Edelbrock 2.055 (30 degree back-cut) testing

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pittsburghracer

pittsburghracer

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I’m struggling with my .300 flow number for the first time in years but that’s for another post. While searching for that lift issue I had a few extra minutes before I quit so I did back to back tests with two brand new 2.055 Ferrea intake valves. I’m sure I did this many many years ago but I keep better notes now so I will add this to them. I had always heard it help low to mid numbers and may hurt high lift numbers but this is the gain from .100-.600 lift.

.100——-+6
.200——-+7
.300——-+8
.350——-+7
.400——-+5
.450———+5
.500——-+3
.550———+4
.600——-+4
 
That's a decent gain for so little work.
 
The thing is, he stated he’s having trouble. That’s the downside.
 
pittsburghracer said:
I’m struggling with my .300 flow number for the first time in years but that’s for another post. While searching for that lift issue I had a few extra minutes before I quit so I did back to back tests with two brand new 2.055 Ferrea intake valves. I’m sure I did this many many years ago but I keep better notes now so I will add this to them. I had always heard it help low to mid numbers and may hurt high lift numbers but this is the gain from .100-.600 lift.

.100——-+6
.200——-+7
.300——-+8
.350——-+7
.400——-+5
.450———+5
.500——-+3
.550———+4
.600——-+4
Click to expand...
Have you ever done any testing with a 30 degree seat & valve face? I know it's not the best HP setup but I read an article where Dulcich suggests it... He says it improves flow from .100-.400 without hurting flow at higher lift much.... He went on to point out the valve sees that .100-.400 range twice for every one time it sees max lift so gains down low can have a bigger effect than max lift flow... He only suggests doing it on the intake side.... I thought it was an interesting idea... Especially for guys like me who only run 550ish lift cams....
 
Did you use the 30* x 0.070" cut? I've heard that this is the most popular back cut for the valve's.
 
1WildRT said:
Have you ever done any testing with a 30 degree seat & valve face? I know it's not the best HP setup but I read an article where Dulcich suggests it... He says it improves flow from .100-.400 without hurting flow at higher lift much.... He went on to point out the valve sees that .100-.400 range twice for every one time it sees max lift so gains down low can have a bigger effect than max lift flow... He only suggests doing it on the intake side.... I thought it was an interesting idea... Especially for guys like me who only run 550ish lift cams....
Click to expand...


No I stick with the old conventional 45 degree valve seat I’m not willing to sacrifice valves and valve seats testing stuff like that because sometimes it’s a one shot deal.
 
1WildRT said:
Have you ever done any testing with a 30 degree seat & valve face? I know it's not the best HP setup but I read an article where Dulcich suggests it... He says it improves flow from .100-.400 without hurting flow at higher lift much.... He went on to point out the valve sees that .100-.400 range twice for every one time it sees max lift so gains down low can have a bigger effect than max lift flow... He only suggests doing it on the intake side.... I thought it was an interesting idea... Especially for guys like me who only run 550ish lift cams....
Click to expand...
I have done a little testing on the china magnum iron heads currently available. We played with a few different valve sizes and seats, and for a low lift situation (oval track rules) those heads pick up really good with the 30° seat. Conventional multi angle 45° is better for anything more than that in my opinion.
 
1WildRT said:
Have you ever done any testing with a 30 degree seat & valve face? I know it's not the best HP setup but I read an article where Dulcich suggests it... He says it improves flow from .100-.400 without hurting flow at higher lift much.... He went on to point out the valve sees that .100-.400 range twice for every one time it sees max lift so gains down low can have a bigger effect than max lift flow... He only suggests doing it on the intake side.... I thought it was an interesting idea... Especially for guys like me who only run 550ish lift cams....
Click to expand...

It’s all about the shape. Vizard was big on 30 degree seats.

While you can’t ignore what goes on at .100 lift, the valve spends so little time at those lower lifts that it’s really hard to make big improvements in power focusing on flow down there.

How much flow can you gain when the valve is .100 or .200 off the seat? The curtain area is so small any gains will be small and may affect flow at lifts where the valve spends most of its time.

You also have to consider what the shape of the flow is getting around the valve with a 30 degree seat. Any time you flatten the seat angle, you force the air to head towards the chamber wall rather than into the chamber.

Visualize what the shape of the flow would be like (or draw it out if you like that better) With a 30, 45, 50, 52, 60, 62 or even a 65 degree seat.

The steeper the seat the more vertical the flow pattern around the valve is.
 
Is there ever any gain to back cutting the exhaust valve? I've heard people say there is, but never seen any testing and I don't see how it could have any effect.
 
RustyRatRod said:
Is there ever any gain to back cutting the exhaust valve? I've heard people say there is, but never seen any testing and I don't see how it could have any effect.
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Weingartner talks about backcutting the intake in pretty much every video, he says there is no real improvement in doing it to the exhaust though
 
Icetech said:
Weingartner talks about backcutting the intake in pretty much every video, he says there is no real improvement in doing it to the exhaust though
Click to expand...
I didn't think so. All the exhaust needs to do is get out.
 
RustyRatRod said:
Is there ever any gain to back cutting the exhaust valve? I've heard people say there is, but never seen any testing and I don't see how it could have any effect.
Click to expand...
It looks good on the flow numbers, but it actually HURTS power in most cases. Exhaust side that is
 
1WildRT said:
Have you ever done any testing with a 30 degree seat & valve face? I know it's not the best HP setup but I read an article where Dulcich suggests it... He says it improves flow from .100-.400 without hurting flow at higher lift much.... He went on to point out the valve sees that .100-.400 range twice for every one time it sees max lift so gains down low can have a bigger effect than max lift flow... He only suggests doing it on the intake side.... I thought it was an interesting idea... Especially for guys like me who only run 550ish lift cams....
Click to expand...
I am sure you know this but anyway some Pontiac engines ran a 30 deg seat from the factory.

I asked about using it on a low rpm big block in a speed talk post. Wound up speaking with Mike Jones himself and he said just run the 45 with his cam.

This was the consensus most of the others had reached prior to him chiming in as well. Talk was the better flow did not translate to better numbers on the dyno.

I am all ears if someone else chimes in with their experience.
 
Hysteric said:
Anything that increases reversion will inhibit cylinder fill.
Click to expand...


That is 100% FACT. I can’t emphasize it too much. Reverse flow is BAD. Anything that can be done to reduce it (within reason) will always make more power even you lose a little in the normal direction of flow.
 
I always thought (and I used)_that any "good" valve job had 30/45/60 degree cuts on the seat, and 45/30 on the valve, to get the proper seat width. I have done a couple of heads for street engines, that I used 30 degree seats, that seemed (butt dyno) to help low end torque, and economy. Caveat: these were heads that needed a valve job to start with.
 
Charrlie_S said:
I always thought (and I used)_that any "good" valve job had 30/45/60 degree cuts on the seat, and 45/30 on the valve, to get the proper seat width. I have done a couple of heads for street engines, that I used 30 degree seats, that seemed (butt dyno) to help low end torque, and economy. Caveat: these were heads that needed a valve job to start with.
Click to expand...


There are far better valve jobs out there than the standard 15 degree cut.
 
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