Alfa Romeo Forums banner

1 - 20 of 47 Posts

·
Premium Member
Joined
·
14,038 Posts
Discussion Starter #1
I was cruising at 55 mph on Saturday then suddenly a loud rattling sound and running on three cylinders. Rattling sound quickly disappeared but still running on three.
First pictures show spark plug from #3 cylinder which had no compression and inside of plenum.
 

Attachments

·
Premium Member
Joined
·
14,038 Posts
Discussion Starter #2
Lifting the head

Lifted the cylinder head - not pretty.
 

Attachments

·
Premium Member
Joined
·
14,038 Posts
Discussion Starter #3
The terrorist

The culprit appears to be a 6mm nut. I had installed 45DCOE Webers the day before the incident. I only used these nuts in one place - attachment of the support strut to the plenum. One was in a very tight spot and I dropped some nuts in the process. I retrieved them from under the car but I obviously missed one. I think that it must have bounced into the Weber so that it could not be easily seen.
 

Attachments

·
Premium Member
Joined
·
14,038 Posts
Discussion Starter #4
Good news - it is repairable

The valve seat is damaged and must be replaced. The piston and combustion chamber look ugly but the damage is superficial and can be cleaned up. Jim Steck can do the head work and he is one of the best, if not the best for this work. He is so good that he has a 5 week backlog so the Spider will be off the road for a while.
I will leak check the other valves to confirm that only #3 intake needs to be fixed.
 

Attachments

·
Premium Member
Joined
·
14,038 Posts
Discussion Starter #7 (Edited)
Do you think that terrorist of a nut will get its 72 virgin bolts
I suppose it depends on if the nut screws the bolt or vice versa. It appears to be a female terrorist!
 

·
Premium Member
71 Berlina 74 GTV 17 Giulia Q4
Joined
·
6,471 Posts
A home grown terroist at that :)
 

·
Registered
Joined
·
6,829 Posts
I believe this is why Alfa generally used studs on the upper airbox and strut mounts. The nuts and washers would be outside of the carb intakes......

Even nylock nuts would have been a good idea.
 

·
Certified Oldschooler
Joined
·
7,033 Posts
I recall the long later Euro sausage air cleaner plenums attach with some small nuts to the carbs. Always puts the hair up on my neck even with lock washers. Ok, Nylock next time.
 

·
Premium Member
71 Berlina 74 GTV 17 Giulia Q4
Joined
·
6,471 Posts
I've got the bolts for the support running to the outside. A bolt can't make it down the chute. If I drop a nut it's always accounted for. That being said it can happen to anyone.
 

·
Registered
Joined
·
266 Posts
****! Where did the nut fall off of? I can't believe that got in there and hammered the cylinder and head so bad. I suppose it could have been worst.
 

·
Premium Member
Joined
·
14,038 Posts
Discussion Starter #15
The strange thing is I was paranoid about something like this happening. I loctited the nuts on the inside of the plenum and used nylock's on the ends of the two bolts that were on the inside.
 

·
Premium Member
Joined
·
14,038 Posts
Discussion Starter #16
****! Where did the nut fall off of? I can't believe that got in there and hammered the cylinder and head so bad. I suppose it could have been worst.
Read post #3
 

·
Registered
Joined
·
273 Posts
Ed, Really sorry to hear (and see) this!!
I've been watching your threads about this motor, as my engine is virtually the same as yours, including RJR cams.
Hopefully you can get her back on the road soon, although it seems like you have a bit of a wait for the head work to get done.

Good Luck!
 

·
Premium Member
Joined
·
791 Posts
This must be very frustrating alfaparticle and an expensive mistake. We live and learn I suppose but I know it's painful...

Exactly the same thing happened to me 4 years ago...

http://www.alfabb.com/bb/forums/gt-1963-1977/176216-im-idiot-screw-finds-its-way-into-combustion-camber.html#post972233

the engine never fully recovered from the incident even after I had a reconditioned head fitted - in the end I had the whole engine rebuilt because it chewed through plugs in the damaged cylinder very quickly (I had to go to a very hot plug - NKG B5ES I think it was) and it burnt way too much oil.

Now I am extremely careful, and stuff an old shirt into the plenum whenever working there.

It is interesting that only 2 months ago I had the air intake filter off while working on the engine. Suddenly, the end of my circuit tester broke off and fell somewhere - but where? I couldn't locate it. I looked into the carbs using a mirror and flash light and I could make out the smallest of 'a something' in the carb air intake but wasn’t sure if my eyes were tricking me as it was so hard to see and the ‘something’ hand managed to find its way all the way back to the throttle valve plate – I couldn’t even reach it with a telescopic magnet. There’s a dip in the carby throat right at the end too which was letting it hide from sight. I decided to wait patiently for several weeks until I had time to remove the carbs and was repaid when the little piece of metal fell out in my had when I took the carby off.

What we need is something like thin wire mesh between the air intake plenum and the carbs but I suppose this would impact air flow...

Thanks for posting this alfaparticle, I think it serves as a warning to us all; I always a) cover up the air intake when working on the engine, and b) if in doubt I wait patiently until I have the time to remove the carbs.

Hopefully, others will learn from our mistakes.
 
1 - 20 of 47 Posts
Top