pros and cons of a flat tappet cam

[eviper21]

I have brand new hydraulic flat tappet lifters, so I figure ill get a cam to go with them. Does anybody know the pros and cons of a flat tappet cam though? I know that the break in period is pretty tedious but is it for better results from say a regular hydraulic roller cam?

Thanks

 

[Lars]

The only real disadvantage to a roller cam is cost. Otherwise I'd choose a roller over a flat tappet every time.

 

[Mopar44134]

$$$$$$ if your on a budget go with the flat tappet and zinc additive. rollers = less friction = horsepower.

 

[1970Duster]

If you got the $ go roller. My 340 was going to get a Flat tappet cam until I heard about that oil/zinc crap. So the motor ended up getting a Full roller setup cam, lifters, and rockers (the roller rockers are not required, but i opted for them. They are comp pro mags).

 

[71beater]

Pros,
Hydraulic flat tappet cams are cheap.
They're reliable... Come on, they came in almost everything for what, like 50years?
Up to a fairly high performance level, no issue.

Cons,
Break-in.
Only good to a certain performance level.

Mechanical, good to higher performance levels.

As for oil arguments, once past break-in any good oil should suffice, and if you must, go for a zinc additive.

Obviously, rollers are the hot **** in this day and age, but flat tappets can still do it....

 

[the wall]

plain and simply flat tappet is cheap and with no block or head mods like grinding to install it the roller is the way to go if its affordable. the manufactures used them (flat tappet)for that reason cheep. they probably still would use them but modern emission laws forces them to go roller. emissions cam profiles are not friendly to hp. but rollers help put some of that power back. still big power can be had with flat tappet cams. even after break in the flat tappets can set a destructive pattern. but very rare for hydraulic type. i have seen countless lobes eaten up on flat tappets but never on a roller. although ive heard stories about the roller wheels falling apart on roller cams and spreading needle bearing threw out the engine. ive not seen that yet, must be and old day type thing i guess.

 

[moper]

I have brand new hydraulic flat tappet lifters, so I figure ill get a cam to go with them. Does anybody know the pros and cons of a flat tappet cam though? I know that the break in period is pretty tedious but is it for better results from say a regular hydraulic roller cam?

Thanks

What is your performance goal?

 

[BillGrissom]

I have heard the "8% mileage improvement" claim for roller cams, which is probably true, but I doubt the reason is due to reduced friction alone. I suspect the improvement is mostly because with a roller cam one can have a more optimal profile.

After-market link-bar roller lifters are very expensive. I wonder if one could use standard Magnum engine lifters with the spring-plate lifter retainer by tapping mounting holes in the block (during a total rebuild). Seems I heard this, but have never seen photos or "I did this" posts.

Failures with flat-tappet cams are probable due to a combination of factors. Many people run much higher than factory spring loads. Metal treatment of lifters and cam might be suspect, especially with so many parts made outside the U.S. today. Less additives in oil today. If the latter, I wonder why many other current engines don't have failures today. I have 80's and 90's cars (OHV cams) that have similar sliding surfaces. Indeed OHV cams fail much quicker from oiling problems, but it doesn't seem to be endemic today.

 

[the wall]

I have heard the "8% mileage improvement" claim for roller cams, which is probably true, but I doubt the reason is due to reduced friction alone. I suspect the improvement is mostly because with a roller cam one can have a more optimal profile.

agreed, if there is a power increase from less friction i would doubt you could even measure it. the performance improvements are from profile, weather it be economy or performance.