Crankshaft Dowel Pin 'C' Engine

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Mark Sabbann
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Re: Crankshaft Dowel Pin 'C' Engine

#76 Post by Mark Sabbann »

The engine is back together and home in my shop but will wait for Spring for the install and startup. Keeping it in the shop with moderate temperatures rather than in my cold Minnesota garage, fogging the cylinders and giving the crank a few rotations every so often. The crankshaft report came back good without issues and the broken dowel pin was replaced. New JE and Shasta P/Cs, Neutek camshaft, main bearings, reconditioned rods and lifters, new oil pressure pistons and springs, gaskets all around and a couple of new rocker arms. Bearings remained stock size inside/outside. Final compression ratio was calculated to be about 8.7. Close to the original 'C' engine CR of 8.5 but not at the max of 9.25 allowable by the pistons. I wasn't out to build a hot rod so I am OK there. And yes, the original goal was accomplished, a new flywheel oil seal. Instead of the former black goo/RTV, an anaerobic Wurth flange sealant was used on the case.

I would like to thank Brad Ripley for being the first to call for a crankshaft inspection. I was reluctant at first but am glad I had the engine opened up and parts examined. Getting to see the tear-down, participating in the rebuild and learning some of the nuances of the process was invaluable. Now I almost feel like I could do it myself, but don't hold your breath!

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Re: Crankshaft Dowel Pin 'C' Engine

#77 Post by Don Gale »

Very nicely done. Good choice of components. Glad the std. crank survived. Let's hope it's a short winter.
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Ken Tuvman
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Re: Crankshaft Dowel Pin 'C' Engine

#78 Post by Ken Tuvman »

Looks good Mark - you & I will may have the freshest 356 motors in Minnesota!
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Mark Sabbann
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Re: Crankshaft Dowel Pin 'C' Engine

#79 Post by Mark Sabbann »

The moment of truth has come. I reinstalled the engine as nice as it may look with new decals and all. Then the rebuilder came and hauled the car to do a new engine start-up at their shop. The initial break-in run went well (I had hoped to observe but opted out given the current virus situation) until the new seal failed. As you can see from my previous photo in this thread that the Viton seal does sit somewhat proud of the crankcase. It was purchased from one of our respected vendors. The shop will now pull the engine and flywheel and try to figure out what went wrong. Their initial response is that maybe the flywheel should be machined but if the seal wasn't proud like I would expect it to be from the factory, then the flywheel shouldn't have to be machined for clearance.
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Re: Crankshaft Dowel Pin 'C' Engine

#80 Post by WilliamVaughan »

Is this another of those truck wheel bearing seals with the dirt excluder lip that should have been removed with a razor blade before installation in the 356 engine. You do not machine a flywheel to make life easier for an inappropriate seal choice.

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Re: Crankshaft Dowel Pin 'C' Engine

#81 Post by Harlan Halsey »

+1
If that's your machine shop suggestion, then best find a shop which knows 356s. The standard seal does sit a little proud of the crankcase. An old trick is to lightly scuff the seal running surface with 600 grit sand paper. That seems to seat the new seal. Removing the second lip has been discussed often on this forum.

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Mark Sabbann
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Re: Crankshaft Dowel Pin 'C' Engine

#82 Post by Mark Sabbann »

I did trim the second lip from the seal prior to installation - a Dremel with a rotary abrasive drum worked better than a razor blade. It is a Viton seal sold by Stoddard for a 356.
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Re: Crankshaft Dowel Pin 'C' Engine

#83 Post by James Learmonth »

Mark
It's been a long time since I was in that part of the engine, but...the photo of the engine with the flywheel removed made me look to
the Workshop Manual. I believe that you have the flywheel oil seal installed backward/upside down. That is going to leak/gush oil.
Check the illustration in the Workshop Manual page E67
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Re: Crankshaft Dowel Pin 'C' Engine

#84 Post by Mark Sabbann »

James Learmonth wrote: Thu May 07, 2020 10:24 am Mark
It's been a long time since I was in that part of the engine, but...the photo of the engine with the flywheel removed made me look to
the Workshop Manual. I believe that you have the flywheel oil seal installed backward/upside down. That is going to leak/gush oil.
Check the illustration in the Workshop Manual page E67
Jim Learmonth
65C Coupe
Houston, TX
Jim, when I look at the diagram on page E67, I see the open side of the seal facing away from the flywheel which is how the seal was installed. When I look at the Stoddard photos for the Viton seal, https://www.stoddard.com/nla11302950-99 ... 0-nla.html they indicate to trim the "outer" lip which faces the flywheel, as installed. My trimming of the outer lip was not entirely even as seen by the different reflections along that lip edge but overall, it was trimmed back to be behind/below the solid face of the seal assembly and should have not touched the flywheel.
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Re: Crankshaft Dowel Pin 'C' Engine

#85 Post by Martin Benade »

I often am confused by pictures and see things as inverted. 3 D views are tricky.
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Re: Crankshaft Dowel Pin 'C' Engine

#86 Post by Don Gale »

Could it be an engagement issue where the tip of the seal lip is barely touching the snout of the flywheel?
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Re: Crankshaft Dowel Pin 'C' Engine

#87 Post by Mark Sabbann »

Don Gale wrote: Thu May 07, 2020 12:35 pm Could it be an engagement issue where the tip of the seal lip is barely touching the snout of the flywheel?

flywheel_seal.jpg
Don, we'll have to see what there is to see when the flywheel is pulled. I think your drawing confirms that the open side of the seal faces away from the flywheel.
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Re: Crankshaft Dowel Pin 'C' Engine

#88 Post by Don Gale »

[/quote]
. . . I think your drawing confirms that the open side of the seal faces away from the flywheel.
[/quote]

Don't take that as gospel, I merely depicted it the way I've always seen them.

edit: but yes, the open side should face inward. That way, if there is any oil pressure build-up behind the seal, it will force the lip to seal tighter against the flywheel. If inverted, any pressure would tend to open the lip.
1958 356A 1600 Super Sunroof Coupe
former 1966 Euro 912 Sunroof
former 1978 Intermeccanica Speedster w/'68 912
Member Since 1983, #4039

"Nostalgia isn't what it used to be"

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Re: Crankshaft Dowel Pin 'C' Engine

#89 Post by Mark Sabbann »

Don Gale wrote: Thu May 07, 2020 12:43 pm Don't take that as gospel, I merely depicted it the way I've always seen them.

edit: but yes, the open side should face inward. That way, if there is any oil pressure build-up behind the seal, it will force the lip to seal tighter against the flywheel. If inverted, any pressure would tend to open the lip.
Thanks for the clarification.
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Re: Crankshaft Dowel Pin 'C' Engine

#90 Post by WilliamVaughan »

sorry for excited response. Just didn't want you machining the flywheel. The Stoddard seal installer is very nice.

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