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Ate a cam, time to switch to roller, I guess, but which one?

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V_TastyTacos_V

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This cam lasted two years, daily driver. Motor looks like a '70 Challenger 383, so 9.5:1 compression. Has headers, Edelbrock Performer RPM, Holley Sniper, TKX, and 3.54 gears. I read so much conflicting info on cams, I don't know what to believe. Thinking about a Comp XR274R 274/280, 236/242@.050 ground on 107LSA, .564"/.570". It's their smallest solid street roller. I just don't want to deal with flat tappets again. Can a cam like this fit on a stock piston motor? I read some say needle bearings fail, others say roller bushings fail. Aren't all stock motors needle roller? Is it just the high spring load cams that cause the problems? I've owned a few stock solid cam motors. Don't mind adjusting valves. I would mind having to remove lifters to inspect all the time.
 
Your screen name cracks me up, man.
To your point though….
I went back and forth on this subject. I hated to spend the money to switch to a roller cam when almost everyone that I know has not had a cam failure. There are far more flat tappet success stories than there are failures. It is the bad news that stands out though.
I’ve started a few threads on this forum and others about this subject and have learned a bit from the comments.
Many people only trust OEM lifters or lifters that have been measured for proper taper. It has been found that the quality of the metal is not the problem, mostly it is the degree of taper in the lifters that leads to failures. I’ve read for years that the lifters must spin in the bores as the engine runs so last year I had a dead 383 in the shop out back. I pulled the Intake and had a buddy crank the engine over with a breaker bar and socket on the balancer. Every lifter spun but the way they spun was weird. They were mostly still but started to spin about halfway up the opening ramp of each lobe. At peak lift, the lifters spun fast but then slowed down as the valve closed. I’m taking that to mean that spring pressure encouraged the lifter to spin fast. After having seen the lifters spin, I’m going to have to do the same to any engine I build in the future that has a traditional flat tappet cam. If all lifters spun in the bores before installing the rocker arms and push rods, that is good but if any lifters don’t spin when rotating the crank and cam, I’d think the lifter has too little taper.
There are shops that will regrind the proper taper into your lifters and the price seems good. I’ve been tempted to stock up on clean used lifters for this very thing.
If you’re convinced on switching to a roller setup, the 800 lb gorilla in the business is Comp Cams by a mile. You’ll hear complaints about them but they have far more success stories than failures.
Maybe send a PM to FBBO member @PRHeads ?
 
I have read about plenty of roller failures as well. Pick your poison, but I am not gun shy on using flat tappet cams with good lifters and zddp oil. Kern is right in that the lifters need to spin in the bores. I currently have a set of used solid lifters going out to Oregon Camshaft to get reground. They lasted from 2016 to a few weeks ago when I installed a different flat tappet cam with more duration.
 
I used Johnson lifters, and now can't remember which ones since there are two Johnson lifter companies, one good, and one bad. I used Driven break in oil, and their Hot Rod oil, started right up, half hour break in, lasted two years of daily driving, then suddenly started backfiring. Pulled valve covers, and there it was.
 
V_TastyTacos_V said:
This cam lasted two years, daily driver. Motor looks like a '70 Challenger 383, so 9.5:1 compression. Has headers, Edelbrock Performer RPM, Holley Sniper, TKX, and 3.54 gears. I read so much conflicting info on cams, I don't know what to believe. Thinking about a Comp XR274R 274/280, 236/242@.050 ground on 107LSA, .564"/.570". It's their smallest solid street roller. I just don't want to deal with flat tappets again. Can a cam like this fit on a stock piston motor? I read some say needle bearings fail, others say roller bushings fail. Aren't all stock motors needle roller? Is it just the high spring load cams that cause the problems? I've owned a few stock solid cam motors. Don't mind adjusting valves. I would mind having to remove lifters to inspect all the time.
Click to expand...

That's the exact cam I've had in my 499"RB street car for 10-years and I absolutely love it.

While you can no longer buy K-Motion valve springs I run it with K-Motion K-800 spring which are not big killer springs.

I've never had any issues or problems running it. If you have really good valve train you rarely have to adjust the valves.

K-Motion K-800 1.460" diameter, 165# @ 1.850", 471# @ 1.200", 1.085" coil bind, 471# rate. Using Comp Cams tool steel retainers.

Most of the time I shift around 6200 rpms, but it has no problem spinning higher than that.

Tom
 
V_TastyTacos_V said:
I used Johnson lifters, and now can't remember which ones since there are two Johnson lifter companies, one good, and one bad. I used Driven break in oil, and their Hot Rod oil, started right up, half hour break in, lasted two years of daily driving, then suddenly started backfiring. Pulled valve covers, and there it was.
Click to expand...
Hylift Johnson (HLJ) in Muskegon, MI makes flat tappet lifters. Johnson in Taylor, MI has not made flat tappet lifters for 10 or more years.
 
