Engine Failure
 

Here's the story of my weekend at Barber for the 45th Mustang bash when the engine "let go".

I was giving my daughter a ride in the afternoon run group designated for passengers when I entered the down hill corkscrew and downshifted to third gear, maybe doing 2500 rpms, loud noise from the bottom rear area of the motor, then a little smoke up the shifter boot, smelled like a burning clutch, shifter vibrating side to side what seemed like a foot, maybe more like 6 inches, vibration got worse, noise got louder and I put the car in neutral and killed the engine and coasted to a safe place on the track and waited for the tow truck.....from start to finish maybe 5 to 8 seconds before I killed the motor.......

At first I suspected the clutch and/or trans, but found out later it was the motor....
After thinking about this for a few days, I wondered if when I spun out and went backwards at about 100mph earlier in the day could have hurt the motor...the spin happened sooooo fassstttt I didn't have time to push in the clutch and the car killed right off and I was going sideways and backward with the car in 4th gear for about 5 seconds, I would guess.........
Here are some pics of the results..... The block actually held up great considering it is a 1971 factory 302 block. No block failure, rod/rod bolt failure........
lots of photos in my gallery.......

David

http://www.clubcobra.com/photopost/d..._stand_051.jpg

more pictures of the carnage..........http://www.clubcobra.com/photopost/d..._stand_058.jpg http://www.clubcobra.com/photopost/d..._stand_057.jpg http://www.clubcobra.com/photopost/d..._stand_056.jpg http://www.clubcobra.com/photopost/d..._stand_052.jpg http://www.clubcobra.com/photopost/d..._stand_055.jpg http://www.clubcobra.com/photopost/d..._stand_050.jpg http://www.clubcobra.com/photopost/d..._stand_048.jpg http://www.clubcobra.com/photopost/d..._stand_047.jpg http://www.clubcobra.com/photopost/d..._stand_031.jpg http://www.clubcobra.com/photopost/d..._stand_030.jpg

The motor had about 3 hours of run time on it from adding new bearings/rings.... the block is now an anchor, as it 2 rods and pistons, I think the crankshaft can be re-used, although I'm not planning on using it in my race engine, maybe a mild street engine in the future.... The cylinder heads are fine as is the solid roller lifters and basically all the top end.....
I'll build a new engine with a new rotating assy. and my BOSS 302 block using pretty much the same combo, but changing the cam to a slighty larger one....

The engine ran for less than 10 seconds when things started coming apart and at 2000 rpms or less, so I think that's why more parts were not damaged......

Only good thing is I have until October before I was gonna race again, so I don't have to rush to build another engine........

David

http://www.clubcobra.com/photopost/d..._stand_039.jpg

http://www.clubcobra.com/photopost/d..._stand_036.jpg

http://www.clubcobra.com/photopost/d..._stand_032.jpg

http://www.clubcobra.com/photopost/d..._stand_031.jpg

http://www.clubcobra.com/photopost/d..._stand_030.jpg

http://www.clubcobra.com/photopost/d..._stand_028.jpg

Ouch!!
 

David, I sure hope you know someone who's cousin's first wife's brother's best friend can put that back together again! (JK) Sorry to see the damage. These toys of ours put out SO much fun and reward I guess the price is still always worth it. Glad nobody was hurt and you and your daughter will enjoy another cobra day!

Dirk

He'll need a lot of super glue to get this back together!!!!!!!!!:LOL::LOL:

David

David,

Do you have any pictures of the rod and main bearings?

are those ARP bolts on the rods --- or pioneer >?

The bearings on the rods/mains all look just fine,cept for # 8 rod, I just found the bearings and broken rod bolt in the oil pan (8 quart road race pan with flapper doors and windage tray), I'll add those pics later, but the bearings looked like wadded up bubble gum. The broken rod bolt was weird, black in the center of the break and kinda silver around the edges, pictures may not show it, just didn't look right....

Looks like ARP rod bolts, but I'll check again. The rods are Eagle forged H beam rods with the "big" rod bolts....

Just checked and the rod bolts have stamped on the head, "EAGLE APR 8740".....
The rods are 5.4 inches long and are the chevy rod journal size,I bought the complete stroker kit....comes with the Eagle 4340 forged crankshaft/5.4 forged H-beam rods/bearings, and I upgraded the flat top pistons to Diamond dome pistons when I ordered the rotating assy.....



David

http://www.clubcobra.com/photopost/d..._stand_066.jpg http://www.clubcobra.com/photopost/d..._stand_064.jpg http://www.clubcobra.com/photopost/d..._stand_063.jpg http://www.clubcobra.com/photopost/d..._stand_067.jpg pictures of # 8 rod bearings I found in the pan and the broken rod bolt....also something else that has me puzzled is 6 of the pistons had marks on them where both valves had "touched" the pistons,but not # 8, just marks, no indentations that you could feel with your finger nail... when I put the engine together I ALWAYS check piston to valve clearance and I had something like 175 thousands clearance on both intake and exhaust, more than enough....
The only thing I can think of is the valves hit the pistons if/when the motor turned over backwards in my spin......that could have possibly done some damage that showed up later when the failure occured....

