should i remove inner spring for cam break in ???

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duster360

duster360

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I have a Lunati Voo Doo 268* cam for my fresh 340 build. The spec sheet calls for valve spring #73949 which it says has a spring rate of 363#. The Lunati tech was kind of vague as to whether or not I should remove the inner spring for cam break in. At first he says I should to be safe but the next thing he says is it would PROBABLY be ok if I just left it in there. not really the answer I was looking for. What should I do?
 
It appears to be a dual spring, so yes, removal of the inner spring would be best. I've known people to ignore that rule, but I don't recommend it.
 
Cam break in is to prevent wear until the lifter starts to spin in the bore. The more pressure the quicker it starts to spin.

Lifters ride off to the side of their circumference causing them to spin . Sometimes new lifters are stiff in there bores preventing them from spinning right away.

Running a motor at 2000 for break in keeps them spinning as does springs that hold them down until the edge is off the lobe. If it drags on the corner off the start the lifter will get a groove and this will stop the spin. If it doesn't spin it will wear out pretty quick.
 
What would be a good break in oil? I am sure I will have to order it cause I am pretty sure my local parts stores don't carry any.
 
I run 10W40 oil in these engines. What weight break in oil should I use?
 
I personally removed my inner springs for break in, I actually haven't had a chance to put them back in yet either. Also I used comp cams 15w50 break in oil in my 440
 
I too have never removed the inner spring for cam break in. It is recommended, but in the end it's your call.
 
Have the same cam for my motor. Realized yesterday that my springs are only 90#s on the seat and 290# open. Good news is that I can break the cam in with these. ....
Not sure if I should keep them in there long term though... Although I wont be revving it hard..just cruising...
 
Depends on what the seat pressure is. If it's 120 or less I don't worry about it. Above 120 lbs. I take it out. When you assemble it make sure all the lifters spin freely in their bore. That's the primary cause of cam/lifter failure. Valvoline VR1 has a good amount of ZDDP so it works well for break-in and NAPA usually carries it.
 
I found the specs on the valve springs in the Lunati book:

Seat - 120
Open - 319
Rate - 363
 
duster360 said:
What would be a good break in oil? I am sure I will have to order it cause I am pretty sure my local parts stores don't carry any.
Click to expand...
There are many good one out there.
http://www.summitracing.com/parts/luc-10631-1
I use this quite often, but virtually any of the break in oils will do.
Comp Cams, Brad Penn, Joe Gibbs, all offer great products. You will need to continue to run a flat tappet friendly oil even after break in. I like Valvoline VR1 20W/50. Again many good oils out there today. I know that O'Riely and AutoZone carry VR1 on the shelf here.
 
duster360 said:
I found the specs on the valve springs in the Lunati book:

Seat - 120
Open - 319
Rate - 363
Click to expand...

Yep...thats what the tech guy said...

Looks like I am about 30# off on both ends....would I be ok to run these springs if I am not beating on it ? Hell , i seldom ever go over 3000 anymore !
 
I always remove the inners. The lifters should rotate with no pressure but gravity on them... that's how I test for rotation during assemly. The reason for the recommended rpm is to fling enough oil onto the cam from the crank because the cams are only spalsh fed. I know many older builders that don't or that run weaker springs for break in but since it's my *** and $$ on the line I always have pulled them.
 
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