Time to go Stage II!

[turbobitt]

The intake has a difference (advertised minus .050") of 37, and the exhaust is 40.

Sounds soft but good for durability. With a cam that large and with the small Buick base circle, spring selection will be touchy. I would run that as close to coil bind as possible with the RPM level you plan on running.

Allan G.

 

[norbs]

Look again because if it is the exteam street profile lobes they are rated at .015 lift and not an apples to apples comparison.

If it is a the extream street it will be good anyway and designed to run at tight lash.[/quote]
It is rated at .015, how do i calculate the ramp rate now?

 

[turbobitt]

Look again because if it is the exteam street profile lobes they are rated at .015 lift and not an apples to apples comparison.

If it is a the extream street it will be good anyway and designed to run at tight lash.

It is rated at .015, how do i calculate the ramp rate now?[/quote]

To be honest I don't really know. You would have to install it and take your own readings using a degree wheel. This was designed to run tight on the lash and is why it is rated at .015. From what Tim Cole at comp cams tells me, these are agressive ramps. I wish I knew how to compare it to rest of the catalog.

Allan G.

 

[turbobitt]

It is rated at .015, how do i calculate the ramp rate now?

To be honest I don't really know. You would have to install it and take your own readings using a degree wheel. This was designed to run tight on the lash and is why it is rated at .015. From what Tim Cole at comp cams tells me, these are agressive ramps. I wish I knew how to compare it to rest of the catalog.

Allan G.[/quote]

Oh ya, and don't forget that it will loose about 4-6 degrees duration from the cam card. Lobes are based on chevy base circles and shrink on Buick cores.

Allan G.

 

[Alky V6]

I just finished degreeing the intake lobe and the difference between .020" and .050" is 34.5 degrees. It looks like they're using .020" for their advertised rating.

 

[Alky V6]

Looking at velocity, acceleration and jerk throughout the curve, it's looking very nice. A noticeably softer landing on the closing end compared to the opening end. Very interesting.

 

[Alky V6]

I'll be degreeing the exhaust tomorrow. That's the one I'm really interested in, since the sim is showing the exhaust side is going to be more of a problem than the intake side.
I'll be loading the exact cam lobe specs into the sim to see how the outputs change. I've been using the generic lobe profile that the sim comes up with using the general specs for the cam. With the more exact lobe profile entered, it will be interesting to see if the valve float predictions change. Hopefully, for the better.

 

[Alky V6]

Some camshaft recommendations taken from Four Stroke Performance Tuning by A. Graham Bell.
The cam follower velocity of a high performance cam is normally about .007" per degree. Some racing cams will produce .009"-.012" per degree velocity which is considered above the safe limit for many engines.
Negative acceleration should be less than -.0002" per degree, per degree, but .0002"-.00028" is tolerable.
Maximum positive acceleration may be as high as .0006"-.0007" per degree, per degree.

 

[Alky V6]

Max values for the intake lobe are;
Lifter body diameter: .903"

Velocity: -.0079406" - +.0079753"

Acceleration: -.0002865" - +.0002599"
-.0002865" occurring at a small point at the start of the valve closing after traveling over the nose of the cam.

Jerk: -.0000832" - +.0000677"

Maintaining maximum lift value through 8 degrees of crankshaft rotation.

 

[turbobitt]

Max values for the intake lobe are;
Lifter body diameter: .903"

Velocity: -.0079406" - +.0079753"

Acceleration: -.0002865" - +.0002599"
-.0002865" occurring at a small point at the start of the valve closing after traveling over the nose of the cam.

Jerk: -.0000832" - +.0000677"

Maintaining maximum lift value through 8 degrees of crankshaft rotation.

Are you comfortable with your spring selection for your intended RPM with that small base circle?

What lifter are you running ? Was thinking of going to the bigger body lifter on the next build.

Allan G.

 

[Alky V6]

Are you comfortable with your spring selection for your intended RPM with that small base circle?

What lifter are you running ? Was thinking of going to the bigger body lifter on the next build.

Allan G.

