Engine Mishap Close Call
 

I had a close call with my engine last Friday!! Since the cam and rocker change the engine only had about 30 actual miles on it not counting garage idle and run time.

The weather was nice Friday so I went home a little early to take advantage and drive the Cobra! I had it out of the garage when I fired it up and noticed that it was not running right. It had a dead miss! I broke out the water spray bottle and found that the number 7 cylinder was not firing! The header was cool. Shut the engine off and checked plug wire but nothing seemed out of place. Started it again, still missing, so I revved it a little and heard a clunk sound from the drivers side valve cover!! That did not sound good!!

Shut it down, pushed it back into the garage and started the process of taking off the driver side valve cover! When I lifted the valve cover away from the head a roller rocker fell out and down to the garage floor!! My first thought was, “Oh great I have broken my engine without even zinging it!” Second thought was where is the nut that holds the rocker arm on? I found the nut lying at the bottom of the head rail where the oil collects to drain back into the engine. The allen head lock nut was still inside the nut so nothing went down into the engine!! (Huge Sigh of Relief)

My guess is that I had not “locked” that nut tight enough and with the engine running had backed itself off until it finally fell off and that is the clunk that I heard. (It only ran for about 10 seconds after I heard the noise!) LUCKY ME!! It was an intake rocker arm so the engine was not getting any air/fuel into that cylinder, hence the cool header.

The roller rocker was fine, the pushrod was fine and the locknut was fine. It just flat fell off!!

I reinstalled everything, checked lifer preload and turned the engine without the coil wire and all looked good. Inserted the coil wire and it fired right up and ran fine.

I checked the other nuts on that side and all were tight! I then drove it about 6 miles and after cooling I rechecked all 16 nuts again!! I drove it about 30 miles on Saturday before the weather got ugly and all seems to be well!!

I was LUCKY!!

Terry,
Good catch! It seems I'm hearing from more guys these days about rocker lock nuts coming loose and causing problems. Glad you caught it in time.

Do you have poly locks or regular nuts with locking set screws?

Spring is almost here- just about time for you to come up to another "Beaches Cruise In".

Bob

Nuts
 

Hello again Bob!!
I emailed Don a couple of weeks ago as I have to travel to Portland for business in the near future and he said to wait a few weeks so I will hopefully be in for some more Cobra music when I need to go!!

I have the regular nuts with the allen head set screws!! Is there a better product to use to keep this from ever happening again?

Poly locks aren't perfect, but they seem to work much better than the set screw type. You can pick them up at Summit and a bunch of places for about $1.50 each.

Looking forward to getting to the Beaches gathering again. Just wish my car would be done for this season, but it's not looking likely at this point.

Bob

Terry,
When I get "Lucky" like that, I like to chalk it up to "Clean Livin'". Those that know me well know it was LUCK!
:LOL:

Chris

Glad you found the trouble and it worked out. I was at work last summer and a super nice 1963 chebbie pickup was pulled over at the side of the road at my jobsite. The thing had about 3000 hours in the paint alone. I pulled up and asked if he needed help. It ran sort of. It obviously wasn't firing all all 8... I'd guess closer to 5.

The owner had some tools and we pulled the valve covers on the 427 to revel 3 rocker arms laying on the head, with 2 push rods completely missing! The guy was on his way to Hot August Nights and I guess was in a hurry and nobody checked the lock nuts on the rocker arms. They'd fallen off the engine.

There was a Corvette shop around the corner and I took him over there. After finding all the parts that had made their way to the valley pan and a valve adjustment he was back on the road. No major damage done it seems... Well except to his wallet. The rush job cost him $600.