I'm getting close to switching to a roller cam in the big block!

[Kern Dog]

Guys that race and turn RPMs well above 6000? Well, that leaves ME out....

 

[gtxrt]

my solid flat cams with a .904 lifter I run have faster ramps the most roller cams like I said before the solid cam is faster off the seat then a hyd roller nobody can deny that. the weight of a roller lifter will require a little more spring pressure. run what camshaft you prefer but everyone should know the real plus and negatives.

 

[ckessel]

There are a lot of specs to a cam besides the obvious lift and duration. Intake centerline/lobe center, opening and closing specs, lobe profile etc. Kind of like, I have a big and tall house. Thats great but what's inside? What happens in those spaces? How many rooms? Stairs or elevator? The cam specs also help dictate cylinder pressure which matters for timing, loads and fuel requirements.

 

[RemCharger]

Ca


Can you share the details?

I know of one: Red Zones, 900 hp, 900 lbs and 0.90” over the nose, 350 passes.

And my point is that just about everytime the subject comes up with running a street roller on a lolly-pop street cam lobe the fear mongers come out and talk about filling your motor up with needles. You’d never guess that we used them for 40 years before the days of: “you have to use bushed rollers.”

Also, word of bushed roller failures are popping up.

Again, buy quality.

There's quite a few 1000+ hp guys at our track now, which I'm sure all have rollers and not all fail. Attention to lash, and newer tech lifters help negate the issue for sure. But after seeing guys putting cars on trailers after going to roller gave me the willy's for years. I'm into reliability and enjoyed zero issues with flat tappet race cams .. but now we will see how the roller works out.
It sure revs quick!

 

[RemCharger]

Guys that race and turn RPMs well above 6000? Well, that leaves ME out....

The real party starts after six grand

 

[Kern Dog]

As strange as it will seem to you hard core guys, I want my cars to be as reliable as possible so I can drive it with the confidence you'd get from a newer car. It is a mix though....balancing reliability with improved performance wrapped in a classic wrapper that looks close to stock.

 

[BLK 68 R/T]

One more piece of advice I can offer is to make sure the new pushrods don’t rub on the heads anywhere. Assuming they will be 3/8” diameter since .080” wall thickness was mentioned? Be sure to rotate by hand with the valve covers off and check for clearance

 

[Kern Dog]

One more piece of advice I can offer is to make sure the new pushrods don’t rub on the heads anywhere. Assuming they will be 3/8” diameter since .080” wall thickness was mentioned? Be sure to rotate by hand with the valve covers off and check for clearance

Good advice. I have 3/8" pushrods in place now but I've not noticed any contact marks on them. I had the engine out in 2022 but I don't remember looking too close at the pushrods.

 

[BSB67]

There's quite a few 1000+ hp guys at our track now, which I'm sure all have rollers and not all fail. Attention to lash, and newer tech lifters help negate the issue for sure. But after seeing guys putting cars on trailers after going to roller gave me the willy's for years. I'm into reliability and enjoyed zero issues with flat tappet race cams .. but now we will see how the roller works out.
It sure revs quick!

Without the details of the parts used, and the conditions, it’s just not particularly helpful info. I do know of several more roller lifter failures, but they weren’t good roller lifters.

 

[BLK 68 R/T]

Good advice. I have 3/8" pushrods in place now but I've not noticed any contact marks on them. I had the engine out in 2022 but I don't remember looking too close at the pushrods.

I believe having the longer hydraulic roller lifters with shorter pushrods will change the angle of the pushrods somewhat, it would still be good to recheck it before running it.

 

[Kern Dog]

Any part that is pushed too far will fail at some point, the best that we can do is try to stay just shy of the failure point.
It has been said that for flat tappet engines, we should avoid extended idling due to insufficient oiling to the cam and lifters at low engine speeds.
What speeds? Under 600 rpms in drive while sitting in traffic? That is where my 2007 Dodge truck sits at when idling in gear. I've made it 410,000 miles by driving it like any other car/truck. The 3G Hemi engines are known for having a small percentage of camshaft and/or lifter failures despite using a roller design. In the case of the new Hemi, some blame is placed at the higher camshaft location in the block along with the position of the oil galleries that don't oil from above like a traditional V8.
Old school flat tappet cams seemed to have a very small incident of failure until a few things changed in the industry.
OEMs switched to roller camshafts and lifters for less friction.
EPA mandated lower levels of ZINC in the engine oil to reduce contamination of catalytic converters.
Factories that used to supply millions of lifters for the OEMs cut production of the flat tappet designs as the market shrunk for them. Those that remained in the flat tappet industry did not have the same budgets or materials nor the financial incentives to maintain the high level of quality that the OEMs demanded.
Fewer flat tappet lifter manufacturers, engines with more aggressive camshafts for more power, stiffer springs, variable quality of the oil used....
BOOM.
The last cam failure is strongly suspected to be because of the oil I used but I can't prove it.
The expense of pulling an engine out to go through it due to a cam and lifter failure is matched by the inconvenience of it.

 

[RemCharger]

Without the details of the parts used, and the conditions, it’s just not particularly helpful info. I do know of several more roller lifter failures, but they weren’t good roller lifters.

