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Holley Ultra HP transition slot not exposed at all
#1748120
02/06/15 08:50 PM
02/06/15 08:50 PM
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Joined: May 2003
Posts: 2,414
St. Croix, US Virgin Islands
David_in_St_Croi
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Hi,
While I do not think this was the problem with the car not running in my other thread, I am looking for opinions on how the carbs were set up when the engine showed up. The carburetors are Hilley Ultra HP 600, a pair on a tunnel ram.
I took the carbs off when installing the engine as I did not want to damage them. I also wanted to know the settings (jets, air correctors, etc) I recorded everything and did not touch either the idle speed screws or the idle mixture screws. What I did notice is that the throttle blades are completely closed. Now, this certainly addresses the situation of avoiding exposing too much transfer slot. These carbs have the idle air bypass screw under the air cleaner stud. It seems as if they were set up to idle with the butterflies closed and just using the bypass. Am I better off popping the carbs off and setting up the blades so the transition slot is exposed in a square fashion? Then close down the bypass screws, then set the idle speed with the bypass screws if needed? Also, the Ultra HP carbs do not seem to have a port to hook up a vacuum gauge. Do I drill and tap the intake manifold for a vacuum gauge? The intake is a Weiand tunnel ram.
Best regards, Dave
Last edited by David_in_St_Croi; 02/07/15 02:42 PM.
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Re: Hollye Ultra HP transition slot not exposed at all
[Re: David_in_St_Croi]
#1748121
02/06/15 10:58 PM
02/06/15 10:58 PM
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Joined: Jul 2004
Posts: 19,318
State of confusion
Thumperdart
I Live Here
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I Live Here
Joined: Jul 2004
Posts: 19,318
State of confusion
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Quote:
Hi,
While I do not think this was the problem with the car not running in my other thread, I am looking for opinions on how the carbs were set up when the engine showed up. The carburetors are Hilley Ultra HP 600, a pair on a tunnel ram.
I took the carbs off when installing the engine as I did not want to damage them. I also wanted to know the settings (jets, air correctors, etc) I recorded everything and did not touch either the idle speed screws or the idle mixture screws. What I did notice is that the throttle blades are completely closed. Now, this certainly addresses the situation of avoiding exposing too much transfer slot. These carbs have the idle air bypass screw under the air cleaner stud. It seems as if they were set up to idle with the butterflies closed and just using the bypass. Am I better off popping the carbs off and setting up the blades so the transition slot is exposed in a square fashion? Then close down the bypass screws, then set the idle speed with the bypass screws if needed? Also, the Ultra HP carbs do not seem to have a port to hook up a vacuum gauge. Do I drill and tap the intake manifold for a vacuum gauge? The intake is a Weiand tunnel ram.
Best regards, Dave
I`d start square so there`s a bit of fuel for a clean transition and w/the air fuel mixture screws 1 1/2 to start and go from there. 
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: Holley Ultra HP transition slot not exposed at all
[Re: Thumperdart]
#1748122
02/07/15 12:02 AM
02/07/15 12:02 AM
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Joined: May 2003
Posts: 2,414
St. Croix, US Virgin Islands
David_in_St_Croi
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Hi Thumper,
Thanks for the feedback. That was the direction I was thinking myself. In David Vizard's Holley book he states to set up the transition slots square, and then use the idle bypass to set the idle if more air is needed. As it is, even closed completely the idle feed hole into the venturi is still exposed, but I wondered if it still always needs the transition slot to also be exposed. Right now the butterfly will open introducing more air in but the transition slot would still not be exposed during that initial motion so that could cause a momentary lean condition as the transition slot is not feeding additional fuel and air while additional air is coming in by the butterflies. Not sure if that made sense.
I know Dan said he had a hard time getting the carbs set up, wonder if this was part of it. He did say he finally got it to idle nice and responsive but it was a struggle.
Right now the idle mixture screws are ~ 1-1/4 turns out.
At some point I should make an adapter to be able to use my Uni-Syn for fine tuning the balance between the front and rear carb.
Best regards, Dave
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Re: Holley Ultra HP transition slot not exposed at all
[Re: Cab_Burge]
#1748124
02/07/15 12:11 AM
02/07/15 12:11 AM
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Joined: May 2003
Posts: 2,414
St. Croix, US Virgin Islands
David_in_St_Croi
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Quote:
A lot of dyno operators will set the idle speed screw so the motor will die and not idle if they pull the throttle back all the way, probally so if somethenig goes south on the motor they can kill the motor with the throttle instead of having to turn the ignition switch off, maybe not   I've seen this on more than one dyno that didn't know each other  Maybe there taught that by the dyno training folks
Okay, that makes sense. In this case, though the engine idled at ~ 1000 without doing anything to the idle speed screws.
