Cam Question !!!

[1stoutlaw]

Have a brand new 502 motor w/Edlebrock RPM Aluminum heads---Getting ready to put in my Baja--they list in the motor info , the cam exhaust lift at .544 ????? Does any motor tech know if this a mild cam-medium cam--- or wild cam ---and will I have water reversion problems???? Thanks Mike !!!!

[Ratickle]

They will need the complete specs. Especially the overlap numbers....

Have you got the complete specs?

[Ratickle]

Also roller or flat tappet hydraulic? I'm assuming the hydraulic part of it...

[1stoutlaw]

The sheet on the engine says----compression 9.6:1 forged steel cranckshaft forged steel connecting rods steel hydrolic roller cam gross lift: .527/.544 E
duration @ .050 lift (.224/243 E)
I hope this will help someone figured out what type of Cam and do should I have a problem...It wll have GIL exhaust which introduces the water later down the pipe,,,about a little over a foot from the elbow bend..Thanks !!!

[1stoutlaw]

I believe I found the answer....Lightening Performance Marine has a talk about water reversion on the internet......As long as I or anyone doesen't have "duration" at .50 lift over .240---you should be OK!!!! Mine is at .234---close BUT also my GIL exhaust will place the water into the exhaust late in the pipe near the transom----not dry exhaust BUT almost-----
Any motor guys have any comments Please add to what I just learned!!!! Thanks---Mike !!!

[rschap1]

L.S.A. lobe seperation angle is the important spec. regarding reversion.
It's the difference between the exhaust and intake lobes.
112 degrees is usually regarded as tolerable for common set ups.
Other factors, especially what type of exhaust is on the motor have effect too.

[1stoutlaw]

OK-----L.S.A. lobe seperation angle is not listed on the motor spec sheet-----SOOooooo these heads are made by Edlebrock strickly for marine use----would you not think they would know the proper limits to the L.S.A. ???? AND w/ my GIL exhaust hitting the water near the end,,,,I should be OK????---The reason this question has come up-and I didn't want to bore everybody is the motor is still at the shop,,,and some guy walked in---had boats years ago and now builds hot rod Chevy's,,,, and looked at the motor and stated I will suffer with water reversion with this cam????????
Now I'm thinking he is talking about a wilder cam that would go into one of his hotrods!!!???? Not a cam for a boat!!!!????-------------------Thanks--Mike !!!

[weekend@burnies]

Wallace Racing - Calculate Over Lap and Lobe Separation Angle

LSA calculator

[1stoutlaw]

Weekend@burnies----Thanks---- I clicked onto that calculator web site---put my numbers in all different ways AND nothing made sense-------The numbers I posted up above are the ones on the engine spec sheet----I'm not sure what set of numbers go into what blocks and tried them all different ways-------
-RSCHAP1 listed above, the lobe numbers should be roughly "112".....mine came as minus numbers in that calculator, so I'm entering the wrong numbers...I have contacted the engine builder several times in the last two days to get the specs BUT.....no luck--he finally said the cam is a radical cam and I should use dry exhaust...........BUT STILL hasen't sent me the Cam Specs !!!!!!! If they thought I needed dry exhaust, would they not put that in their sale pitch with the other recommendations(drive-carb-cooling) when buying the motor???
Thanks--------------Mike !!!!

[1stoutlaw]

OK GUYS-----thanks so much for the help----the engine builder finally got off his seat and sent me the L.S.A. number which is "110".....SOOoooooo know I can use my GIL Exhaust and not Dry exhaust and I'm feeling better !!!!!! Thanks------Mke !!!!!

[ROGUE]

From the description it looks like that cam is an Edelbrock Torker 2. IT is very very close to reversion (75 degrees overlap) but I have run it succesfully for years with Gil silent choice risers which put the water in very close. You should be ok. I do run the best valves. unknown if earlier valve issues were due to water hitting the valves but not likely as they have been quiet for some time (knock on wood). I will post the cam card if I can figure out how to attach something here.

[Ratickle]

Thanks, you should be able to insert pic and load it that way.

If not, email it to me and I'll try.

On the Wallace LSA Calculator above, he doesn't have enough numbers to plug in with what he's listed, correct?

[ROGUE]

No, you really need the cam card. Ill try and email it to you, the attachment manager isnt working for me.

[ROGUE]

Oh wait, I just read its a roller cam? If so, never mind. Since a roller can get up and down much faster than the flat tappet, with those spces you posted there will be little overlap or risk. My flat tappet has more overlap than a 741. However, that being said, you realy need to know the lobe seperation, it could be some wild 108 or something and still be at risk.

[1stoutlaw]

Thanks Rouge and Ratickle-----the lobe seperation angle is "110", so I assume it is a mild cam if it is between 109 and 112!!! ???????

[Ratickle]

I can't explain it like an engine guy can. The reason a hydraulic cam can be "bigger", is because the roller allows steeper ramp-up so overlap is less.

Do you have a complete cam card? It will have all of the specs needed to calculate overlap.

[ROGUE]

Darn 110 lobe seperation can be dangerous. 112 usually ok unless radical, 114 ok is most cases except extreme. You really need the cam card now to find out actual overlap.

Just a quick adder

Flat tappet cams can be solid or hydraulic

Roller cams can be solid or hydraulic.

The hydraulic part just makes life a little easier for adjustment, and as a downside, dont make as much power.

[Ratickle]

Here is the Cam Spec Sheet Tom emailed me. You should have one that looks identical.

[ROGUE]

And its the bottom row of numbers that determines overlap. They can also be listed as "timing events at .006" or some do it at .005 lift.

[1stoutlaw]

OK GUYS------I'll e-mail the engine builder and see if he will send me the Cam card--and I'll get back on here for more advice----the builder did say it was a radical cam----but he gave me such a run around I thought he was an office/e-mail guy not knowing much about the motor....Thanks !!!!!