Can timing

[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 the 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 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.

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

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.

[LilSick]

first - do not list a intake or a exhaust lobe centerline on a cam card

that will confuse anyone who understands valve timing

comp cams does not know what those numbers will be because the cam is still in a box, why would they put them on a card?

second - please print out all the specs you have on a stock 6.4 cam (mostly just need rate of lift, think i have the rest) and post them here, thanks

third - put a list of your masters here (with all the duration numbers), so we can accurately compare their rate and see how they stack up against both oem, and one another



do that and i will help you write your instructions : )

[briannutter]

Awesome. Hey I moved the question to it's own thread to not muck up this one. I can dig up everything you are looking for. over the next two days. With the 6.4 Cam, I can give you .006 SAE and .050 numbers and those make it pretty easy to compare to our ramps. Giving the specs and valve events on all 25 cams is pretty easy too. That's generally how we put them on our site and as "catalog images" so people can easily compare. Already printed cam cards with C/L's but they are tiny numbers lol. I very much appreciate your help with this. Thanks, Brian

[james1595]

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 the 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 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.

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

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.

So what would be the point when the valves touch the piston for each motor?

[PurpleRam]

OK, The Hemi VVT's work backwards from full advance.
Full advance is the default/idle position and they retard from there.
So the stock phaser can retard 14 cam degrees (28 crank degrees) and if you fit a 7deg limiter, it then limits retard to 7 cam degrees(14 crank degrees).
Now with the stock cam we know the start position of the cam as the cam is ground with 14 degs advance and has a LSA (6.4L) of 120.5.
So at full advance it has an ICL of 106.5 and exhaust 134.5

Now with an aftermarket cam the LSA and cam advance are most likely now different.
I cant remember the 270 off the top of my head but do know the 274 which is probably similiar.
It has LSA of 116 and is ground with +3 Adv.
So installed and at full advance this cam will have an ICL of 113....but the PCM will still use the numbers 134.5 ex and 106.5 int as it doesnt know the cam has changed.

This cam will like to be run somewhere from 113ish to 119ish ICL so we will have to tell the PCM to keep it nearly fully advanced and retard up to max of maybe 6 degs.
So the exhaust cam table numbers( as these are the numbers that actually control the cam not the intake numbers) will run from 134 (full adv) to 128 (6 degs retard) approx.
This would make the intake go from 113 CL to 119 CL Actual.
The exhaust numbers would be 119 to 113 CL Actual.

So you can see that when swapping cams the numbers can get a little complicated.
Hope I have explained it clearly...if not, ask away..

^^^^^^^^^^^^^^^^^^^^this is the best response in this thread.^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


1st thank you for thinking of the Hemi Guys

the thing to remember is that no matter what #s are put into the tune, the engine will not retard past the mechanical limits of the Phaser. it's why you see a lot of "protuners" not even touch the #s when a cam is locked(I don't agree with that myself)

I'm sure you guys at Summit talked to Comp about their Cams, each cam was designed with Full retard taken into account with their Limiter in mind. Remember no matter what phaser is in there , Stock,(28*) limiter( 14*) or just Stright up locked they all start FULL advance and retard from there....so the stock 392 cam starts at 134* and retards from there. 5.7s start at 128 and retard from there. if the cam has a 114CL the computer starts it at 134/128 respectively unless the #s in the tune are changed.......you can put list the stock cam as 86 as a start # it might throw a code or 3 but the cam will never get to 86* because it can only move 28* from the ICL of 120.5 (+14 =134* ,-14= 106*) I've run stock 392s with the Comp limiter, (120 + 7= 128* ,120-7=113*) now they run better when the #s are imputed correctly , because the Spark tables have an Actual reference point.

*** I have always operated on the thought that the 134/128#s that are in the OS are there for the spark tables to reference, not base off of but reference. ................I could be wrong, but it's been working for me.

A few custom grinds I've had ground over the years, I've used them in both VVT and None VVT , some were on Custom LSM cores.....you'll know which ones
some too big for the average person...but it's all bench racing at this point.
1) 232/[email protected], .590/.610 110 LSA , needs 3k stall , but will make roughly the same Tq as the OEM eagle cam, likes to rev , it's cam that'll pull to 7k-7.5k if you have a top end and exhaust system that'll let it breath , was designed with the 03-08 5.7 head in mind, works very well with the eagle head( 09-10.......no stay away)

2) same specs as above except 112 LSA , still need 3k+ convertor , but is easier to tune with the 09-10 ECUs makes slightly less HP then #1 but pulls harder in the 3k-4k, will rev to the moon, but after 6800 it's a wasted effort unless there's a single plane intake in use.

