428 CJ build: Version 2.0

[aj]

Let’s see if average guy (me) can avoid engine damage during dyno run this time.  6 months ago, the first try ended with detonation and dyno guy letting motor run way lean on top end.  Found scratched cylinders and although not sure of exact cause,  decided to tear down and start over.

 Just picked up short block and heads (5 month wait but well worth it).  This time running lower compression (from 11 to 9.5) and am more confident with the shop that built version 2.0 shown in photos.  I’ll dyno again soon and see how compression drop changes numbers.  I noticed rotating assembly spins noticeably easier than before  Guessing the new/different type rings have something to do with that.

For anyone who gives a hoot, my first attempt and description of motor is in the dyno section of this site.  Only changes are dished pistons, modem ring package and fine tuning of valve job.

Adrian

[6667fan]

Odds are in your favor AJ. Good luck
JB

[plovett]

I like compression, but if on pump gas, lower compression with more (and faster) ignition timing is preferable over high compression with less (and slower) ignition timing.

I haven't looked at your combo yet, but in general, use more initial timing than is traditional and make the total come in at a fairly low rpm, like under 3000 rpm.  I run 18-19 initial and 36-37 total all in somewhere in the 2500-3000 rpm range.  Lower compression allows you to be more aggressive with the ignition timing. 

JMO,

paulie

[My427stang]

It should do really well with that combo.  Just be sure the first pull is conservative for timing, especially if you go to the samedyno, I'd say 34 total is plenty, and be 100% sure it's all in even if you have to go to 4000 rpm to be sure with a light load, then the first pull's goal is to watch mixture.

Once you get the mixture right, do subsequent pulls with increasing timing.  Likely will be around 38 I'd expect when done.  Might even want to do a pull with the air cleaner on if you have the time to see how mixture changes.  In the car, run that total, but I'd have initial at 14-16 and total all in by 2700-2800.  The dyno won't see the rate or initial, but the increased base timing and quick curve will make it far more responsive and happy to drive

I am not sure your numbers will go way up from last time, in the end, as good as the CJ heads and intake are for stock pieces, they have their limits without significant work when you add cubic inches, but I bet it will be one of those engines you fall in love with in the car.  However, you have a very good match there and the dyno can't read