rhoads v max
 

So a while ago I had my 455 rebuilt. Had a new HFT cam and rhoads vmax lifters installed also. While the intake/valley pan was off the lifters were set at .018 lash. Ran it on the dyno and had bearing issue. Engine was torn down again and fixed . A different person at the machine shop installed the lifters and set the lash. I dont believe he set them correctly.They went to run it on the dyno and they couldnt get it started,,i was told it would just pop and fart.They let it set overnight and set the lash again the next day and they got it running but never removed the intake. Its been back in the car now for awhile but since the car is still in the middle of a restoration it hasnt been driven down the road. While idling, the passenger side sounds noisier than the driver side as far as valve train noise. So,,,the car has been sitting about a week since I last started it. Today i popped the pass. valve cover off so I could check the lash and see where the machine shop set them. I rolled the motor over and checked 2 cylinders. Just when the exhaust started to open,i checked that intake. I tried my .018 feeler and couldnt get it in. Then I tried a .012 and the same thing. Then tried a .008 and had to push hard but got it in there but with too much pressure. Then I went back to the .012 and with force I got it in. To me it sounds like these are too tight but without the intake/valley pan off I cant see whats going on in there. Youre supposed to insert feeler gauge,tighten nut til the plunger bottoms out in the lifter shell and the valve begins to open. Back off til the valve closes and you can just spin the pushrod and then lock it down. At this point the plunger should be pretty much at the bottom of the shell and not against the retainer clip. But It says you can adjust these after the engine is together and has been run. If these lifters have been run and have oil in them can they give false readings? It makes me wonder if the guy didnt know how to set vmaxs,,tried to run it on the dyno,,wouldnt run ,,then they set the lash with the engine on the dyno but with the intake on how can you do it properly if you cant see the lifter plunger?

I can’t answer I’m the how, but any time I find myself in this type of situation where I’m questioning the work of others, I verify it myself. If I do t the issue just haunts me.

So my advice would be to pull the intake and set the lash yourself for piece of mind. If you find it was done incorrectly, take it up with the engine builder.

Except V-Max lifters are adjusted from being bottomed out, and not lashed like a solid lifter. There is an acceptable range between .010" and .040" from the bottom and -.018" from bottom would be acceptable.

"Make sure the lifter being adjusted is on the low side (base circle) of the cam when adjusting, just like you would when adjusting any solid lifter cam. In this position, the valve would be in the fully closed position. For street use place a .020” feeler gauge, (use .030" for racing), or for aluminum blocks use a .010" feeler gauge (or .020" for racing) between the valve stem and rocker arm as if adjusting solid lifters, and tighten the lock nut until the lifter plunger bottoms out in the lifter shell and the valve begins to open. Now back off on the lock nut until the valve just closes and the pressure of the valve spring just begins to release on the feeler gauge. When you can just slide the feeler gauge back and forth with slight drag from the spring, the adjustment is correct. Repeat this process until all lifters are adjusted. After the adjustment, the plunger position should be nearly all the way down to the bottom of the lifter shell, and not up against the retaining ring, with no clearance in the valve train whatsoever. Please remember to adjust the lifter when the valve is in the closed position, or the adjustment will be wrong. For absolute accuracy, the adjustment can be repeated when the engine is at normal operating temperatures, but the adjustment should be made with a .020" feeler gauge (.030" for race) for both cast iron and aluminum heads when the engine is hot. Also, never adjust the lifters at zero lash or looser so that the plunger is up against the retaining clip as standard anti-pump up lifters are adjusted. This will cause valve train damage."

Very easy to do when they are new with no oil and it is very easy to feel the bottom. After they are run the valves have to drain down with spring pressure to insure that you are not riding on a cushion of oil when adjusting.

Yes,, the instructions are pretty straight forward with the lifters exposed. But it also says you can do this with the intake on but that's all they say. Yes,,when the lifters are new and haven't been run yet and lifters exposed is the best way. That's why I let it sit for a week so to let them drain out. Anybody have a procedure they use for vmax lifters that have been in my situation or do I have to tear it apart? Seems crazy that youd have to see the lifters each time you adjust them. Them being so tight with a feeler gauge makes me think theyre too tight or theres oil holding up the plunger still.

