Re: A few question about the E MW victor head
[Re: mopar dave]
#2712543
11/03/19 09:15 PM
11/03/19 09:15 PM
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Joined: Jan 2003
Posts: 14,531 So. Burlington, Vt.
fast68plymouth
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Looks like that valve is using up most of the seat OD.
What’s the valve diameter?
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: A few question about the E MW victor head
[Re: mopar dave]
#2712698
11/04/19 02:33 PM
11/04/19 02:33 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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Not sure... "at least 3", but it's entirely possible there is at least one under the 3rd (60+?) that's not obvious because it's been blended in w/ the bowl work. I recall seeing a close-up of a SBM that Hughes worked which clearly showed another 70-ish angle under the 3rd angle, so my a$$umption is the bottom angle has been blended it. Different shops have their own ideas w/ respect to # of angles, width of angles, how far up they blend into the valve job, etc. Some stuff makes sense to me; other things I read about... ------------------------- EDIT: Including the Hughes work shown above, four different shops, four different valve seat configs... and possibly the only thing they have in common is a 45* seat.
Last edited by BradH; 11/04/19 02:50 PM.
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Re: A few question about the E MW victor head
[Re: mopar dave]
#2713017
11/05/19 02:17 PM
11/05/19 02:17 PM
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Joined: Jan 2003
Posts: 14,531 So. Burlington, Vt.
fast68plymouth
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3? 4? 5? Over 5 angles??
Is there a magic number of angles that needed?
Those heads went 9.70’s with 3 angles....... they can’t be that bad.
Many times there is a bottom angle that gets blended into the bowl...... and sometimes some of it is still visiable...... sometimes it’s not.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: A few question about the E MW victor head
[Re: mopar dave]
#2713026
11/05/19 02:57 PM
11/05/19 02:57 PM
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Joined: Aug 2011
Posts: 2,904 Pattison Texas
CSK
master
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master
Joined: Aug 2011
Posts: 2,904
Pattison Texas
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I dont know about any magic, but when you back cut an intake valve do use see an improvement in flow, a loss in flow or does the back cut intake valve make no difference? Back cut valves help the low lift flow, & I have seen it hurt OR help high lift flow, as it is said by some members here, IT depends
1968 Charger COLD A/C Hilborn EFI 512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim 2020 T/A 392 Stock 11.79 @ 114.5
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Re: A few question about the E MW victor head
[Re: CSK]
#2713050
11/05/19 04:06 PM
11/05/19 04:06 PM
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Joined: Jan 2003
Posts: 14,531 So. Burlington, Vt.
fast68plymouth
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I Live Here
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Over on Speed Talk, back cuts are definitely not universally accepted as being something you want done to your heads.
As for the angles...... not only can the number of angles play a part in the flow....... there’s also the length of the various angles, and how that relates to where you’re looking to make changes to the flow curve.
Last edited by fast68plymouth; 11/05/19 04:07 PM.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: A few question about the E MW victor head
[Re: mopar dave]
#2713110
11/05/19 06:46 PM
11/05/19 06:46 PM
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Joined: Jul 2004
Posts: 19,318 State of confusion
Thumperdart
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I Live Here
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State of confusion
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FWIW here's what pettis did to my valves.
Intakes Margin .060 Seat 45* x .070 BC/BA 32* x .070/12*
Exhaust Margin .080 Seat 45* x .085 BC/BA 36*x .050/15* Not a machinist and not 100% on this stuff so maybe someone can educate us here.....
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: A few question about the E MW victor head
[Re: Thumperdart]
#2713116
11/05/19 07:03 PM
11/05/19 07:03 PM
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Joined: Nov 2015
Posts: 896 Missouri
jwb123
super stock
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super stock
Joined: Nov 2015
Posts: 896
Missouri
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all valve jobs should have three angles. The norm is 15 degrees from the seat angle. So a 45 degree seat gets a 30 top angle and a 60 degree bottom cut. The main reason for the narrowing angles is to control the width of the seat, and control where the seat contacts the valve face. The valve can only really dissipate heat when it contacts the seat, wider the seat the cooler the valve runs, narrower the seat the hotter. Generally as a rule the narrower you can make the seat and it still live the better the flow. Depending on how deep the valve seat is in the chamber and how the chamber is made, another top cut is done usually around 15 degrees. I even use a 70 degree some times as another bottom cut. And just because it improves flow on the bench does not mean it will make more power on the track. I seldom back cut a performance style replacement valve. On stock type valves the back cut seems to help on the intakes the most. It is just one of those things somebody has to spend the time and money to actually see what works the best. And as a rule the more you grind or cut the seats the less HP they will make, because as you cut the seats they sink into the heads, because you are taking material off. And the more they sink they loose flow, at least that is my experience. The main thing is the valves have to hold compression, if they leak, no matter what the seat flows, it will just not run right. I use a vacuum tester and a leak down tester as I am assembling to make sure they hold air. On a ported aluminum head if you over torque them for example, I have seen it warp the seats and they will leak compression. And I do not know how many times I take a new head ready to go out of the box and the valves leak air.
Last edited by jwb123; 11/05/19 07:04 PM.
