SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: eliminator18 on June 11, 2015, 10:46:13 AM

Title: Piston to wall?
Post by: eliminator18 on June 11, 2015, 10:46:13 AM

Taking the block to the machine shop today, can someone please tell me how much over I need to have the cylinder bored? .001 or .004


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Title: Re: Piston to wall?
Post by: fullfam1 on June 11, 2015, 11:33:22 AM

Marine range is 0.0035-0.005 I ran 0.005 on mine due to adding nitrous


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Title: Re: Piston to wall?
Post by: eliminator18 on June 11, 2015, 11:42:04 AM

This is going to be an all motor set up


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Title: Re: Piston to wall?
Post by: fullfam1 on June 11, 2015, 12:02:53 PM

What pistons?


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Title: Re: Piston to wall?
Post by: eliminator18 on June 11, 2015, 12:19:23 PM

Wiseco forged Pistons


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Title: Piston to wall?
Post by: zoomzoom on June 11, 2015, 12:36:34 PM

Take the Pistons to the shop the should Mic it and do it all


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Title: Re: Piston to wall?
Post by: fullfam1 on June 11, 2015, 01:56:01 PM

0.0040-0.0045


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Title: Re: Piston to wall?
Post by: Flusher on June 11, 2015, 03:14:18 PM

It will vary depending on bore size, alloy, and skirt design.  I would call them and get their recommendation.

800-321-1364

http://www.wiseco.com/PDFs/Manuals/Automotive.pdf

Title: Re: Piston to wall?
Post by: crewchief22 on June 11, 2015, 07:00:57 PM

Be sure to tell everyone that will listen that these pistons are being used in a marine engine with an open cooling system.  The machine shop should know what to do, but getting a spec from Wiseco would be a good start.

Title: Re: Piston to wall?
Post by: TIMINATOR on June 14, 2015, 04:22:43 PM

Make SURE that the machine shop knows the differences between a boat and a car motor, especially a jet! In the Phx,AZ area, only a few do. We get to repair the carnage from the car shops all of the time. Weisco has instructions with the pistons that have recommended clearances. When in doubt, use the larger recommendation. A little extra piston/ wall won't affect anything but longetevity, and I can't even say when we had a jetboat motor in here that the bore was worn out, usually rust rings from the O.T headers, or from leaving the carb uncovered/rain. If the shop argues with you on the clearances (car guys think that the clearances need to be TIGHTER, because boats "have the whole lake to cool them") RUN!!!!!   The block and heads do run cooler, but the pistons and valves run hotter because the boat engine is making more HP at the same speed as a car, and therefore they are larger and need that extra clearance.  EVERYONE ELSE: DON'T USE HYPEREUCTETIC PISTONS IN JET BOATS!!!!!!   There's a post explaining it.    TIMINATOR