Reply
 
Thread Tools Display Modes
 
Old 04-13-2016, 08:11 AM   #21
Guru
 
City: Seaford Va on Poquoson River, VA
Country: United States
Vessel Name: Old Glory
Vessel Model: 1970 Egg Harbor 37 extended salon model
Join Date: Jan 2016
Posts: 1,304
On lean burn, gasoline is injected into combustion chamber called stratified charge.

https://en.wikipedia.org/wiki/Stratified_charge_engine

Quote:
A stratified charge engine is a type of internal combustion engine, used in automobiles, in which the fuel is injected into the cylinder just before ignition. This allows for higher compression ratios without "knock," and leaner air/fuel ratio than in conventional internal combustion engines.
I have read maybe, gas engines will equal diesel for efficiency or come close to it.

The green thinking governments, I hate green, but you know things are what they are, are pushing to favor gasoline engine over diesel now in Europe, due to diesel pollution versus cleaner running gas motor.
Same here with EPA, all sorts of schemes to clean the diesel engine up, and outlawing use of older diesels.
__________________
Advertisement

sdowney717 is offline   Reply With Quote
Old 04-13-2016, 09:40 AM   #22
Guru
 
City: gulf coast
Country: pinellas
Join Date: Jun 2014
Posts: 2,199
All the design changes in the world will not offset the fact that diesel fuel has a higher specific energy content than gasoline.
__________________

bayview is offline   Reply With Quote
Old 04-13-2016, 11:29 AM   #23
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,715
Thanks very much Dave and 717,
I remember the start-up stumble very well and "fixed" a few offenders.

I also remember "sticking" a few two stroke air cooled ultralight aircraft engines from running too lean both while flying and on the ground running up. On WOT climb out one needed to run a tad on the rich side of full power .. about 200rpm. My first flight to 1000' was at max power (lean) and at 1200' it seized up. Depending on the engine about 400 degrees F cyl head temp was maximum but synthetic lube, wide ring gaps or even lower ring removal was used to increase rpm and intolerance to heat.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 04-13-2016, 11:36 AM   #24
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,715
Quote:
Originally Posted by bayview View Post
All the design changes in the world will not offset the fact that diesel fuel has a higher specific energy content than gasoline.
But friction, heavier pistons and other features of diesels limit their ability to turn the energy of their fuel into shaft rotating power.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 04-13-2016, 11:48 AM   #25
Guru
 
City: gulf coast
Country: pinellas
Join Date: Jun 2014
Posts: 2,199
BSFC of diesels is better that gas despite that.
bayview is offline   Reply With Quote
Old 04-13-2016, 11:53 AM   #26
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,715
bay that's true.

But ...Forbes WelcomeForbes Welcome
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 04-13-2016, 11:55 AM   #27
Guru
 
High Wire's Avatar
 
City: Cape May, NJ and Englewood, FL
Country: USA
Vessel Name: Irish Lady
Join Date: Dec 2007
Posts: 1,602
1.5 gph for one 392 cu in gas v8 is normal in my experience with gas flowscans.
__________________
Archie
1984 Monk 36 Hull #46
Englewood, FL and Cape May, NJ
High Wire is offline   Reply With Quote
Old 04-13-2016, 12:27 PM   #28
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 3,889
Quote:
Originally Posted by manyboats View Post
bay that's true.

But ...Forbes WelcomeForbes Welcome
A guy with a plastic model is a long way from proving his concept. Neat idea, but HCCI is notoriously difficult to manage. It has stumped engineers for at least 20yrs.
Ski in NC is online now   Reply With Quote
Old 04-13-2016, 04:55 PM   #29
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,715
Ski,
Consider it thread entertainment.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 04-13-2016, 05:20 PM   #30
Guru
 
City: Venice Louisiana
Country: United States
Join Date: Dec 2013
Posts: 1,097
717, is that 392 the first gen Chrysler Hemi design. If so, thats about the best looking engine ever. Even in an old Desoto.
kulas44 is offline   Reply With Quote
Old 04-13-2016, 09:00 PM   #31
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,715
Klass 44,
That's an International truck engine ... as in International Harvester. Probably considerably better for a boat than the Chrysler Hemi.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 04-14-2016, 07:51 AM   #32
Guru
 
City: Seaford Va on Poquoson River, VA
Country: United States
Vessel Name: Old Glory
Vessel Model: 1970 Egg Harbor 37 extended salon model
Join Date: Jan 2016
Posts: 1,304
It is a heavy duty engine. Consider it is from 1970 and still working good.


Here is an album with a few videos of it running right after the rebuild.

https://photos.google.com/share/AF1Q...RCR0EtQ2ZmeGxR

I found out the gas in the boat over the winter went stale, about 35 gallons is in one tank, other tank is empty.
I think I should plan on not leaving any gas in the boat when it will sit a long time.
I switched over to the boat tank from my portable fuel tank and engine started missing and could barely run throwing up lot of smokey exhaust. Fuel decay is one reason I hate E10 gasoline. Due to ethanol, gas decays rapidly compared to before E10. You have to keep dosing it with Stabil and I neglected that. I can likely dilute it and run it in the car.