Yes that's true, I don't have any thing solid to bring forth for helpful info. I just mentioned my own personal fears about it. It's more of an internal fear mongering lol

 

[PRHeads]

The expense of pulling an engine out to go through it due to a cam and lifter failure is matched by the inconvenience of it.

To put it in slightly different words………
It just sucks and is a royal pita when a cam goes bad……….but at least it’s expensive.

 

[Kern Dog]

New pushrods will be needed. The exact length is an unknown since many factors come together to get an accurate number.
Keep in mind that some of what I'll mention here is what I have done before, other stuff is only what I have heard.
I can only guess but I suspect that all engines had a target for their finished dimensions, deck height being one of those things. The 440/RB deck height is no different so it could vary a little from block to block. Add in the times the decks have been resurfaced and the deck height gets shorter. The same goes with the heads. Then there is the thickness of the head gasket. Don't forget about the height of the rocker shafts. Does that ever vary even by a couple thousandths?
My current pushrods are 9 1/8". I have a pushrod length checker that has a range of 8.8 to 9.8 inches. That is with a solid flat tappet setup and Mancini roller rocker arms. Given that the roller lifters are physically taller than any flat tappet lifter, the pushrods I'll need will be shorter. Could they be shorter than the 8.8" limit of my pushrod checker?
Looking on the Summit Racing website, I checked for some options. Plenty do exist and they are fairly cheap.

This may be good enough though:

 

[ckessel]

If you do need pushrods that are not already done in the needed spec, along with Smith Bros, there is Manton down in Lake Elsinore[ Riverside county].

 

[ckessel]

Something else from my memory bank. Back in the mid 80's I was putting together a W2 head package for a 340 stroker to go into my 73 Duster. DC/MP didn't have a ready made set available and getting custom done units, or those in needed dimensions, was not a choice for me. However, MP/DC did have a semi done, you finish, set available. These already had the lifter end done, you just determined the needed length, cut them down/ream them with supplied reamer, then pressed in the supplied cup ends. I made my own pushrod length checking tool, modded stocker with adjuster on it. A friend gave me access to his lathe to do the cutting/reaming/pressing in the cups. Once I figured out the lengths needed, exhaust and intake were different due to rocker offsets, it was a slam dunk.

 

[RemCharger]

Something else from my memory bank. Back in the mid 80's I was putting together a W2 head package for a 340 stroker to go into my 73 Duster. DC/MP didn't have a ready made set available and getting custom done units, or those in needed dimensions, was not a choice for me. However, MP/DC did have a semi done, you finish, set available. These already had the lifter end done, you just determined the needed length, cut them down/ream them with supplied reamer, then pressed in the supplied cup ends. I made my own pushrod length checking tool, modded stocker with adjuster on it. A friend gave me access to his lathe to do the cutting/reaming/pressing in the cups. Once I figured out the lengths needed, exhaust and intake were different due to rocker offsets, it was a slam dunk.

That's the fun doing it back in the day. Did you chamfer for the radius of the tip to cup relation? My elder Mennonite friend showed me that. I was an aspiring hot rodder, and he was a machine shop German.
That being said, get all of their needed specs( probably on the website, then make the call and answer the questions. Smith brohs are great to deal with . Get 18

 

[Kern Dog]

Christmas in April?

It has been a long time coming. I have resisted and delayed but I did order and have now received most of the parts needed to make the swap.
I love it when parts arrive at home.
Yeah, it is great to have an auto parts speed shop nearby too.

Those specs are based on a 1.5 ratio. My rockers are 1.6 so the lift will be .582 and .579.
The difference in the shape of the lobes versus a flat tappet….

I’m having a hard time understanding how a lobe with so much meat in it before max lift can not be so much wilder.

 

[Kern Dog]

I won’t be tearing into this right away. I’m planning on a 900+ mile road trip in a few weeks and don’t want to risk getting elbow deep in this and unable to get it running in time.

The billet core looks so much different than a cast cam core. The base circle of the roller cam seems smaller to the eye but the old cam to the left was that ‘528 I wiped out in 2022. None of the lobes share the same numbers! The base casting of the 528 cam is thicker by .060.

This is exciting for me. FBBO member @HawkRod was my inspiration to use Comp Cams. Dwayne Porter listened and advised on the specs.

I briefly looked at the instructions then tossed them into the trash can

Who needs those?

Kidding, of course.
The whole retro-roller cam swap is 100% new to me so I will not just wing it…
I’ll be asking for advice when needed and willing to see comments from others with experience in this stuff.

Over $700 for a set of lifters and these are not even the most expensive ones! These have a good reputation and came recommended.

 

[BSB67]

Those specs are based on a 1.5 ratio. My rockers are 1.6 so the lift will be .582 and .579.
The difference in the shape of the lobes versus a flat tappet….

I’m having a hard time understanding how a lobe with so much meat in it before max lift can not be some much wilder

Because the actual lifter action is totally different between the roller and flat tappet.

If you put a roller lifter on a FT cam lobe, the valve would move way slower and the motor would see it as a lot smaller cam.

Roller lifter, by their nature move a lot slower than a FT, so the lobe shape is more aggressive to make up for it.