TERRIBLE OIL FAILURE ( WE GOT A WINNER!!! ) becomed on pushrod lenght discussion

[FLG]

Also did you make sure the rocker arm bars are in the correct orientatio so they get oil?

[Nacho-RT74]

yes, they are.

Ok John, how to find the correct lenght ? being rocker with adjusters I think is not that important to get an EXACT measurement since will be adjusted at the need.

If stock is 8.57, something on 8.20-30 ratio should be enough ? adjusters looks to be long enough to reach this .27-37 diff with stock lenght ( plus the rocker diff height )

and... 3/8 or 5/16 ? I think 3/8 is the stock and still good to use

[mhinders]

Nacho,
regarding the lenght of pushrods and valvetrain geometry, I have a document that looks pretty good.
It's too big to be attached here, I'll try to send it to you if I find your address. It's from Hughes Engines, but I can't find the document on their web-site right now. 

[Nacho-RT74]

thanks for the file.

OK, I don't have handly a dial type indicator or adjustable pushrod. Neither know who has them ( friend )

beside that there is ilustrated a cup kind pushrod and advices for BB around 0.3" for the adjuster screw protusion... what about a round kind pushrod ? Round kind pushrods adjusters are shorter due unexistant ball on them

[FLG]

I think  the closest youll be able to get with no checking pushrod is a stock pushrod cut in half and slowly shaved down, than measure using a caliper.

Or thread the adjusters in and measure how much further down the screw goes and than subtract that from your current pushrod size?

How about putting 0 lash on the lifter, than adjusting it to where it should be sitting with a correct length pushrod (obviously putting too much preload on the lifter but making sure its not bottomed out) than measuring the distance the lifter went down?

Just a few ideas.

Assuming i can find it, would it take too long if i sent you my checking pushrod?? (you can have it, with my new rocker setup i no longer have use for a ball-ball ended checking pushrod)

[Nacho-RT74]

Or thread the adjusters in and measure how much further down the screw goes and than subtract that from your current pushrod size?

Thats why I thought on simply buy something like 0.20-.030 shorter pushrods than stock then screw in aprox that the adjusters, then began with that for adjusting propperly each pushrod. What mostly sure will be required, being I'm pretty sure new valve seats made diff heights valve stems

about what you want send... I'll try to figure out first how to make it Thanks. Will let you know if will need it

[FLG]

Ok if you want it it's yours for nothing you are an asset when it comes to wiring and your diagrams you've drawn have helped me out plenty of times

Just helping out in return

[mhinders]

thanks for the file.
OK, I don't have handly a dial type indicator or adjustable pushrod. Neither know who has them ( friend )
beside that there is ilustrated a cup kind pushrod and advices for BB around 0.3" for the adjuster screw protusion... what about a round kind pushrod ? Round kind pushrods adjusters are shorter due unexistant ball on them

I'm no professional in this game so maybe I'm talking a lot of rubbish here, but what I would do first is to check how the roller rocker moves over the top end of the valve, opening the amount of lift you have and closing again. When that pattern of movement is correct (you may need shims or something), I would start checking what lenght of the pushrods is needed.

[Nacho-RT74]

I have a shims kit, from MRE.

however on the file you sent me, they list that as 3rd priority, before lenght and lift

[Nacho-RT74]

got a quote for the Smith Brothers pushrods... $8 each. 3/8 tube 5/16 ball, .049 thick wall

[mhinders]

I have a shims kit, from MRE.
however on the file you sent me, they list that as 3rd priority, before lenght and lift

Well, you see, I should read before I send...sorry I haven't read it myself...will do asap.

Ok, I had a brief look, but I think it is the first point "check the wipe pattern". With this I understand you should check how the roller moves across the top of the valve, and adjust accordingly with shims, because they have an influence on the lenght of pushrod needed. And then, when everything is installed and tightened down you check the wipe pattern again. That's my understanding of it.

[Nacho-RT74]

but will need to get the propper lenght first LOL... and I have the MRE shim kit ready to go

[mhinders]

but will need to get the propper length first LOL... and I have the MRE shim kit ready to go

I think deciding the proper length is second...you know how much lift you are supposed to have with the cam and rocker ratio, and then you should be able to check the wipe pattern and adjust the shims. 

[Nacho-RT74]

ok, maybe will get time o check everything at once.

