New 428!! detonation?
 

I finally fired up my new 428, so far so good I think. This is my first big motor build, and the thing runs, so im pretty damn pleased. BTW, a huge thanks go out to everyone on this board who have helped me along the way, there is no way I couldve done it without you.

I may have a detonation problem. I've never heard detonation before so im not sure what it sounds like. I've posted a couple of links, so maybe you can take a listen and let me know what you think. To me it sounds like loose lifters, but I've zero lashed them twice.

http://video.google.com/videouploadf...E1vdmllIDI.mpg

http://video.google.com/videouploadf...E1vdmllIDM.mpg

Here is my setup and why i think it might be detonating.

428 stock rods and crank. .30 over.
#62 heads
1.65 rollers
comp cams xe268h
edelbrock 750 and performer manifold
1 5/8" headers.... Im sure these things are leaking.
PYPES 3" exhaust w/ X pipe
MSD billet distributor set 12 degrees btdc

My guess is that its detonating because of the high compression heads and crappy gas.

Also, this thing is burying the oil pressure gauge. 100+ psi. Is this a real problem?

I broke the motor in running it around 2000 rpm for about 30 minutes or so. changed oil and only the slightest little speck of metal in the oil, cut the filter open, nothing in it.

Have a listen and let me know what you think.

Matt

Be certain to set the timing for NO VAC ADV:

34 degrees Total in at 2300 RPM.
1x initial ADV. depending on you Cam, Brake vacuum boost, lowest idle, etc.

Mechanically Limit the Vacuum Advance to < 10Deg, or try not to us it at all.
For awhile anyway.

Your combo WILL need 93 Octane or better. You will have to take on an intentional effort ot reduce ping:

Whack the Plug lugs back for side-gapping.
Enrichen the Primary circuit & tune the Accel Pump gas shots for Ping-free Part-Throttle and situational pedal ping.

Lean the idle circuit for tear-free warm-up.

Run the 180 thermostat.
Run a remote oil filter for cooler oil.
I hope you Filled the Exhaust crossovers for best results. :ranger: HIS

You didn't mention your pistons, are they dished like the factory ones?

yep they are dished. In fact here is a link to one of my previous posts. :)

http://forums.maxperformanceinc.com/...d.php?t=473659

You mentioned leaky headers, that probably accounts for most of the "ticking" noises you heard.

I would describe detonation (if it is so bad you can hear it) as litterally sounding like there is a little gnome inside your engine banging on the sides of the block with a ball-peen hammer.

Take it out for a run under load and then check your plugs. Any signs of black or silver specs on the white porcelain part of the electrode base (not on the outside porcelain where the wire boot goes on) means you have detonation.

Good luck... looks and sounds good to me!

100+ psi is a problem on a street motor. I'd suspect faulty gauge, too thick oil, too small bearing clearance, clogged filter or housing, or stuck relief valve in pump. Check dist drive gear for damage. Hope you got a hardened oil pump shaft in there. It can take several HP just to drive oilpump making that kinda pressure, which can break stuff.

I'm guessing you have hydraulic lifters. Don't mess around with zero lashing them. Put a 1/2 to 3/4 turn preload on them. Could be the lifters making a lot of noise because you didn't lash them correctly. Spin the pushrod gently with your fingers while tightening the lash. As soon as you feel resistance with the pushrod then tighten 1/2 to 3/4 of a turn. The zero lash thing is trouble.

Tim C

i agree...thats how i adjust my hyd lifters. the problem can lie in the interpretation of when the pushrod resistance starts.....

so adjust them just slightly past tight... does it matter if the engine is cold, warm or hot?

i do mine warm. mostly just because i take it for a ride to get a feel and then adjust. by the time i am really into it the motor has cooled some. then i go back out and get another feel for the adjustment i did. it can make a big difference........