jcb999

i screwed something up.. hammered it in first and it started popping and backfiring through the carb. Would not stay running. All rockers and valve springs look fine. I am going to check the distributor in daylight.


I knew it.. it was running (and starting) good.. i had got the oil leaks somewhat under control.

Vader

I've done the same thing before (at higher RPMs) and floated a valve. Instead of damaging the piston, the valve got bent and wouldn't seal, and finally burned. It would backfire constantly, and I was shocked that the piston hadn't taken any damage. The valve must have just "kissed" the top of the piston and took the brunt of the energy on it's undercut stem. That looked like where it had bent, since the valve slid right out of the guide with no friction. IIRC, it was at about 6,800 RPM with marginal springs and lightweight valve train parts with no rev kit.

AlkyIROC

I'l have to take a picture of my last engine damage. I have a nice forged piston with bent con rod that has the head of a valve sticking out the top. War souvenir. Might make a hardluck trophy out of it some day.

It did lots of damage including punching a hole in the head and cracked the cylinder wall.

It sounds like yours might just be bent. If the coolant hasn't left the rad and entered the crankcase, it's a good sign.

Did you check valve clearances with putty? You should have a minimum of .100" clearance.

jcb999

The revlimiter is set a 6400 and I did not hit it. It has an AFR hydra-rev. The way it sounds, there is not just one cylinder missfiring. Its several... but i can't tell for sure.

Vader

You don't s'pose you got "lucky" and just slipped some chain links, do you? Prob'ly not, but if you have "several missing" it may be less of a basic mechanical problem. We'll cross our fingers anyway.

99Hawk120

I'm no Vader, but I'd really suspect the distributor or the timing chain slipped. Either that or you bent multiple valves, and, well, let's just hope it's the former.

RB83L69

Bummer dude...

Sounds to me like a blown head gasket

Todds1987iroc

The only other thing I think it could be is the cam went flat. This happened to me in my '69 camaro and at idle the car seemed fine but would break up bad after 2500 rpm. Just a thought

99Hawk120

Blown headgasket should be easy to rule out. If there's no oil in the coolant, no coolant in the oil, and you're not blowing smoke, you probably didn't blow a head gasket.

jcb999

I found part of the prob.

http://cis.tamu.edu/~jcb9392/DCP_0001.JPG
http://cis.tamu.edu/~jcb9392/DCP_0002.JPG
(sorry about pic focus)

I don't like the fact that it just broke...

time for some comp-pro mags.

It was #6 ext.
i should have noticed it the first time i had the vc off.

jcb999

from http://atlanticspeed.com/
they guy sold them to me for 12bucks off their web price. I hope to get them by wed next week. Dyno jet is scheduled for saturday.

RB83L69

There must be some reason I don't use aluminum rockers... I think that might have something to do with it!!! I think you'll like the steel ones much better.

Matt87GTA

YIKES!

That is some serious parts failure-age there... At least it appears to have broken off clean and didn't spew metal into the rest of the engine (gotta look at the bright side when this ****e happens ).

This also serves as yet another reason for me to go to the Comp Pro Mags..... I already don't like how noisey my AL Crane Golds are :nono: ......

Sounds like you really have it under control though

Laterzzzzzzzz,
Matt

99Hawk120

Well. I was already leaning towards steel rockers over AL. I think that just clinched it.

jcb999

I kind of contributed to the failure.

I was still kind of rolling slowly forward when I stuffed it in low and hammered it.. it kind of reved a little faster than it would have normally.. but..
regardless.. it was obviously marginal.

Makes u wonder how some of the cars with solid rollers hold up with alum rockers.
I can't see how an harland sharp or anyother would have been much better.

Vader

JCB,

You DID get lucky. Now you'll have a REAL set of rockers. 1317's? 1318's? The Pro Magnums are solid units and worth the little extra mass. Actually, the design is so well engineered that the reciprocating mass is actually less than most aluminum rockers. I just like real steel, whether it comes from abroad or North America.

Be environmentally responsible - save the aluminum for beer cans and aircraft, please. Or sell the remaining six pairs as a set for a 262 V-6 on eBay?

BTW - Your picnic table looks just like mine...

jcb999

1305s
1.6 ratio with 7/16" studs.

I probably get about as much use out of that table for parts as the birds do.


and yeah it was a clean break.. thats the first thing I checked.

Damon

Damn, haven't seen many rockers that look like THAT before! No bent pushrods in all the carnage?? Usually the pushrod gives before other stuff like rockers. I still wonder if you floated a valve into a piston.

jcb999

but.. it seems that ups has turned my 3day select into 4day .

Scheduled Delivery: Mar 27, 2002
Shipped to: BRYAN, TX, US
Shipped or Billed on: Mar 22, 2002

frikin ups.

they don't count the ship date as one of the 3 days. WTF?

Don't know about Pushrods.. they look straight.

grafx

Yeah at least it broke clean. I had a staped steel rocker shatter on me in a car I use to have, look like the thing exploded, not to mention a bent pushrod.

MikeH

iTrader: (10)

A few months back, I had the exact same thing happen on my 406, Broke clean right in the middle, looks like the same(Blue)rockers even. Proform I think, I bought mine used, but new so IM not sure of the brand name. Ive had stock rockers break in the past so I had a good idea what it might be.

I will never use aluminum rockers on the street again, I replaced mine with a set of steel Comp cams rockers, no problems yet.

MikeH

iTrader: (10)