I have been reading a few books by David Vizard and a few other authors who propose the idea of installing stand-off pipes in the lifter valley on a roller camd engine.

The idea is to make the oil drain to the pan at the back and front of the engine, but still allow pressures to vent and oil to drain down if there is too much.

They do not say exactly how high to make them. Has anyone else dealt with this or know how long to make them?

 

http://www.compcams.com/Technical/Cu...g/HTML/390.asp

Their purpose is to keep as much oil from dripping down onto the crank as possible, to minimize windage.

 

Yes, I knew what they were for, I am wanting to know how tall to make them.

 

It probably doesn't matter much. Some people just use pipe plugs and block the drains completely, and some use cheap hose barbs instead of expensive stand-offs.

 

Did you look at the page?

Shouldn't be too hard to figure out how tall those are, at least, from their pic. Plus, given that they're PIPE THREAD, just sort of screwed into the casting however it happens to be cast and however you tap it, it would seem that extreme precision is not paricularly necessary.

 

Yes, I looked at the page. It can be hard to tell if the picture was taken close up or further away. If it was taken when they were on a block or next to a lifter or something, the picture would be more useful.

I did tap it to a 1/4" 18 npt pipe thread as you had previously mentioned. I did not think it would be too important. It was said in the books that if it is a roller cam'd block than you could just use plugs. I just do not want to make them too short and then have the whole purpose defeated.

It looks like they can only go out 2-3" once I put the spider retainer on though. So I guess the stand offs will go out to almost touch the spider. Does that sound right.

 

A max of 2" or so sounds believeable...

They don't need to be more than 1.5", I wouldn't think; there's just not that much oil available that can accumulate there. That's all you really have to accomplish: get them up above whatever level of oil can pile up there, on its way back to the sump. More than that would be unnecessary.

 

Here's how dumb I am - I always thought they were called "standpipes."

 

The real purpose is to keep broken roller lifter or other valvetrain parts from falling down into the spinning crank during a valve train failure.

 

I will go for about 2" than.

So would they be just as good as putting the catch screens in the oil drain holes of the cylinder heads to catch broken lifters? How do you get the screens to stay in the heads anyway?

 

Epoxy.

http://store.summitracing.com/partde...rt=MIL%2D23150

If all you wanted was to strain broken parts out of the oil return holes, you could screen over all of the return holes in the heads AND the lifter valley, as some of us sometimes do. That's only one piece of the total purpose.

In fact, some people (notably people with flat-tappet solid cams) have been known to "point" their drainback holes (screened, of course) at cam lobes; to add to whatever oiling they might be getting by whatever other means. Of course, sometimes it might be thought, that oiling the cam is more important than windage. I've even seen people DRILL MORE drainback holes for this purpose (and usually the sort of people who do that, will screen them as well).

The main reason for using the standpipes specifically, as opposed to any of a list of other broken-parts-filtering methods, is windage control.