RON - Cams and Torque Converter

[Rolling_Thunder]

RON - got a question - posting openly to help others....     got a guy who has a monsterous cam in his 526" Hemi.

It is not known 100% what cam is in there...    but I know it is a COMP mechanical roller....    It was custome ground on a wider LSA because it was originally for a blower motor...       These specs are on COMP's website...    I would Assume these are close

Duration: 317* / 337*
Lift: .822" / .793"
LSA: 112* ?

He is thinking of the TCI six speed automatic which uses a lock up style converter...    he is debating on what stall speed.  His goal is a strong street car - not a drag car...    He does not want a really loose converter (less than 4000rpm stall) -

I told him he might be better off pulling the cam and having it ground into something a little more streetable.

opinions

[firefighter3931]

I told him he might be better off pulling the cam and having it ground into something a little more streetable.

Hi Alex 

If this engine is going to see extended street duty and cruising, i would have to agree with you. Less cam will live a lot longer. With .800 lift at the valve the spring pressure has to be stout. It will be eating lifters/springs every 1500 miles.  Something with .650 lift and no more than 600lbs spring pressure is much better suited for that type of application. 

If he was insistant on keeping the set-up "as is"....the best course of action would be a dyno session to determine the power curve and then decide on the appropriate converter. I'm currently having a custom converter built for the 572 and the shop wanted all the engine build data/specs as well as a dyno sheet. 

As for the trans....i would probably lean towards a 727 with a GV OD unit or maybe the SMR trans listed below :

http://smrtrans.tripod.com/smrtransmissionsintro/id32.html


Ron

[Rolling_Thunder]

This customer really has his heart set on the 6 speed auto - He has an infatuation with paddle shifters....   

I'll inform him that the best way is to remove the cam and have it cut down...       that gets rid of all the questions and all the problems...   

any recomendations ?

It will keep the billet roller in it but I have no idea what size to recomend.

526" Hemi
Fully ported D5 heads
10.25 Compression
Street intake (dual plane for now)
950 Proform carb on order
2" primary headers

[firefighter3931]

That's a pretty mild combo with the 10.25 compression and dual plane. It sounds like he plans to drive this on the street...ALOT 

It needs and endurance grind roller profile and some milder springs to match the less agressive lobes. 

Give Dwayne a call : 802-951-1955



Ron

[Rolling_Thunder]

it was originally paired with a 10-71...    that's why the compression is low and it now has a dual plane.

[firefighter3931]

it was originally paired with a 10-71...    that's why the compression is low and it now has a dual plane.

Ok, that makes sense...it sure would have been massively overcammed if this was a naturally aspirated build. 

Something in the mid 250's @.050 with .600-.630 valve lift on a 110* LSA would be in the ballpark. 



Ron

[Challenger340]

I agree,
get off those aggressive Roller Ramp speeds/seat/spring pressures for Street Duty !

It's NOT "IF", but rather "WHEN" your Buddy has an OilPan FULL of broken Valvetrain parts/Lifter Trunions etc.

Get a "Street" type Roller !

Ray's got some good grinds for that application;
Ray Barton Race Engines
610-693-5700

[firefighter3931]

Alex, if you're going to re-use the roller lifters with the new cam...do yourself a favor and send them in for a rebuild. It won't hurt to have new axles/roller bearings installed and it's cheap insurance. 

Rebuild is lees than half the cost of a new set. 



Ron