Stiff Big Ends
Posted: Mon Feb 05, 2024 11:53 pm
Hi all,
New to the group so apologies if I’m going over old ground / posting this is the wrong place…
I’m in the process of building a ‘warm’ 998cc engine to put into my Morris Minor (bored out from 948cc, flat top pistons, cooper head etc).
After having received everything back from the machine shop I appear to have fallen at pretty much the first hurdle (or perhaps second!) - I’ve installed the crankshaft which rotates freely. I’ve put the pistons in, and the first two con rod big ends, all torqued up still allow me to move the crank, albeit with a bit of resistance (mainly from the new piston rings I guess). However as soon as I put any torque on the third and fourth big ends, it makes the crank incredibly stiff - when they’re both done up I can’t really move the crank at all, even with a spanner.
The crank was ground to 10thou under and there are new bearings to suit.
I’m going to speak to the machine shop, but this forum has been such a hive of information I thought I would also try here in case there are any bright ideas!
Many thanks,
James
New to the group so apologies if I’m going over old ground / posting this is the wrong place…
I’m in the process of building a ‘warm’ 998cc engine to put into my Morris Minor (bored out from 948cc, flat top pistons, cooper head etc).
After having received everything back from the machine shop I appear to have fallen at pretty much the first hurdle (or perhaps second!) - I’ve installed the crankshaft which rotates freely. I’ve put the pistons in, and the first two con rod big ends, all torqued up still allow me to move the crank, albeit with a bit of resistance (mainly from the new piston rings I guess). However as soon as I put any torque on the third and fourth big ends, it makes the crank incredibly stiff - when they’re both done up I can’t really move the crank at all, even with a spanner.
The crank was ground to 10thou under and there are new bearings to suit.
I’m going to speak to the machine shop, but this forum has been such a hive of information I thought I would also try here in case there are any bright ideas!
Many thanks,
James