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K&N Filters added so whats needle should I be running?

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Ballybob Avatar
Ballybob Rob McKellar
Wollongong, New South Wales, Australia   AUS
1958 MG MGA 1500
1968 MG MGB "NED"
1969 MG Midget
I recently installed K&N filters to my 1500. The car has always ran on the rich side so I have purchased new jets. Before I pull out the carbs can someone tell me if I should upgrade the needles to the #4 needle (rich)? The existing needles are GS which are standard.

Thanks in advance!

Rob

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barneymg Avatar
barneymg Barney Gaylord
(Somewhere in USA), Pick one (or more), USA   USA
1958 MG MGA "MGA With An Attitude"
Keep the GS needles. Do not go rich. Air filters on or off should make no difference in air flow or fuel mixture, as the flow restriction should be negligable.



Barney Gaylord - 1958 MGA with an attitude - http://MGAguru.com - barneymg@mgaguru.com

oleanderjoe Avatar
oleanderjoe Gold Member Joseph Baba
Fresno, CA, USA   USA
Rob. Wait until you install the NEW JETS. Some times they are really worn and it is hard to see. Change only one thing at a time to avoid confusion. Put in a fresh set of plugs and drive a little. See what happens after a few miles.


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Ballybob Avatar
Ballybob Rob McKellar
Wollongong, New South Wales, Australia   AUS
1958 MG MGA 1500
1968 MG MGB "NED"
1969 MG Midget
Thanks for the responses guys.

GS needles stay

The jets are presently screwed all the way in at the moment

The car runs well except it fouls up if its idling in traffic for too long.

I will put the new jets in this weekend and see how she runs.

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Blueosprey90 Avatar
Blueosprey90 Jeff Sienkiewicz
New Milford, CT, USA   USA
https://www.knfilters.com/filter_facts.htm

If your car runs rich and fouls your plugs, have you tried to lean it out? I take the dashpots off of the carbs and measure the distance between the top of the jet and the bridge of the housing kin which it slides up and down. I run at about 0.08" but I think a street car should shoot for about 0.10". Once you have it set where you are happy, you can tweak the carbs with the adjusting nuts if / when you need to. I confess that I was never able to tune the carbs otherwise.

Rob Z Avatar
Rob Z Silver Member Rob Zucca
Camarillo, CA, USA   USA
1960 MG MGA
Here’s a page from Barney’s site. If your adjustment nut is all the way up and you’re still a bit rich, you can drop the needles a bit for more adjustment.http://mgaguru.com/mgtech/carbs/cb119.htm



"Time flies like an arrow......Fruit flies like a banana"

oleanderjoe Avatar
oleanderjoe Gold Member Joseph Baba
Fresno, CA, USA   USA
ROB: YUP, best to wait for the new jets first. If after installing them and they are ALSO, all the way up. The needles can be dropped a bit as mentioned. (I know you know how to do that). I have seen this a lot on the Zenith Stromberg Carbs on MGB's, In California the CO level has to be ???? I believe now "Less than .05" % ????? Most as measured are over 7-8% NASTY "GROSS POLLUTER" Changing out the jet, EVEN THOUGH it looks "Perfect", gets the levels down to almost 0 % percent, passes with flying colors. SOOOO, I would wait if I were you. Cheers.


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Rob Z Avatar
Rob Z Silver Member Rob Zucca
Camarillo, CA, USA   USA
1960 MG MGA
Yep, agree with Joseph. Wait till you install the new jets and see if it’s still too rich. Adjust down the average 12 flats and go from there.



"Time flies like an arrow......Fruit flies like a banana"

Ballybob Avatar
Ballybob Rob McKellar
Wollongong, New South Wales, Australia   AUS
1958 MG MGA 1500
1968 MG MGB "NED"
1969 MG Midget
Ok will install jets and see how we go.

After reading up on Barney's site I discovered my carbies still have the original damper units with the longer piston valve thing at the bottom.

Will this be a problem or should I update them too?

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oleanderjoe Avatar
oleanderjoe Gold Member Joseph Baba
Fresno, CA, USA   USA
ROB: You are like my Grand Daughter at the "CANDY BOWL" Leave it alone until you know how the jets work. For now Wash and Wax the Car. He, He, smileys with beer


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revans Avatar
revans Richard Evans
Hampshire, UK   GBR
In reply to # 3695573 by Ballybob Ok will install jets and see how we go.

After reading up on Barney's site I discovered my carbies still have the original damper units with the longer piston valve thing at the bottom.

Will this be a problem or should I update them too?

Hi Rob,

I also have K & N's. I noticed recently that my damper pistons were also the original long type.

Follow Joseph's advice.

Richard

barneymg Avatar
barneymg Barney Gaylord
(Somewhere in USA), Pick one (or more), USA   USA
1958 MG MGA "MGA With An Attitude"
The damper mod only makes a difference at full throttle and fairly high revs, where the dashpot piston would be at full lift. You won't notice the difference, but it could make a couple more HP on a dyno.



Barney Gaylord - 1958 MGA with an attitude - http://MGAguru.com - barneymg@mgaguru.com

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Ballybob Avatar
Ballybob Rob McKellar
Wollongong, New South Wales, Australia   AUS
1958 MG MGA 1500
1968 MG MGB "NED"
1969 MG Midget
In reply to # 3695820 by oleanderjoe ROB: You are like my Grand Daughter at the "CANDY BOWL" Leave it alone until you know how the jets work. For now Wash and Wax the Car. He, He, smileys with beer

Love your reference hahaha

I will wax very soon.

Ballybob Avatar
Ballybob Rob McKellar
Wollongong, New South Wales, Australia   AUS
1958 MG MGA 1500
1968 MG MGB "NED"
1969 MG Midget
In reply to # 3696232 by barneymg The damper mod only makes a difference at full throttle and fairly high revs, where the dashpot piston would be at full lift. You won't notice the difference, but it could make a couple more HP on a dyno.

I thought as much Barney.

As a matter of interest what sort of RPM is deemed excessive for the three bearing 1500? I have heard if the crank flexing at high RPM.

Don't worry I don't want to race the engine just want to conserve what I have.

barneymg Avatar
barneymg Barney Gaylord
(Somewhere in USA), Pick one (or more), USA   USA
1958 MG MGA "MGA With An Attitude"
I used to autocross with SCCA, all through the 90's, about 25 race dates per year. I have fairly often had it north of 7000 rpm, but never for more than a few seconds at a time. very commonly ran it in the 6000-6500 rpm range. I did blow the rod bearings a few times, before I figured out the oil pump was cavitating at 7000 rpm. Changing the pick-up screen (and pump bottom end) to the later style fixed that. Never broke a crankshaft while racing it.

I did break a crankshaft in 1989, while cruising down the road at constant 4000 rpm. This was about 15,000 miles after an engine rebuild with reground crankshaft. It may have been a grinding error with too-sharp fillet radius. To be fair, the engine had 150,000 miles on it before the rebuild.

I broke another crankshaft in 1992, but only because the starter motor fell out and jammed up the flywheel.

Back on topic, I have been running K&N air filters since June 2000, a quarter million miles by now. I don't like that they have to be cleaned and re-oiled occasionally (more often in dusty conditions) or the fact that the plastic body of the filter will shrink when in contact with oil (blow-by from the crankcase).



Barney Gaylord - 1958 MGA with an attitude - http://MGAguru.com - barneymg@mgaguru.com



Edited 1 time(s). Last edit at 2018-03-13 09:17 AM by barneymg.

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