3) 260/260 @.050,.640/.640 110LSA , Max effort /7k+ RPM type cam and delivers...one of my favorite "here Chevy,Chevy,Chevy,Chevy" cams... with the right supporting mods(IE lot's of investment Money) it'll hit 1.9ish Hp/CI (640-650HP from a 345ci) but realistically it's good for 600hp @ 7000.....Not daily driver friendly.

4)242/[email protected] ,.640/.655 106 LSA , I called this one "cut throat" cam, difficult to tune for stable idle with the OEM ECU , it will Chop/Chop/Chop any tree down without "ghost tuning" the OEM ECU/PCM hates it, RPMs are your friend with this cam., but still makes reasonable Tq #s under 3k RPMs..... will not work with 2009-2010ECU , best suited for the Carb/MSD Hemi 6 types

5) 225/230 @.050 , .575/600 112 LSA I've used it 10x and all ten times it's delivered over 500RWHP in 5.7s and 540ish in 6.4s , it's another cam that lends it's self well to the smaller Eagle Exhaust valve.

6) 225/231 @.050 .550/545 114 LSA , it's a solid mid 400HP cam, the better the exhaust side the higher the HP, it's tuner friendly, very broad power curve.

7) 208/212 @.050 , 540/545 114 LSA , it's a Hughes Engine cam spec it'll get you into the mid 400Hp zone, very tuner friendly , works with a stock convertor we used it once in a 2011 QC , stock Exhaust ,no headers, stock Intake ,No cold air intake,.....truck was straight up off the dealer lot stock type truck, it was a 13.40's all day deal, with a PB of 13.31 @102 MPH weighing in at @5500lbs race weight(roughly 460hp)....and it sounded stock.

8) 224/228 @.050 ,573/578 114 LSA (another Hughes spec cam) , it's performance is even with TSP's stage 3 cam , easier to tune then TSP's cam and will clear 500hp before TSP's stage 3cam will....but it needs a good convertor, a little less stall the TSP's stage3 , 2009-2010, you need 3k stall , 2011+ you can get away with 2800, 2500k convertor is not out of the question, but makes the tuner's job harder, because it wants to "bounce" off the convertor in Idle situations.

All the above cams have been used with or tried with OEM ECU/PCMs some of these cams when used with aftermarket PCM's or "old school" Carb and MSD box will Make 10-15% more HP.

the power potential for the 5.7 is greater per cubic inch then the 6.4, with "stock" heads, (IE Eagle on 5.7, Apace/BGE on 6.4)

I've seen 392 strokers (5.7based 3.9XX x 4.05/08 ) out Hp/Ci OEM 6.4s with the same cam/head combo which bucks the "accepted" thinking that large bore/short stroke makes better power at the same Ci

5.7s with stock convertor, 215/[email protected] is about the limit before convertor becomes an issue, Changing the Pedal% and Pedal request to request more TQ earlier can help but it's only a band aid.

If you guys at Summit feel a little adventous with the above specs , you have my consent to try them.

Richard Gehring.

[PurpleRam]

Food for thought , the Eagle head in stock form needs all the exhaust help it can get from the cam, dual pattern cams are a Eagle heads best friend but once the valve size is changed to 1.60/1.63. then straight pattern cams OPEN up a whole new world of power potential.
Apache/BGE/Hellcat heads are the opposite, they like Intake leaning Dual pattern cams , 2.18 or 2.20 valve same as a large Ex valve Eagle.

Edelbrock heads, don't flow any better than Apache/BGE/Hellcat , but they work better in stock form because of the 2.16 Intake.

AFR heads........thank God someone got it right.

[PurpleRam]

The SRT392 cam is a popular swap in to the 5.7's(09+) the 5.7 OS will not recognize the 134 max # no matter what we put in that table, it will log max 128* because that is the limit written into the base code of the program.......... now we know both 6.4 and 5.7 OEM phasers are 28* swing....... now we know Physically the cam starts at 134 degrees no matter what the OS system thinks. and ends at 106 degrees no matter what the OS thinks.

the stock 5.7 cams are 114 center( I forget what the LSA is + whatever advance) , cam swings to 128(114+14) and 100(114-14) but you'll never see a 392 cam in a 5.7 log anything less then 106 why? because the CL is 120.5 Physical .

[LilSick]

Awesome. Hey I moved the question to it's own thread to not muck up this one. I can dig up everything you are looking for. over the next two days. With the 6.4 Cam, I can give you .006 SAE and .050 numbers and those make it pretty easy to compare to our ramps. Giving the specs and valve events on all 25 cams is pretty easy too. That's generally how we put them on our site and as "catalog images" so people can easily compare. Already printed cam cards with C/L's but they are tiny numbers lol. I very much appreciate your help with this. Thanks, Brian

dont you guys refer to the 0-050 as the minor ramp and 050-200 as major?

i was working with laurie and debbie at web. we used different numbers but same principle.

thats the only way to really see how aggressive a cam is

i dont need the numbers above 200 thou lift but need everything below that

[james1595]

how much exhaust do you recommend? most off the shelf cams are 6-10, but from research ive done, they should have more around 12-15 degree split. would headers reduce this split or increase it?

