Regrind lifters (cam followers)?
05-14-2013, 11:23 AM
#31
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okay so they have a small taper, so technically are they flat or convex?
05-15-2013, 01:56 AM
#32
Drifting
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After reading the above article I came to a few hypothesis, but no solid fact conclusions for our application. There are also some terms to be defined.
Also remember they are referring to a V8 where the lifter/tappet is inverted so when they say bottom it is top for us.
There are true flat tappets and flat tappet cams. These cams don't have tapered lobes. Apparently, this is for very old engine designs, like 60's and older.
Newer hydraulic lifters also called tappets wish they would pick a term and stick with it, are convex or crowned to the tune of 8-15 thousands of an inch. I have not seen a drawing but would assume high in the middle with a uniform taper. The cam lobe for this application is also "tapered" to reduce friction and increase rotation of the lifter which aids in lubrication.
When installing a new cam and or lifters they should be broken in for 20-30 minutes at 2-2.5K rpm's. Making sure to use plenty of assembly lube in conjunction with a break-in oil or at least add a ZDDP additive. They also recommend not using strong valve springs with a closing pressure of more than 100 psi. After break in larger valve springs can then be added.
If any of my statements are incorrect Harry can clear it up as he is much more of an expert on this subject.
After reading the above article I came to a few hypothesis, but no solid fact conclusions for our application. There are also some terms to be defined.
Also remember they are referring to a V8 where the lifter/tappet is inverted so when they say bottom it is top for us.
There are true flat tappets and flat tappet cams. These cams don't have tapered lobes. Apparently, this is for very old engine designs, like 60's and older.
Newer hydraulic lifters also called tappets wish they would pick a term and stick with it, are convex or crowned to the tune of 8-15 thousands of an inch. I have not seen a drawing but would assume high in the middle with a uniform taper. The cam lobe for this application is also "tapered" to reduce friction and increase rotation of the lifter which aids in lubrication.
When installing a new cam and or lifters they should be broken in for 20-30 minutes at 2-2.5K rpm's. Making sure to use plenty of assembly lube in conjunction with a break-in oil or at least add a ZDDP additive. They also recommend not using strong valve springs with a closing pressure of more than 100 psi. After break in larger valve springs can then be added.
If any of my statements are incorrect Harry can clear it up as he is much more of an expert on this subject.
05-17-2013, 10:31 AM
#33
Three Wheelin'
I defer to Michael on the lifter shape.
To clarify my comments on the button, if you can compress it, they will bleed down over time. This does not mean they will not function but you will get some clatter until they pump up after initial start up. How quickly they bleed off is a variable though and is the reason I would replace them. But, that is just my opinion and YMMV.
To clarify my comments on the button, if you can compress it, they will bleed down over time. This does not mean they will not function but you will get some clatter until they pump up after initial start up. How quickly they bleed off is a variable though and is the reason I would replace them. But, that is just my opinion and YMMV.
05-17-2013, 04:56 PM
#34
Burning Brakes
My .02, spend the money and buy new ones. I find it funny how guys will spend $2000.00 for new rims, $1000.00 for a new turbo, $500.00 for polished intercooler pipes, $350.00 for cool boost gauges, ect..... but think new lifters cost too much.
Carry on......
Carry on......