I still have to measure the available spring height for the guys at Crower before they can recommend a spring for me. I'll be doing that tomorrow, after I degree the exhaust lobe. I'll also be weighing valvetrain components to enter into the sim.
The lifters are the Enduramax by Crower, with the pressure fed, bushed roller. Left offset on all lifters.
On the past build I was running Crowers also, but they were the typical needle roller type. I don't believe they were pressure fed. They worked just fine.

 

[turbobitt]

I still have to measure the available spring height for the guys at Crower before they can recommend a spring for me. I'll be doing that tomorrow, after I degree the exhaust lobe. I'll also be weighing valvetrain components to enter into the sim.
The lifters are the Enduramax by Crower, with the pressure fed, bushed roller. Left offset on all lifters.
On the past build I was running Crowers also, but they were the typical needle roller type. I don't believe they were pressure fed. They worked just fine.

Thanks for the info. Do the Enduramax have the oversize bearings/bushings ?

 

[Alky V6]

Thanks for the info. Do the Enduramax have the oversize bearings/bushings ?

I expect that they are oversized. Here are the dimensions of the roller;
Diameter: .812".
Width: .450".
Pin diameter: approx .365".

 

[turbobitt]

I expect that they are oversized. Here are the dimensions of the roller;
Diameter: .812".
Width: .450".
Pin diameter: approx .365".

OK, Found them on the website but not on the PDF catalog. They look like a new line of lifters with the needleless bearing and Hippo oiling standard. Listing says .903 and .937 come with oversize shaft. Keep us posted on the durability of these lifters. The conventional needle rollers are only available with oversized shafts on the .903 or larger bodies only.

Allan G.

 

[Alky V6]

OK, Found them on the website but not on the PDF catalog. They look like a new line of lifters with the needleless bearing and Hippo oiling standard. Listing says .903 and .937 come with oversize shaft. Keep us posted on the durability of these lifters. The conventional needle rollers are only available with oversized shafts on the .903 or larger bodies only.

Allan G.

I talked to Dave Crower about the new bushed lifters and he told me they have thousands out there being used. He could only recall one failure on an application that restricted oil to the lifter galleys. He said to run unrestricted oil to these lifters.

 

[turbobitt]

I talked to Dave Crower about the new bushed lifters and he told me they have thousands out there being used. He could only recall one failure on an application that restricted oil to the lifter galleys. He said to run unrestricted oil to these lifters.

What would be considered unrestricted ? For example, I have a .040" feed hole to each lifter but the lifter galleys themselves are unrestricted.

Allan G.

 

[Alky V6]

Max values for the exhaust lobe are;
Lifter body diameter: .903"

Velocity: -.0082512" - +.0080027"
Max velocities (velocities over .0079) occurring halfway into the opening and closing ramps for only a very short span. 2 degree span on the positive (opening) side, 20 degree span on the negative (closing) side.

Acceleration: -.0003045" - +.0004205"
Maximum positive acceleration occurring at the tail end of the closing ramp. Well past the clearance ramp.
Maximum negative acceleration occurring just after passing over the nose of the cam and at the beginning of the closing ramp.

Jerk: -.0001184" - +.0001803"
Max jerk values occurring at the beginning and the ending of the curve.

Maximum lift dwell time over the nose is 6 crankshaft degrees.

 

[Alky V6]

What would be considered unrestricted ? For example, I have a .040" feed hole to each lifter but the lifter galleys themselves are unrestricted.

Allan G.

I got the impression from Dave that you want full flow and pressure to the lifters. The oil holes (there are two) in the lifters that feed the pushrods are clearance fed. The pushrod feed holes are about 180 degrees from each other, slightly above the large machined groove around the middle of the body of the lifter. There is no trench machined into the body from the large groove around the middle of the body to these holes. The holes are truly clearance fed.

The roller bushing is fed through a small .024" hole that opens into the deep machined groove around the middle of the lifter body, and sees full galley pressure. I'll try to post a picture tonight.

edited: July 26th, 2012

 

[Alky V6]

Next operation is to clearance the heads for the pushrods.

 

[Alky V6]

Here are the lifters. The oil feed holes in the body of the lifters coincide with the location of the pushrod seats. I'm running left offset on all the lifters.