Solid Roller Cam (Mad Porter Custom) Degree Question

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Solid Roller Cam (Mad Porter Custom) Degree Question

Post  t120r on November 4th 2016, 5:50 pm

I'm checking over my cam (Custom XR274R by The Mad Porter) with a degree wheel and I came up with the following numbers:

Cam Card:
IN Open = 7.7 BTDC
IN Close = 47.9 ABDC
IN CL = 109.9 ATDC
EX Open = 59.4 BBDC
EX Close = 7.6 ATDC
EX CL = 116.6

Measured on engine:

IN Open = 15.5 BTDC
IN Close = 44 ABDC
IN CL = 104.5 ATDC
EX Open = 63.5 BBDC
EX Close = 0.5 ATDC
EX CL = 120.8

Difference:

IN Open = 7.8 ADV
IN Close = 3.9 ADV
IN CL = 4.5 ADV
EX Open = 4.1 ADV
EX Close = 7.1ADV
EX CL = 4.2ADV

There is a part of the camcard that says 3.8adv. That tells me there is built in advance on the cam right? Does that mean I should leave the cam gear as is due the centerlines being close to that advance number, or should I retard it to bring the IN and EX openings to that advance number?


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Re: Solid Roller Cam (Mad Porter Custom) Degree Question

Post  IDT-572 on November 4th 2016, 10:51 pm

You have something slipping when your degreeing or the cam is ground wrong.

The duration @ .050 is way different than what the card says.

Card says 235/247 you measured 239.5/244
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Re: Solid Roller Cam (Mad Porter Custom) Degree Question

Post  460bronco on November 5th 2016, 10:33 pm

Do you have a new timing set? Did you reverse the rotation of the engine ever while measuring?
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Re: Solid Roller Cam (Mad Porter Custom) Degree Question

Post  t120r on November 7th 2016, 2:08 pm

For any and all watching this thread, I called Scott at RHP and we talked about my cam and engine combo. He explained the cam card vs what my readings were and I am pleased to say that the engine will be getting closed up today and I am glad I called him. I should have called him in the first place. At the end of the day I am happy with the customer service and advice he provides and I will recommend RHP to my friends and I will also be a repeat customer in the future. Thank You Scott.

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Re: Solid Roller Cam (Mad Porter Custom) Degree Question

Post  IDT-572 on November 7th 2016, 2:25 pm

What was the problem?
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Re: Solid Roller Cam (Mad Porter Custom) Degree Question

Post  The Mad Porter on November 11th 2016, 9:59 pm

IDT-572 wrote:What was the problem?

The primary issue was the timing set / keyway locations. When checking cams for our crate engines I rarely if ever have to move the cam as they are spot on. The last hydraulic roller I did in My 557 had to be retarded 2 degrees with my chosen timing set. Another timing set showed proper timing at straight up.

Secondary was that when I ordered the cam instead of 236 / 242 I asked the cam grinder to use tooling that would grow several degrees when ground on the BBF billet and added exhaust timing. Though labeled as an XR274R it is actually a custom grind with added exhaust timing with a wide lobe sep due to high static c/r.

I recently ordered a custom cam from comp 252 / 266 hydraulic roller. When we ran it on the cam doctor / performance trends software it showed 253.xx / 267.xx... I have stood there and watched 3 different tests on the same lobe come up with slightly different results. As the cam is rolled by hand the results can change based on how evenly cam is rotated. Clients cam was ground in 2011 and at the time Delta was using different software to measure the cam's events.



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