1G FP1 intake/FP2 exhaust cam degreeing

[Anthony Boni]

Hello all.

I have a FP1 intake and an FP2 exhaust cam. Looking at the cam cards, how am I supposed to degree them? I figured it would have an opening and closing event for each cam, but I’m not sure how to determine that just from looking at the information from these cards.

I watched Jafro’s cylinder head 205 video with him explaining how to degree cams, but he doesn’t cover how to degree cams using the centerline method. Is that what I have to do with these cams? I can look up how to do the centerline method if need be cause I have no idea how . Thanks.

 

[Anthony Boni]

Anyone able to give me a hand?

 

[Anthony Boni]

Oops I think I overlooked this part. So the intake valve is suppposed to open at 0°BTDC and closes 180° ABDC. The exhaust valve has to close 0°ATDC and opens 0° BBDC.

As for the FP1 intake cam, I’m measuring the valve timing from .006” and the FP2 exhaust cam valve timing from .050”. Right?

 

[tektic]

You look at the card for the measured height. You start turning the crank until that height is reached. You mark that on the degree wheel. Keep cranking until it stops going up mark that as peak. keep going slow till it goes down mark that and your centerline will between those two marks. And continue to the measured height and thats your closing event. Write down all those numbers and do it a few more times to make sure its accurate. Advance or retard the can gear to make it line up with the events on the card.

Go to next can and repeat.

 

[Anthony Boni]

You look at the card for the measured height. You start turning the crank until that height is reached. You mark that on the degree wheel. Keep cranking until it stops going up mark that as peak. keep going slow till it goes down mark that and your centerline will between those two marks. And continue to the measured height and thats your closing event. Write down all those numbers and do it a few more times to make sure its accurate. Advance or retard the can gear to make it line up with the events on the card.

Go to next can and repeat.

Explaining it like that makes things easier . Measured height being what I highlighted in this picture, correct?

 

[tektic]

No. @.050"

 

[DSMPT]

You should do the .050" lift/1mm lift method. Would be more accurate than the centerline method unless you are sure the cams are really symmetric.

 

[Anthony Boni]

No. @.050"

oh okay I understand what you’re saying. I think. So the valve timing on the exhaust cam is .050”, while my intake cam says .006”

Do I complete the process on each cam gear as you described in post #4 except for the intake I proceed to .006” and the exhaust I proceed to .05”?

You should do the .050" lift/1mm lift method. Would be more accurate than the centerline method unless you are sure the cams are really symmetric.

Sorry, I don’t understand. Care to elaborate a bit? My first time degreeing cams and I thought I had everything down after watching jafros video. Then I pulled up the cam card and I’m pretty confused

 

[DSMPT]

oh okay I understand what you’re saying. I think. So the valve timing on the exhaust cam is .050”, while my intake cam says .006”

Do I complete the process on each cam gear as you described in post #4 except for the intake I proceed to .006” and the exhaust I proceed to .05”?

Sorry, I don’t understand. Care to elaborate a bit? My first time degreeing cams and I thought I had everything down after watching jafros video. Then I pulled up the cam card and I’m pretty confused

I feel you, it is complicated especially at the beginning. The best way to understand is you play with a degree wheel and a dial indicator.
As for the centerline method, this method is for cams with symmetrical lobes. So you can't do that accurately if they are asymmetrical.

Here is a good write-up by Kelford.

https://www.kelfordcams.com/global/technical-advice/the-sole-purpose-of-degreeing-your-cam/

 

[motomattx]

I just realized that the Kelford cam company is close to the Link Ecu company, they look to be neighbors...interesting.

 

[donniekak]

Use the centerline method. If you try to match opening and closing events it’ll never come out right.

 

[Anthony Boni]

I feel you, it is complicated especially at the beginning. The best way to understand is you play with a degree wheel and a dial indicator.
As for the centerline method, this method is for cams with symmetrical lobes. So you can't do that accurately if they are asymmetrical.

Here is a good write-up by Kelford.

https://www.kelfordcams.com/global/technical-advice/the-sole-purpose-of-degreeing-your-cam/

That’s a really good link, thanks!

Use the centerline method. If you try to match opening and closing events it’ll never come out right.

Why is that? These are two different cams. They’re not symmetrical so it wouldn’t work, right?

 

[donniekak]

I’ve degree’d cams 50+ times with the centerline method. I’m not sure if I’ve ever seen a set that kept the valve open exactly as long as advertised. So if you set them up according to when they’re supposed to open the closing event will always be wrong.

 

[Anthony Boni]

I’ve degree’d cams 50+ times with the centerline method. I’m not sure if I’ve ever seen a set that kept the valve open exactly as long as advertised. So if you set them up according to when they’re supposed to open the closing event will always be wrong.

Is the centerline method the same method that was explained by @tektic in post #4? If not, what is different?

 

[donniekak]

Just use an online calculator. The cam card will have the intended centerlines on it.
http://www.wallaceracing.com/camcalc.php

 

[Anthony Boni]

Just use an online calculator. The cam card will have the intended centerlines on it.
http://www.wallaceracing.com/camcalc.php

That site is not working for me. Press calculate and it just resets everything . The centerline for the Intake is 99° and for the exhaust is 102°, according to their respectable cam cards.

 

[EVLGSX]

I couldn't get that one to work either.

Is there a degree wheel you guys prefer?

 

[donniekak]

I use a 9” comp wheel. The bigger the better.

 

[Anthony Boni]

So I was outside for close to 4 hours today trying to degree these cams with those cam cards I originally posted. They’re way wrong. I found the correct ones and I will try again tomorrow. I’m not sure what happened there. Hope I didn’t mess up my valves though. I’ll have to do a compression test after I get everything degreed correctly

 

[Anthony Boni]

I need some help reading these cam cards I found on the post just above this one. How do I read those opening and closing events? It says -3° BTDC for the 101100 cam. Wouldn’t that just be 3°ATDC?