Author Topic: Rebuilding a 350 - Bottom End  (Read 1814 times)

consol

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Rebuilding a 350 - Bottom End
« on: February 06, 2013, 09:00:08 AM »
Okay, a new to me FL350 that had a burnt out piston (nice ragged hole dead in the top)

I've pulled the head and the jug for inspection, so far they both look pretty darn good, we'll see after I clean them up and dial inspect the bore

Quick questions:

I plan on cracking the case, inspecting and rebuilding it (it's 25 years old and there was alot of carbon deposit chunks from the top end)

I've got the shop manual, and do search for as much info as possible beforehand, but I thought I would ask those that have done this a lot

Any recommendations on must replace parts, experience learned rebuild tips on the case, etc.

I know there is info out there, I use the search functions, etc. but it never hurts to ask

I'll be asking questions like this for certain items as we go, but will keep them in their own topics

Thanks a bunch in advance,

Bill

« Last Edit: February 06, 2013, 09:05:43 AM by consol »

LiveWire

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Re: Rebuilding a 350 - Bottom End
« Reply #1 on: February 06, 2013, 10:15:57 AM »
A hole in. The piston indicates detonation. I would suggest determining why that was so you know it won't happen again. A good possibility is leaking crank seals due to age. A big leak will make it lean. A smaller leak, a little lean, which makes it run hotter encouraging detonation. Bad fuel causes detonation.

Read: http://www.aftershockmotorsports.com/technical-articles/FL350-Rebuild-Tips

consol

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Re: Rebuilding a 350 - Bottom End
« Reply #2 on: February 06, 2013, 11:39:25 AM »
Somewhere along the line, a previous owner had a 3" pipe snorkel (pieces from a car intake kit most likely, with a few bends) straight from the carb elbow up to an open element cone type filter, so unless they jetted it correctly, it could have been running lean up top just from that

I plan on checking the crankcase pressure stability via a leak down, but I pulled the jug off and one of the cylinder studs needed to be cut out, so I'll need to redo that

Anyhow step by steps out there on this for this particular model

I assume I just close up every vent, apply some light compressed air through the spark plug hole, and see if it will hold 25 psi or so for a few hours

Am I close on that process

LiveWire

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Re: Rebuilding a 350 - Bottom End
« Reply #3 on: February 06, 2013, 12:19:26 PM »
25psi will blow the seals out. I use 6. The only extra hole is the pulse line for the fuel pump. If in the machine, I test with the pump on since it should not leak either.