Cylinder head pitting

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rjkoop
Posts: 976
Joined: Thu Nov 08, 2012 6:45 am
Your car is a: 1981 Fiat Spider
Location: Ottawa, Ontario, Canada

Cylinder head pitting

Post by rjkoop »

I noticed on the cylinder head that one of the cylinders (#2 I think) that there is pitting in the valve area.

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The other cylinders look fine.

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And idea what could have caused this? A mechanic mentioned that something may have been inside the cylinder at 1 point, bounced around and then got ejected. How do I know if this have to be resurfaced? Or if it will still run fine?

It seemed to run fine before I took the head off.
narfire
Posts: 3959
Joined: Sat Dec 27, 2008 2:14 am
Your car is a: 1980 124 spider
Location: Naramata B.C.

Re: Cylinder head pitting

Post by narfire »

rjkoop wrote:A mechanic mentioned that something may have been inside the cylinder at 1 point, bounced around and then got ejected. How do I know if this have to be resurfaced? Or if it will still run fine?
I'd be thinking the same thing. Perhaps something around the spark plug recess dropped in when plug was out. What does the piston look like?

Are you planning on doing some head work? Valve guides& seals? valve grind? Look into having the head shaved a tad. I was told once upon a time that a stock head could have up to 15-20 thou. shaved off but I don't think that much would have to come off in your case.
Chris
80 FI spider
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
User avatar
rjkoop
Posts: 976
Joined: Thu Nov 08, 2012 6:45 am
Your car is a: 1981 Fiat Spider
Location: Ottawa, Ontario, Canada

Re: Cylinder head pitting

Post by rjkoop »

narfire wrote:
rjkoop wrote:A mechanic mentioned that something may have been inside the cylinder at 1 point, bounced around and then got ejected. How do I know if this have to be resurfaced? Or if it will still run fine?
I'd be thinking the same thing. Perhaps something around the spark plug recess dropped in when plug was out. What does the piston look like?

Are you planning on doing some head work? Valve guides& seals? valve grind? Look into having the head shaved a tad. I was told once upon a time that a stock head could have up to 15-20 thou. shaved off but I don't think that much would have to come off in your case.
Chris
I'm going to check the valve seals to ensure they aren't cracked/chipped and then I think I'll use as is. I checked the valve shims already and they are perfectly in spec. Eventually I'll resurface or get a new head I guess. For now I'd like to see if I can get this car running and use it for a few months before it has to go away for the winter. :(
So Cal Mark

Re: Cylinder head pitting

Post by So Cal Mark »

make sure there aren't any sharp edges that could cause pre-ignition
Pushpull76
Posts: 3
Joined: Sat Sep 06, 2008 6:38 am
Your car is a: 124 spider 1971 1608cc.

Re: Cylinder head pitting

Post by Pushpull76 »

Resurface. If you cant, the damaged part is easily rebuildable (alloy tig welding and resurface).
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rjkoop
Posts: 976
Joined: Thu Nov 08, 2012 6:45 am
Your car is a: 1981 Fiat Spider
Location: Ottawa, Ontario, Canada

Re: Cylinder head pitting

Post by rjkoop »

So Cal Mark wrote:make sure there aren't any sharp edges that could cause pre-ignition
And if I see sharp edges what can I do to clean them up? At this point I don't want a full head rebuild so I'm looking for something I can do at home (ie. sanding, dremel, grinder, brush on a drill, etc...).
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