Excellent work by Todd as usual. This is interesting timing as I have a cam question. I have the Crower 62822-4 cams. I understand the 222/222 @ .050 valve lift and their 264/264 total advertised lift, but, why do they list that as at the valve and then say 252/252 and 206/206 @ .050? http://www.crower.com/camshafts/ford-4-6-5-4-4-valve-modular-camshaft-1999-up-set-5032.html
Mark Olson's cam calculator is excellent as well. I'm actually widening my LSA (to cam card specs) as I had low vacuum at idle and tuning idle is a bitch when you have even a little overlap allowing air to hit your O2s. Thanks

cam card: https://www.crower.com/camshaft-tim...t-timing-tags/index/downloadPdf/id/165535/key/1b72c0fb1a6f164c33a055f673fff97b/

PS: Would the fact that Crower states they have 4 degrees of advance ground into these cams account for the fact that the card states LCs of 110/118 and in the spreadsheet they're listed as 114/114?

 

Excellent work by Todd as usual. This is interesting timing as I have a cam question. I have the Crower 62822-4 cams. I understand the 222/222 @ .050 valve lift and their 264/264 total advertised lift, but, why do they list that as at the valve and then say 252/252 and 206/206 @ .050? http://www.crower.com/camshafts/ford-4-6-5-4-4-valve-modular-camshaft-1999-up-set-5032.html
Mark Olson's cam calculator is excellent as well. I'm actually widening my LSA (to cam card specs) as I had low vacuum at idle and tuning idle is a bitch when you have even a little overlap allowing air to hit your O2s. Thanks

cam card: https://www.crower.com/camshaft-tim...t-timing-tags/index/downloadPdf/id/165535/key/1b72c0fb1a6f164c33a055f673fff97b/

Mark's Valve Timing Calculator is nothing short of excellent RacerX (BTW name?). While the two tools serve different purposes, I find Mark's tool to be a real handy gizmo!

The measurement of timing at the valve on OHC engines is somewhat of a convention because of the various ways the valve can be actuated in OHC engines. Pushrod engines have a very convenient at the lobe measurement capability. OHC engines don't, they have to do it at the valve. when looking at cams minimally look at the 0.050" at the valve figures. Some companies will offer a 0.100" or 0.200" duration figure. It is a way of getting a feel for how fast the cam opens the valve but you need to compare apples to apples and use either both 0.100" figs or both 0.200" figs.

 

The Crower 62824-4 have the wrong specs unless Crower changed them. I used to run those cams and my cam card from Crower shows them at 228/228 at .050. The chart that was posted shows them at 212/212 at .050. Can anyone confirm if Crower changed the specs?

 

Disregard. The specs I have on my cam card stats that the values are taken at the valve. I believe the values posted on the above spreadsheet are taken at the cam.

This is what the current Crower website shows Jim,

which is the same figures the spreadsheet shows. Modmotor cams are usually spec'd at valve lift rather than tappet rise as in the pushrod engines. The reason is most likely the timing variations created by the various forms of valve actuating mechanisms in use. The possibilities go from a direct acting model with the cam lobe acting directly against the tip of the valve or a cup on top of the valve, to one of the many finger follower models that use one or more followers to control lift and duration. The multiple follower model is the BMW (and possibly others) approach where multiple cams and multiple followers are used to actuate a single valve controlling both lift and duration numbers.

If the lift timing events were to be measured directly off the cam lobe, it would be necessary to have a way to reference or index the readings from the sensor probe to the actual engine's crank position, which while not rocket science is non-the less a PITA. I would not be surprised to discover Crower revisited their profile numbering. I wanted to get to Crower before they closed today to ask but some thing about the plans of mice and men ...

Cam specs and advice from cam manufacturers is only slight removed from the 19th century art of snake oil sales. Even Crower says, that particular profile is 'specifically for supercharged applications for 3/4 race.' The absurdity of the comment is only exceeded by that of a 13/16 or 7/8 race engine. Of course the poor guys with a 9/16 race engine are just out of luck as are the 13/16 or 7/8 race crowd.

I would not place a lot of faith in the manufacturer specs. It is easy enough to "measure" the cam in the engine with a dial indicator and a degree wheel by checking lift at the valve and referencing it to crank degrees.

 

I am not sure right now Jim. I tried going over to the Crower site to check them and it is non-responsive. I'll take a shot at it again in the morning.

Ed

 

Disregard. The specs I have on my cam card stats that the values are taken at the valve. I believe the values posted on the above spreadsheet are taken at the cam.

 

It's Bill. thank you. So it would be nice if Crower would state the lift measurements for the other durations lol.

