| Author | Message | ||
     Xldevil  |
Hallo.I´d like to use adjustable pushrods on my M2,but how to adjust them? Regards,Ralph | ||
| Aaron |
What kind of lifters do you have? There are basically 3 types: solid, hydraulic, hydrosolid. All 3 have different procedures. Stock lifters are hydraulic. The idea with them is to get about .100" of lifter plunger preload ... they have about .200" of travel so preloading them .100 puts them in the middle of their range. So, with tappet sitting on the base circle of the cam (i.e. valve closed position), extend the pushrod by finger until the slack is taken up. Then extend it another .100". You'll probably need a wrench to go that .100" as there's oil in the lifter and it takes a little while to bleed down, so as you extend the pushrod you're actually opening the valve. Tighten the lock nut and then wait a little bit for the lifter to bleed down and the valve to close. If you turn the motor over before you've let the lifter bleed down, you may bend a valve as the piston goes smashing into it. You can tell it's bled down when the pushrod can be turned easily by finger again. The lifter has bled down, the valve closed, and there's no longer valve spring pressure pushing on the pushrod. An easy way to hit the .100 preload mark is to use the thread pitch on the adjuster as a reference and count the turns of the pushrod. But pushrods come in a lot of different thread pitches, you need that piece of info. For 40tpi go 4.0 turns, 32tpi go 3.2 turns, for 24tpi, go 2.4 turns, etc. If you need to know how to adjust solids or hydrosolids, let me know. It's different. (Message edited by aaron on December 23, 2004) | ||
| Sportyeric  |
Collapsible pushrod tubes is the simple answer. And they cost as much as the pushrods do! Unless you adjust the pushrods without the tubes, then disassemble enough to get the tubes in place, meaning re and re the rockers. (use an old gasket the first go-around if this is the case.) | ||
| Xldevil |
@ Sportyeric. Sure I will take Collapsible pushrod tubes. But once adjusted,do I realy need them again using Hydrosolid lifters?  @ Aron. You´re right,I´m thinking about hydrosolids. Can You tell me how to adjust the pushrods,please? Do I need adj.pushrods using them and why? Regards,Ralph (Message edited by xldevil on December 24, 2004) (Message edited by xldevil on December 24, 2004) | ||
| Aaron |
You only need adjustable pushrods on standard hydraulic lifters when you change things such that the lifter plunger preload is no longer in a good operating range. Things that move the plunger preload would be stuff like valve stem protrusion,rocker arm geometry, small base circle cams, milling of the heads and/or cylinders, and thin gaskets. I generally start getting concerned about .050 away from stock. An alternative is custom made fixed-length (non-adjustable) pushrods. Milling heads and using thin gaskets is so common that we offer a set that's .040 shorter than stock as an off-the-shelf item, although we can make customs in any length you want. Ours are heavy duty heat treated chrome moly in .065 wall, to reduce deflection when used with stiffer valve springs. On a solid, you need adjustables to set the running clearance, which you measure with a feeler gauge in between the rocker tip and the valve tip. On a Hydrosolid, you need adjustables because the lifter is designed to run with the plunger nearly bottomed. So to adjust them, you extend the pushrod until the valve opens and stays open, even after bleed down. You can tell because you can't spin the pushrod by finger. Then shorten them until they just go loose, and tighten the lock nut. Sometimes they'll run a little quieter if you loosen them 1/4 to 1/2 a turn from there before you tighten the lock nut. You can also put travel limiters in stock lifters and accomplish the same thing, although in my experience the regular Hydrosolid seems to run a little quieter. Also, the Hydrosolid has a longer flat for the anti-rotation pin, allowing more lift without running into the pin, although you can machine that flat longer on a stock lifter. | ||
| Snowdave |
How do I know which type of lifters I have? I assume they are the standard hydraulic, but since this is a race motor, I have found very few stock components inside it. Since I tore it down for a big-bore kit, I am now reassembling and not sure what to do about the adjustable pushrods. The lifers look stock and have a clip holding a seat on the topside. Thanks, Dave |
