New Summit Pro Hemi Cams. I need advice on giving good phaser tuning instructions.

[briannutter]

Hi fellas, it's Brian from Summit Racing. We have new 2009+ Hemi cams ready for release.

1.) 5.7 truck cams
2.) 6.4 truck cams
3.) Turbo Cams
4.) Supercharger cams
5.) Higher lift automotive naturally-aspirated cams with limited VVT
6.) "Big Guns" for pistons with valve reliefs in the 232 to 251 duration range

We're asking customers to bring you the cam cards with the four valve events and centerlines and doing our best to stress the importance of adjusting the phaser table BEFORE startup.

Here's where it's a little weird. I'm finding some manufacturers do their best to hide specs and I guess that's somewhat understandable. It's troublesome because it can result in a lot of bent exhaust valves if the phaser table isn't corrected prior to initial start. Comp, TSP and FRP do a good job with Duration, LSA and Advance. Those can *at least* be entered into the Summit Cam Timing Calculator to generate the Intake Opening, Intake Closing, Exhaust Opening and Exhaust Closing Valve Events. Some of the bigger cams are locked out with the intake open a few degrees btdc and the exhaust closing a few after and that's fine too. For those who will enable VVT, it's probably safer to never let exhaust closing go much further retarded mechanically than 0 ATDC to keep the exhaust valves from tagging the pistons.

I've gone through a lot of threads here where the valve events weren't thoroughly calculated prior to folks being given phaser advice. Two cams with seemingly the same duration and LSA can have drastically different events if cam advance is different.

Here is an example with the 6.4 Scat Pack Cam. 215/221 121 + 13. This converts to 0 I/O, 35.5 I/C, 64.5 E/O and -23.5 E/C. A little close on the intake but the phaser doesn't advance so that's fine. Even with a 14 degree phaser limiter, exhaust would never get closer than 9.5 btdc.

Here's one of our new cams though and I'll show you where it could cause trouble.

SUM-5723 5.7 TRUCK STG. 3 218 int. / 224 exh. 112.5 LSA, 3.5 ADV, -4 Overlap, 0 I/O, 38 I/C, 48 E/O, -4 E/C

This particular cam couldn't ever tag an intake valve BUT if a 14 degree phaser limiter alone is used with no phaser adjustment, the exhaust closing would be 10 ATDC and would likely crash.

I'm considering adding a note that states: "Hemi cam phasers start at full physical advance and retard from there. In general, this increases intake valve clearance and reduces exhaust clearance as the phaser retards. It is safest to set the exhaust closing point no later than TDC. If you see -8 degrees exhaust closing point on the cam card, you MUST limit total phaser travel to 8 degrees maximum before initial start to avoid catastrophic damage. Most cams will perform best with maximum advance from idle to peak torque and taper from there to redline. It is the engine builder's responsibility to check piston to valve clearance during the initial cam install to insure it matches the cam card value."

What are your guy's thoughts on this? I need to keep the message simple. As much as I wish everyone had your tuning abilities, that isn't the case and I try to keep our customers out of trouble. I also don't want customers putting these cams in and having them perform poorly due to loads of physical cam retard when they shouldn't have. I don't know if they understand they shouldn't run the engine AT ALL if the table hasn't been adjusted. Rather than trying to express it to them as a exhaust centerline difference (because they don't know the duration difference), it seems giving them a maximum value would always be safest if 138 is *always* the exhaust number.

Thank you for your help with this. If I've completely missed the ball on something or my knowledge of the phaser itself is incorrect, please let me know. It's very appreciated and we try to get these things right out of the gate! -Brian Nutter, Summit Racing R&D guy.

[spoolboy]

Tell your buyers to anticipate more demand for hemi valves and pistons.

[james1595]

So what would be the max value for valve events before piston to valve clearance issues become a problem

[rays04gtx]

So what would be the max value for valve events before piston to valve clearance issues become a problem

It's not that clear cut of an answer because of Valve lift, stock piston vs Aftermarket with Valve reliefs.

I applaud summit for reaching out to the G3 market, here's some advice from some one who has about 500hrs of G3 Dyno time.

