I'm assembling a 1.8 16V race motor with 288 Schrick cams and a high CR (11.8:1) . I've got two sets of rods - solid and the type with a central oil channel. The solid type is in much better condition and matched for weight - I'd prefer to use them obviously (and they might even be a bit stronger). Would the solid type be less reliable than the hollow set due to perhaps less oil to the small ends? Your advice will be much appreciated
The wee ends don't see a lot of wear, and if it's a race motor I wouldn't worry - use the balanced ones IMO.
I've always wondered about this myself- why do some motors have solid and others hollow rods? I stripped a project motor recently that I had acquired from a local scrappy for a good price - as I inspected the parts I realised that it may not have been such a bargain after all - the crank was 20thou undersize and it had three hollow rods and one solid (that weighed a full 30grammes more than the others!)Surely there must be a sound reason as the one type gets high pressure oil through the central oil feed from the bigend and the other gets passive drip lube from the piston crown. How often do small ends fail?
They all get a feed to the big ends - it's just that some of them have a feed right through the rod, to the small ends as well. Small end fail is VERY rare. There is a sound reason for it - it makes them last longer and reduces frictional losses. But as your typical VW engine (the older ones at least - no expert on the new stuff)can go 300k without small end feeds, I don't see it as a massive issue.
This is an old tech motor -circa 1988. Thanx I'm gonna use the solid weight matched set - they're going in this evening. I'll keep you posted how they perform (first race in two weeks time)- I'll keep the rev limit std for starters (7200) and assemble the thing with ARP rodbolts
