SBC combination critique
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Re: SBC combination critique
What would the perceived benefit of valve seat angles greater than conventionally used?
Not sure Im getting the jist of that.
High rpm or higher rpm usage I presume? Seems like it would be a negative to overlap exchange and therefore VE
Not sure Im getting the jist of that.
High rpm or higher rpm usage I presume? Seems like it would be a negative to overlap exchange and therefore VE
Re: SBC combination critique
In simple terms, super high lift, high rpm engines use steeper seats to prevent valve bounce, from a power prospective the reduced overlap effect allows a bigger cam than normal which allows you to take advantage of more lift earlier in the intake stroke.Sumtingwong wrote: ↑Wed Feb 13, 2019 10:08 am What would the perceived benefit of valve seat angles greater than conventionally used?
Not sure Im getting the jist of that.
High rpm or higher rpm usage I presume? Seems like it would be a negative to overlap exchange and therefore VE
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THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
Re: SBC combination critique
GARY C wrote: ↑Wed Feb 13, 2019 10:22 amIn simple terms, super high lift, high rpm engines use steeper seats to prevent valve bounce, from a power prospective the reduced overlap effect allows a bigger cam than normal which allows you to take advantage of more lift earlier in the intake stroke.Sumtingwong wrote: ↑Wed Feb 13, 2019 10:08 am What would the perceived benefit of valve seat angles greater than conventionally used?
Not sure Im getting the jist of that.
High rpm or higher rpm usage I presume? Seems like it would be a negative to overlap exchange and therefore VE
Lift is NOT a factor. Wasn't this covered in the other threads? It was. As for durability...there is no reason why a 50 degree seat is any less reliable than a 45. Just like a 45 is no less reliable than a 30.
You can stay stuck in the past or move forward. If it's a performance deal, you should at least look at a 50. IIRC, one guy used a 50 on his tow rig. Had under .500 lift. I forget his name. Look it up.
Re: SBC combination critique
Then I guess it's settled.ClassAct wrote: ↑Wed Feb 13, 2019 12:02 pmGARY C wrote: ↑Wed Feb 13, 2019 10:22 amIn simple terms, super high lift, high rpm engines use steeper seats to prevent valve bounce, from a power prospective the reduced overlap effect allows a bigger cam than normal which allows you to take advantage of more lift earlier in the intake stroke.Sumtingwong wrote: ↑Wed Feb 13, 2019 10:08 am What would the perceived benefit of valve seat angles greater than conventionally used?
Not sure Im getting the jist of that.
High rpm or higher rpm usage I presume? Seems like it would be a negative to overlap exchange and therefore VE
Lift is NOT a factor. Wasn't this covered in the other threads? It was. As for durability...there is no reason why a 50 degree seat is any less reliable than a 45. Just like a 45 is no less reliable than a 30.
You can stay stuck in the past or move forward. If it's a performance deal, you should at least look at a 50. IIRC, one guy used a 50 on his tow rig. Had under .500 lift. I forget his name. Look it up.
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THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
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Re: SBC combination critique
How could there not be an increase in pressure concentration as that inclination angle increases????????
Re: SBC combination critique
So how many 50 degree valve jobs have you done? I had them in street cars (including my own) drag stuff and circle junk. I have NEVER seen the seats look any worse than any other valve job. Sure, beat on it and they look at bit worse but I've never had one fail.GARY C wrote: ↑Wed Feb 13, 2019 12:25 pmThen I guess it's settled.ClassAct wrote: ↑Wed Feb 13, 2019 12:02 pm
Lift is NOT a factor. Wasn't this covered in the other threads? It was. As for durability...there is no reason why a 50 degree seat is any less reliable than a 45. Just like a 45 is no less reliable than a 30.
You can stay stuck in the past or move forward. If it's a performance deal, you should at least look at a 50. IIRC, one guy used a 50 on his tow rig. Had under .500 lift. I forget his name. Look it up.
Again, it's about the shape.
I suggest the OP do his 30 degree seat and be happy. It's what he wanted. I should have never said anything because moving forward for some is just too damn hard.
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Re: SBC combination critique
So you know enough to use big words like that but can't build a run-of-the-mill 350 in any of 500 magazines without help?Sumtingwong wrote: ↑Wed Feb 13, 2019 12:44 pm How could there not be an increase in pressure concentration as that inclination angle increases????????
Something doesn't add up.
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Re: SBC combination critique
Can you provide a link to a 500 horse pump 350?midnightbluS10 wrote: ↑Wed Feb 13, 2019 1:31 pmSo you know enough to use big words like that but can't build a run-of-the-mill 350 in any of 500 magazines without help?Sumtingwong wrote: ↑Wed Feb 13, 2019 12:44 pm How could there not be an increase in pressure concentration as that inclination angle increases????????
Something doesn't add up.
Re: SBC combination critique
A 4.00" bore with 2.080" intake valve and stock valve guide placement is a waste of time because of little to no bore edge to intake valve clearance. You need to pop a head on the bare block, flip it over and see what you have for clearance, if any. No problem with a bigger bore.