Eg:
INT/EXH - Dur @ .050” Lift: 206°/206° RR: 1.8/1.8 Gross Lift: .475”/.475” LSA: 114°
Advertised Duration: Intake / Exhaust 252 / 252
Advertised Duration at the Valve: Intake / Exhaust 264 / 264
Duration @ .050" Lift at the Valve: Intake / Exhaust 222 / 222

The 206/206 is likely @ .100 or .200 then since it only makes sense you'll have a shorter duration at higher valve lift measurements.
So answer me this, if I use Mark's cam chart, should I be using the 110 ICL and 118 ECL to punch in the numbers or 114/114 since 4 degrees of advance are ground in according to Crower? It's still a 114 LSA. Right now I have a LSA of 112.25 (ICL 107.5/ECL 117) and will set it to 110/118 on the new build. I now it's a difference of close to 4 degrees less overlap @ .050, but, that may be enough to help with idle tuning. At 21psi with a PD blower, I really don't want much overlap. Thoughts?

 

It's Bill. thank you. So it would be nice if Crower would state the lift measurements for the other durations lol.

Eg:
INT/EXH - Dur @ .050" Lift: 206°/206° RR: 1.8/1.8 Gross Lift: .475"/.475" LSA: 114°
Advertised Duration: Intake / Exhaust 252 / 252
Advertised Duration at the Valve: Intake / Exhaust 264 / 264
Duration @ .050" Lift at the Valve: Intake / Exhaust 222 / 222

The 206/206 is likely @ .100 or .200 then since it only makes sense you'll have a shorter duration at higher valve lift measurements.
So answer me this, if I use Mark's cam chart, should I be using the 110 ICL and 118 ECL to punch in the numbers or 114/114 since 4 degrees of advance are ground in according to Crower? It's still a 114 LSA. Right now I have an LSA of 112.25 (ICL 107.5/ECL 117) and will set it to 110/118 on the new build. I know it's a difference of close to 4 degrees less overlap @ .050, but, that may be enough to help with idle tuning. At 21psi with a PD blower, I really don't want much overlap. Thoughts?

You are reading the tea leaves correctly with respect to idle and overlap, Bill. The overlap will not kill it, but it does make it more challenging from a tuning perspective. With the excellent low lift flow that 4V heads have you can easily get away with zero or negative overlap like Ford does on their OEM cams albeit they do have shorter durations, usually.

The engine will respond very favorably to advancing the intake for low-speed and midrange torque improvements. If you phase the exhaust to close with zero to no more than 10 degrees of negative overlap you will have an excellent idle vacuum (15 inches maybe more) and very easy idle tuning along with the potent low-speed and midrange torque that makes these engines fun to drive. As long as you equal the OEM intake closing point your top-end peak power rpm will at least look OEM-like. If you exceed the OEM closing point (don't get crazy) the top-end peak power rpm will increase.

There are two ways to set camshaft phasing one uses opening and closing points and can get confusing for all the reasons and others that you identified. Instead, if you phase using the max lift point, opening ramps and all the other stuff will not impact the precision or accuracy of the job. Pick a point 0.050" short of the max valve lift, and record the crank angle. Pick a second point 0.050" past the max lift, and record the crank angle. The cam centerline that you have set is exactly midway between those two crank angle measurements. This is the most accurate and repeatable way to phase the cams. You escape all the BS the cam grinder may or may not have added to the job with his grinding and spec card printing practices.

 

I might have to put them in my mock up engine and measure them to see what the actual specs are, they did run great when installed per the cam card and made great power. They have since been removed in favor of some some custom ground bullet cams and have been sitting on the shelf ever since.

 

Lol at 3/4 race cam terminology. Good info on that for the curious here: http://www.enginelabs.com/engine-tech/cam-valvetrain/tech-quickie-what-is-a-34-race-camshaft/

 

Excellent walk down memory lane there Bill. :thumb3:

 

I'm not sure if this has been posted, but, there's a lot of mod motor info all in one place here: http://enginetech.com/wp-content/uploads/2014/10/High_Performance_Ford_Modular_Edition.pdf

 

What they have is a rather complete parts catalog for 2/3/4 valve Modmotor and also Coyote parts Bill. You can find similar breadth on the FRPP site with the Ford catalog. The magic is creating your own secret sauce out of the broad range of product offerings they have listed. Significantly they miss a number of the specialty manufacturers that produce the best of breed products that the guys on the site here have discovered through first hand experience.

I think the TToC and its various subsections will get you to the kind of engine you are trying to create faster (and potentially less expensively) than their parts catalog and you will have the additional benefit of actual builders / users experience with the parts.


Ed