hadams

There is such a great deal of controversy any time you start a Cam Beak-In thread but here goes……

My position:

I plan to install the CAM and execute the Hydraulic FT break-in procedure exactly as recommended by Lunati.

I’m really hoping after reading the copious cam posts re: lobe wiping, break-in/no break-in, failures and differing opinions that the primary causes for failures are:

1. Improper break-in or no break-in procedure conducted
2. Improper oil with limited or inadequate Zink/Phosphorus
3. Manufacturer failure that seems higher based on a larger market share
4. Long term failure due to improper oil usage

Here’s the new question:

I have double springs on my valves for my new Trick Flow Heads. The builder (they are reworked) claims about 320 lbs spring tension at the open position and the max lobe specs for the cam are 233 degrees @ .050 with a .504 max lift.

A friend of mine suggested removing the inner springs for the break-in. I’ve thought about this quite a bit and I’m not convinced it would be the right thing to do. In fact, it almost seems contrary to a proper break-in evolution.

I’d sure like to get a technical opinion on that approach

mds3013

Be sure to use the Lunati break in additive they sell. It is required to warranty cam. This from their phone sales rep.. I used the pre lube that came with cam, Joe Gibbs break in oil, the additive and pre oiled with a drill motor. I have been advised to run this for 250mi.. Then change to Joe Gibbs Hot Rod oil. Run springs that have seat and open pressures in matched set from Lunati or springs that have same specs. Use matched lifters also from Lunati. When I set my valves I saw the lifters rotating when I turned over the motor by hand. Use Lunati's break in procedure. It is a bit stressful but not as intense as I first thought. This is what I know. Good luck with it. mike...

SH-60B

Yes remove the inner spring. During break-in you're not going to rev the motor to 7000 RPM, so you'll be safe during break-in. You're not going to experience valve float during break-in. All that spring pressure with dual springs could be too much for fresh parts to handle untill break-in is complete.

Bruthish

Comp cams also recommends removing the inner springs on their new cams during the break in period.

Gordonm

Yes remove the inner springs. I even drove a little without the inner springs. Being careful after break in to not rev it past 3500 rpm.

billla

FWIW, with all above

Tim81

I agree with Billla

Ironcross

I run them in just like the manufacturer did...warm them up, check the oil pressure, and look for leaks....if everything is satisfactory drive um...any way you desire too, built correctly you cant hurt them......., and no where does GM or any other company change valve springs...thats ridiculous.....

pauldana

send the cam to CompCams and have it nitrated.... cost is about $100 I believe..... this will help a lot.

63mako

This was fine 30 years ago. The ramp rates from then to now on aftermarket cams is drastically different, lift is higher.
Here is your cam. Notice the difference between advertised duration and duration @ .050. and gross valve lift. This is Typical of a modern cam design.

Lunati Part Number: 60104

Advertised Duration (Int/Exh): 276/284
Duration @ .050 (Int/Exh): 233/241
Gross Valve Lift (Int/Exh): .504/.525
LSA/ICL: 110/106

Now lets look at a GM factory cam from back in the day. This was the hot cam back in the 60's.

OEM #3863151, 350 HP, L-79 327

Advertised Duration (Int/Exh): 306 306
Duration at .050 (Int/Exh): 222 222 -
Gross Valve Lift (Int/Exh): .447” .447”
LSA/ICL: 114/110

As you can see the ramp design is night and day different. This is a lot of the reason for the rash of cam failures and why there are now different break in procedures recommended. The newer designs allow more power with less compression but also require different break in and will not have the life expectancy of a factory grind.

Ironcross

Interesting information except neither cam is in my 62,....

I have never experienced any cam failures and all are solid lifter...I have my own idea why there are so many so called bad cams.....I would say over half the people on the forum cant install a timing chain and know what cylinder is firing......let alone be able to lash a cam correctly either hydraulic or solid ....information that is never in books

Gordonm

Cam failures, my take is crappy oil, truck like spring pressures, lack of oil at startup and as said improper setting. Also I think some of the cam cores I have seen are terrible. You can visually see the porosity of the cam core.

63mako

I don't doubt you not experiencing cam failures if your using a stock cam in your 62. Big difference between your specs and modern profiles which is my point. Here are some solid lifter cam specs.

This is in your 62 if it is stock.
GM 3736097 (Duntov 097) 1962 Corvette 327 340-360 HP

Advertised Duration (Int/Exh): 287/287
Duration @ .050 (Int/Exh): 228/230
Gross Valve Lift (Int/Exh): 394/400
LSA 108

Spring Specs 3911068
#80 closed
#200 open @ 1.25

Here is a modern solid lifter grind with similar advertised duration. Compare the ramp, lift and the spring difference!

Comp Cams XS282S

Advertised Duration (Int/Exh): 282/290
Duration @ .050 (Int/Exh): 244/252
Gross Valve Lift (Int/Exh): 520/540
LSA 110

Spring 987-16

#121 closed
#343 open @ 1.20

My take is many cam failures are due to the huge increase in ramp rates and the heavy springs needed to control the valvetrain with the increase in the velocity of the valve opening faster and farther and closing faster and farther in the same time from seat to seat. Remember @ 6000 RPM the valves are opening and closing 50 times a second. as you can see from the specs above the distance lifted is increased 25% and the speed from seat to duration @ .050 is increased from 59 degrees to 38 degrees on the intake. That is a huge difference when it is happening 50 times a second.

billla

Agressive near-roller lobe profiles, brutally high spring pressures to keep the lifters on those profiles. No question there are other factors as well - I agree regarding ZDDP issues, basic valve adjustment skills and manufacturing quality - but those are the most dramatic. I noted this elsewhere, but the turning point for me was having to scrap my old valve spring compressor for one of the big C-frame units as the old compressor bent when I was trying to remove some modern springs

As a flat-tappet approaches .500 lift, we're no longer talking about a 100K or even 50K lifetime - but these cams are pushing the limits of what a 60+ year old design can do...

pauldana

63mako and Gordonm are correct.... several things, wrong oil with low zinc, higher and quicker lifts, higher or improper spring pressure, bad break-in procedure, improper lash settings.... these are the things that do it. And as far as "soft" cams go???????? like i said, get it nitrated, this gives the cam an extremely hard surface, this will help you get through the break-in procedure.