I did an experiment with this rebuild. Rather than buy new pistons, I sprayed the skirts with KG Nano Gun Kote blue.
It is a high temp phenolic resin with moly lubrication and I built up the skirts to go from .006 - .007 to .003 clearance. Cheaper than buying new pistons and I wanted it tighter, did not want any piston slap. Only way to tell how it does long term is time.

If it works, maybe next time I will ceramic coat the piston tops. That reflects heat back into power and keep pistons running cooler. ALthough the improvement is likely minor, it may help with overheating or detonation.
sdowney717 is offline   Reply With Quote
Old 04-14-2016, 08:33 AM   #33
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,531
"did not want any piston slap. did not want any piston slap."

The usual is to have a machine shop knurl the pistons.

Quite cheap.
FF is offline   Reply With Quote
Old 04-14-2016, 09:18 AM   #34
Guru
 
City: Seaford Va on Poquoson River, VA
Country: United States
Vessel Name: Old Glory
Vessel Model: 1970 Egg Harbor 37 extended salon model
Join Date: Jan 2016
Posts: 1,304
Quote:
Originally Posted by FF View Post
"did not want any piston slap. did not want any piston slap."

The usual is to have a machine shop knurl the pistons.

Quite cheap.
Still it costs money, and I like to experiment.
Knurling also does not last, don't know how long, but that is what I read.

My other engine the pistons were knurled, the knurls were worn away.
Knurling makes a small surface area of ridges.

I was wondering if it was factory, since all the parts were standard sized and marked with IH factory numbers on the bearings.

From a few years earlier my port rebuild, that one got new pistons.
Although, now maybe I could have just Gun Koted them, instead of paying $400 for a set. The contour tops are usually much more than the other flat top IH design, likely because the engines are less common, less demand for parts.

https://photos.google.com/share/AF1Q...V3a2J2bWk3cGRR
Attached Thumbnails
Click image for larger version

Name:	0125121839a (1).jpg
Views:	35
Size:	71.1 KB
ID:	50726  
sdowney717 is offline   Reply With Quote
Old 04-14-2016, 10:25 AM   #35
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,715
717,
Amazing ..
You've got 260hp, I've got 40 and we've got the same transmission.
What's that rectangular thing on the big end on the con-rod? Counter weight? Oil splasher? I'm suprised the pistons have shch a short skirt. It was vouge in the day though. Crankpin has large OD. I agree w you about the knurling. I've heard it gives better lubrication though but small bearing surface and in your case on a very short skirt.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 04-14-2016, 11:27 AM   #36
Guru
 
City: Seaford Va on Poquoson River, VA
Country: United States
Vessel Name: Old Glory
Vessel Model: 1970 Egg Harbor 37 extended salon model
Join Date: Jan 2016
Posts: 1,304
They are velvet drive 72C with 2.57 to 1 gears.

The big blob is odd. It can be ground to aid in getting the engine balanced.
It may aid the piston putting the weight offsetting to one side, instead of drilling offset pins, really just guessing. Short skirts less frictional loss same with thinner rings. These skirts are large compared with many gas engines today, but compared to diesels they are small. THe IH 392 pistons have an embedded steel or cast iron ring in the crown to help keep the piston in proper dimension when running under load.
sdowney717 is offline   Reply With Quote
Old 04-14-2016, 12:07 PM   #37
Guru
 
City: Seaford Va on Poquoson River, VA
Country: United States
Vessel Name: Old Glory
Vessel Model: 1970 Egg Harbor 37 extended salon model
Join Date: Jan 2016
Posts: 1,304
Quote:
Originally Posted by bayview View Post
All the design changes in the world will not offset the fact that diesel fuel has a higher specific energy content than gasoline.
Yes, but not that much difference.
Quote:
1 gallon of gasoline = 120,476 Btu
1 gallon of diesel fuel = 137,381 Btu (distillate fuel with less than 15 parts per million sulfur content)
I think it has to do with at low speeds diesels are very lean burn because of the nature of the combustion being a compression ignition verse gas spark ignition has to remain at 14 to 1 homogeneous charge or it will miss fire.

However, they are now working on direct injection of gasoline into the combustion chamber and experimenting with finding ways to do this lean burn at low power demand.

Diesels as power demands increase they do burn more and more fuel. Maybe someday gas motors will be much more efficient heat engines, closer to diesel, All engines waste lots of energy radiating heat. Engineers are seriously making big changes with engines efficiency and gasoline engines are getting most of the research since governments say diesels pollute too much and gasoline can burn cleaner easier.

http://www.hybridcars.com/will-ameri...esel-problems/
http://www.scientificamerican.com/ar...n-diesel-cars/
__________________

sdowney717 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 03:43 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012