cosworth knocking noise. when on start up from cold the engine sounds mint. until after 2 / 3 minutes then when you up the revs and drop em off again theres a knocking noise. sounds quite heavy. when engines warm it dosent do it, but sounds very cami. its had new block, pistons, crank, shells, tappets, the only thing i didnt change is little end bearings, and cams, it was timmed up the other day by a cozi specialist thinking it was that. but still the same the following day, please help;

 

Did you use 2WD pistons ?, if so could just be piston slap, which any cossie specialist will know straight away, as it goes when it is hot I wouldn't worry so long as oil pressure ok etc, 2wd were famous for it, sound like tractors when cold.
tabetha
if your "specialist" thinks it may have been timing, time for a new specialist

 

as above; likely to be piston slap - all 2wd suffer

mine sounded awful for about 10 mins before it went quiet after warming up

even the original ford hand book said expect a nosiy engine from cold

if you're worried, post up a video using photobucket.com so we can have a listen

 

i used a new 205 block with new 4x4 cozi pistons, 0.5 o/s. new crank and rods, stripped her out yesterday to check and measure everything. the only thing i could find realy is the wrist pins seem to be very loose when inserted into piston, i think i may have used the pins from another set of pistons. all the shell are spot on, still has the hone marks on the bores and no evidence of the piston slapping the bores. thinking now it could be these peski wrist pins.

 

Did u find the problem in the end? Seem to have the same problem with mine, the engine has only done 500 milles from rebuild.
Cheers

 

Yes found the problem. When i rebuilt the engine i checked the sizes of everything thinking i could you some parts again. Big mistake. It was the little ends in the conrods and the gudeon pins. They was a tiny amount of play. I got them checked and renewed. Icould see when the conrod and piston were put in a vice i could see the amount of play. The piston was slapping about not through bore wear cuz it had a rebore but because the amount of wear of the little ends.

 

Its never wise to use old parts with new, always comes back to bite you in the ass

 

There was nothing wrong with the old little ends, but got them replaced just to be sure, got them done by a well known company and when i was assembling the engine they didn't feel right, so got the redone by a different company, and still the same problem. i knew there was to much play on them, now after 500mls it sounds like a tractor. it cost me £80 a go.
Just taking engine appart and going to fit them myself.