Here is what CompCams has to say about it: http://www.rlengines.com/tech/FlatTa...chBulletin.pdf

this from HotRod mag:
http://www.hotrod.com/techarticles/e...h/viewall.html

a few excerpts from from the above websites:
Six Steps To Increased Flat Tappet Camshaft Durability
�� Double check your camshaft and lifter set-up prior to the break-in process,
and use an ample amount of the supplied assembly lube on all lobes,
distributor gear and the bottom face of each lifter.
�� Use flat tappet lifters with cam face oiling provisions, such as COMP
Cams® Part #800-16 (GM) or #817-16 (Ford). Always use high-quality;
U.S.-built COMP Cams® lifters to make certain you are receiving the best
quality lifter you can buy. Avoid “brown bag” lifters.
�� Use a COMP Cams® Lifter Bore Grooving Tool (Part #5003 GM engines;
see catalog or website for other engine makes) to increase oiling.
�� Nitride your new flat tappet cam to increase the case hardness and lobe
surface lubricity; available as an added service for any COMP Cams® flat
tappet camshaft (COMP Cams® #1-111-1).
�� Use high-lubricity, high-ZDDP content engine oil to help during the break-in
process and always use COMP Cams® Camshaft Break-In Oil Additive
(Part #159).
�� Always remove inner valve springs from dual valve springs during break-in.
In addition, COMP Cams® offers low-ratio break-in rocker arms to give you
an additional measure of camshaft break-in protection.

hadams

Thanks to all,

Lots and lots of really good advice.

I still plan to stick to the verbatim instructions for the Lunati Break-In procedure. I’m not completely sold on having the CAM Nitrided or Nitride Treated. I did some research on this that suggests the possibility of microscopic surface cracking to differing degrees as a result of the Nitride process and the additional possibility of premature wear to the lifter surface due to unlike hardness between the cam and the lifter.

New request for technical opinion and advice:
I have a new concern that my approach to avoid roller rockers in lieu of roller tip rockers in order to keep the L-82 Valve Covers (due to clearance issues) may put me at risk of additional early wear to my flat tappet cam. I know I need to have appropriately lengthened and hardened push rods and that there is a small HP loss with conventional (roller tip) rockers but I wonder if non-roller rockers present a significant risk of accelerated wear on more aggressive flat tappet cams with dual high pressure valve springs?

Anyone have a solid opinion with technical OQE on this?

pauldana

I have the stock L82 valve covers and am running full compcams 1.52 magnum roller rockers... they do fit, but i did add a 1/4 aluminum spacer later, but it was more for the oil slinging around..

every bit of friction reduction helps everything... involved...

A post script.... I would NEVER go flat tappet, and I would never recommend anyone going flat tappet... full roller is the only way to go imho. just to many problems, concerns, and even in the long run the flat tappet cam will last half as long as the roller.... so, save a little here.... pay more later. again, jmho... p

427Hotrod

As you assemble it...install the cam and drop the lifters in the bores with just a little oil on them. Leave timing chain off and install just the cam gear. Spin the cam and verify that each and every lifter rotates slightly in its bore as it closes. Mark them all with a sharpie pen and make sure they spin. Often the issue is varying sized lifters and bores and if the lifter doesn't spin..it's going to die very quickly.

I usually pull the springs on aggressive stuff too just to be safe. Some of this stuff has pretty stout springs approaching 400#'s open.

I think the Nitriding is a good idea.

As mentioned by everyone...the more aggressive the cam the more the issue. Overdosing on Phos/Zinc isn't a good idea either. Use the right lube initially and use good oil. Make SURE that it fires immediately. No extended crank times. Time it right andhave timing light hooked up to verify timing after it starts, fill carb bowls, radiator, set idle speed up before you even try to crank it, have a water hose handy to keep radiator cool during break in.


JIM

Ironcross

that wasn`t it ither...the '62 actually has since 1970 a new at that time, crate 70 LT1 used with the OE FI on top.....the engine cost delivered was $612.00......I have used both flat and roller camshafts and complete valve trains from Iski, Howard, and Crower....to correctly use the roller style its necessary to run a rev kit in the intake valley with the Howard and Iski that did add unwanted valve train weight...The Crower used light weight rollers out of magnesium negating the heavy rev kit....triple springs were necessary to keep the rollers on the cam at high RPM`s and titanium valves lightened the load for both roller and flat applications...the RPM`s were extremely high with lifts well over 600....and that was over 30 years ago....and they were all donated to me...the engine I used is a 471 Donavon...I will not use a roller on the street that even remotely has a chance to fall apart.....maintenance is too high and race cars don't have fenders {except NASCAR and a few others}........

Les

The above info is pretty much all you need to know- it's really that simple. Good luck on your break in.