Re: SBC combination critique
Who said anything about one failing?ClassAct wrote: ↑Wed Feb 13, 2019 1:14 pmSo how many 50 degree valve jobs have you done? I had them in street cars (including my own) drag stuff and circle junk. I have NEVER seen the seats look any worse than any other valve job. Sure, beat on it and they look at bit worse but I've never had one fail.GARY C wrote: ↑Wed Feb 13, 2019 12:25 pmThen I guess it's settled.ClassAct wrote: ↑Wed Feb 13, 2019 12:02 pm
Lift is NOT a factor. Wasn't this covered in the other threads? It was. As for durability...there is no reason why a 50 degree seat is any less reliable than a 45. Just like a 45 is no less reliable than a 30.
You can stay stuck in the past or move forward. If it's a performance deal, you should at least look at a 50. IIRC, one guy used a 50 on his tow rig. Had under .500 lift. I forget his name. Look it up.
Again, it's about the shape.
I suggest the OP do his 30 degree seat and be happy. It's what he wanted. I should have never said anything because moving forward for some is just too damn hard.
Please Note!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
Re: SBC combination critique
Food for thought from the valve mnf and some pro engine builders on this subject.
https://www.enginelabs.com/features/val ... rk-engine/
EDIT
I found this interesting.
"There certainly isn’t a downside to 45-degree valve-seat angles. There are plenty of winners using a standard 60-45-30 valve job. And in a recent report by Race Engine Technology, there was an in-depth retrospect on the Cosworth CA Formula 1 V8 engine from 2006. Revving to 20,000 rpm, this 2.4-liter engine featured 41.3mm (1.63-inch) solid titanium intake valves with a 1mm (.039-inch) wide 45-degree seat. On top, there were four progressive shallow angles before blending into the stem. The intake also featured four different coatings to improve durability. On the exhaust side, there was 35.0mm (1.38-inch) sodium-cooled titanium valve with a 2mm wide 42-degree seat. So, the fastest-spinning V8 in racing used a 45-degree angle on the intake and even shallower on the exhaust."
And this!
“The seat angle is not always the magic,” reminds Boggs. “The magic is in the angles above and below it and how that shapes the venturi. People tend to fixate on the seat angle. It’s only one piece of a multi-angle puzzle. The whole thing is about creating the shape of the venturi.”
https://www.enginelabs.com/features/val ... rk-engine/
EDIT
I found this interesting.
"There certainly isn’t a downside to 45-degree valve-seat angles. There are plenty of winners using a standard 60-45-30 valve job. And in a recent report by Race Engine Technology, there was an in-depth retrospect on the Cosworth CA Formula 1 V8 engine from 2006. Revving to 20,000 rpm, this 2.4-liter engine featured 41.3mm (1.63-inch) solid titanium intake valves with a 1mm (.039-inch) wide 45-degree seat. On top, there were four progressive shallow angles before blending into the stem. The intake also featured four different coatings to improve durability. On the exhaust side, there was 35.0mm (1.38-inch) sodium-cooled titanium valve with a 2mm wide 42-degree seat. So, the fastest-spinning V8 in racing used a 45-degree angle on the intake and even shallower on the exhaust."
And this!
“The seat angle is not always the magic,” reminds Boggs. “The magic is in the angles above and below it and how that shapes the venturi. People tend to fixate on the seat angle. It’s only one piece of a multi-angle puzzle. The whole thing is about creating the shape of the venturi.”
Please Note!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
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Re: SBC combination critique
You said it!
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THE ABOVE POST IN NO WAY REFLECTS THE VIEWS OF SPEED TALK OR IT'S MEMBERS AND SHOULD BE VIEWED AS ENTERTAINMENT ONLY...Thanks, The Management!
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Re: SBC combination critique
A 2.02 valve with 45 seat is more than capable of 500hp atSumtingwong wrote: ↑Wed Feb 13, 2019 1:42 pmCan you provide a link to a 500 horse pump 350?midnightbluS10 wrote: ↑Wed Feb 13, 2019 1:31 pmSo you know enough to use big words like that but can't build a run-of-the-mill 350 in any of 500 magazines without help?Sumtingwong wrote: ↑Wed Feb 13, 2019 12:44 pm How could there not be an increase in pressure concentration as that inclination angle increases????????
Something doesn't add up.
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Re: SBC combination critique
Sumtingwong wrote: ↑Wed Feb 13, 2019 8:48 am So perhaps I will keep it simple with a three angle 45 degree 2.02 valve seat job and hope it comes close to meeting my goals....
I could be wrong, but I think the Dart Platinum heads already come with a 45 degree valve seat angle-based 5 angle valve job. -You planning on intentionally "downgrading" your heads with a new 3 angle valve job over the stock 5 angle valve job???
https://static.summitracing.com/global/ ... 20head.pdf
Stock intake valve job: 32, 45, 60, 70, 80
Exhaust: 37, 45, radius
Adam