Cracked Cylinder Fin

[jackson51]

Opinions on this Mahle 2.2S cylinder? I suspect the damage is too severe to repair and use on a refresh / rebuild. Still, would like to read other takes, just for the education.

It’s part of a very nice complete set (less ONE!) of 2.2S P&C. I am looking for a single match to replace it… so, if you guys have any source recommendations? That would be great.

Added photo’s in reply below. Still a Rookie

The top two fins are still attached but bent - about a 2, 2.5” crack on top fin adjacent to sealing surface and stud hole.

In the meantime -
SPECS: 2.2S Mahle Nikasil Cylinder: Height Group 5, Bore Set 1 (83.955-83.965 mm).
ID #’s: 84P8 + W2. 84ZD3

[jess p]

Pics would help. Do you still have the broken pieces? Fins are just to dissipate heat. When there were broken fins on my motorcycle cylinders I would just weld them back on. A few missing fins are not going to effect cooling. If you don’t have the missing pieces, make them.

[Turbo_pro]

Originally Posted by jackson51

Opinions on this Mahle 2.2S cylinder? I suspect the damage is too severe to repair and use on a refresh / rebuild. Still, would like to read other takes, just for the education.

It’s part of a very nice complete set (less ONE!) of 2.2S P&C. I am looking for a single match to replace it… so, if you guys have any source recommendations? That would be great.

edit: I guess I can’t load attachments yet. Will add photos later,

Minor fin anomalies really don't matter much.
There are two difference height groups and bore tolerances but if the height group matches you can us a 2.2 or 2.4 cylinder. They are essentially the same 84mm bore.
Height groups 5-6 in a triangle.
Early cylinders were marked 0, 1, 2, 3 for bore size.
Later cylinders were marked a, aa, b, bb

[PeteKz]

Really need pictures or a more detailed description.

[jackson51]

Some pix…

[PeteKz]

Dropped it on the floor, huh? I can't tell from the picture, is that th top of the cylinder, or the bottom? If on the top, I wouldn't worry about it. If on the bottom, I would use it anyway, but move that piston and cylinder so it is on the outside edge of the engine, where it will get less heat from surrounding cylinders. If you try to straighten those, they will just break off. I would not try to weld them back on, unless you plan to rehone the cylinders anyway. Or at least have a machine shop carefully measure the bore to make sure you didn't cause any distortion.

[ahh911]

That sucks.
Have something similar on my 81sc, back from machine shop, studs through other fins, one section broken like yours. Clipped off the broken section, thought about the ratio of total fin to reduced fin, I put mine in as is, but still bitter about how careless the machine shop was in it's packaging after charging 3x more for valves. I digress.

Anyhow, my Dad recommended not to weld the aluminum, so that's the way it went. I'm finless in that same area

Phil

[jackson51]

thanks for replies, top of cylinder is oriented to top of photos in all three shots. Damaged during a move.
Went through a bunch of threads on this topic this afternoon. About 50/50 on repair vs replacement.

Pro: probably no big deal. Con: more problematic when crack is closer to cylinder wall and on top of cylinder. Hot spot can speed up a cylinder going out of round.

Can anyone recommend possible source for a replacement? Ebay sellers only have p&c pairs.

[911 Vintage Par]

Originally Posted by jackson51

thanks for replies, top of cylinder is oriented to top of photos in all three shots. Damaged during a move.
Went through a bunch of threads on this topic this afternoon. About 50/50 on repair vs replacement.

Pro: probably no big deal. Con: more problematic when crack is closer to cylinder wall and on top of cylinder. Hot spot can speed up a cylinder going out of round.

Can anyone recommend possible source for a replacement? Ebay sellers only have p&c pairs.

we should have what you need.

[dannobee]

Well, 3.3L turbo engines didn't even have fins on the top.

Looks like a fine candidate for your #1 cylinder.

[ahh911]

I'm mistaken. It was the head that had a broken fin at the sealing surface as delivered back to me, along with studs through other fins.
Phil

[phunt]

Head hogs is a place that repairs Harley Davidson cylinders and heads. Cast iron and aluminum. I also think it really isn’t that big of a deal. They could be welded they would need to be pre heated and welded slowly

[917_Langheck]

Raced many an IAME (Komet, BM) kart motor with missing fins with gas, methanol, and/or nitro, with no issues (but these were run with liners, so that may be a factor).

Look at a 930 cylinder; no fins on the up-facing surface at all.

[PeteKz]

Thanks for the reminder about the 930 cylinders not having fins on the tops of the cylinders. I always wondered how Porsche figured they could eliminate them. Well, if it's okay on a turbo motor that generates more heat, then it should be okay on a non-turbo motor too. I'm with Dannobee, use it for your #1 cylinder. Just be sure to keep the matching piston with it.

[Henry Schmidt]

No judgement intended.
Although the damaged fin will make zero different in the way it performs and you won't be able to see it, we would replace it because an used replacement is relatively cheap and pride in our finished product matters.
I fired a contractor recently because when I questioned him about some ugly work [no craftsmanship] he said "don't worry, you won't see it". The second time he said that he was finished.

[H-viken]

Originally Posted by Henry Schmidt

No judgement intended.
Although the damaged fin will make zero different in the way it performs and you won't be able to see it, we would replace it because an used replacement is relatively cheap and pride in our finished product matters.
I fired a contractor recently because when I questioned him about some ugly work [no craftsmanship] he said "don't worry, you won't see it". The second time he said that he was finished.

Thanks for this Henry, good to see there are still those who truly care to deliver the best product they can!

[PeteKz]

No judgement taken. . Many of us are DIYers and will accept some things not being perfect when we know what they are and it won't make a functional difference. Of course you run a premium shop that needs to deliver high quality products for your customers, so that's a different expectation. And I would have that expectation if I wanted you to build my engine too!

[jackson51]

Thanks very much for all the reply’s and info. Much appreciated.

Another variable… this 2.2S P&C set might end up in a 2.4T engine.
C/R could be set to 9.25 to 10.50?

Would that change anyone’s opinion or choice?