Friday, October 21, 2005

Roller Rockers, Weight Saving, Suspension.

Few images. Top is my new polycarbonate hardtop window. Pretty easy to make, apart from buying acrylic and breaking the first one as its brittle even when heated...I though it would be more glass like, anyway polycarb was super flexy and did the job perfectly..Incidently the side windows are acrylic as its stiffer. The window is rock solid and under tension all over no bows or warps bar a little by the hex bolts holding it on, fits perfect and was siliconed into place. I sprayed the a 1cm black rim round the edge of the entire window from the inside. This means the silicone cant be seen squishing about behind the window in an ugly fashion. Took 22 bolts to fix it, tapped into the hardtop no nuts needed...Seal, trim, and glass was 7.6kilos...I thought it was more, but the new setup is 1.5kilos complete using 3mm polycarb sheeting.

Next down was bargain roller rockers, how successful or durable will be found out on my crap engine. They are 1.75 ratio, ie loads'a'lift. You can see how much further the pin is towards rockers main axis on the shaft. You couldnt run tubular pushrods on these, atleast not without removing 3-5mm from the chamber in the head that the rods pass down through and into the followers, as they rub the head on a standard skinny pushrod, so minor dremeling needed or a wad removed for tubular pushrods.

Incidently I had one of those fall apart and cause a rockers to blow as it increased the tappet gap when the base that sits in the follower became loose in the main rod, so it span and jumped up and down the distance of the tappet clearance, no bother till it got more worn. This causes the gap to increase at the valve end which I didnt notice and then of course the rocker arm hammers down on the valve tip (as evident via minor squishing of it compared to the other tips) and overloads the rocker, it broke at 7K rpm in 2nd taking 3 more with it.

Anyway, modification was needed to the end main pedestals, as the rocker fouled them, 5 second job with a bench grinder.

I will add them to the standard engine and test them, they would give an extra 0.090" valve lift over 1.45, in theory, on the 89 cam, which is an extra 2.2mm of lift.

Valve Lift =0.424"@ 1.45 @ 0.293" (camlift)
0.454"@ 1.55 @ 0.293"
0.484"@ 1.65 @ 0.293"
0.514" @ 1.75 @ 0.293"

Or something like that over the rest of the ratios. Anyway I have access to a rolling road I could rent, so may back to back them on the new engine and see when retuned if they do anything worthwhile...

Bottom pic, wishbones. Just need some slowbies to send my rod-ends and then weld em up.

Got two new flanges for a new prop as the flanges on the others have spun caps now -even though appearing good and being built professionally onto a new prop of smaller diameter and weight. Protech in Hartlebury Trd Est, Kiddiminster do me a good job normally and fit decent joints for OE spec modern cars for me as an option. I have no complaints about these on the driveshafts, mated to new flanges every time they will last ages. So hopefully the prop will hold together now it has nice new flanges and decent on the joint caps.

MOT time, added a washer bottle in the space to the left of the passengers feet in the footwell, speaker hole?, speedo and few other legal items.

Have some nice new Bridgestone RE720's in 185/55/14 for the back going on next week, perfect winter tyre and summer tyre, scores the best rating of any road tyre on the market in German tests, wet and dry grip are meant to be superb as they are very soft! A wolf in sheeps clothing I read, so why not..I may leave 175/60/14 on the front, as understeer is something the chassis rarely does usually straight to oversteer, which slows you down and means getting out the power, a tiny bit of understeer is ALWAYS quicker if using wide tyres, cambered suspension and modern setup where long duration oversteer isnt really the shit. But will leave a decision on that till further revisions to the suspension are complete, and the car gets aligned, cambered, corner weighted etc.

Thats about it! Phew!

1 comment:

David Powell said...

Hey JP I really wish you'd come to see me, so I can lock you in the cellar and torture you slowly, over many years.