Idle surge
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From: Reidsille
Idle surge
The idle on my recently rebuilt 352 (basically bone stock apart from headers and electronic ignition) surges somewhat regularly from the spec 550-575 rpm (where I set it to be) to around 800rpm. It will idle for about 10-15 seconds and for about 3-5 seconds it will surge to 800 give or take. I set the timing at 12 deg BTDC. Spec is 6 deg but I got 12 as a recommendation. It doesn't seem to hinge on fuel mixture either. I just rebuilt the carb about 800miles ago. Anybody got any ideas?
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From: Long Island USA
Re: Idle surge
Originally posted by n2ovals
The idle on my recently rebuilt 352 (basically bone stock apart from headers and electronic ignition) surges somewhat regularly from the spec 550-575 rpm (where I set it to be) to around 800rpm. It will idle for about 10-15 seconds and for about 3-5 seconds it will surge to 800 give or take. I set the timing at 12 deg BTDC. Spec is 6 deg but I got 12 as a recommendation. It doesn't seem to hinge on fuel mixture either. I just rebuilt the carb about 800miles ago. Anybody got any ideas?
The idle on my recently rebuilt 352 (basically bone stock apart from headers and electronic ignition) surges somewhat regularly from the spec 550-575 rpm (where I set it to be) to around 800rpm. It will idle for about 10-15 seconds and for about 3-5 seconds it will surge to 800 give or take. I set the timing at 12 deg BTDC. Spec is 6 deg but I got 12 as a recommendation. It doesn't seem to hinge on fuel mixture either. I just rebuilt the carb about 800miles ago. Anybody got any ideas?
Vacuum leak? Do you have a power-brake booster? PCV valve hanging up?
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From: Reidsille
On another forum someone recommended 10-12 deg BTDC instead of 6 I think it was for acceleration or mileage or something(?)...don't remember.
The only vacuum lines I have are from the vac advance to the carb throttle plates and from the pcv valve to the carb spacer. It's a new pcv valve.
So you think If I idle up a little it might go away?
The only vacuum lines I have are from the vac advance to the carb throttle plates and from the pcv valve to the carb spacer. It's a new pcv valve.
So you think If I idle up a little it might go away?
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From: Long Island USA
Originally posted by n2ovals
So you think If I idle up a little it might go away?
So you think If I idle up a little it might go away?
Check the throttle plate shaft - if it's loose in the carb housing, it will give you problems.
Could it be an intake manifold leak? Using any oil? Decelerate hard from 4000 RPM in a low gear and then hit the gas. Puff of oil smoke? Intake manifold gasket is leaking...
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i am having trouble with surging at idle as well. what causes the puff of smoke when you decelerate and accelerate? i tried blowing propane around my intaked manifold and tbi base and could not find any leaks but i have a regular mild surge at idle. at times it will go away but it is generally there at idle. any ideas?
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Originally posted by djmac
i am having trouble with surging at idle as well. what causes the puff of smoke when you decelerate and accelerate? i tried blowing propane around my intaked manifold and tbi base and could not find any leaks but i have a regular mild surge at idle. at times it will go away but it is generally there at idle. any ideas?
i am having trouble with surging at idle as well. what causes the puff of smoke when you decelerate and accelerate? i tried blowing propane around my intaked manifold and tbi base and could not find any leaks but i have a regular mild surge at idle. at times it will go away but it is generally there at idle. any ideas?
In some cases, it can be the rings allowing oil past at high vacuum, but I think they would have to be pretty worn (or VERY brand new).
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From: Reidsille
My rebuilt engine has about 800 miles on it and just for whatever reason I decided to recheck the torque on the intake bolts (despite having put loctite on them during assembly) and lo and behold they were loose as ****. I retorqued them and no more idle surge! 
Now I've got to go back and clean out the bolt holes and apply more loctite but at least the problem is fixed!
Thaks for the help!
Now I've got to go back and clean out the bolt holes and apply more loctite but at least the problem is fixed!
Thaks for the help!
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From: Long Island USA
Originally posted by n2ovals
My rebuilt engine has about 800 miles on it and just for whatever reason I decided to recheck the torque on the intake bolts (despite having put loctite on them during assembly) and lo and behold they were loose as ****. I retorqued them and no more idle surge!
Now I've got to go back and clean out the bolt holes and apply more loctite but at least the problem is fixed!
Thaks for the help!
My rebuilt engine has about 800 miles on it and just for whatever reason I decided to recheck the torque on the intake bolts (despite having put loctite on them during assembly) and lo and behold they were loose as ****. I retorqued them and no more idle surge!
Now I've got to go back and clean out the bolt holes and apply more loctite but at least the problem is fixed!
Thaks for the help!
Racers, yeah, they like to locktite everything, but your talking major problems for the guy behind you if you lose a bolt ...
I always like to check torque on everything after the first warmup and cool-down (cam breakin, usually) and then every hundred miles or so for the first month or two. That includes the heads, also...
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From: Reidsille
I'm a technician for Land Rover and we use loctite on all intake manifold bolts. I would never use loctite on exhaust bolts. They're hard enough to get out as it is. I've tried to avoid that difficulty this time around by using stainless bolts everywhere except for heads and any other bolts that aren't visible.
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From: Long Island USA
Originally posted by n2ovals
I'm a technician for Land Rover and we use loctite on all intake manifold bolts. I would never use loctite on exhaust bolts. They're hard enough to get out as it is. I've tried to avoid that difficulty this time around by using stainless bolts everywhere except for heads and any other bolts that aren't visible.
I'm a technician for Land Rover and we use loctite on all intake manifold bolts. I would never use loctite on exhaust bolts. They're hard enough to get out as it is. I've tried to avoid that difficulty this time around by using stainless bolts everywhere except for heads and any other bolts that aren't visible.
Just kidding... the Rover 3500 is a Buick 215. Are the new motors still basically the same as the 70's/80's 3500's?
I've owned three Triumph TR7's, so I know something about English vehicles... now if I could find a TR8 cheap, I'd be running a 3500
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From: Reidsille
All Land Rover V-8's, less the '03-'04 Range Rover, are based off the Buick 215. The 3.5 is pretty old and not too many made it to the states or just made it in general. The more common old ones are 3.9 and 4.2 and the newer ones are 4.0 and 4.6: all based off the Buick. The new Range Rover has a BMW 4.4 (in the X5) and we're going to doing away with the Buick series altogether for Aston Martin and Jaguar engines.
As far as needing help, at least we got rid of Lucas!
As far as needing help, at least we got rid of Lucas!
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From: Long Island USA
Originally posted by n2ovals
All Land Rover V-8's, less the '03-'04 Range Rover, are based off the Buick 215. The 3.5 is pretty old and not too many made it to the states or just made it in general. The more common old ones are 3.9 and 4.2 and the newer ones are 4.0 and 4.6: all based off the Buick. The new Range Rover has a BMW 4.4 (in the X5) and we're going to doing away with the Buick series altogether for Aston Martin and Jaguar engines.
As far as needing help, at least we got rid of Lucas!
All Land Rover V-8's, less the '03-'04 Range Rover, are based off the Buick 215. The 3.5 is pretty old and not too many made it to the states or just made it in general. The more common old ones are 3.9 and 4.2 and the newer ones are 4.0 and 4.6: all based off the Buick. The new Range Rover has a BMW 4.4 (in the X5) and we're going to doing away with the Buick series altogether for Aston Martin and Jaguar engines.
As far as needing help, at least we got rid of Lucas!
As for Lucas, yeah, well, for me with Triumph's, I'm glad Bosch made relays with the same pinouts as Lucas, that's for sure!
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