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#846 Cummins Swap.
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andy1canada
Posted 2019-01-26 7:27 PM (#6227 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Extreme Veteran

100100100252525
Location: Victoria, BC. Canada
Howdy,

Well I spoke to the fellow today that bought the 440' & trans out of my coach; he's mostly got it ready to run already and shared with me what he discovered during the partial tear-down.

Before I say dick, I need to say that I always thought #846 was running pretty good and had pretty fair power output during the paltry 5000 or so miles I've put on it since I've owned her; moreover, considering the job this old rat-motor was tasked with, I thought it was getting comparable fuel economy to what I'd calculated on the trip home in #509 when I brought her up here from Santa Cruz a few yrs back (ie. 6 - 7 US mpg, or, 8 - 9 Imp. mpg).

Today I learned that I really don't know much about the venerable ole' 440' Chrysler.

The buyer, Paul, is reasonably confident that this was the original engine in #846. He told me that this engine, in the condition it was in when he got it home, was down 100 to 150 HP over what it should have been making.

This really blew my mind! (what's left of it after the 60's & 70's)

Here's Paul's autopsy results:

- camshaft lobes on a few cylinders severely worn down about 1/8".
- TQ carb over-fueling so badly that there was nearly '0' ignition spark and causing a huge carbon build up.
- timing chain worn out & very loose.
- engine did not have the big-rods but did sport a steel-crank.
- cylinder walls and rings (after 85,000 miles) were still in serviceable condition.

Epilogue: Terry has yet to realize what the true potential of the 440' is in the FMC application.

Almost regretting pulling it for the Cummins swap vs rebuilding it.

Almost...

Terry
#846

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LCAC_Man
Posted 2019-01-26 9:08 PM (#6230 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Elite Veteran

50010025
Location: Oceanside, CA


Flat tappet hydraulic lifter cams are really tough to keep healthy nowadays, even many of the modern synthetic oils don't provide the protection that the old high zinc(ZDDP) oils used to have. Amsoil has a good one, but, not everyone has access to that. Modern engines with all roller valvetrains don't need near as much lube film(much less friction) and can run much lower viscosity lube..
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B. Sitton
Posted 2019-01-27 10:05 AM (#6233 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Extreme Veteran

10010010025
Location: Ignacio Colorado
We can start by saying it was not the original engine or it would have had the big rods. The very late coaches didn’t have the big rods but up to at least #902 did. If it was 100-150 hp down it wouldn’t have run like it did. Your guy must only think race crap.
The stock RV 440 camshaft had .430” valve lift. I’m running a camshaft with .366” valve lift. Also smaller valves. Nobody would think this a smart change. They would say, “I thought you wanted more power! Well I got more useable power that is right where it counts now that I have the 0.69 overdrive.
With the stock 440 pulling the steep grades at high elevation I would have to go to first gear and back out of the throttle. I could run through first and catch second gear but it could not hold second. I would have to drop back into first. Now with the torque down where it is needed I can run second gear at 2,500 rpm up the steep grades. If it was to drop rpms it is only coming down into its peak torque curve and more power is waiting. Not like the more, more, more attitude that winds up running worse where you need it.
Better breathing intakes and exhaust would seem smart but they only gain power on the top end. Smaller port (runner) intakes and single exhaust make more low rpm torque! Yes the broken record speaks again. Less is more!
Bill
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LCAC_Man
Posted 2019-03-20 10:20 AM (#6317 - in reply to #6035)
Subject: Re: #846 Cummins Swap.


Elite Veteran

50010025
Location: Oceanside, CA
Well it's been 4 months since you removed the bumper...(insert finger tapping here)
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