With the intake on, you use the exhaust opening/intake closing method. This method sets the intake valve when the exhaust valve is just starting to open and the exhaust valve when the intake valve is open and just starting to close.

Just watch the valve motion as you rotate the engine and adjust as above.

Tighten them all the way without a feeler gauge. You should be able to tell when the valve starts opening with the intake on. Then back off until the gauge will slip in tand tighten. I really don't think that having the intake off will help you much other than seeing when the lifter is on the base circle, which is not that hard to figure out with the intake on. You will need to tighten them slowly to allow any oil inside to leak down. The shop likely screwed it up, but you should be able to get it right pretty easily unless they had them tightened way down so a piston hit a valve and bent it. Might not hurt to pull the plugs and do a compression check and check all the pushrods for straightness. I have had 'professional' mechanics do serious damage when working on non-standard aftermarket equipment.

I have changed the lash on them for testing. Adjust the lash, gone for a test drive, came back, adjusted them test drive, ect, ect. To do that type of testing the feeler gauge goes in really tight. Snapping in place like what you described when you used the .008” feeler gauge. It sounds to me like they are set around .008” right now. If they didn’t do a good job setting them the lash probably varies a lot.

They collapse quickly, I am not sure why one would need to let it sit overnight or pull the intake of see anything better. There can be some residual hydrualic preload and there is spring preload on the lifter. Pressing down on the plunger the hyd preload disappears quickly, seconds, not hrs. The only thing different than adjusting the vmax than a solid cam is if you want to do a good job you have to make sure that preload is all collapsed. I ussually pull the feeler gauge out and try stepping up the lash a couple thousands just seeing if it fits, mainly just to make sure the lifter is collapsed. If it is totally collapsed with the .008”, forcing a .010” in you can usually feel the start to valve open. Usually once you do that on a couple valves you can just get the feeler gauge to snap in place at the lash your shooting for.

If an engine won’t start or runs but make popping sounds the is lash too tight. You have a big range that you can run the lash. .008” is fine. But on your 4 speed car it is probably advantageous to change the lash to .020”. It really isn’t that big of a deal if they aren’t all exactly the same. Other than some extra sowing machine noise the engine won’t care. You can even set them by ear while the engine is sitting there idling, or evenly do partial turns on the adjusters and leave the feeler gauges in the tool box.

The bleed rate is fairly high on those lifters, so collapsing them for adjustment is easy to accomplish.. It truly sounds they were too tight, re run the adjustment and adjust to your favorite flavor! (not really lash, your setting plunger distance from bottomed out....amount of bleed down till pumped up.

Years ago, the Pontiac RAM AIR IV lifters used a special "thick" pushrod cup that reduced the plunger travel distance. I believe the extra thickness of the RA-IV pushrod cup was .100" so the plunger travel was reduced .100" by the design of the parts.

Maybe others can add to that design information.

The Rhoads VMAX lifters seem to work very well if adjusted properly.

Tom V.

Well today I pulled the passenger side valve cover. I checked cylinders 2, 6 and 8 intakes rockers. I used a paint stick on the locking nut so I could see if I ended up roughly back where they had it. Loosened the nuts and put a .015 feeler gauge in And tightened until the valve started to open. Then loosened it until I could just start to spin the push rod. All 3 Nuts ended up right where they had started so i guess they had them correct and I don't see the need to check the rest. Number 8 intake was just a tiny bit tight,,ended up about 1/16" of a turn less then the way they had it. might pull the driver side cover and just check 1 or 2 for the heck of it. I do remember them saying they milled the locking nuts down because the crowerr rockers set up high and wouldn't clear the stock valve covers. Still had to double gasket them to clear. The nuts are very close to the rockers but I ran them through the range and they seem to barely clear.