Go Back  Offshoreonly.com > Technical > General Q & A
9.8 deck 598? >

9.8 deck 598?

Notices

9.8 deck 598?

Thread Tools
 
Old 03-17-2016 | 04:35 AM
  #31  
Full Force's Avatar
Gold Member
20 Year Member
Gold Member
 
Joined: Oct 2005
Posts: 11,692
Likes: 217
From: Olmsted Falls,Ohio Marblehead,Oh
Default

Warranty don't do chit when your missing seasons... that's why I went 540 not 565 in new engines using the 4.25 crank I might have been ok but was worried about rod angles.
Full Force is offline  
Reply
Old 03-17-2016 | 04:54 AM
  #32  
Registered
 
Joined: Aug 2011
Posts: 2,733
Likes: 8
From: bel air, md
Default

The difference in angle between a 4.25 and 4.375 is about 1.7 degrees

Last edited by Black Baja; 03-17-2016 at 04:58 AM.
Black Baja is offline  
Reply
Old 03-17-2016 | 05:02 AM
  #33  
Registered
 
Joined: Aug 2011
Posts: 2,733
Likes: 8
From: bel air, md
Default

Compression height goes from 1.29 to 1.2275 which both give you plenty of piston.
Black Baja is offline  
Reply
Old 03-17-2016 | 05:08 AM
  #34  
Registered
 
Joined: Jan 2001
Posts: 1,098
Likes: 4
From: cedar springs mi
Default

Getrdunn im building a 565 with a 4.375 stroke right now that I'm going to be selling tall deck
dennis r is offline  
Reply
Old 03-17-2016 | 08:45 AM
  #35  
Registered
 
Joined: Mar 2008
Posts: 1,181
Likes: 2
From: Vancouver BC
Default

I've done lots of 4.375 short decks, some are over 10 years old and have been in for a few freshen ups. I don't see any more wear that could be attributed to the little extra stroke then I do on a 4.25 stroke. On endurance stuff that's going to run a decent amount of boost 12+, I usually go with the 4.250. I don't know if it really matters, the 4.375 would probably be fine but I like shorter stroke and bigger bore given the choice. The other consideration is piston availability is usually off the shelf for the 2590stroke and you need to do a pin height change on the 375
HaxbySpeed is offline  
Reply
Old 03-17-2016 | 09:17 AM
  #36  
Panther's Avatar
Frank's Marine Service
20 Year Member
Gold Member
 
Joined: Sep 2002
Posts: 11,959
Likes: 142
From: Elkton, MD
Default

Originally Posted by SB
Makes total sense in circle track in the regard of lower weight and lower CG. Racing does not always make $$$$ sense though. LOL.
He said the skirt was very short and the pin was pretty far up. He also used a diamond piston with coated skirts and gas ports.
Panther is offline  
Reply
Old 03-17-2016 | 11:34 AM
  #37  
Registered
 
Joined: Aug 2012
Posts: 620
Likes: 7
From: Cincinnati ohio
Default

My new boat has short deck 572s in it. Been in there for quite a few seasons and one freshen up no issues more than any other
dsmawd350 is offline  
Reply
Old 03-17-2016 | 02:34 PM
  #38  
Thread Starter
Registered
15 Year Member
 
Joined: Feb 2009
Posts: 8,356
Likes: 1,515
From: NW Michigan
Default

Originally Posted by dennis r
Getrdunn im building a 565 with a 4.375 stroke right now that I'm going to be selling tall deck
I think we're gonna be doing similar builds. You going NA or SC? I sent you a pm last week regarding cam. I need to stick with 9.8 for clearances etc.
getrdunn is offline  
Reply
Old 03-17-2016 | 06:41 PM
  #39  
Thread Starter
Registered
15 Year Member
 
Joined: Feb 2009
Posts: 8,356
Likes: 1,515
From: NW Michigan
Default

Any suggestions on Pistons with the 9.8 deck, 4.375 crank and 6.385 rods? Wondering what shelf Pistons to be looking for and what pin heidth also - 1.21, 1.22? Would like to avoid custom Pistons however If need be not a huge deal.

Last edited by getrdunn; 03-17-2016 at 09:44 PM.
getrdunn is offline  
Reply
Old 03-17-2016 | 09:11 PM
  #40  
Panther's Avatar
Frank's Marine Service
20 Year Member
Gold Member
 
Joined: Sep 2002
Posts: 11,959
Likes: 142
From: Elkton, MD
Default

Good question on the pistons.

For instance, my 572 tall-decks have a 6.70 rod. Oher than some flat top pistons options, dished pistons were like non-existent off the shelf and I had to go custom.

In retrospect if I built it from the ground up I would have gone 6.535 and I don't think the longer rod made all that much of a difference in the rod angle/wear and dwell benefit.
Panther is offline  
Reply


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.