UPDATE: 5.5agze 20v coming Spring 2015 by gaijin_rokurunner

By diyauto
( 4 )

3 minute(s) of a 106 minute read

3-13-2013

Ok first let me correct the numbers posted yesterday......engine was only revved to 8500 rpm at 8600 it committed suicide and the numbers at 8500 were 249hp and torque peaked at 155 ftlbs at 7300 rpm...... now this is still with a rich A/F mixture and 32 degrees of timing....final tune will have 37 or 38 degrees like the atlantics and a leaner A/F mixture they were just being safe getting it all the way up to the max redline which will be 9500 then adding timing and playing with the A/F mixture until they were comfortable prior to the final power run....Now the carnage....yeah looks pretty bad but could of been a lot worse and good thing is its all fixable...and the shop is covering it since it was their over-site during the build....the determination of the issue...CP cut the relief pocket angles improperly and when QRE cut the reliefs deeper they didnt check that so all 8 exhaust valves were rubbing on the wall of the relief half way down....its very minimal but enough to bend all 8 and one must of got tired of being pushed around and blew its top...literally.. anyhow QRE is going to weld up the combustion chamber to fix it...ordered a new piston today and pulled all the valves and sent them to Ferrea for inspection and replacement..im assuming 8 exhaust and 3 intake valves will be needed. Once the piston is back the reliefs will be properly cut on all 4 pistons and sent back to swain to be coated again. once back everything assembled and we can do a short break in and pick up where we left off...so im guesstimating a 2 month process as CP stated 3-4 weeks for one damn piston. Im disappointed the engine blew but i rather it do it at the shop then in my car....that would of sucked and the damage would of probably been worse on the good side im happy with the numbers and hope to squeeze a few more ponies out once its all back on the dyno and has the final mapping. 


Dan the valve springs are good to go they are actually a spring Ferrea did up for suzuki moto gp...they fit the 20v perfectly just required a seat and new retainer....thats a 15000 rpm engine so it definitely not an issue there.








Comments

A lot of detail!

Posted by Diggymart on 3/24/20 @ 4:53:18 PM