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Author Topic: Interesting Hilborn problem - advice?  (Read 4160 times)

Offline matt b

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Interesting Hilborn problem - advice?
« on: July 30, 2018, 12:58:48 PM »
Hi y'all. Got the 406 in my MW car fired up this weekend. 406 / 3 piece Hilborn / DSR pump / 36 degrees timing / 115 main bypass/ 90 high speed at 50# on alcohol.

Started with BV leaked to 25% - small adjustments leaner have it idling pretty well and it's crisp on the throttle once I blow it out.

Passenger side cylinders seem very fat - 2/4/6/8 - most particularly #2 and #6. They are blowing lots of raw fuel at idle. They clean out fine when I hit the throttle but they appear to be very very rich.

Checked nozzles last night (clean), checked valve lash (all good at .02), fresh spark plugs. Going to check / gauge butterfly adjustment on that bank tonight after work.

Anybody wanna take a stab at why it's really good on one bank and super fat on the other....got butterfly adjustment in my head....what else might I be missing?

Thanks in advance!

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Offline masracingtd1167

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Re: Interesting Hilborn problem - advice?
« Reply #1 on: July 30, 2018, 01:23:17 PM »
Throttle plates side to side adjustment is off ! One side is open more than the other !
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Offline matt b

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Re: Interesting Hilborn problem - advice?
« Reply #2 on: July 30, 2018, 01:32:26 PM »
Thanks - I’ve breathed enough alcohol fumes this weekend to be second guessing myself!
Will check and set them tonight and report back.
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Offline Paul New

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Re: Interesting Hilborn problem - advice?
« Reply #3 on: July 30, 2018, 02:41:00 PM »
Stack injection is difficult to get even out! 
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Offline masracingtd1167

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Re: Interesting Hilborn problem - advice?
« Reply #4 on: July 30, 2018, 03:16:20 PM »
I used to use a uni sync tool to adjust them
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Offline cad500justin

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Interesting Hilborn problem - advice?
« Reply #5 on: July 30, 2018, 10:32:37 PM »
Phone won’t let me copy a link, but spud has an article on his site called belligerent butterfly’s that should help.
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Offline Paul New

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Re: Interesting Hilborn problem - advice?
« Reply #6 on: July 31, 2018, 06:43:31 AM »
Quote from: cad500justin on July 30, 2018, 10:32:37 PM
Phone won’t let me copy a link, but spud has an article on his site called belligerent butterfly’s that should help.

Here you go
http://www.fuelinjectionent.com/butterflies.php

My phone worked  ;D
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Offline matt b

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Re: Interesting Hilborn problem - advice?
« Reply #7 on: July 31, 2018, 07:35:59 AM »
Thanks for that!

Glad to report success - reset butterflies, adjusted BV to 25% and fired right up. Went about three flats leaner and while it's not quite perfect it's 100% better than it was.

Now that I've heard it run and filled my shop with methanol fumes....out it comes. Needs a new pan gasket and it's finally time for chassis paint, re-cert and assembly!

Thanks all.

MB
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Offline Paul New

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Re: Interesting Hilborn problem - advice?
« Reply #8 on: July 31, 2018, 08:23:55 AM »
Get the cert prior to paint just in case!
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Offline matt b

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Re: Interesting Hilborn problem - advice?
« Reply #9 on: July 31, 2018, 10:43:24 AM »
Yah - absolutely!
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