I got an idea for pushrod lenght... cut one of the bent pushrods ( once straightened ) in halfs, removing one small center section and use some kind of tube ( plastic, PVC, steel ) to link between them and be able to slide in and out as required. Of course, very tight into the tube to be able to keep it on place on the process.

better if metal to be able to weld one of the halfs into the tube. The other one could simply be taped to the place where fits propperly with rocker arm

[elacruze]

Nacho,

The recommendation from Hughes for PR length is that the PR and rocker adjuster are parallel/inline/coaxial at 50% valve lift, and only a couple threads showing on the PR side of the rocker. Having the adjuster short on the bottom reduces side loading on the head, and places the joint in the correct position to oil. Centering the axis at 50% lift keeps the joint angle at the least possible, both at full open and full closed positions.

Just for sport, verify that the radius of the pushrod end matches the radius of the adjuster socket; a mismatch can easily cause a jump-out, I've seen it many times back in my Harley-Davidson days.

[firefighter3931]

Pushrods are too long.

Yep, the proper length pushrod will have the adjuster with 1-2 threads showing on the underside of the rocker body. 

Your's has too much of the adjuster threads showing on the topside of the rocker arm 

For simplicity's sake i would just run the factory non adjustable rocker arms 



Ron

[b5blue]

BOY! You guys have sold me on ordering a set of Smith Bros adjustable pushrods now!    Good luck Nacho! 

[FLG]

BOY! You guys have sold me on ordering a set of Smith Bros adjustable pushrods now!    Good luck Nacho! 

From what you guys have said adjustable pushrods are fine (but i still dont like em lol just paranoid about things loosening up)

Not knocking nacho (he's got a much more limited range of tools and parts) but all this would have easily been avoided by purchasing a checking pushrod and measuring.

[Nacho-RT74]

damn, adjustable pushrods and adjustable rockers ? LOL... to much adjustable things LOL

[Nacho-RT74]

Pushrods are too long.

Yep, the proper length pushrod will have the adjuster with 1-2 threads showing on the underside of the rocker body. 

I talked with DON at FBO and told me around the same.. 2-3 threads showing underside

[heyoldguy]

BOY! You guys have sold me on ordering a set of Smith Bros adjustable pushrods now!    Good luck Nacho! 

From what you guys have said adjustable pushrods are fine (but i still dont like em lol just paranoid about things loosening up)

Not knocking nacho (he's got a much more limited range of tools and parts) but all this would have easily been avoided by purchasing a checking pushrod and measuring.

AMEN! There, the rumbling chaos all about, a tiny voice of reason once again.

[John_Kunkel]

In most cases the threads showing above is relative to the threads showing below, with 1-2 threads showing above the lower extension will be correct.

[heyoldguy]

How many of you offering advice on where to set the adjusting on this PRW rocker arm, have actually removed the screw from the rocker arm and looked at the oil band on the adjusting screw and where it lines up with the oil hole in the rocker arm?

Hummm, how many?

To get it centered, you back the adjusting screw all the way into the rocker body and turn it out ONE turn. It gives you one turn up and one turn down of adjustment. Not one single thread will show below the rocker arm. Even if you turn it down two turns NO threads will be showing! Pushrod length on RHS (AH, not RHS, PRW is what I ment) rockers must be very precise to get the full oil flow to the pushrod.

Turn it down one turn from fully backed into the body all the way, check the length precisely with a pushrod length checker, measure that length, add to that length the amount of preload you want and order a pushrod that long.

Should you so chose, you may ignore this post and do it any way you want.

[Nacho-RT74]

ok, sounds logic. I have to make my own lenght checker ( homemade adjustable pushrod LOL ) anyway first and will let you know. And will remove one of the adjusters to check that

[heyoldguy]

For those of you who have not used the PRW rockers, look at page 2 of this thread, reply #47. There Nacho has given us some close up pictures of the rocker arms. Look at the top two pictures of the left bank, i.e. cylinders 1, 3, 5, & 7. Notice that the #1 intake rocker has the ball cup slightly protruding from the rocker arm and NO threads are showing. This is approximately what the rocker arm assembly will look like when it is ready to be checked for proper pushrod length. #1 exhaust and #3 intake are what they should look like when the adjuster is screwed all the way into the rocker body. If the adjuster screw looks like #1 intake and the adjuster screw is turned all the way up, SOMETHING IS WRONG with the rocker arm and adjusting screw. I get a couple of rocker arms that look like that each time I get a PRW set. Sometimes you can run a tap through the rocker body and that will fix the problem. If it doesn't, I get a replacement rocker arm.