Ausmini
It is currently Mon Jun 23, 2025 4:24 am

All times are UTC + 10 hours




Post new topic Reply to topic  [ 2 posts ] 
Author Message
PostPosted: Thu May 28, 2015 3:14 pm 
Offline
848cc
848cc
User avatar

Joined: Sat Apr 30, 2011 7:18 am
Posts: 110
Location: Gold Coast
Wondering about any advice on the engine I have.

I have a 1275 40thou oversized pistons with a double row timing chain. Currently fitted with Isky cam followers and Kent 286 cam.
Running a 45 Dellorto and GR inlet manifold, Ultralight flywheel and Aldon Electronic Dizzy.
The head is being built now with 1.401 dia inlet and 1.219 dia exhaust valves, with new guides and valve seats. New springs are being fitted that are replacing the 200LB dual springs that were on the head.

I am wondering about advice on rockers, springs and any other advice before I bolt the head back on? The rockers are standard at present. Also any modifications or specific adjustments recommended would be helpful? Thanks

_________________
1975 1310cc Street Mini Custom
1974 Leyland Mini daily driver
2008 Cooper S R55 Clubman


Top
 Profile  
 
PostPosted: Thu May 28, 2015 5:21 pm 
Offline
848cc
848cc

Joined: Wed Oct 01, 2014 6:35 pm
Posts: 131
Get a set of Minispares 526 springs for it and check/adjust their fitted length. Don't run roller rockers - If you're looking for the cheapest option, find the best set of pressed steel rockers you can and put a new rocker shaft with them. If you want to buy new then Minispares also do a forged 1:1.5 set.

Check your cam lobes and followers for wear. Check the nose radius on the followers as some have been completely flat which will greatly accelerate lobe wear.

While you're having the head done measure everything and calculate your compression ratio. Also measure your dynamic compression ratio. This can be done (basically) by measuring where the piston is when the intake valve closes and then calculating the volume left in the cylinder. Then you can calculate the compression ratio as you normally would but use your measured volume. You want to aim for a figure as close to 7.5:1 as you can get. As the 286 is getting to be on the 'hairy' side optimising your dynamic compression ratio will greatly improve the low end and make the car much more driveable.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 2 posts ] 

All times are UTC + 10 hours


Who is online

Users browsing this forum: No registered users and 12 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  

© 2016 Ausmini. All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.