The V8 Owners Forum -

hello all,

Looking for a good preload setting for the latest rebuild of my 4.6 rover v8 engine.

Reading the "des hammil" book, 0.02ins or 0.50mm is quoted as the optimum on page 79, with quite a substantial reason why.

Info I got with my adjustable pushrods says 0.04 to 0.06ins is better.

I'm using rhoads lifters and a piper 285 cam.

Heavily skimmed heads and decked block.

Book also says 0.02 to 0.03ins is best if using anti pump lifters.

Its probably not that much of a deal, just want to make sure in my own mind, I have asked the question first.

cheers

scott

How does a push rod know what lifter its fitted to! - I would go with information from the lifter manufacturer as to the best preload setting.

From the Rhodes installation info



HOW TO INSTALL AND ADJUST ORIGINAL RHOADS LIFTERS

Before installation, each Rhoads Lifter should be fully filled with oil. To fill with oil, completely submerge each lifter upright into a container of oil and compress the inner plunger with a pushrod or screwdriver until the plunger is driven to the bottom of the lifter. Hold several seconds and release slowly. Repeat several times until the lifter is fully filled. NOTE: Soaking lifters in oil will not fill them. Also, make sure to apply assembly lube to each cam lobe and lifter bottom.

ADJUSTMENT PROCEDURE FOR ADJUSTABLE ROCKER ARMS

STEP 1
With intake manifold removed and camshaft installed, begin by inserting all lifters (well oiled with assembly lube applied to the bottom of each lifter) into engine block. Keep the intake manifold off so that the lifter can be viewed while adjusting. DO NOT PUT PUSHRODS IN AT THIS POINT.

STEP 2
Bring number one cylinder to top-dead center of the compression stroke. Both intake and exhaust lifters for this cylinder should be riding on the low side (base circle) of the cam at this point. Insert pushrods securely into both intake and exhaust lifters for this cylinder only. Put rocker arms in place and make sure pushrod is securely in the rocker arm socket and ready to adjust.

STEP 3
Tighten rocker arm nuts until all play or looseness is removed and the plunger in the lifter just starts to compress. With the intake manifold off and lifters in sight, it will be easy to see when the plunger starts to compress. At this point, tighten the locknut until the plunger is compressed at least a sixteenth of an inch below the retaining ring (approximately 3/4 turn for a Small Block Chevy). While the amount the plunger is compressed is not critical, the important thing to remember is that the plunger must be compressed below the retaining ring so that there is no clearance or looseness in the valvetrain whatsoever, but not so much that the plunger bottoms out on the lifter shell. Now you can rotate the crankshaft until the next cylinder in the firing order is at top-dead-center of the compression stroke. Adjust this cylinder in the same manner as cylinder 1, and repeat the process until all cylinders are adjusted. No further adjustment will be necessary after the engine is started.

IMPORTANT NOTE: If the intake manifold is installed before adjusting lifters and you cannot visually see the point at which the lifter plunger begins to compress below the retaining ring, it is best to determine this point by moving the pushrod up and down in a vertical movement while tightening the locknut until all looseness is removed and the pushrod can no longer be moved up and down with light pressure. DO NOT DETERMINE THIS POINT BY TWISTING THE PUSHROD IN YOUR FINGERS WHILE TIGHTENING. YOU WILL BOTTOM THE PLUNGER OUT BEFORE YOU FEEL ANY RESISTANCE WHICH WILL RESULT IN AN INCORRECT ADJUSTMENT AND POSSIBLE DAMAGE TO THE ENGINE.

FOR NON ADJUSTABLE ROCKER ARMS.: Install Rhoads Lifters in the same manner as you would standard hydraulic lifters. Check the lifters to see that the plungers are compressed below the retaining ring at least a 32nd of an inch and preferably between 1/16th and 1/8th of an inch when the lifters are riding on the low side of the cam. Longer pushrods are ofter needed when using larger cams with smaller base circles to get the proper plunger compression. NEVER START OR RUN ENGINE IF THE PLUNGERS ARE NOT COMPRESSED TO THE RECOMMENDED SPECIFICATIONS. ENGINE DAMAGE MAY RESULT.

IMPORTANT NOTE: RHOADS LIFTERS SOUND SIMILAR TO SOLID LIFTERS AT IDLE. THIS MILD TICKING IS GENERALLY NOT HEARD UNTIL THE ENGINE APPROACHES NORMAL OPER




So you will be pleased to read that you have chosen a product that the manufacturer states makes no difference to performance whether they are .8mm or 3mm below the retainer so probably no need for those adjustable push rods also does not appear to be important if they are all the same.

Perhaps all these complaints about noise are due to them not being set compressed enough - 2mm seems the rule from Rhodes

Glad I am on nice simple noisy solids.

ETA

One of the articles on the Rhodes page goes another way of adjusting stating that the best was is to compress the plunger all the way in until it hits the inner retainer whilst having a 35 thou feeler in the valve - with a 1.6 ratio that would be 20 thou off the bottom up not from the retainer down - hmmmmm

hello darkspeed,

Many thanks for that information, never thought to look on the rhoads site for info.

So looks like 0.060ins should do the trick for me.

Interesting how rhoads says filled with oil, and real steel say without though.

Cant remember what I did last time, I probably followed the real steel advice, this time I think I will follow the rhoads advice.

cheers

scott

Having a look how they work I would use as much preload as possible - it depends if standard Rhodes or V-Max type. It would appear that if you only use a little preload - as they do not pump up - you run the risk of them bleeding down too far and being noisy and losing cam / valve lift.

The key seems to be having as little oil in the lifter body as possible - which makes a lot of sense - less to compress and less lift to loose -(it will) and less weight in the train - what goes up must come down and all that.

I am wondering if Des Hammill fully understood the preload setting on the anti pump Isky lifters

The correct way to set anti pumps appears to be - bottom them out and then wind them back for clearance - rather than let them bleed out the lift.

1.5mm will certainly be safe. And winding on more would be a simple enough ask if needed to experiment in the future.

Seight-V8 wrote:hello darkspeed,





Interesting how rhoads says filled with oil, and real steel say without though.



cheers

scott

I believe that if you fill the lifters with oil it may be difficult to push down the innards to achieve any space between the plunger and the circlip. Some oil yes but don't soak over night and pump to disperse all the air from inside the lifter.