After the spin, when the dust settled, I hit the starter button and the motor fired instanly and I finished the lap and came in, didn't hear anything unusual in the engine, then a couple of hours later,went back out on the track and had made 4 or 5 laps went things broke, all easy laps with my daughter, never turning the motor more than 5,500 rpms.... of course I know if things are gonna break, rpm level doesn't really matter, I've seen engines grenade at idle!!!!!!

http://www.clubcobra.com/photopost/d..._stand_068.jpg


David

Sorry to see this David. Happens to everyone if you stay at it long enough. When you spun did you lock the brakes up? This prevents anti rotation of the motor as well as makes you a predictable object for following drivers. Seems like a lot of damage from just a spin and possible anti-rotation.

To satisfy your concerns contact ARP they can diagnose if the rod bolt was the failure point. Without placing blame I would certainly like to know what failed or caused the failure.

Not right off, the car started coming around on me and I steered into it, but it kept coming around till I did a 180, then, I guess with the banking it started to straighten out some on it's own and I was trying to help it with steering input, hadn't touched the brakes yet, then as it was coming back, I began heading for the wall, then I turned back on purpose and locked up the brakes to put into a spin to keep it off the wall and that part worked....

I should have taken Rusty Wallace's advice: "When in a spin, both feet in", meaning clutch and brake pedals to the floor....

I had no warning and had not been "lose" or anything, the spin caught me by suprise as it happend so fast with no indication, the rear end just snapped out from under me in an instant and before I knew it, I was completely sideways, probably doing at least 100mph at that point...

I was worried cause it's a pretty good downhill left hand turn and I knew there were at least four cars about a half a straight away behind me.... The flag man did his job and they got slowed up enough to go around me safely,cause when I finally stopped, I was sideways in the middle of the track!!!!!!!!!!!!!!!

The damage may not have been from that, only thing that led me to think that is the valve marks on the pistons.

I've been involved in racing from one type or another since the early 90's and know that things happen and motors blow up and I accept that. I certainly don't blame the manufacter of the parts nor the company that sold them to me, I would never go into any business selling anything for "racing purposes"....

I'm just posting the pictures and info for others to see....

Actually, this motor has served me well,I can't complain, I've been running this engine for almost 4 years now and this is the first time for anything with it.I'm please with the parts and I'm gonna build another motor using the very same parts, new of course.

I've chalked this one to the heading: "$hit Happens",especially in racing...

David

Rick; I'm not really concerned about it nor placing blame on anything or anyone, just posting for other to see what can happen....I'm guessing those parts had between 75 and 100 hours of run time on them, from 3,000rpms to 7,000 rpms... They served their purpose......

David

David,

i wanted to go to that event, guys on SVT were talking about the R race, i wanted to enter.

sorry to hear about the failure. You must remember what you learned in driving school..."In case of spin...both feet in!"...helps prevent this type of crap from happening.

I like putting my foot in it on the front straight at The Glen and having this happen....

http://www.cobranet.com/coppermine/a...IMG_0633~0.JPG

Ya shoulda came, there was a ton of those SVT guys, some serouis cars too......I know, I was on the track with most of them at one time or another... They had some wicked fast cars and drivers!!!!!!!!!!!

I guess I've learned my lesson about "both feet in" now, but for some unknow reason, I tend to NOT do it and try to save the car when in trouble.........

BTW: MY boat anchor is BIGGER than yours now!!!!!!!!!

David

wow david

i'd prob crapped my pants after a spin like that. immediate adrenaline rush!

too bad about the engine, i would say the fancy parking maneuver did you in.

better luck on the next build. maybe find something available in the for sale section.

i would guess the bolts broke after the implosion, not the cause. maybe bent or twisted a rod initially.

Hey Dave

That engine has given you some grief ..... in leak out fix, in leak out fix, in leak out fix, in leak out fix .. now this :CRY:

I do have plenty of superglue, and even some loctite. For the hole in the pan I think I'll go with some duct tape.

Doug

Doug;

yep, and the worse part is the leak was down to a small seapage at Barber!!!!!!!!!!!!!!

Not gonna have to worry about that anymore........the block is junk.....:CRY::CRY:

Gonna have a machinest look at the crank, I think it is still good, he'll check it out and make sure, but I'm gonna get a new one anyway and save this one for a "street" motor later on........

BTW: I got a nice paper weight for you, should look good on your office desk and make a nice conversation piece!!!!!!!!!!!!!!:LOL::LOL:

David

Actually it all happened soooo fassstttt no time to crap pants,no adrenaline rush, no nothing, just act and re-act to what's happening.....Now afterwards in the paddock, I sat down and smoked a couple of cigarettes back to back and had a coke and thought "man, what a wild ride", hope I don't do that again anytime soon!!!!!!!!!!

Looking at all the damaged parts and pieces on the work bench trying to figure out what happened, well, it's kinda like the chicken and the egg thing!!!!!!!!;);):LOL::LOL:
In the end, it's pretty much all junk,cept for maybe the crank, the top end is o-k.... I'll get a new rotating assy., have a block already and build another motor and go at it again.....

Just wish I had had my in-car video camera in the car and on at the time!!!!!!!!!!:mad::mad: Would have made great video to one day show the grandkids when I do have some.....

David