ratio rockers 1:1.25 On DJ engine

syncromad · Post by **syncromad** » Fri Apr 14, 2006 11:17 am

Anyone tried this?

André

WBX Man · Post by **WBX Man** » Tue Apr 25, 2006 5:03 am

No, but I thought of it... you probably need solid lifters too !?

I've tried with solid lifters from a T4 engine, and they make a lot of noise in my opinion... not sure, maybe it was something else.
It was a 2,1 with engel W100, solid lifters and CM pushrods.

Does anybody now if the 1:1.25 rockers have any effect on a std. DJ engine ?

tencentlife · Post by **tencentlife** » Tue Apr 25, 2006 8:28 am

If a DJ is the same as an MV, the North American 2100, then sure, I've run a set of 1.25 rockers with Rhino feet adjusters for many miles, on two different engines. I installed them at the same time as an S&S header system, turbo type muffler, no catalyst, and in the absence of any obective testing I can say that the combination gives a definite SOTP (seat-of-the-pants) power increase. I needed to add shims, perhaps 1.5mm, under the rocker blocks to get clearance under the adjusters, mainly because the Rhino feet under the rocker heads are so large. My rockers are the modified OEM ones, where they just drilled the pushrod socket a bit closer to the axis.

After about 90k miles, the wear on the valve stems and Rhino feet is flat and even. I really like these adjusters for their flat contact pattern, no more valve and adjuster mushrooming.

Post by **Piledriver** » Tue Apr 25, 2006 8:23 pm

Swivel foot adjusters really shouldn't be used with hydraulic lifters, supposedly prevents them from oiling properly.
(Per John C IIRC)

OTOH... If it works...

I have read many places of folks running SCAT (really Berg design) 1.4 rockers on the stock hydro cam w/o issues.

IIRC you DO need hardened lash caps with those.

tencentlife · Post by **tencentlife** » Tue Apr 25, 2006 9:26 pm

I think when people say "swivel-foot adjusters", they may mean different things. I can see how some of the ball-and-socket adjusters that meet the end of the pushrod rather than the valve stem may not have the oil passages in them that route oil to the rocker shafts. That would be a problem, but I don't know, I haven't used that type. As for the Rhino feet, which replace the stock adjusters and ride against the valve stem, I can say that they do the job very nicely. No valve stem deformation whatsoever, and a nice oval contact pattern on the bottom of the "foot". That contact point, at the valve stem, is only oiled by splash in the rocker chamber, anyway.

I can't imagine why hydro vs. solid lifters would make any difference. They both pass oil up the pushrod the same way.

The Bergs have the adjuster on the pushrod side, I believe. Lash caps might be a good idea with those, as the rocker action would kind of wipe across the top of the stem. Although I would think if you set up the contact pattern carefully, the lash caps wouldn't be needed and would only make you have to shim up the rocker stands further.

Bottom line is, it definitely works. I have 90k mi. on this setup and everything is clearly well-oiled, with nice consistent contact patterns on all valves.

Read this article at Berg for some insight into the dynamics of hi-ratio rockers vs. having more lift on the cam
( http://www.geneberg.com/cat.php?cPath=6_203 ).

At a desired valve lift, and especially with heavier hydro lifters, there is substantial inertial efficiency gain in the valvetrain if you get more of the lift from the rocker. All the components but the valve/spring itself and half the rocker will have to reciprocate in a shorter range for the same desired valve lift, 13% shorter with 1.25's vs. 1.1's, 27% with 1.4's. The change in leverage will also be a force multiplier to help the valve spring keep the pushrod and lifter riding on the cam. With 1.4's I would even consider lessening the valve spring pressure, unless really high revs is your goal.

syncromad · Post by **syncromad** » Wed Apr 26, 2006 5:55 am

My biggest worry is if the valves would hit the piston (A DJ engine is the High compression version of the MV 2.1 )
How can I check this without getting the head off ?

Thanks for the input sofar!

André

tencentlife · Post by **tencentlife** » Wed Apr 26, 2006 10:31 am

Well, it's possible, with good lighting and a great deal of patience, to see the valve heads come off the seats inside a built engine by peering down the sparkplug hole. If you did this with your stock rockers, you may be able to get a reasonable idea of how much room you have to play with. It's only an issue at TDC on the overlap stroke, and at that point both valves are only partially open.

The real test, of course, is to install the hi-ratio rockers, set lash or preload, and turn the engine slowly by hand thru a full cycle and feel for resistance. At the same time, you should also be looking down the plug hole to find out if you can see what's going on in the cylinder during the valve overlap on either side of TDC. There would need to be a bit of extra room for potential valve float, but I couldn't guess how much. Maybe you could make a feeler from wire or use a hooked scribe to feel the gap between the valve head and the piston top.

My guess is, with only 1.25 rockers, you would have plenty of room. I know with the MV pistons there is plenty, and they have 8.6:1 compression stock. Changes in compression were made with the volume of the piston dish, but very small changes make for big changes in compression. I would be more concerned if you wanted to try 1.4's or higher.

tencentlife · Post by **tencentlife** » Wed Apr 26, 2006 1:51 pm

Andre, read this topic

http://www.shoptalkforums.com/viewtopic.php?t=92049

The comments from farmer pertain to your application

Another way to check for clearance would be to set up a dial indicator on the valves in situ. Measure how much lift the intake and exhaust have at TDC on the overlap, then depress them further (lever bottom of rocker arm upward, using gasket surface as fulcrum. Careful not to gouge, and don't let the pushrod fall out of the lifter!!) so they touch the piston and measure how much farther they could go. Do the math on your increase in lift with your ratio rockers, and you can determine whether you would still have good deck clearance, without having to have the new rockers in hand.

syncromad · Post by **syncromad** » Thu Apr 27, 2006 11:44 am

thanks for pointing me back to that topic, I think I didn't got online for a few days back then and forgot to follow that topic .
I have the same setup as 51 MAN had, I'm going to fit a new stainless steel exhaust first (the old one is leaking on all sides)and then put in the new rockers. (intresting story about the carbs too btw)

André

51MAN · Post by **51MAN** » Thu May 18, 2006 4:49 am

Hi Andre
What system are you going to use? I will be sorting my full merged setup later this summer..

syncromad · Post by **syncromad** » Tue May 23, 2006 3:08 pm

51MAN,

Sorry, I sold the DOKA so I canceled the ordered exhaust.

Have to find another(cheaper) toy to play in the Mud.
Iltis maybe?

André

1303wasserbug · Post by **1303wasserbug** » Tue Jul 04, 2006 11:01 am

hey all, any idea bout euro spec DJ's 2.1 with digijet? wanna put 1.4:1 rockers on with stock injection, i need new airflow meter and fuel pressure regulator anyways, was thinking bout using bmw e30?
Cheers al