#2,#5,#6,#8,#9,#11 through #26 WILL NEED TO BE LOCKED NO IF ANDS OR BUTTS ABOUT IT

#4,#7,##10, Limiter will depend on Valve pockets and tuning




If you want to make real NA power from G3 Hemi under 400CI ,, LSA has to be around 108-110, The OEM ECU has issues with 108's and lower, which is why we make 10-15% more Hp with a carb/MSD Hemi-6 , or Haltech.

Boosted 114-116 seems to be the magic Number.

#18,#22,#25,#26, those would be great with 110 LSA , .............. oh wait one of my cams is .640/.640 250/258 110 LSA 2 advance , its the cam that's in my 830HP 468 with AFR heads

Cam specs similar to #2 were tested during the Eagle's development ,Before the SRV intake decision was made. , that cam will work great with the 8speed trucks, but the 6 speed trucks will need some gear to make up for the loss Tq under 3000k, Remember over half of the people who cam these trucks are driving QC4x4s and at 5400lbs Min weight , your going to have a lot of disappointed customers...............For what it's worth # is almost a copy of the 6.4 Truck cam

[rays04gtx]

Tell your buyers to anticipate more demand for hemi valves and pistons.

See Don, I told you Denis is one of the smarter guys here.

[LilSick]

definitely

crashing valve trains has been a thing for quite some time tho

its nothing new - rocker to retainer, or pushrod to cyl head or...

i know a phaser creates a whole new aspect in the checking process but i dont have a gen 3 on a stand or a spare phaser to tear apart

all i can do is ask questions and throw ideas out there


I think someone is gonna have to make a tool to make a phaser adjustable while checking clearance. A adjustable limiter. Something so i can back the cam i have chosen up to whatever ECL creates the clearance i have deemed as minimum. Do that and it cant crash no matter what someone puts in the tune or how much error the phaser allows

As for the ones that are gonna bolt stuff in and not physically check everything... I imagine they will keep crashing

[james1595]

It's not that clear cut of an answer because of Valve lift, stock piston vs Aftermarket with Valve reliefs.

I applaud summit for reaching out to the G3 market, here's some advice from some one who has about 500hrs of G3 Dyno time.

#2,#5,#6,#8,#9,#11 through #26 WILL NEED TO BE LOCKED NO IF ANDS OR BUTTS ABOUT IT

#4,#7,##10, Limiter will depend on Valve pockets and tuning




If you want to make real NA power from G3 Hemi under 400CI ,, LSA has to be around 108-110, The OEM ECU has issues with 108's and lower, which is why we make 10-15% more Hp with a carb/MSD Hemi-6 , or Haltech.

Boosted 114-116 seems to be the magic Number.

#18,#22,#25,#26, those would be great with 110 LSA , .............. oh wait one of my cams is .640/.640 250/258 110 LSA 2 advance , its the cam that's in my 830HP 468 with AFR heads

Cam specs similar to #2 were tested during the Eagle's development ,Before the SRV intake decision was made. , that cam will work great with the 8speed trucks, but the 6 speed trucks will need some gear to make up for the loss Tq under 3000k, Remember over half of the people who cam these trucks are driving QC4x4s and at 5400lbs Min weight , your going to have a lot of disappointed customers...............For what it's worth # is almost a copy of the 6.4 Truck cam

I should have been more specific. With just the factory bottom end, what would be the limits.also the numbers you posted, which cams are those? Are they on the summit website?

[LilSick]

even if he could tell you the exact exhaust centerline number for min acceptable clearance

(the furthest you could safely retard cam grind number _____ )

and cam grind number ______ never varied and none of the factory machining ever varied and every cam chain in the world is stretched the exact same amount...

who is to say the cam is even at ECL ______ when the PCM thinks it is???

to give you a safe number that number would have to have a good bit of "insurance" built into it : )

[PurpleRam]

I should have been more specific. With just the factory bottom end, what would be the limits.also the numbers you posted, which cams are those? Are they on the summit website?

There the cams on the excel sheet that was posted in the other thread (Can Timing)

[james1595]

I know there are alot of variables, but even just a general this is as far as you should go, and any farther is up to car gods

[briannutter]

There is some REALLY great advice here and I appreciate it. The cams are on the shelf, but we haven’t flipped the switch to make them live on the site and for sale until I think we’ve done what we can to guide people.

