Ok another installment.

 

The valve train or the 36hp has come under a lot of consideration. The first area I was looking at is the lifters.

 

So my first thoughts were about swap modifing the lifters to be seperate to the pushrods. I had been thinking of ways to make seperate lifters. Then I saw the way that the guys from blackline57.com made caps and it was so much simpler and well better than what I had been thinking. I messaged them but at the time no joy.

 

Then I got into the idea of reducing recripricating weight. This exposed the one problem with blacklines solution it added weight. I started by toying with the idea of drilling the stock lifters to lighten them, it was a good idea but the hardening makes it very difficult to do. Sctatch that idea. So I got into the idea of titanium lifters, basically following the stock design with caps like the blackline guys. I have yet to work out who to ask re the right titanium alloy to use and what/how to harden it to. Plus I haven't found out where to get them made. I did ask at the science engineering workshop, but we got distracted before I found out for sure if they could do it. I was previously given the name of a guy about an hour up the road who had the kit to surface grind and harden stuff but I couldn't find him in the phone book so he might have retired. I really need to come into a lot of money to make this happen. To be honest I have a feeling that it never will. Right back to dream land.

I also thought about lightening the pushrods. The first and most simple way (I think) would be to pull the stock large ends and fit the smaller late model ones. I haven't tried yet as the only late pushrods I have here are good ones that I don't want to chop up. I would have sworn that I had some scrap ones up here but for the life of me I can't find them. I sure I had a set pulled out of a 1500 T3 motor last year but I have a feeling htat I chucked them.

Over the years I have also thought of a different pushrod design, that basically uses a thinner wall to give the same strength.

 

Another thing was titanium push rod ends, to be honest the difference would be very very little but then where I want to take this it is a game of fractions. The last few percent takes more effort than the first ninty whatever.

 

I'm sure if you have made it this far into my ramblings you will already know the reasons but i'll explain my thing for reducing the valve train weight. I had been into the weight loss thing for ages but reciently I saw a thing that said that a winston cup motor looses 200hp through frictional losses, most of the losses are from the valvesprings. NFI what power the motors make but i'd imagine it is a lot. The way I look at it, the lower the weight in the valve train, the lighter the spring needed to keep the components bunched together and following the cam. When thinking of the weight in the valve train (and other parts of the car for that matter) I try not to just think of the total dead weight but the moment on that weight. Simply to try and reduce the inherent momentum in the system.

 

The whole rocker thing came about from thinking about the stock tappet adjusters. First I thought how much weight would you save if you swapped from a 14mm to a 13mm later model lock nut on the adjuster, next, what about a 12mm, then it was shortening the adjuster, then rifle drilling it ¾'s of it's length from the slotted end. Soon it was drilled titanium nuts and adjusters. In this situation i'm sure you can see why the cast iron lifter was an easy target for replacement with a lighter one.

 

Another area of the rockers that came into consideration was lubrication. Simply, the oil galley from the pushrod to the shaft hole exits into the shaft hole in an area that tome doesn't seem ideal. It feds almost 90 degrees from the area of the rocker that sees the most ware. One of my ideas is to move the gallery so it exits damn close to the point of max ware. Reduce the friction, reduce the ware... reduce the friction reduce the power losses (more gets to the flywheel which is were you want it :) ). it is a win/win for little extra effort. I was also planning on having them bushed so that if they had a long life and wore you could simply replace the bush instead of messing around with more painful/expensive solutions

 

Rocker ratio's... as a base standpoint i'd prefer to keep the rocker ratio's close to 1:1 if possible. Of course to be able to have the luxury to do so would mean that it is feasible to fit a cam with the desired total lift in the case and that the ramp angles needed weren't rediculous. I would probably go to 1.1:1 ratio but not more if I could help it.

Ok i'm trying to think out the way ratio rockers will effect the valve springs needed. Part of me says that the net result will go one way and the other says it will be the other... now i'm confusing myself. I think some more research is needed there.

 

Spring retainers. I'm not sure if they would be up to taking the forces involved but I was wondering if you could spin spring retainers. By spin I mean metal spinning. It would definitely be a more materiel effective way of making them as opposed to machining them from rod, plus, in my mind at least, ir they were spun the grain directions in the retainer would be closer to what you would want than machined ones. The production time would be quicker than machining them from billet and the tooling costs would be much much less than making dies to stamp them from sheet. apart from strength my biggest concernin spinning the retainers would be if they could be spun with the detail and accuracy that required.

 

I had also toyed with the idea of titanium stem lock thingies but considerred that they would probably need to be forged to get the strength and grainflow needed to last, so I gave up on that one.

 

Obviously I would love titanium valves and I had considered titanium springs but have yet to look into that one.

 

Right, from the above you can probably tell that in my mind no area of valve train hasn't been thought about.in my dream motor basically no part would be stock.

 

The concept of moving the rocker shaft has come to my attention. For me the most logial way to do so would be to machine off the saddle bit of the rocker shaft and make up late model style blocks, then the stud could be moved. These thoughts were discarded as they are a big and visable (with the wheel off anyway

 

In the past I had considered the idea of running an oil line to the head to pressure feed the rocker shaft but I think this would be a little over the top.

 

I have thought of several ways to do the windage pushrod tube thing but have yet to come to a firm conclusion. At the moment extending one end of the tube seems like the most effective solution thought not the cheapest/easiest. The oprimum would be if someone made stainless windage tubes but I doubt that that is going to happen.

 

In the past I did spend some time working on the name that I wold like to market my parts under and I spent some time while working on my sports car design working out a logo. It isn't finalised but i've settled on the rough logo. I did start to look up what was involved in setting up a legal buisness but didn't get too far along with that.

 

Ages ago I spent some time tring to find a suitable piston for this motor. Basically I want a slipper skirt design to reduce weight and friction with much thinner rings than a stock vw to reduce flutter and friction at high rpm's. From memory the leading contender was an overbored audi piston made by mahle with a slipper skirt for 83mm bore with a 20mm pin. I never did find out if it had an offset pin like the stock ones do. btw i came to the 83mm max bore size by measuring the bore and stud spacing, it was only a rough measurement but i'm working with it for now. much larger and then you would loose and space between the outside of the cylinderwalls.

 

Damn there is so much more to write about. Too much more for now.