478 v. 501 top end differences

Maestro, SEI-V

478 v. 501 top end differences

Postby simonnorthroad » 03 Apr 2018 10:48

I found an old posting from Norbert from 3 years ago, thusly:


the pushrods of the 500 motor are longer than the ones for the 501 because the 478-cilinders are higher! Another diference is the axe of the balancines (spanish :wink: ) They are 71mm long instead of 69 (350 and 500) if I remember it well, and the distance washers are put in another order. The reason is that the center of the valves in the 501 heads are more apart to avoid the problem of the fissure between them (still happening :( ) That means that the puschrods are positioned a bit out of vertical.

I once took the longitudes of the diferent pushrods in mm (over all) the rear ones are more or less 2 mm longer than the front ones, as you know:


500 and 250T: 205/207 (I supose the 250T 205)
501: 202/204
350: 182/184

Can this be true? Shorter pushrods and longer rocker-arms in the 501 motors? Sounds pretty extrvagant by Morini standardisation standards!
simonnorthroad
 
Posts: 68
Joined: 16 May 2017 10:57

Re: 478 v. 501 top end differences

Postby simonnorthroad » 11 Apr 2018 21:27

Anyone?!
simonnorthroad
 
Posts: 68
Joined: 16 May 2017 10:57

Re: 478 v. 501 top end differences

Postby norbert » 15 Apr 2018 15:21

The rockers are the same, but the axle of the rockers in a 501 head are 71mm long. In all others 350 and 500 the axles are 69 mm long.

norbert
norbert
 
Posts: 321
Joined: 15 May 2007 15:15
Location: Lübeck/Germany

Re: 478 v. 501 top end differences

Postby simonnorthroad » 02 May 2018 21:57

what about the pushrods Norbert?
simonnorthroad
 
Posts: 68
Joined: 16 May 2017 10:57

Re: 478 v. 501 top end differences

Postby norbert » 02 May 2018 22:14

The length of the pushrods is like written above. The 501 rods are shorter than the 500, because the cilinders are shorter (with 71 bore instead of 69). The crankshaft is the same, but the position of the "eye" of the piston is different, so it works with the shorter cilinder.
norbert
 
Posts: 321
Joined: 15 May 2007 15:15
Location: Lübeck/Germany

Re: 478 v. 501 top end differences

Postby simonnorthroad » 04 May 2018 11:59

I knew you'd know! No wonder my 500 pushrods dont work in the engine!
simonnorthroad
 
Posts: 68
Joined: 16 May 2017 10:57


Return to The 500

Who is online

Users browsing this forum: No registered users and 4 guests

cron