roller camshafts

[Stephen B.]

Re: roller camshafts

If you want the engine to exhibit its OE idle and low speed operating characteristics, massaging the heads will give you more bang for the buck than an aftermarket roller cam, most of which have too much overlap that will screw up the idle and kill low end torque.

The OE cam is a very good design - similar to the L-79, but slightly milder, which makes huge torque right off idle in the longer stroke big block, and the head work will make usable power to about 6000. The actual .050" durations are 214/218 with a inlet POML of 110 and a LSA of 115.

If you want to trade a little low end torque for more top end power, install it five degree retarded, and if you want to restore the low end torque and then some, use a 454 crank and pistons with a target compression ratio not to exceed 10.25:1.

As far as the valve train is concerned, the OE components work fine, but make sure you use the second design dual valve springs that have been discussed here a number of times. The early single spring/damper design has a high failure rate.

You don't need special oil for any OE cam and valve spring setup. Any CJ-4 available at Walmart is more than adequate, and if you use replacement parts from Tier 1 OE suppliers like Federal Mogul and Dana Corp. it won't wipe out lobes like Comp Cams flat tappet cams are prone to.


Duke

Duke
I endorse your statement about ported heads to this degree. I always port my heads to varying degrees while the engine is apart. Fortunatly for me I have that ability. I endorce any improvement that has no moving parts.It's only my opinion that even a dead stock rebuild can benefit from some porting of the heads.I have begun in recent years to even check my combustion chambers for CCs. I'm just a gear head and have been accused of over restoration as well. Oh well gilty as charged.
stephen Barrett (21558) 59,66,71,73

[Duke W.]

Re: roller camshafts

Pocket porting/port matching/chamber relieving/mulitangle valve seats with top cuts off the valves to remove unused portions of the valves' seat area and optimizing the compression ratio for the specific configuration will yield about 10-12 percent more top end power on any Corvette engine, including base engines, and what is even better is the useable range of peak power is extended by 500-1000 revs, and it's undetectable in Flight judging and PV. The OE machining left a lot of power and revs on the table.

The limitations of low cost mass production yielded relative low port flow coefficients, and the above operations will significantly improve port flow coefficients without making the port materially larger, which can foul up low speed operating characterstics. Idle behavior is not affected and low speed torque is only marginally affected even it you retard the OE camshaft several degrees to goose the top end more or use a camshaft optimized to the flow characterisitcs of massaged heads like the McCagh Special camshaft for base small blocks, which can broaden torque bandwidth even further.

More details are in the "Tale of Two Camshafts" article in the Fall 2010 Corvette Restorer, and the compression ratio article in the Fall 2009 issue.

It's not a difficult task. Any amateur restorer can do all but the final valve seating. It's time consuming, so it's fairly expensive to have done professionally, but it will considerably light up any OE engine.

Too often aftermarket camshaft designs result in a ratty idle, loss of low end torque, and durability issues that owners end up regreting.

Duke

[Clem Z.]

Re: roller camshafts

Clem
Just an opinion but, I have always thought it wise to buy a cam kit that included the same brand cam ,lifters,push rods,and timing chain.I also have always felt comfortable using the springs recommended by the manufacture for that cam. I never try to out think the engineers be they GM's or Comp Cam. I have always felt it very important to shim springs to obtain the recommended height and therefor uniform pressure. Just common sense to me,not rocket science.
Stephen Barrett (21558) 59,66,71,73

it was the aftermarket cams and parts that caused the panic because of inferior materials,wild ass cam lobes,extra heavy springs because of the radical lobe design and they stopped parkerizing the cams to save money. i understand they now will parkerize the cam for a extra charge. the only thing i would recommend is polish the bottom of the lifters to remove any grinder marks unless they are coated

[Joe L.]

Re: roller camshafts

I feel Joe and Mike's comments (#2 & 4) have provided you as much information as you will ever need.
The 4 main points are:
Better all around performance
Gear compatabilty
BIG initial cost
No worries about lobe wear.
Yes, WITHOUT QUESTION, a retro roller cam (for either BB or SB) is considerably more expensive than a flat tappet cam---------------------------------------until the day comes that you have to halfway tear down the engine to replace the cam/lifters!

Remember the old Fram commercials, "You can pay me now or you can pay me later"? That was the ONLY thing Fram EVER had that was any good!