That cam will be very nice & torquey in a 383. With only 9.5:1 CR, it would be easy to over-cam the engine & turn it into a dog...
I would buy quality bushed lifters such as Isky or Crower. Yes, expensive, but you get peace of mind that there are no pesky needle rollers to fail. I have had Isky's in my engine for about 15 yrs, driven weekly. I would also look at Beehive or Conical valve springs. They require 10-20% less pressure.
 
Geoff 2 said:
That cam will be very nice & torquey in a 383. With only 9.5:1 CR, it would be easy to over-cam the engine & turn it into a dog...
I would buy quality bushed lifters such as Isky or Crower. Yes, expensive, but you get peace of mind that there are no pesky needle rollers to fail. I have had Isky's in my engine for about 15 yrs, driven weekly. I would also look at Beehive or Conical valve springs. They require 10-20% less pressure.
Click to expand...
It'll put me at 8:1 dynamic compression and 165 cranking psi with 63° of overlap. I really just wanted to put this motor in another car since I have a stroker for this one, and I don't want to do much to this 383 like bigger heads, or rebuilding it. I also don't want to waste my time dealing with flat cams. I don't know what I could have done differently. Maybe we just have to get new lifters reground locally just to make sure they are machined properly, but then we still have the cam to worry about. I don't know what their ******* problem is. I reground lifters when I was a teenager, building up to three motors a day, and never had one come back with a flat cam, or at all other than the dumbass trying to claim a warranty with a bone dry engine case, no oil, but I digress. Here's what a new lifter reground half way with Dykem looks like. Not good.
 
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For what you could have done different, the easiest and cheapest option with current production parts is having a HFT cam Nitrided. That gives the cam an hard shell on the surface and allows the poor lifter machining to mate to the cam removing a minimal amount of the cams taper during the break in. I would not do another HFT with current production parts without Nitriding the cam. If you could have some old OEM lifters machines for find some NOS lifters that would be better yet. . One of the toughest combination for the street is a Nitrided mechanical flat tappet with EDM oiling.
 
I am in complete agreement with Powell also. The lifter machining is terrible on new lifters. It takes 2 sets or 3 sets to find a good set of 16 that are usable. It is pathetic. The machining has gotten so bad that a lot of times I can spot face machining issues looking at photos on my small phone screen. I still will do some HFT’s. But is it less and less every year.

I generally prefer mechanical cams. The Comp XR that you were looking at is a tight lash cam that doesn’t need a lot of spring pressures. I agree I think it was a pretty good choice.

For a roller cam direction for the street that is still pretty budget friendly you might also consider a Howard’s Hydraulic roller cam with solid roller lifters w/pin oiling, then use standard HR dual valve springs that have the seat pressure increase some. On several occasions we have found near new SR lifter that just had dyno time or a short use for 3 or 400 dollars on EBay. When the engine is cold set the lash so the push rod have light friction. The Howard’s cam lets you run the stock dizzy stock gear, you save money there. The mechanical lifters pretty consistantly make about 5 to 10 HP more thru the entire powerband than the same cam with HR lifters. It would be something like this cam in the link below. You could go a step smaller if you wanted. It is another option to the full SR cam. It isn’t easy to find a SR profile that you can run a 370 to 400 lb/in spring rate, 150 to 170 seat pressure and spin it to 7000. We have found hybrids have their place. Bullet makes some outstanding HR profile cams that work with SR lifters too.

DODGE Howards Cams 728045-09 Howards Cams Rattler Camshafts | Summit Racing
 
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This cam lasted two years, daily driver.
Click to expand...

How many miles is that?
What is the cam?
Springs/pressures?
Rocker ratio?
Oil and weight?
Oil change frequency?

If you take queues from the factory……..
Milder cam profiles, combined with less spring and lower rocker ratios……. should be more reliable than the opposite.

The same holds true for rollers as well.
 
The XR274 is not the smallest you can get, just maybe smallest in the catalog. They have lobes down to 250s. And the even milder High Energy lobes are probably still available to.
 
PRHeads said:
How many miles is that? Around 15,000 miles
What is the cam? Lunati pn:10230702 220°/226°@.050" 265°/271° 112°/108° .475"/.494"
Springs/pressures? Lunati pn:73815 120@1.820" 315@1.250 342lbs/in
Rocker ratio? Stock rockers
Oil and weight? Joe Gibbs Driven 10W40 Break-in Oil, then Driven 10W30 HotRod oil. 60psi idle according to dash.
Oil change frequency? Three times. I only do it when weather's good.

If you take queues from the factory……..
Milder cam profiles, combined with less spring and lower rocker ratios……. should be more reliable than the opposite.

The same holds true for rollers as well.
Click to expand...
 
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With that small of a cam like a 702 you could think about one of the smaller high energy SR cam. They are quite a bit less aggressive than a tight lash Extreme energy SR. The high energy are not real powerful cams, but they are pretty durable SR cams.

