Tuesday, November 08, 2005


Well, thought it best to make a start.

So ordered a new cam FastRoad89 again as its quite revy and torquey, fitted cam bearings in my old block, to save the block as No4 had bored some rings in the block on the bearingless cam...anyway the cam bearing is solid fit and would be just fine.

Found some lighter con-rods, my old ones were late small crank Herald 13/60...turns out the early Spitfire and Herald small crank motors had a lighter rod, having now checked this on a few engines its true. The later rod is slightly wider in the beam and more excess material on the cap. The late type are 595 stock with little end bush and my lightened versions of these that came in the engine were 576 with a little end bush.

The earlier type are 568 with a little end bush fitted! over an ounce lighter item for item!...After polishing the main and ends, removing 30% of the cap beams, and equalising the caps they ended up at 533 each with a little end bush or 517 without. Thats pretty damn light...I could take the rods further but the fact they are 43grams lighter than my old ones will do me i think.

They say remove the little end oiling conical when lightening, but I don't see how a flat surface with a hole is going to feed anything into them....so I left these alone....its about 2grams you save....I understand that the windage will blow oily air into the little end on the upstroke via hole and X feed recesses inside the bush, but it has to be better with a conical V giving greater surface area, rather like adding a trumpet to a carburetor, suddenely you have an ability to get more air into the same size hole via increasing the potential surface area that feeds the hole...anyway...

I have actually done two sets of rods, both the same.

The rods i will be using had only done a few miles since being reconditioned, I checked the bearing distances on an opring machine and these were the best rods the others werent as good, the best set were just fine under thou variation in throw, so no piston milling should be needed to get a near perfect deck height. I was going to replace the little end bushes but its pointless as when heated to 80C with the pins inserted they are interferance fit and tight, showing only a tiny clearance cold...so thats a few quid saved! and my OE little bushes remain spares for another day.

I check the big end openings for ovalality on a machine, this showed about half a thou which is mircoscopic, but I reamed then out anyway as they were very slightly undersized by around 1/3rd of a thou.

Incidently whoever did the rods before was handicapped I think...as the caps were all off centre and no cap seemed to be perfect on any rod, even the right ones! probably why it was it tight when I built it, but not tight enough to worry about, and as the big ends were so nice clearly no ill effects!

This set of rods should prove much improved for running in and build up and longevity or bearings as there were a number of issues on the others, all within "book" figures, but that means nothing in the world of doing it properly.

Incidently they were of course sonic cleaned before any of this, nice when you can screw in the bolts and there is no resistance at all, no gritty bits etc, again amazing where all this crap comes from that ends up on the bottom of the sonic bath.

I tried rigging up and end-to-end balancer but couldn't get reliable results....so they go to Midland Balancing with the crank etc, dropped the crank off for grinding also....which to be fair is a waste of time...the big ends were really good having only done maybe 9000-11000miles. The mains have been maybe 50000miles on their 3rd set of bearings, the surfaced bar mild tramlines on the middle bearing were hardly marked! thats not hardeneded either! Amazing really....hense I hope with everything right this next engine should truck on for ages, especially not doing 300miles a week in it as a daily driver, as bar a few annoying problems it was in great shape, for a used and abused trashed from cold motor...used as a base for many experiments and subjected to all manner of horrors!

They will get ground anyway as I cannot get any VP-VP2 in either size of current grind for less than the combined price of other sized shells and a grind! .....bearings were steal @ £12.95 a set and grinding costs me about £35 for 4 journals...up to + 30 mains and + 40 big ends so the life of this crank is limited! be swapping bearings next time before they munch the crank up.

So thats about all you can do to the rods......I was going to mill out a bit of material from the ends of the gudgeon pins, maybe 10grams per pin and investigate any material inside the piston skirts that looks excessive...I'd like to save an extra 50grams over the old setup....

Also the old rods were only balanced in weight, not end to end...as that motor was pretty smooth up over 7K this once can only be better!

The flywheel I had lightened was never balanced with the crank so I would imagine that was a bit out as well....

I will be replacing the 4 exhaust guides and valves with new ones....same as before Ford Capri, Cortina 1600 valves....Part Number 34322. cheap and quality 1.25" valves.....to use these ford valves the guides for triumphs need shortening by 5mm or so...

The old exhaust valves had been 50000-60000miles and are rather good still! but ebay turns up valves at £4 OE spec you can't turn em down! The backs of course will be reshaped, by grinding them in them removing any material on the valve back that hasnt got a silver mark on it showing it is seating on the head...here is were most of the extra torque and power is made I think, especially at low rpm (my modified engine has shit loads more idle power and 1000-2500 power than a standard motor... to match my flow at 2mm of lift the standard valve with a 4mm! seat has to be twice as open....that cains flowat small lift so badly...once the cut valve is off seat it can flow immediately and out over the raduis of the entire valve back...standard valve it has to creep out over the valve back, do a quick 45degree turn and come through the gap for the first few mm....

She will be 0.060" overbored also.

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