PT Boat Forum


Moderated by: Dick, Jeff D

The PT Boat Forum ª PT Boats of WWII ª  PT Boats - General

Page: 1 of 1

Back to Topic Index Page 53 | Replies: 7

 Author  Topic: 305 emgine #2
  RANDY SMITH

MASTER
  

    
Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of RANDY SMITH   Send Email To RANDY SMITH Posted on: May 31, 2015 - 2:31pm
Saturday we ran #2 under load for 45 minutes from 600 rpm up to 2700 rpm. The exhaust got a little hot.

 photo 380.jpg




Total Posts: 182 | Joined: Jul 16, 2012 - 7:16pm | IP Logged

  Jerry Gilmartin

TOP BOSS
  

    
Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jerry Gilmartin   Send Email To Jerry Gilmartin Posted on: May 31, 2015 - 7:10pm
Hey Randy,
Sounds like you figured out the problems with the dyno from last time. In looking at those cherry red exhaust pipes, it reminded me of when we suffered the same exact problems with those exhaust pipes getting so hot. To fix the problem, we had a total of 6 of those water cooled exhaust pipes custom made -2 to fit each engine. I have read several examples (from the wartime diary of RON13) of Higgins Boats "blowing out an exhaust stack" and having to replace them because a steam bubble formed inside the cooling passages and prevented water flow, which in turn melted the internal copper exhaust pipe. I can see how this might happen when the melting point of copper is not too far from the temperature of those flames coming out of the exhaust manifold during operation. I also found the startup procedure makes sure to check the cooling water inside the stacks is primed before operation and also drained after shutting them down to prevent the formation of steam bubbles inside the pipes. I wonder just how hot that pipe got? Pretty cool picture I must admit.
Good luck on the rest of your tests!

Jerry Gilmartin
PT658 Crewman
Portland OR

Total Posts: 1388 | Joined: Oct 8, 2006 - 11:16pm | IP Logged

RANDY SMITH

MASTER
  

    
Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of RANDY SMITH   Send Email To RANDY SMITH Posted on: May 31, 2015 - 7:39pm
Gerry we used a laser thermometer it was around 1100 degrees at the elbow. We still have to find a bigger dyno with this we can only pull 1000 hp. So we are running them up and checking for leaks and braking them in. I have a lead on one around 80 miles away. We are trying to make a deal so we can get the hp and torque curve to make the wheels.


Total Posts: 182 | Joined: Jul 16, 2012 - 7:16pm | IP Logged

  Jerry Gilmartin

TOP BOSS
  

    
Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jerry Gilmartin   Send Email To Jerry Gilmartin Posted on: Jun 1, 2015 - 10:33am
OK, so I just looked it up and copper melts at 1981 F so I guess it was the steam bubble formation that caused the historic failures or the rubber outer hose melting and not the copper.
Anyway I am glad you guys have a lead on getting that other dyno. Thanks for the updates and photos! Jerry

Jerry Gilmartin
PT658 Crewman
Portland OR

Total Posts: 1388 | Joined: Oct 8, 2006 - 11:16pm | IP Logged

RANDY SMITH

MASTER
  

    
Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of RANDY SMITH   Send Email To RANDY SMITH Posted on: Jun 8, 2015 - 3:13pm
TAPE OF THE ENGINE RUNUP




Total Posts: 182 | Joined: Jul 16, 2012 - 7:16pm | IP Logged

  rickas

Advanced Member
  

    
Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of rickas   Send Email To rickas Posted on: Jun 9, 2015 - 6:59pm
What kind of numbers are you looking/hoping for?

Rick Schaefer
Splinter PT 63

TM2c John E Mirus
Solomon Islands
Dec 43 - Jan 45

Total Posts: 82 | Joined: Dec 26, 2013 - 5:16pm | IP Logged

RANDY SMITH

MASTER
  

    
Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of RANDY SMITH   Send Email To RANDY SMITH Posted on: Jun 10, 2015 - 8:27am
Rick we are hoping to get 1500 to 1600 hp. The problem is the dyno will only hold 1000. with a right hand rotation engine.


Total Posts: 182 | Joined: Jul 16, 2012 - 7:16pm | IP Logged

RANDY SMITH

MASTER
  

    
Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of RANDY SMITH   Send Email To RANDY SMITH Posted on: Jun 21, 2015 - 9:56am
Engine 2 hit 1325+ 2850 ft lb of torque. but still only building 14.6 inm on the boost, it should be 46.inm We are going to check the spacing between the
fan and the housing we feel the gasket stock was to thick and we are lousing pressure in the gap.




Total Posts: 182 | Joined: Jul 16, 2012 - 7:16pm | IP Logged


Lock Topic

 

Forum Legend

New Member

Reply to topic

More than 25 posts | Full Member

Reply to topic with quoted message

More than 50 posts | Advanced Member

Edit Message

More than 150 posts | MASTER

View profile

More than 300 posts | TOP BOSS

Email member