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351w crankshaft help

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428CobraJet View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: December-03-2018 at 6:29pm
I've got a ton of money in this boat. Many times what I anticipated originally (and probably 10x what I could liquidate it for!). I'm lucky, as a retired teacher, that I could do it. Its beautiful.   The engines represent maybe 20k. The machine shop only a small portion of that. Its probably the best Nova24Vdrive out there.

I'm not looking for blame. I'm looking for the cause so that we can all rectify it.

The machine shop owner couldn't find an obvious cause. I reached out to you guys because so many of your boats run the blue oval...in small block form. More than anyone else except, perhaps, Shamrocks. I also reached out to the CC Commander and Donzi Restoration fb sites because there are some ccw Fords in there.

These guys are not Walmart.   These are artisans. The machine shop came highly recommended by a car/motorcycle shop i deal with (who is extremely demanding). The Machine shop received boxes of parts from me (as opposed to tired but running motors). I knew nothing about them. We ended up sourcing different blocks, stroker kits, and 1 head. Marinization stuff/breakin were done 70 miles away by me and the restoration guys/friends. And this is custom work.

He's a gentleman, well regarded in the machine shop end within the Houston area, and a pleasure to deal with. I am not holding his feet to the fire. I'm thankful he's easy to work with. I will deal with him again.

It will cost me some money, but I'm confident I'll be treated fair. It's just teething issues. And, as we all know, owning a boat is a source of joy no matter the minor ups and downs.

I sincerely appreciate all your comments and suggestions. You told me things I couldn't find elsewhere. And I'm not even a Correct Craft owner (I own a 1967 390 powered Century Arabian in addition to the BossaNova).

:-) Craig

ps...1st splash in April. Me on the right. David (brother of Restoration shop) on port side.
https://youtu.be/w5fucqpyOys
going under bridge in August testing oil pressure validity
https://youtu.be/Smn_j-Pn4sQ
You are what you drive.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Duane in Indy Quote  Post ReplyReply Direct Link To This Post Posted: December-03-2018 at 8:40pm
edit: I posted this before seeing the above post, yet I still stand by my post. Duane

Originally posted by MrMcD MrMcD wrote:

The engine turned hard right from the machine shop


There is NO way that .001 out on the crank scrapped this build. I doubt that the builder could duplicate his .001 error in the crank checking it the way that he did. Guys .001 is nearly nothing in a span of 24 inches. I still feel that there are two contributing factors that must be resolved before another build is performed.

1.   Verify that the block is straight. I highly suspect there in lies the problem (needs align bored) At the very least it should have be deemed a good block to build on.

2.    Have someone check this guys work or take it elsewhere. He obviously dropped the ball when he sent an engine out the door that was destined to fail.

Tight rotating assemblies don't get better.   They get hot and seize. This guy holds all the credentials to be a "back yard hack" (in the words of our Grand Wizard)

Warranty or not I would not be comfortable with another job from that assembler. NO good builder will ship an engine that is "tight" on rotating.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TRBenj Quote  Post ReplyReply Direct Link To This Post Posted: December-03-2018 at 8:47pm
Sure seems obvious that there was insufficient clearance on the mains. Either the machining/bearing matching wasn’t done right (or verified, or both), or something is either bent or not straight. Tight when assembled = bad. If it were an oiling issue, I’d expect the rods to suffer first- not the mains.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: December-03-2018 at 11:10pm
Since the Crankshaft is aftermarket you might consider having it ground .010 undersize.
Any oddities would show up on the crank grinder.   A crank polish will probably cost $40 while a grind and polish might be $100-$120. Money well spent to have peace of mind.
This crank ate a set of main bearings o the surface is compromised right now and will at least need a polish so a grind/polish is not a big step up.
AER in Dallas is well known and builds thousands of engines for GM, Ford, Chrysler, Nissan and Mazda.   They know how to grind a crank with proper finish.
For many years most of the GM rebuilds sold at the GM dealerships were built by AER.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: December-03-2018 at 11:19pm
The crank is at a place in Houston...Pete's Crank Grinding and Repair.   Waiting for a decision from me.

