Black Pig Too

[brock]

   Hey sam, according to the manufacturer we should have been good up to 14:1 static before it needed O ringing, something obviously not quite right there though. Heads and block check out Ok for flatness and I'm pretty confident about my torque wrench, but, I don't remember retorqueing the heads after the first weekend, it may have been missed while we were busy trying to kill the motor in other ways

[brock]

   bit of a delay whilst I played games with the cam timing, I thought that it would be a good idea to get a feel for what is happening when I move the cam timing about, having the block stripped and a DTI mounted seemed to be the right time to do that, answer, keep it where it should be, any more than eight degrees advance leads to contact with the rod shoulders, see, I would have done it and wondered where all that swarf was coming from !
   So, here we are again short block buttoned up and in the rails, heads built up and old outer springs mounted

[brock]

   yesterday we set the lash, built the top end up, cobbled together a water system to keep it all cool...ish and after a deep breath fired it up. It needed to run for about half an hour at a fairly fast tickover to break the new cam in, basically to seat the new lifters to the relevant lobes and hopefully get all the assembly lube out of the system. All went swimmingly well, quite bizarre really.

[brock]

   Today we drained the oil and sieved it, all very clean and just like it should be, sort of black and sticky from all the zinc and other additives we flung in it. Next we stripped the heads, re-torqued them and replaced the springs with the new 400lb ones, new titanium caps and locks and had a brief look at the rockers before reassembly, that's where it went slightly awry. Two rockers had impact marks from the spring packs and, a little more worryingly, four had heavy scoring under them from contact with head studs.

[brock]

   I pulled the offending studs out, checked the threads, measured them, measured the depth of the heads, reset them and measured the projection, all exactly as it should be and as it ever could have been, strange. No problem to us though, out with the die grinder and dremmel and relieve them a bit more, keep telling ourselves "this is engine building, not just assembly" ! As I was doing the last one a faint glimmer of light glowed above me, was that a thought ? Check the cam spec card, just as I thought, to get the extra lift the cam is ground on a small base circle, this means that the lifters have to go deeper in the bores to reach it, in turn the pushrods do the same and this means that the rockers need to be lower on the posts  to achieve that lash figure, if I had thought it through before I would have ordered 0.10" longer push rods, however !

[brock]

   Finally we nailed it all back together, topped up the oil, that's nearly four gallons this weekend, and fired it up again. With the heavy springs in there was no need to be gentle with the revs, so we weren't, nice !

[Manky Monkey]

Be honest -does anybody here have any idea what he's talking about? 

[brock]

   nope, not a clue. Pretty much sums up the entire endeavour really.

   Some of the problems we have encountered can be traced back to faults in the major components, the block is a '76 vintage and we have soundly beat it about for some years now, That Time is nearly upon us, evidenced by failure of previous repairs and even the mighty Helicoil letting us down, next time round I am going to have to do some fairly intensive work to the cylinder deck area and have a real close look at the heads, or go to plan B.
   Thanks to a fellow racer, Dex, wanting to be out of some of his surplus stock, and Scotty ( http://www.movinghotrods.co.uk/ ) wizzing around the country, we are now the proud (?) owners of a high nickel four bolt block and a host of associated gubbins just right for a bit of a refurb and another build. It'll be a true budget job this time as I want to build a lot of the "special" bits myself, (they'll be special all right ! ) I'm thinking tall tunnel ram with twin 650's and big exhaust valves  There's a couple of other projects in front of it in the queue but we'll get there

[Blackpig]

Be honest -does anybody here have any idea what he's talking about? 

I do

[gsxrsam]

just in case, i have 2 spare sbc in garage, and some boxes of very shiny things in loft if you run out of engines   

do you engineer blue valves to see if contact pad is central to rollers?

[TwistedPatience]

Be honest -does anybody here have any idea what he's talking about? 

I do

Me too!

[Clive]

I got a few of the words in his last post!!

Problems....faults....failure....budget....'special'....other projects

they all seem to be in my vocabulary fairly often. The rest............................................not a clue!!!!!

Clive

[toad]

now to really confuse ya all what about harmonic balancing then? and that dont mean the big ring on the crank pulley correct answer wins a packet of jaffa cakes

[cunningplan]

now to really confuse ya all what about harmonic balancing then? and that don't mean the big ring on the crank pulley correct answer wins a packet of jaffa cakes

Is that where you get a big weight attached to the exhaust (Or other part of a car) to stop resonance??

[brock]

   I was talking to a young lad at work the other day, he was trying to explain about a damper that made exhausts quieter, did I dismiss him too lightly ?

   Problems....faults....failure....  crop up far too often for my liking

   Sam, if you ever find yourself in the strange position of having too much of Mr Chevrolet's kit laying around ( almost inconceivable I know ) you know where to find us, if I'm allowed full rein with the next one there will be breakage before I master it, and yes, we blued the valve tips, although round here that looks very much like a big felt tip pen, the contact is further back than ideal, as you might expect with the pushrod thing, but acceptable. I'm on the phone to the Colonies later in the week to sort the proper solution.