Please help evaluate cylinders
 

Had a #5 rod failure 3 months ago, probably due to oil starvation or failed rod bolt, and finally got all 6 cylinders out today. The pistons cannot be removed yet because the crank is stuck by debris of the broken big end of the rod. Please help me evaluate the cylinders, thanks a lot!!

1. the #5 cylinder, a small part of the cylinder base is missing, with a reverse L-shaped crack extending upwards. Guess it cannot be used any longer.:(
http://forums.pelicanparts.com/uploa...1245594499.jpg

2. the #4 and #1 cylinders with carbon deposit along the upper rim, these two cylinders have the best looking spark plugs, almost like new, so they must have been running pretty well but why the carbon deposits not seen in other cylinders not running as well?
http://forums.pelicanparts.com/uploa...1245594784.jpg

http://forums.pelicanparts.com/uploa...1245594878.jpg

3. the #6 cylinder with a fouled plug showed some oil pooling besides the piston when the head was removed.
http://forums.pelicanparts.com/uploa...1245595219.jpg


Cyl #2 and #3 looked like cyl #6, hence not shown here. Please note that all the vertical scratch lines shown on the cylinder walls felt very smooth to the touch.

If the crank isnt bent, it will be scored big time. Most of the damage is done before the rod breaks loose.
I d get another set of cylinders or P/Cs. If its just cylinders, you need deck height and size, it stamped on the base of the cylinder.

Bruce

Bruce is right, crank is probably toast. new piston and cylinders probably good idea too. The difference in carbon deposit could be from adjustment on the carbs. The scratch lines are not abnormal. The busted one is definitely dead, but wear and possible cracks may be in the others too. It is not unheard of to find hairline cracks on cylinders with magnaflux inspection after a rod failure as the sudden change in the engine balance and rotation slam the pistons around, especially on lighter weight engines like Porsche where there is less "hard" material around the cylinder. If you decide to reuse your "good" cylinders double-check the measurements and get them inspected for cracks first.

Thank you both! Did learn more than had expected. Have to consider a good set of used p/c now.

My vote is measure the broken cyl for "round' as a hit like that may have distorted the whole thing
If round..looks like you could just "eyebrow it " like a lot of us do any way.
Send it off to your favorite re chrome -nich place, have therm done, and call it good.

The "eyebrow" mod you talk about is on the sides, not the top and bottom. Those look like Alusil to me so why not just get a nice used set of Nikasil.

-Andy

The photos don't show the flare of Nikasil because I want to show the scratches clearly.
They are definitely Nikasil.