But, yes, plan on turning and polishing directionally, demagnetizing, straightening...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: December-05-2018 at 1:15pm
new development...just heard results of magnaflux of crank. 1-1.5 inch crack. I'm guessing caused by dropped valve of 1st engine...but dunno

sounds like the cause of whole mess.

Best news I've had in a few weeks.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: December-05-2018 at 4:34pm
You can rap on a crankshaft with a small hammer or piece of steel. If it rings like a bell you have no cracks. If it makes a thud sound it is cracked. Quick and easy test.
Obviously you don't hit it on any of the machined surfaces and you don't hit it hard, just a tap to make it ring.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: July-08-2019 at 10:56pm
ok...we swapped in a new crank. all is good. testeded boat up to 50mph/4000 (needs more prop I believe), and the port engine stuck a valve!

back to machine shop, redid valves on that engine (too tight in guides) and hope to never go back there!!!!

now sorting cooling system. waterpump vibrates and off comes hose to engine. questioning mounting as the factory setup is a real 'Debbie Downer' because of the vdrives and deep v
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: July-08-2019 at 11:42pm
Thanks for your update and very sorry for the bad news.

I witnessed the stuck valve issue after rebuilds many times over the years.
The story is normally the same.   " we took the engine to the machine shop got it fully rebuilt and then did not get a chance to start it for nearly a year"
The engine is built correctly but the GASOLINE in your tank ages quickly.
Old gasoline can turn to a varnish like product. It causes the valves to stick.
If you put your nose near the carburetor you can smell a strong smell when this happens.   
In one case I went into a friends Machine shop, he was having a conversation with an Automotive Shop owner, 50 year old guy that had run a great shop for years.
Without giving me any hint at all the Machine Shop owner asked me to walk with him and this Shop owner to the rear of his shop where the engine tear downs take place.
When we got within 10 feet he looked at me and asked what happened to the engine on the bench.   The smell is so distinct that I quickly told him "someone used old gas".
Now the Auto Shop owner looks at me and says he has been arguing with the Machine shop owner about this for 30 minutes already. I took him to his block and showed him the varnished tops of his pistons and the sticky varnish building up on his valves.
He apologized to the Machine Shop owner and said he could not believe he never saw that before.   Once you smell it you don't forget it.   Not a bad smell but a strong smell and the pistons come out almost Pretty. Looks like you varnished them on the piston head but when you touch it you find it sticky.
The good news is normally a cleaning and set of gaskets gets it running again.
Clean out the Fuel Tank and dump the old fuel.
There are other things that can do this but based on the age of these posts I think you might be into old fuel. Sorry, I bet I witnessed similar old fuel issues 20 times.
Stabil is sold to avoid this but if you read the fine print stabil only claims to work for 6 mos.   Sea Foam advertises the same thing but Sea Foam claims to be able to keep gas good for 1 year.   Any untreated fuel over 6 mos old is suspect
Please let us know what you find.
Mark
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 428CobraJet Quote  Post ReplyReply Direct Link To This Post Posted: July-09-2019 at 12:22am
new tank. pumps lines, carbs. all new. he said...he set both engines too tight because he didn't figure the 140 degree thermostat...

not buying. but fingers are crossed
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Post Options Post Options   Thanks (1) Thanks(1)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: July-09-2019 at 12:39am
There is not doubt coolant temp changes clearances. Glad it is not old gas this puts repairs back on the shop.
Ask what clearance he gave you on the valves both exhaust and intake and ask what your piston clearance is to the cylinder wall.
Also need to know what type piston is in the engine, Forged or cast, aluminum or hypereutectic.   It all makes a difference in a marine engine.
Good Luck, I hope you get it running strong soon.
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