I’m re-checking the Hellcat cam as compared to our biggest 232 Vvt cam. .006, .050 ,.200 numbers and degrees “to the pin”. The 20 other VVT capable cams fall inline soon after lol.

What Comp and some others have done is close the exhaust at 14 btdc and going earlier from there. So full mechanical retard would be 0tdc. if/when when the phaser isn’t behaving correctly.

Although it’s good they match to their phaser limiter, it also limits overlap to -14 degrees max.

Our cams are designed to be “right” with phaser lock. The 206, 212 and 218 truck grinds for instance will make great power down low and we can spread that tasty goodness with those 8/6/4 degrees of retard.

I want to double dog make sure I’ve got the info right, so we are remeasuring and I should have the data for you Thurs. It was going to be today but I was playing with a certain ‘73 Cuda project today!

Finally, you guys have favorite cams and favored phaser angles. Our cam timing calculator allows you to plug in the numbers. You will see exactly why it works well (and where) and then you’ll have direct comparison to the Pro Hemi’s and their behavior at the same phaser angles. I think you will like what you see in terms of valve events and it will help you make an informed decision.

As you can see, I’m pretty fearless about sharing data with you. You deserve it. Thank you.

[LilSick]

Rad. Thx. the cams i would love to see spec'd out are the non mds 6.4 cam and HC.

Duration at

006

020

040

050

100

150

200

300

[PurpleRam]

My customers want to know What is Summit going to do for the None VVT crowd ?

[LilSick]

thitek head and 750 mike jones solid roller

*odd question from a "i am not a off the shelf" motor builder

[PurpleRam]

thitek head and 750 mike jones solid roller

*odd question from a "i am not a off the shelf" motor builder

Never said "I'm not an off the shelf Engine builder" yes I do some odd ball stuff , finished up a 7.0l Toyota 3UR-FE V8 with custom XAT cams ,

[LilSick]

you know how it works

you look at what you have now and come up with a idea of where you want to go

you look at the list of masters, pick two, and decide where you want to put them

this is why i cannot believe no one here knows how quick the oem 6.4 ramp is



*you are all trying to use google maps without a starting location

[PurpleRam]

I know what the ramp rates are and for Roller Hyd cams they suck, and most of the Aftermarket cams are not any better, Melling, Comp and one other are the only 3 core makers out there for G3 cams and there're fundamentally the same dimensions.... you need to step up to a billet core and solid Dog bone type lifters . if you want big boy race car power ramp rates......and they tear up a lot of stuff in the G3 platform.

with OEM style Lifters Max Net Valve lift is .400 (1.5 base + .40 lobe lift) . 4 X 1.65(RR)=.660 Ex , .4125X1.6(RR) = .660 , we can't go smaller than 1.5 Base circle, the OEM style lifters will fall below the lifter valley casting. .4 lift net lift only allows us to get so aggressive with ramp rate be fore we over load that poor old .842 DIA wheel......Now when we machine out the Lifter bore for .904/.905 DIA lifter bodies we can get WAYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY more ramp rate.

for 1 we're dealing with Hydraulic roller lifter cams we can only get so aggressive with these , too much opening rate and we suck it up with Lifter travel, especially with the VVT's the OEM 5.7 Valve spring is close to PSI 1511specs which are overkill for OEM None VVT production, but needed to control the VVT motion, key thing we all forget about VVT is , the cam is pulling the lobe away from the Roller wheel during 1/2 VVT cam movements.
2nd 99% of the cams out there use Beehive springs and they're not known for taking aggressive ramp rates. the OEM 392 cam falls in around the 37% the 1st 5.7 cam Summit offers is 38.5% the Oem 5.7 Truck VVT cam is 39.2%

We used to say that a solid lifter was worth 10-15 hp over a hydraulic lifter with all things being equal...... in the G3 Hemi , it's worth almost as much as 30hp depending on Airflow, going with .904/.905 Dia lifters is easily another 5 hp.

Also keep in mind where the Lifters are in relation to the cam, traditional V8s are 90* to the cam, G3 is 120* (just wanted to toss that out there)