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Guys that race and turn RPMs well above 6000? Well, that leaves ME out....
I'm getting close to switching to a roller cam in the big block!
- Thread starter Kern Dog
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gtxrt
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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.
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ckessel
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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.
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!
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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
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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 
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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
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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
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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.
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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.
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.
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
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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.
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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:
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
Well-Known Member
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
Well-Known Member
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
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