Tom------

Yes, you can be sure that GM did not go to roller cams and lifters because flat tappet worked just as well. Of course, better fuel economy was PART of the reason but I hardly think it was the whole reason----just too much additional cost for a very marginal benefit in fuel economy.

As far as the Fram commercial goes, it was probably one of my top 2 or 3 favorite commercials of all time. I wish I had a copy of it. It was absolutely PERFECT in every way.

[Duke W.]

Re: roller camshafts

it was the aftermarket cams and parts that caused the panic because of inferior materials,wild ass cam lobes,extra heavy springs because of the radical lobe design and they stopped parkerizing the cams to save money. i understand they now will parkerize the cam for a extra charge. the only thing i would recommend is polish the bottom of the lifters to remove any grinder marks unless they are coated

Crane Parkerizes their cams, no extra charge. That's one reason why Crane is the only vendor I recommend beyond the Tier 1 OE suppliers like Federal Mogul and Dana Corp.

Duke

[Joe L.]

Re: roller camshafts

Crane Parkerizes their cams, no extra charge. That's one reason why Crane is the only vendor I recommend beyond the Tier 1 OE suppliers like Federal Mogul and Dana Corp.

Duke

Duke-----


As far as roller cams go, I don't think that very many are Parkerized, including most GM OEM cams.

The only ones that I think are Parkerized are the "austempered ductile iron" aftermarket roller cams available from Speed Pro/Federal Mogul. Most, if not all, other roller cams are steel and are not Parkerized.

[Joe C.]

Re: roller camshafts

Parkerizing is a corrosion inhibiting process which has been used extensively for firearms since the early 20th century. It creates pores for oil absorption at the surface, and doesn't impart any additional hardness to the treated ferrous metal. For mechanical parts, such as camshafts, it is done primarily to protect the surface from degradation prior to installation and immersion in oil......basically as a means of preserving the part while it is in storage.

Ion nitriding is a process whereby a ferrous metal is infused with nitrogen ions, which form a surface layer, much like case hardening. One of the more remarkable aspects of ion nitrided parts, is their resistance to scuffing abrasion.

Competition Cams offers an ion nitriding service for their ductile iron camshafts. It is recommended for their more "aggressive" flat tappet lobes, costs $100.00, and can be applied to billet steel roller cams as well.

http://www.arielcorp.com/application_manual/arieldbIonnitriding.htm

[Duke W.]

Re: roller camshafts

Duke-----


As far as roller cams go, I don't think that very many are Parkerized, including most GM OEM cams.

The only ones that I think are Parkerized are the "austempered ductile iron" aftermarket roller cams available from Speed Pro/Federal Mogul. Most, if not all, other roller cams are steel and are not Parkerized.

I don't know about roller cams, but the several flat tappet camshafts that Crane has produced to my designs were Parkerized, and I assume they Parkerize all their flat tappet cams that are ground from the same Textron CWC blank that everyone else uses.

All Chevrolet OE flat tappet cams were Parkerized because it aids the break-in process. OE cams did not receive a specific break-in process and the Parkerizing prevented lobe/lifter scuffing during the typical low RPM/short run time that cars received as they went from plant to shipping to the dealer. Probably few ever achieved full warmup until taken for a test drive at the dealer or delivered to the retail customer.

It was absolutely the worse possible service environment for a new engine, but the Parkerizing was extremely effective at preventing premature lobe/lifter failure due to scuffing.

Sealed Power, Dana Corp., and Crane cams with OE lobes and springs don't need a specific break-in process, but I recommend it because at some point you have to start the engine, check for leaks, check timing, etc, so you may as well run it at 2000-2500 for 20 minutes and full warm-up.

The Parkerizing on well used cams is usually not noticeable because it wears off with use (I don't think it's more than a few ten-thousandths thick), but it might still be visible on the base circle. A Parkerized cam is recognizable by a medium gray mottled surface on the entire camshaft except the journals. After Parkerizing the journals are polished to remove it, so they will appear silver.

Duke

[Clem Z.]

Re: roller camshafts

[quote=Joe Ciaravino (32899);536838]Parkerizing is a corrosion inhibiting process which has been used extensively for firearms since the early 20th century. It creates pores for oil absorption at the surface,
i believe this is the reason this helps with the cam break in as it hold the cam lube better than a smooth surface.

[Duke W.]