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Re: Holley Ultra HP transition slot not exposed at all
[Re: Cab_Burge]
#1748127
02/07/15 02:42 PM
02/07/15 02:42 PM
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Joined: May 2003
Posts: 2,414
St. Croix, US Virgin Islands
David_in_St_Croi
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Hi,
Thanks for the tips and advice. I like the reminder to count the number of turns from fully closed to square, along with the number of turns to further openings. I will add it to the sheet I made that lists all the carb settings such as jet and air corrector sizes, power valve, pump cam, squirters.
The carbs are mechanical secondaries so I have the adjustment screw on top for the secondaries, which is certainly convenient.
Next question. Should I set both the primaries and the secondaries to the transfer slot showing square as a starting point? The linkage is progressive, not 1:1, so the secondaries are not opening with the primaries if that makes a difference.
I understand the try to make it idle as lean as possible, that makes sense. It will take a while to get all 8 circuits dialed in but I think there is much more potential to get it right with this setup than with the old 950HP it used to have before the latest rebuild that only had pressed in air correctors etc. That one always seemed rich at idle no matter what. These newer carbs seem to be much more versatile. Also more places to screw up hence the logging the as delivered settings
Cab, I think the tunnel ram will definitely be worth the effort. I am looking forward to getting it sorted.
Best regards, Dave
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Re: Holley Ultra HP transition slot not exposed at all
[Re: David_in_St_Croi]
#1748128
02/07/15 03:00 PM
02/07/15 03:00 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Next question. Should I set both the primaries and the secondaries to the transfer slot showing square as a starting point? The linkage is progressive, not 1:1, so the secondaries are not opening with the primaries if that makes a difference. I understand the try to make it idle as lean as possible, that makes sense. It will take a while to get all 8 circuits dialed in but I think there is much more potential to get it right with this setup than with the old 950HP it used to have before the latest rebuild that only had pressed in air correctors etc. That one always seemed rich at idle no matter what. These newer carbs seem to be much more versatile. Also more places to screw up hence the logging the as delivered settings Cab, I think the tunnel ram will definitely be worth the effort. I am looking forward to getting it sorted. Best regards, Dave
I would set them square... its still the point when
the blade starts to move that counts.. and make sure
that the squirter sees that movement point(starts
to squirt)... yeah keep a record of the turns on
the blade to square the slot.. saves you from pulling
the carb off... on the mixture screws.. if you slowly
turn each one in you will find that at a point the
engine will want to die.. find that point on each
one and turn it out a quarter turn.. you will have
to adjust the trottle blades to get back to the idle
rpm.. each time you move the blades go back to the
mixture screws and do the same thing over again...
when you near the perfect point you will see a 1/8
turn out from that lean point should be a little
closer to the best mix(mainly because your running
2 carbs)
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Re: Holley Ultra HP transition slot not exposed at all
[Re: David_in_St_Croi]
#1748129
02/07/15 03:26 PM
02/07/15 03:26 PM
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Joined: Dec 2014
Posts: 304
Florida
Mark Whitener
enthusiast
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enthusiast
Joined: Dec 2014
Posts: 304
Florida
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In the case of dual carb setup you do not want the t-slots exposed like a single carb. Set them so the t-slot edge is within the thickness of the closed blade, make your idle adjustments with the bypass. Otherwise with 8 t-slots it will start too early and end too quick. Part of the tuning with 2 carbs also involve smaller idle jets and air bleeds to extend the t-slot operation without over fueling. I might start with .025 idle jets, .055 idle air bleeds, adjust the air bleeds to suit the transition circuit.
Mark Whitener
[url=www.racingfuelsystems.com[/url]
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Re: Holley Ultra HP transition slot not exposed at all
[Re: David_in_St_Croi]
#1748131
02/07/15 03:43 PM
02/07/15 03:43 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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David... before you start messing with the carbs.. start out with fresh fuel... sounds like you have some old fuel in there from your other post
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Re: Holley Ultra HP transition slot not exposed at all
[Re: Mattax]
#1748133
02/07/15 06:25 PM
02/07/15 06:25 PM
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Joined: May 2003
Posts: 2,414
St. Croix, US Virgin Islands
David_in_St_Croi
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Thanks everyone.
Mark, thanks for the feedback on the throttle blade positions. I will confirm that and make sure they are at that location. Sounds like that is how Dan had it set up then. The idle jets in it now are 32 and the air bleeds are 73 on all 8 circuits. Considerably more than what you mention. Might account for the black plugs but with the ignition problem I had there are several possible sources for the carbon. What are your thoughts on the jet difference. I have not been able to determine the OOTB settings for this model of carb, the info I found on the Holley web site doesn't seem to show it so if anyone knows that would be great.
Mr P Body, good point on the fuel, I will pick some up tomorrow. I did add some fresh fuel but more will only help.
Mattax, I think the slots are the same but will confirm.
