Why is it that retro roller lifters have to have the tie bar on them and oem roller lifters don't? Also, is it necessary to run a cam button for a flat tappet cam? Thanks.

Why is it that retro roller lifters have to have the tie bar on them and oem roller lifters don't? Also, is it necessary to run a cam button for a flat tappet cam? Thanks.

The tie bar keeps them centered so they don't try and rotate. Keeps them square to the cam lobe since the original blocks were designed to have the lifter rotate as the cam went round-and-round.

The OEM Roller blocks use a retainer set up to keep the lifters from rotating.
That is why the OE lifters have flats on them.
Cam buttons are good in all aplications.

To clarify a little, flat tappets are designed to rotate. They have a slight crown on the bottom surface which is rotated by the cam lobe which has a slight bevel which contacts the lifter slightly off center making it rotate. The bevels on the cam lobes are set up to pull the cam toward the rear of the engine making a thrust button unnecessary but still a good idea.

With a roller setup, the roller on the lifter must align with the lobe or they will destroy themselves in very short order, hence the tie bars on retro setups. The factory did it differently with retainers that engage flats on the lifters, but the result is the same-holding the rollers in alignment with the lobes.

Roller cams have no bevel on the lobes so the cam is free to move forward and aft as it will making some sort of thrust location such as a cam button or thrust plate necessary.

I got it. Thanks guys. I think I am going to go roller next time. I have an issue with a lifter not spinning and instead of going through the pulling the engine and the money to have it bored, sleeved, and honed, I'll just go roller.

To clarify a little, flat tappets are designed to rotate. They have a slight crown on the bottom surface which is rotated by the cam lobe which has a slight bevel which contacts the lifter slightly off center making it rotate. The bevels on the cam lobes are set up to pull the cam toward the rear of the engine making a thrust button unnecessary but still a good idea.

With a roller setup, the roller on the lifter must align with the lobe or they will destroy themselves in very short order, hence the tie bars on retro setups. The factory did it differently with retainers that engage flats on the lifters, but the result is the same-holding the rollers in alignment with the lobes.

Roller cams have no bevel on the lobes so the cam is free to move forward and aft as it will making some sort of thrust location such as a cam button or thrust plate necessary.
And to clairify even a little more; flat tappets are ground with a 50" circle. I forget the proper name. Crown ground? No. That's for pistons. Well, maybe it is. Aren't pistons cam ground? (this is my Geoge Carlin tribute) Anyway, you can see it. Take two new flat tappets and hold the flats against each other. They are high in the center. And that high spot, if extended to a full circle, equals 50". ( or there abouts) Did I clear up more for ya?:D

Somewhat

Charlie,

Imho, pull her out AND check her over to see why the lifter didn't rotate b/c if that bore is off that much, it MAY be off too much for a roller lifter to work correctly too!

Guys have posted before about GM's crappy machining tolerances in this area before!

pdq67

I had the lifter out and honed it and then re-installed it. For a split second, the lifter spun, but then it stopped. It doesn't feel tight when I install the lifter, nor is it hard to get out. It also spins easily in its bore. The oil passages along the bore feel good. No sharp edges. I don't get it. It moves up and down freely as well by hand. I am not sure what I am going to do. I will see where I am at financially when the time comes. I may just go with a new GMPP short block or go roller with this one. More than likely I will get the short block. Maybe, provided I have the funds, I'll get a GMPP long block. I am not sure, but I am tore with the idea of either going with E.F.I. or going back to the Quadrajet. If the Quad, then I am going to get the Jet Performance stage 2 Quadrajet. Either the 750cfm or the 800cfm, but the idea of never having to tune the engine for hot and cold weather driving ever again with the F.I. sounds VERY VERY enticing.

The term Retro-Fit Rollers Hydraulic or Solid refers to converting an Engine designed with Lifter Bores using Flat Tappet again Hydraulic or Solid. The Biggest problem associated with this conversion is Cam Walk as Engine designers were not the particular about the accuracy of lifter bore alignment when using flat tappet. Actually the flat tappet Cam lobe profile is ground on a Taper or Bevel, thus higher on one side of the lobe surface so that the lifer rotates. This rotation prevents Cam Walk.

In order to prevent Cam Walk when converting Flat Tappet Engines to Roller, Anti Cam Walk Devices are used. The Correct procedure would be to have the Lifter Bores Aligned Machined and also utilize an Anti Cam Walk Device.

Newer Designed engines with Roller Tappets do not require Lifter Bore Alignment or Anti Cam Walk devices as they already have it built into the design.