Free 7 Day Trial RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > POWER TRAIN GARAGE FORUMS > Cummins Engines
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
 
Thread Tools Search this Thread Display Modes
 
Old 06-05-2017, 09:13 AM   #1
Senior Member
 
Winnebago Owners Club
Join Date: Jun 2012
Location: British Columbia
Posts: 600
Engine classifications: big block vs small block

I have read discussions on big blocks vs small blocks. If the ISB is a small block and an ISX is a big block, at which designation does it go from small block to big block? ISL?
__________________
2008 Newmar Dutchstar 4023, 425hp Cummins ISL
SOLD: 2005 Winnebago Journey 39K, 350HP C-7 Cat
Toad: Flat deck car trailer hauling a 1932 ford tudor sedan
Deucenut is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 06-05-2017, 10:41 AM   #2
Senior Member
 
Join Date: Sep 2010
Posts: 4,168
Big block diesel engine have a couple different measures. One is the size of the engine which usually starts around 11 liters for a big block or big bore engine. A 6.7/5.9 would be a small block engine and a 8.3/8.9 would be mid-level diesel engine. Within those 3 different engine sizes are horse power and torque. As a general statement most HD big block engines are designed to last over 750K miles.
tom chelbana is offline   Reply With Quote
Old 06-05-2017, 10:53 AM   #3
Senior Member
 
Mr_D's Avatar
 
Country Coach Owners Club
Solo Rvers Club
iRV2 No Limits Club
Join Date: May 2011
Location: Vancouver, WA
Posts: 37,695
To me ISM and up is "big block" in the CAT lineup it's C-9 and up.
__________________
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft, HWH Active Air
Charter Good Sam Lifetime Member, FMCA,
RV'ing since 1957, NRA Benefactor Life, towing '21 Jeep JLU Rubicon Ecodiesel
Mr_D is offline   Reply With Quote
Old 06-05-2017, 05:06 PM   #4
Senior Member
 
Smitty77's Avatar
 
Join Date: Aug 2010
Location: Over the next hill, around the next curve...
Posts: 5,139
Quote:
Originally Posted by Mr_D View Post
To me ISM and up is "big block" in the CAT lineup it's C-9 and up.
The lines sure have blurred over the years!

As the Cummins ISL is 8.9 and is to me Medium Block Size, I consider the CAT C-9 to be also Medium Block Size!

I consider the Cummins ISC 8.3 to also be Medium Block Size.

I consider the CAT C7 to be at the upper end of the Small Block Size. Along with ISB from 5.9 to whatever the heck size it is now (6.7!) to also be Small Block Size.

I had an old veteran salesman say he always considerer 10L and larger to be BIG BLOCK, like the old CAT C-10.

And you know, it really is just buzzword vocabulary. As what matters as far as pulling ability, is the combo of any give engine in relation to coach weight. Thus the Power To Weight formula is a pretty important item when shopping for a coach. (A bit of a hypocrite with that statement, as I quite often suggest getting the BIGGEST BLOCK ENGINE YOU CAN GET IN A COACH THAT YOU LIKE AND MEETS YOUR NEEDS! I like extra HP/Torque reserves, and I also like as much Braking Horse Power as possible with Jake Compression Brakes (Or Allison Retarder Transmissions. Big blocks do add that above just 'Power to Weight Ratio'!).

Best to all,
Smitty
__________________
07 Country Coach Magna Rembrandt 45' ISX600
Roo II was our 04 Country Coach Allure 40'
OnDRoad for The JRNY! Enjoy life...
Smitty77 is offline   Reply With Quote
Reply

Tags
cat, engine



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
BIG Block Gas Engine Rides Again DriVer RV Industry Press 31 07-21-2016 10:17 AM
1988 Chevy 454 Big Block Engine Air Filter(s)? wajell Vintage RV's 12 04-09-2016 07:53 AM
450 small block vs 500 big block StuartS Class A Motorhome Discussions 5 03-15-2015 09:28 AM
Engine Sound, 454 big block, in 86 Holiday Rambler Hemi Vintage RV's 48 10-16-2007 05:35 PM
Engine pull, 454 big block in p 30 GMC chassis Hemi Vintage RV's 9 11-03-2005 04:53 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 06:17 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2022, vBulletin Solutions, Inc.