Best, Dave
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Re: Holley Ultra HP transition slot not exposed at all
[Re: Mark Whitener]
#1748135
02/09/15 10:32 PM
02/09/15 10:32 PM
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Joined: May 2003
Posts: 2,414
St. Croix, US Virgin Islands
David_in_St_Croi
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Quote:
The larger jet and bleed would more suit a single carb app, likely what they were built for. I would also consider relocating the idle jets if they are in the top location the following link shows.
http://racingfuelsystems.myfunforum.org/viewtopic.php?f=25&t=18
Thanks Mark and everyone.
That makes sense. Unfortunately you can not order these carbs in a twin configuration.
Went sailing on Sunday on a friend's trimaran and by the time we got home we had dinner and went to bed so no reply until now.
I did however spend some time on Saturday afternoon. Here is what I did:
I drained the float bowls, pulled the carbs and set up the throttle blades on all the venturis so that the transfer slot was not exposed. Basically 1 turn from fully closed is where the transfer slot just starts to show so that is where I started.
I removed the aircleaners and studs. Good thing I only used purple loctite.
I started the engine and let it warm up.
I started turning in the idle screws 1/4 turn at a time. The RPM's immediately picked up. I had to start closing the bypass valve, ended up with them fully closed. At 3/4 turns on all idle screws I stopped messing with it. I had to close the butterflies about 1/8 to 1/4 turn to get the idle down to 1000. I tried screwing in an idle screw to full closed and the engine would not die. Of course, that is only 1/8 of the idle fuel supply.
I believe this all supports the reduce the size of the Idle jets and air bleeds.
Now my question. Are the idle jets (idle feed restrictors) the same as the emulsion jets as I do not find anything in Summit or on Holley.com that lists a part number for an idle feed restrictor made by Holley.
I have looked at the link and would like a little clarification. Am I tapping an already existing hole? It appears so, I think it is the bottom of the idle well where it goes up and over.
Not sure if anyone down here carries a bottoming tap. The IFR's currently are in the top hole, standard for the Ultra HP series as far as I can tell. What are the pin drills for, to drill out the set screws and make your own jets?
I assume I should stick with the Holley pieces? The Quick fuel bits are definitely cheaper but I have read that the sizing is not like for like (not bashing any brand).
Best regards, Dave
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Re: Holley Ultra HP transition slot not expoosed at all
[Re: Thumperdart]
#1748137
02/10/15 05:27 PM
02/10/15 05:27 PM
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Joined: May 2003
Posts: 2,414
St. Croix, US Virgin Islands
David_in_St_Croi
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Quote:
Can u send the blocks out to be tuned to save on shipping? Cos you could do the t-slot mod yourself at home................
I'm a little confused as to why I would want to send out the metering blocks? Worst case is I have to order a bottoming tap. Of course, I could be missing something. 
By t-slot mod do you mean relocating the IFR?
I don't mind doing the work, I like the learning process as does Michelle, who has been doing a lot more of the work with me both on the RR and on our two Land Rovers. It has been nice seeing it, she even removed, cleaned up, and reinstalled the clutch assembly on her Land Rover after it stuck from corrosion from sitting due to a dead starter (drain hole in bellhousing was clogged with grease and water was trapped hence the corrosion in a short amount of time).
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Re: Holley Ultra HP transition slot not exposed at all
[Re: Mattax]
#1748139
02/11/15 10:03 PM
02/11/15 10:03 PM
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Joined: May 2003
Posts: 2,414
St. Croix, US Virgin Islands
David_in_St_Croi
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Thanks for the link to the clear metering block. It really helped me with the understanding of the circuits and how they interrelate. What just dawned on me is that I am not so much tuning the actual idle with the IFR and idle air bleeds as I am tuning the transition circuit. The curb idle is pretty well controlled with the screw, unless of course the IFR is way too small. The number of turns is a good indicator of whether or not the IFR and idle air bleed are correct, but does not so much affect the transition slot mixture (recognizing that on a certain level all circuits are interconnected). The transition circuit is controlled by the IFR and idle air bleed only, in a similar fashion to the main jets and main air bleeds, correct?
Having said that, I have read through the modification and think I understand and why I would want to do it. It appears to me that it requires the use of the set screws, I can not put in a standard Holley IFR, correct? The Holley IFR has the shoulder which will not be there in the new location. The IFR's are 8.42 a pair so I need 4 pairs which adds up to over $33 before shipping. Not sure if I can get the pin drills locally. Pretty sure I can get the set screws no problem. Still have to get the air bleeds, shipping is almost as much as the air bleeds, so need to make sure there is not anything else I need. On the other hand, just realized the .025 emulsion jets are out of stock at Jegs and Summit so maybe I will go the set screw route. I will call the hardware store in the morning see if they have the drill bits.
I will definitely let everyone know the results when I finally do get it sorted. It is already much improved.
Best regards, Dave
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Have fun and please let us know what you end up getting the best results with 