Well, the time came for the 305 to go to a better place

I was racing in Yorkton today.

I had the 125hp shot jets in.

I got the Digital rpm window switch working.

Did my first run
0.560 R/T
1.88 60ft
83.6 mph
8.216 sec.
This is the fastest run of the year for me! It felt sloppy out of the hole b/c I had the rpm window switch to turn the n2o on at 1200rpm. I had way more in it. I raced a '69 Satellite and beat him(8.906 sec)

For my second run I did everything the same
0.502 r/t !!!! My best time EVER!!!
1.924 60ft
82.8 mph
8.337 sec
This run felt good except that the tranny wouldn't want to shift to 3rd gear.
The motor bounced off the rev limiter at 5900rpm and shifted to 3rd.

I saw alot of people looking at my car as I came back to the pits.

After seeing alot of oil underneath the hood we took an infrared temp gauge and tested each header. Number 8 was 30 degrees cooler.
Pulled plug and this is what I saw

I guess when the motor bounced off the rev limiter the nitrous was still pumping and there was no spark on that cylinder.
Too much pressure and popped a ring. The piece hit the plug strap.

Oh well, I have no excuses for not putting the 383 in now!!

 

Sad to see a good running 305 leave this earth. Good luck with the 383!!

 

Tell me this isn't what you meant to type?

 

Umm, what?

It would've felt better if the n2o turned on as soon as I hit WOT.

 

So you do have a wot switch? I thought you were spraying off the window switch at 1200 rpms?

 

If you had a window switch, how were you bounching off rev limiter? Did you have a 1200/6000 modules in it?

Sucks to see it a motor bite the dust. Where was the oil comming from, if you only killed a ring? I would think the rings butted during the pass, if the ring is what actually failed.

 

Yes, sorry , should've said that before.

I made the ultimate stupid mistake!!!! The window switch should ALWAYS shut off the n2o before the rev limiter
Rev limiter=5900
window switch cut-out=6200
=Very stupid mistake


The oil came from the dipstick tube. When I opened the hood, the stick was about 3 inches out. When we pulled the plug, there was still compression,not as much as should be. If it was a piston, there would be no compression, right?

I have not taken the heads off yet, I am just guessing at this point.

 

You are on the right track with the compression thing. Did you check all of the cylenders? What were the numbers?

The 305 died an honorable death lol.

 

I didn't do a compression test.
I didn't check every plug yet(the car is already stuffed in the corner of the garage), but I check them. By the temp guauge on each header, it was only #8 that was out on the temp.

Yah, but I didn't hit my 2 goals this year.
1. Get 1 tire off of the ground on launch
2. Hit a 7.999 in the 1/8th(about a 12.5 1/4)

 

That's sad to hear man, what kind of rev limiter were you using? I bounced mine with the Digicon rev limiter at 6000rpm and it didn't hurt anything, were you using the factory one that cuts the fuel?

 

I have a MSD digital 6+ for the rev limiter
I have a MSD digital rpm window switch

When you hit the rev limiter, were you using n2o too?

n2o and fuel with no spark= bad

 

I was using a 150 wet shot when I hit the rev limiter and I hit it pretty hard. I guess I just got lucky on that one, the rev limiter on the Digicon is a soft touch rev limiter so that probably saved me. The crappy thing is the Digicon's tach reads about 600rpm faster than my 5in tach at anything above 3500rpm, solution was; raise the rev limiter 300 rpm and drop the shift light 200rpm. Pull that motor apart and see if you can get away with a budget rebuild, then convert to a wet kit and hit that 7.9!!!

 

My rev limiter is a soft touch, too.

 

Bad luck man, I hate to hear that.

 

I don't understand. Shouldn't the cylinder pressure be less if fuel&air are there without spark. It sounds like something else caused the failure.

EDIT: I seem to remember you running your engine with N2O and the NBO2 was reading about 750 mV.............roughly 13.xx AFR.....on the lean side of things for nitrous.

 

haha pill it till you kill it! im still trying to kill the 305 with the 150 wet shot! it seems to like it though, but then again it only has 80k on it

 

Here's #8 piston. Notice the ring landing on the left side is gone and the top is pitted.

Not good.

The wall is scored but not sure how much.

 

That sucks. Good thing you didn't have a turbo on it to chew up the piston piece that broke off.

Is the top pitted from detonation or the piece that broke off?

 

No other pistons are touched so I think that it is pitted from the ring landing bouncing around.