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Re: A few question about the E MW victor head
[Re: jwb123]
#2713262
11/06/19 10:07 AM
11/06/19 10:07 AM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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I believe there are a lot more factors taken into account these days for high-end performance valve seats. Valve angle, chamber style, lift requirements, RPM... all these -- and more -- seem to have an influence on the configuration.
Here's something I copied from a Darin Morgan post on SpeedTalk that could be a decade old easily. He's talking competition heads, but it gives a good feel for how much different the config may be than the traditional 30/45/60 3-angle. I put the valve seat angles in bold.
"Yes you can run a 50 degree seat on 14 and 15 degree heads and I have even seen it work on 18 degree heads just so long as someone has not blown the chamber out a ridiculous amount. I use a 40 degree top cut .100 wide, 50 degree seat .045 wide, 62 under cut .080-.090 wide and a 72.5 degree if I plan on blending and a 75 if I want to run sharp angles about .200 wide. I then set my throat diameter proportional to the valve diameter ( 90-91%). I think the real trick or should I say " rule" with steep angle seats is that if you do not have the material in the chamber for a top cut that is 10 degrees less than the seat angle itself and you can not continue that angle for at least .250, don't go there!
A 50 degree seat takes a 40 or 45 degree top cut at least .100 wide. If you have to clean up the chamber with a 35 or a 30 top cut, it wont work, period! You really need to try and not turn the air into the chamber any more than 10 degrees.
A typical low profile chamber on say a 10 degree valve angle ( like Pro Stock) has valve angles like this. 50 degree top cut for at least .300 then rolls back to about a 40 degree at deck surface. The seat is 55 degrees at .045 wide. the under cut is 65 degrees .090 wide and the last cut is a 74.5 .400 wide then an 85 degree .200 wide. This way by the time I am through blending the throat in, it turns into a 75 degree under the 65 degree. I hope that is not confusing.
These are common valve jobs I use. Notice the top angle differs from the seat by only 10 degrees or less, not 15 or 20.
35-45-60-70 Blend 70 up to 60 Good for concave chambers like conventional BBC heads. 18 to 26 degree heads, Dart, Brodix ect ect.
40-45-62-72.5 Blend 72.5 up to 62. Works good for chambers that are concave like 15 degree heads.
40-50-62-72.5 Blend 72.5 up to 62. works well for 12 to 14 degree heads with true convex or strait wall chambers.
45-50-65-72.5-85 Blend 72.5 up to 65. works well for 12 to 14 degree heads with true convex chambers. mainly for high lift, high valve speed, high rev engines that need good seat life.
50-55-65-74.5-85 Blend 74.5 up to 65. for heavily convex shaped chambers. 10-12 degree heads. For ultra high lift, super high valve speed, extreme high rev engines.
55-58-65-75-85 Blend 75 up to 65. Don't even go here! Its hard on seats and very tricky to make work. I hate it but its worth a little power.
58-60-70-75-80-85 Don't blend anything. leave everything sharp even the transition into the bowl. Not worth the valve replacement bill. Worth 4 horsepower above 8800rpm.
I hope this helps."
He also had some comments about his approach to reworking the late-model GM LS7 head, which is a production 12* valve angle raised-port LS-series head, not a dedicated race head:
"The chamber in the LS7 head was designed for low lift flow. The chamber is at 30 degrees off the 45 seat so any steeper seat angle will be a disaster. Some have used 50 degree seats in this head but they had to use very wide back angles cuts on the valve to turn the air and that just adds valve weight. I dont agree with that approach.
I like a 38 or 40 as well and i agree it would be better,,,,,,but,,, the chamber is already 30 and I hate to sink valves so I use a 30. Its the best compromise in my opinion.
Standard 45 degree valve job.
30 .150 45 .045 60 .090 75 .100 85 .100"
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Re: A few question about the E MW victor head
[Re: BradH]
#2713265
11/06/19 10:16 AM
11/06/19 10:16 AM
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Joined: Jan 2003
Posts: 14,531 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
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So. Burlington, Vt.
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35-45-60-70 Blend 70 up to 60 Good for concave chambers like conventional BBC heads. 18 to 26 degree heads, Dart, Brodix ect ect.
40-45-62-72.5 Blend 72.5 up to 62. Works good for chambers that are concave like 15 degree heads.
After the blending, those become 3 angle valve jobs. With the victor, it’s worse than the LS head. You have to transition from the seat angle to the basically zero degree chamber. The only way you’re going to be able to gain any length on the top angle is sink to the valves. And...... the steeper you make the top angle........ the more you need to sink the valve, if you want that length. Someone good with trigonometry could easily calculate if you had a 45 seat sitting on/in a zero degree chamber...... and you wanted to add a 30* top cut that was .150” wide....... how far you’d have to sink the valve to accomplish that. The pics of Dave’s seats look like there is very little length to the top cut....... so, they opted for the least amount of valve sinking. It’s a little tough to clearly see the top angle and transition into the chamber though. Some carb cleaner and a piece of scotch-brite would clear that up. The chamber pic of the heads I ported for Brad appear to have a wider top cut.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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