If you broke in the 702 cam with the 815 springs shimmed with the springs @ 1.82”, I think that is pushing it on nose pressure with a 702 for a good break in for the parts we have now. Even after the break in goes well, it doesn’t necessarily mean the cam will last. 702 is a pretty aggressive smaller HFT cam.

Our 67 Valiant has a bigger 704 Voodoo with the Micro-tol lifters in a 383 with the same 72815 valve springs. We broke it in with the install height higher to lessen the seat pressure down to 90 and nose 270 over. It was built 7 years ago and more it is more of a race car with a big shot of NOS, and we were not worried about the cam lasting a lot of miles. It broke in ok, but I doubt it will last much over 10k miles. I use to think as long as you had less than 280 lbs of nose pressure you could break the cam in ok. These days I think that is to high, with the parts we have to work with, 240 lbs might be closer to max nose pressure break in a HFT.

Already this year I helped with 2 friends with cams that lost lobes after the break in with similar single springs both with HLJ lifters. If you want to successfully break in a HFT cam these days plan on completely switch springs if you have single springs. That or Nitride the cam, but keep in mind the cam shouldn’t be Parkerized before it is Nitrided. You have plan on getting it Nitrided when you order it. Over all though it is still a lot cheaper than going with a roller cam, and the 702 would not have went flat. Nitriding has gone up some, I think it last I knew it was just under $170 at Comp.
 
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I had a little bigger Lunati cam, same springs I think, same oil and break in an it started to go bad after 4 seasons
 
V_TastyTacos_V said:
This cam lasted two years, daily driver. Motor looks like a '70 Challenger 383, so 9.5:1 compression. Has headers, Edelbrock Performer RPM, Holley Sniper, TKX, and 3.54 gears. I read so much conflicting info on cams, I don't know what to believe. Thinking about a Comp XR274R 274/280, 236/242@.050 ground on 107LSA, .564"/.570". It's their smallest solid street roller. I just don't want to deal with flat tappets again. Can a cam like this fit on a stock piston motor? I read some say needle bearings fail, others say roller bushings fail. Aren't all stock motors needle roller? Is it just the high spring load cams that cause the problems? I've owned a few stock solid cam motors. Don't mind adjusting valves. I would mind having to remove lifters to inspect all the time.
Click to expand...
Depending on which "stock" pistons are in the engine, the larger cam might have piston to valve clearance issues.
My 383 was rebuilt with the forged flat tops, but also the engine deck was milled so the pistons were just slightly below the block deck, and my heads were also milled 0.040" for compression, all of which moved the valves closer to the piston at TDC limiting cam duration because of P-V clearance.
I would put checking springs on the valves of one cylinder, set cylinder at TDC, and measure how far the valves can drop before contacting the piston.

I would call Bullet / Ultradyne cam and have them custom grind you a cam to match your engine combination and application.
 
451Mopar said:
Depending on which "stock" pistons are in the engine, the larger cam might have piston to valve clearance issues.
My 383 was rebuilt with the forged flat tops, but also the engine deck was milled so the pistons were just slightly below the block deck, and my heads were also milled 0.040" for compression, all of which moved the valves closer to the piston at TDC limiting cam duration because of P-V clearance.
I would put checking springs on the valves of one cylinder, set cylinder at TDC, and measure how far the valves can drop before contacting the piston.

I would call Bullet / Ultradyne cam and have them custom grind you a cam to match your engine combination and application.
Click to expand...
This is good advice but they won’t be closest at tdc.
 
comp cams have solid rollers as small as 218@.050 with 256 advertise duration
 
padam said:
This is good advice but they won’t be closest at tdc.
Click to expand...
Correct. That just give a known starting value. Piston position down the bore can then be calculated for each degree of crank rotation.
Cam grinder should be able to calculate lift around TDC overlap (with an installed ICL position) to have a good idea of what P-V will be.
You can do these calculations too, but you would need the actual full cam profile. lobe lift for each degree of cam (or crank) rotation.
I think the Piston to valve clearance might be a non-issue as it sounds like the block and heads have not been milled, and the cam will likely be in the 220ish @ 0.050" duration range.
 
I guess I’m not totally surprised that a fast rate Hyd cam has failed in 15,000 miles.
While it does suck, unfortunately you’re not alone it your predicament.
Unfortunately 2, it’s a big step up in $$$ to get into a roller set up.

I have customer putting together a very mild SB stroker for a truck(that will get used as a truck).
Initially they were going to use a solid roller, but that really just wasn’t the right choice for a DD type truck.
The builder just hates HR cams, and really for the application, a HFT just makes the most sense.

For about the last couple of years Comp has had affordable DLC coated HFT lifters available for Chevies.
I’ve seen several reports of people having good results with them.
They are now available for Mopars, so my customer decided to try a set out, along with a non-fast rate nitrided cam for this build.
We’ll see how it goes…..fingers are crossed.
 
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