolts around the body. I tend to use the calibrated wrist snapping method to get them all equal.
Title: Re: Tightening torque, hunting idle
Post by: MGBV8 on July 29, 2023, 11:46:27 PM
Boxed end wrench.  Do not overtighten.  I have seen the mounting ears broken.
Title: Re: Tightening torque, hunting idle
Post by: BlownMGB-V8 on July 30, 2023, 08:36:19 AM
If they are too tight the throttle shafts tend to bind.

Jim