When are Offset Lifters Needed ?

[Sajomatic]

I was looking at some shaft rocker setups for a small block chevy Gen 1 for the Dart Pro One 215 heads. It will run solid roller lifters from Crower. Most all of the shaft rocker setups have a .220 to .250 offset intake and .100 to .170 exhaust setup. The Crower lifters are available with the .150 offset on the intake or exhaust. The also have them with offsets on both sides.

[Alaskaracer]

They are needed when the valve centerlines have been moved from the original stock locations. Many head designs now have moved things around to improve breathing and performance, but the lifter positioning in the blocks has not. To accommodate that, offset lifters and offset rockers were produced. On high end builds, lifters can be relocated as well but depending on the amount they are moved, it may also require a special cam core to allow for it, and the lifters used in these applications are very expensive.

[Walter R. Malik]

Do everything you can to NOT use offset lifters.
They are sometimes needed because they can get enough pushrod to cylinder head clearance for whatever reason.

[swampbuggy]

Walter, you said---Do everything you can to NOT use offset lifters. Please explain in detailed text why you say this. Thanks Mark H.

[Walter R. Malik]

Walter, you said---Do everything you can to NOT use offset lifters. Please explain in detailed text why you say this. Thanks Mark H.

Offset button lifters create unwanted extra stress on the lifter bodies, the lifter bores, lifter tie bars and lifter bore pins, (if they are pinned bore lifters), which centered button lifters don't exert that additional stress.
It is that simple

[swampbuggy]

I will not have to worry about tie bars, there won't be any employed. .937 keyway .150" intake offset centered exhaust. Mark H.

[steve cowan]

I was looking at some shaft rocker setups for a small block chevy Gen 1 for the Dart Pro One 215 heads. It will run solid roller lifters from Crower. Most all of the shaft rocker setups have a .220 to .250 offset intake and .100 to .170 exhaust setup. The Crower lifters are available with the .150 offset on the intake or exhaust. The also have them with offsets on both sides.

I ran my 383/gen 1 block a few years ago with Dart platinum pro 1 heads 215 cc with 60/40 valve spacing.
Jesel shaft rockers with 0.300" offset on intake only.
Solid roller 0.680" lift
230-600psi valve springs
7500-7600 rpm on the gearshift at the track.
Ran a full year, plenty of street time and approx 50-60 passes.
Pulled engine apart, no issues I could find.
No offset lifters.

[gmrocket]

Walter, you said---Do everything you can to NOT use offset lifters. Please explain in detailed text why you say this. Thanks Mark H.

Offset lifters are brutal on tie bars at max lift the lifter is trying to be turned and is solely relying on the ty-bar. During opening and closing the lifter is using the lobe to keep the lifter from turning.

That would only happen if the lifter and p Rod are not parallel, correct?

Would the slight change in being off parallel , as it changes slightly through the lift cycle, hurt that much?

This is only talking about engines with very near parallel lifter and p rods to start with.

An example of off, or way off parallel would be some small block mopars with big port heads..I can see an offset lifter cup really screwing, literally, the lifter in its bore.

[steve316]

If you run lifter bushings that will help with lifter wear from side loading. I have ran offset lifter starting in the mid 90's with no problems; but they should be checked on a regular schedule.

[Caprimaniac]

Let me ask a question regarding this.....

In the spplication I work on, the geometry asks for offset lifters. However- people report great resuluts with centered lifters. I measured and checked- yes, it will work.

So, digging in on some older threads over at YB, I found a statement something like this:

Using centred lifters with offset rockers (angled pushrods) is way better than offset liftets UP TO 7500 rpm...

Ok- Engine is going to see 8200rpm+. So- am I screwed?

[n2omike]

I have Trick Flow High Ports for the 8.2 deck 363 SBF I'm building. I'm using Crower Shaft Rockers that have... I believe... a 0.075" and 0.100" offset. I asked about using offset lifters to match, and was told they were not needed. I thought it would be best to keep the pushrod square with lifter with no angle. Was that the best advice, or should I have looked for lifters? Do they even make lifters with that little offset?

[Walter R. Malik]

Walter, you said---Do everything you can to NOT use offset lifters. Please explain in detailed text why you say this. Thanks Mark H.

Offset button lifters create unwanted extra stress on the lifter bodies, the lifter bores, lifter tie bars and lifter bore pins, (if they are pinned bore lifters), which centered button lifters don't exert that additional stress.
It is that simple

If your specific combination needs to use offset buttons in the lifters than do so but, not unless you absolutely have to.

[gmrocket]

Offset lifters are brutal on tie bars at max lift the lifter is trying to be turned and is solely relying on the ty-bar. During opening and closing the lifter is using the lobe to keep the lifter from turning.

That would only happen if the lifter and p Rod are not parallel, correct?

Would the slight change in being off parallel , as it changes slightly through the lift cycle, hurt that much?

This is only talking about engines with very near parallel lifter and p rods to start with.

An example of off, or way off parallel would be some small block mopars with big port heads..I can see an offset lifter cup really screwing, literally, the lifter in its bore.

Take a lifter with no tie-bar and see what happens at max lift using an offset lifter.

I've run .150" offset lifter cup in a 6800 rpm max with 900lbs over the nose. .460" lobe, 1.8 offset rocker. The lifters have been reused on several cams

The p rod distance c to c is identical at the lifters and the rockers, the lifter bore is also parallel with the p rods from just after base circle , and gets off parallel later on.. but having a real tall block and a p. Rod that's over 10.5", it's not much off parallel

These are the full round button tie bar link style, not the slotted removable ones...so lots of contact to prevent twisting in the bore. I checked for wear between link bar and button with feeler gauge.. it's not changing

[gmrocket]

I have Trick Flow High Ports for the 8.2 deck 363 SBF I'm building. I'm using Crower Shaft Rockers that have... I believe... a 0.075" and 0.100" offset. I asked about using offset lifters to match, and was told they were not needed. I thought it would be best to keep the pushrod square with lifter with no angle. Was that the best advice, or should I have looked for lifters? Do they even make lifters with that little offset?

Sq with lifter in both planes? It's the for and aft plane that's the problem where the p Rod will tend to turn the lifter. If that angle is to far off parallel, you will have problems

Also , thes shorter the deck, the shorter the p Rod.. which will be more angular as it goes through a lift cycle compared to a longer rod and taller deck

[Mikej26]

Offset lifters introduce a torsional/rotational load on the lifter that doesn’t exist when the pushrod cup is centered. Personally I’d avoid adding the extra element of stress unless it was absolutely required to make the setup functional.