Thursday, October 05, 2006

Engine - Best start doing something!

I have a few pennies to start on the bottom end.

I was pondering using decent rods, but I think I'll prepare another set of rubber ones. I will be using forged pistons, which are about 1/4 to a 1/3rd lighter than the stock ones, so the load on them should be a reduced.

They are from my FD engine I brought a while back.

They are light ones at between 553 and 561 grams in the "set"...Nicely balanced by Triumph! NOT! My first engine had 568gram rods AFTER lightenin, heavy to start!

My last engine had 530ish gram items after lightening, end to ending etc...I wan't these to be a touch lighter again I didn't go mad on the last ones. I could see from the VP2 shells that come from them (very low mileage if run at all! re-useable) that they are not oval and in good order. I will get them honed anyway before they are finally weighted and peened.

I might make a start on lightening them this weekend, can get the beams polished and little ends.

I don't trust the no4 rod from my old bottom end, its been hammered.

Also I never checked those old rods for straightness or examined the bores of the block they came from they were unknown. I noted there was a tiny bit of odd bore wear in No3 cylinder. Which could have been down to the rod being a touch off straight..So a new set is the way forward. I have seen the engine these came from and its all sound.

There they are.

I will treat them to some new YB Cosworth bolts £3 each. As my old ones have been used a good few times now. Bit too much clearance in the little ends if you ask me, but I have 4 vandervells to fit and hone. I will get them peened at the end.

I will try to find a crank main bolt stud kit this time, Arp.

I will be changing my machine shop for crank, honing and bore work now. The guy who does heads there is good and keeps his kit on fine fettle, heads there ok, but the old boy 75! Who does the cranks and rebores is not keeping his kit in good enough fettle for my engines now, as he's a bit quiet and his kit needs a good service. I wasn't happy with a couple of things he did in my last engine so thats it for cheap work.

Not sure who I will use. Maybe Rob Walker, used to work for Osellis.

My block will be given to someone soon for an acid dip, clean, rebore to + whatever needed for forged pistons. I will get my crank inspected to and if needed ground to +10 on the big ends and then nitrided and micro polished. I have cash for this work so best get things underway.

I will pull the old motor out and see whats what with it soon, before I start on the new one incase there's anything I want to change. I will re-use the cam for now, sump, timing gear etc etc. The block is toast and on +60.

I will enlarge the centre main bearing feed on the new block too.

If I can get a bottom-end together in the next two months that just leaves a head.

Kinda getting itchy feet. I want to lighten the chassis too.

1 comment:

David said...

Dave, Been reading up on your past blogs. Seem to remember you from the TTN website forum a while back. Amazing work you are doing on your Spit, no idea how you find the time to get it all right! Speaking of chassis lightening I've always wondered why people don't go down the space-frame route and utilise the heavy roll cage tubes as chassis members to mount suspension and body etc on to rather than the heavy old chassis. You'd need to extend the basic roll cage front and rear obviously but getting rid of the old chassis entirely must be worth it. Drawbacks and reason's why it hasn't been done already are, I suspect, rules and regulations for licensing. I suppose it would cease to be a spitfire and would need the SVA mega-mot. Anyway, nice blog.

David J