Re: roller camshafts

That's the reason! It's ground off the journals because it could damage the soft babbit bearing material under boundary lubrication - like when cranking - but at idle speed and above the cam bearings experience full hydrodynamic lubrication.

Duke

[Clem Z.]

Re: roller camshafts

That's the reason! It's ground off the journals because it could damage the soft babbit bearing material under boundary lubrication - like when cranking - but at idle speed and above the cam bearings experience full hydrodynamic lubrication.

Duke

you can tell how absorbent it is when you paint on the moly kote as it sticks to the lobe surface. i always use pure moly kote just thinned with a little engine oil. if you get moly kote on your fingers it is hard to get out of the pores of your skin so you can see how it wets the parkerizing coating on the lobe

[Mike H.]

Re: roller camshafts

I want to thank you all for your insightful comments on my original post. As is the usual case there are verying opinions. Taking your comments into consideration and because of the way I use my car and the fact that as time marches on antiware properties will continue to degrade I have deceided to use a roller cam. For those interested its Comp Cam 11-413-8. It didn't help that on initial start I just lost a lobe on a Federal Mogal cam CS 1093M. Not interested in repeating the process. First lobe I have lost and it will be the last.
CORDially Mike

[Clem Z.]

Re: roller camshafts

I want to thank you all for your insightful comments on my original post. As is the usual case there are verying opinions. Taking your comments into consideration and because of the way I use my car and the fact that as time marches on antiware properties will continue to degrade I have deceided to use a roller cam. For those interested its Comp Cam 11-413-8. It didn't help that on initial start I just lost a lobe on a Federal Mogal cam CS 1093M. Not interested in repeating the process. First lobe I have lost and it will be the last.
CORDially Mike

remember to clean the the rollers in a solvent because they use grease to assemble the needles and you want to remove the grease. then soak them in oil over night. also remember that unless the lifters are pressure oil fed you need to keep the idle RPMs up around 1000+ to keep the oil from the rotating assy flying around to oil the lifter needle bearings. solid roller cams are not made for 450 RPM idle. to prevent "skipping" of the rollers on the lobe i would also use a rev kit to keep the rollers in contact with the lobe at all times. if you are using a hydraulic roller you do not need to do this because the lifters are under pre load to keep them on the lobe

[Stephen B.]

Re: roller camshafts

Parkerizing is a corrosion inhibiting process which has been used extensively for firearms since the early 20th century. It creates pores for oil absorption at the surface, and doesn't impart any additional hardness to the treated ferrous metal. For mechanical parts, such as camshafts, it is done primarily to protect the surface from degradation prior to installation and immersion in oil......basically as a means of preserving the part while it is in storage.

Ion nitriding is a process whereby a ferrous metal is infused with nitrogen ions, which form a surface layer, much like case hardening. One of the more remarkable aspects of ion nitrided parts, is their resistance to scuffing abrasion.

Competition Cams offers an ion nitriding service for their ductile iron camshafts. It is recommended for their more "aggressive" flat tappet lobes, costs $100.00, and can be applied to billet steel roller cams as well.

http://www.arielcorp.com/application...nnitriding.htm

Joe'
Back in the early to mid 80s I had my first exposure to the nitriding process while working as a Tool and Die maker at GM. We started using nitrided punches in many of our heavy metal progressive dies,making parts like anchor plates and hinges.The life expectancy must have increased by 10 fold.You couldn't wear them out.I'm still impressed.
Stephen Barrett (21558) 59,66,71,73

[Joe L.]

Re: roller camshafts

remember to clean the the rollers in a solvent because they use grease to assemble the needles and you want to remove the grease. then soak them in oil over night. also remember that unless the lifters are pressure oil fed you need to keep the idle RPMs up around 1000+ to keep the oil from the rotating assy flying around to oil the lifter needle bearings. solid roller cams are not made for 450 RPM idle. to prevent "skipping" of the rollers on the lobe i would also use a rev kit to keep the rollers in contact with the lobe at all times. if you are using a hydraulic roller you do not need to do this because the lifters are under pre load to keep them on the lobe

clem------


I've never really considered or recommended the use of a mechanical lifter roller cam for street operation. Among other things, the vast majority, if not every, off-the-shelf grind for these cams is too radical for street operation as far as I'm concerned. Maybe OK for a little-driven street hot-rod but not for a Corvette that one wants to use in all-around driving.