[Hemituna]

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

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

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.


You cannot trust the cam phaser to always be accurate enough to prevent a crash.
Log desired vs actual cam position and you will see the variation.
A good engine builder (and the OEM) makes sure that it is physically impossible to crash the valves NO MATTER WHAT the user does to the tables.
That is the reason for the use of limiters and also why some cams are locked.
You need to limit the retard or if it is too close, lock it out.

[briannutter]

dont you guys refer to the 0-050 as the minor ramp and 050-200 as major?

i was working with laurie and debbie at web. we used different numbers but same principle.

thats the only way to really see how aggressive a cam is

i dont need the numbers above 200 thou lift but need everything below that

Ok here's what I have for you first and I'm working on the rest.HemiCamsBeta.xlsx

We looked at the 2018+ Hellcat cam p/n MOP-05038835AA. When we measured it, we found specs to be 209/229 123 + 8. This would make the valve events -10.5 I/O, 39.5 I/C, 65.5 E/O and -16.5 E/C. Lift at TDC is .036/.031 BUT I'm going to get the .006/.050/.200 numbers for it tomorrow and try to put those into engine degrees as well.

Our biggest VVT cam is SUM-5719. It's a 232/248 120 + 4. 0 I/O, 52 I/C, 68 E/O and 0 E/C. .006 timing is 283/299. We'll get the .200 numbers and where it is in relation to the Hellcat.

Our lobes aren't super aggressive so they will rpm well with common aftermarket beehive springs. That being said, the more I learn about the phaser...the more I realize it slips and doesn't have fine control.

One other thing to clarify (for me) is that I think in engine degrees and that's how the valve events are written in the spreadsheet. Is the Phaser tuning in cam degrees or engine degrees? If the Comp phaser limiter has 14 engine degrees (7 cam degrees), that's something. MORE IMPORTANTLY..if the Phaser tuning is in Cam Degrees....that could get me into trouble twice as quickly. In other words, if I want to keep the cam from going from -8 to anything past zero in engine degrees, I need to limit the phaser to 4 cam degrees?

I'm more than happy to explain the thinking behind the events etc. And yes we can certainly add more later.

Thanks ALL you guys for your help. We want to build something beautiful here with Pro Hemi.

[LilSick]

Is the Phaser tuning in cam degrees or engine degrees?

i rethunk it all

centerliine is a measurememt of the center of the lobe from tdc

its in cam degrees

if it were in crank degrees it would be a number that is larger than 180 : )

[briannutter]

Ok that’s what I hoped because I think of engine degrees. The other is mostly worthless. So phaser limiter being 14 degree spread is too much…. I’ll have more data for you guys on acceleration etc soon. Thank you again.

[james1595]

I thought the computor looked at it in cam degrees? Thats how its always logged for me when looking adjusting the vvt

[rays04gtx]

so do you know what the actual Rocker arm ratios are ?

Intake is 1.59-1.63 depending on the ORG source , Comp used 1.60
Exhaust is 1.64-1.68 depending on the ORG source, Comp used 1.65


The OEM rockers are investment grade castings, so there's a bit of variance.

[LilSick]

there is no actual ratio

they vary : )

want a actual ratio buy aftermarket rockers

[james1595]

The crank spins twice for every cam rotation. So saying the computor reads the vvt table in crank degrees would mean for every degree you retard, it would move the cam 2 degrees. But it doesnt, it only moves 1. So it reads cam angle, not crank.

[briannutter]

It would be very odd if they limited the resolution to two degree crank increments. Those are pretty critical.

[LilSick]

?would mean for every degree you retard, it would move the cam 2 degrees. But it doesnt, it only moves 1. So it reads cam angle, not crank.

Single digit numbers are spark timing bro. Positive for advance, negative for retard

Cam centerline numbers are triple digit (usually)

This is by the lady that taught me and the method I use:

http://www.webcamshafts.com/pages_misc/degreeing.html

Really all that matters is that you check the clearances and true centerlines (full adv and full retard; if clearance permits) and compare it to what the ecu says once you fire it

Then you can start building your map

[james1595]

Im not sure we are both on the same page. I know the difference between the spark timing tables and cam vvt tables. What im saying, is that when you go and adjust the vvt tables, like for my 5.7, 125 is max advance, and then retard it 1 degree to 124, it moved the cam 1 degree, as shown in the log for cam position. If the tables were showing crank angle, it would be showing 123 degrees, sense the cam moves 2:1 from the crank.