crankshaft help

[jlw35]

Culprit was a small nut that evidently worked its way thru the carb (don't ask how it got there) then the intake and over to the #2 cylinder on the exhaust side. It kept the #2 exhaust valve from closing all the way.

I'll try to post pictures in a bit of the cylinder head and the block. It all looks functional still, but I do not have a practiced eye, this is as deep as I've ever delved into an engine.

Jeff

[jlw35]

[img]http://i657.photobucket.com/albums/uu29 ... G_1282.jpg
http://i657.photobucket.com/albums/uu29 ... G_1281.jpg[/img]

[jlw35]

Mission creep. Looks like the two exhaust valves (#1 & #2) are pitted.
How difficult, or what new tools must I buy to replace all the valves and associated other parts?

[RoyBatty]

Hold on before you go on with new tools and such.
When you turn the cams, do the valves freely and fully open and close?
Are there any holes in any of the pistons?
If all looks to be working properly, and the valves aren't too badly damaged in the seating area, you might be able to just reinstall the head with a new gasket.
I helped a friend with his 75 in this manner earlier this year after a piece of metal had fallen into a spark plug hole. Once we pulled the head and removed the FOD, we put it all together with a new head gasket, after a good inspection, and it runs better than ever.

[76was124]

Mission creep. Looks like the two exhaust valves (#1 & #2) are pitted.
How difficult, or what new tools must I buy to replace all the valves and associated other parts?

Are they pitted or just have carbon build up?

[jlw35]

RoyBatty,
No cracks to be found and yes the valves do move freely, fully open and close. I was premature in my assessment, so I think you are right in that I'll just clean the mating surfaces thoroughly and reinstall the head.

76was124,
Once again, I went to the worst case scenario. They are not pitted after all, just some heavy carbon buildup. I just finished cleaning them and they are smooth and shiny.

Thanks to both of you for the insight, greatly appreciated!
I'll post my progress later, still getting the order together for the appropriate gaskets.
Also, going to rebuild the carburetor for peace of mind to make sure nothing else might be rattling around in there.

Still not sure how the nut got in there, I always keep a plastic baggy over the openings when the air cleaner is off.

Jeff

[fiatfactory]

.

[jlw35]

Thanks Steve, will do.
Jeff

[djape1977]

damage pictured is nothing to worry about, 99% chance that everything will be working fine once you put it back together.

if i were you, i'd do a leak down test on the cylinders, check exaust valve guides for radial play and try to determine where all that oil came from. carbon buildup on exaust valves is a sure sign that oil was burned in combustion chambers

[jlw35]

djape1977,

what would a likely source of the oil be? I would just as soon have it correct before I put it back together.
Also, any guide on the leak down test? I'll do a search on the forum, but any guidance would be appreciated.
As I said, this is as far into an engine that I've been, I'm ok as a shade tree mechanic but no real training.

Thanks Jeff

[chrisfiat]

take that head to your local trusted machine shop and have it gone through, guide wear check, check valve seats for pitting( much more important than shiny valve faces ) you will save your self a lot of grief, and find out where that nut came from !!!

[RoyBatty]

That nut looks to be about the right size for one that secures to top of the air filter assy to the carb or secures the air filter assy to the top of the engine.
It could have fallen thru a spark plug hole or came off a stud inside the air cleaner and entered the combustion chamber thru the induction system.
Yes, the 100% correct thing to do in this case could be a full going thru of the head.
However, it depends on your time and money constraints which direction you go.
If this car is something you are just getting started with, and you need to drive it to evaluate what other systems need your attention, I would say just do a head gasket, water pump, idler bearing,timing belt and hoses.
If the pistons are OK and the cylinder bores aren't all scored up. The valves are working as you describe, then you most likely are OK for reassembly from where you have things now.
The liquid leak check of the valves may be a bit too critical for evaluating your situation as things are now.
As long as the valves are not showing localized hot spots and aren't missing any material in the seat area, you should be good to get the engine running for further evaluation of the car.
If you already have a good idea of the condition of the rest of the car, and know that it isn't a money pit, then go ahead with the full head overhaul.
Just the way I approach things.

[jlw35]

Just as a rough estimate, what does anyone think that taking the head to the machine shop would cost?
I know it depends on what damage, if any, they find, but assuming that all seems to be working normally.

Anyone in the St. Louis, MO area with a recommended shop?

Also, I have the cam covers off, the intake and exhaust manifold off as well. Is this the condition that a machine shop would expect to receive the head?

Thanks
Jeff

[djape1977]

leak down test

rotate the crank so that pistons are in half way down position aproximately
pour perol in cylinders to cover the pistons
see how long it takes for petrol dissapear.

if it's gone in minutes, piston rings and/or cylinders are shot.
if it stays there for at least 15minutes, bottom of engine is ok

do the same to test if valves seal properly. this will determine if any of the valve is bent or burned.

[jlw35]

Thanks Djape1977, will do that today.

Jeff