Location: Scottsdale, Aridzona
(68.2.104.9) | hemi354az, FMC #120, Louis Cruse - I have added paragraphs, (words for clarity LC), and spelling corrections . . . but it is exactly as he wrote in the YahooFMC Website.
Jim Black RVS - Yahoo FMC Website - MSG #6181 - Feb 28, 2008
At FMC we built a modified nose cap to accept a front cross flow radiator.
We used 1-1/2" copper tubing to route coolant to the front. Cooled poorly.
We added a 12 V boost pump to secure (? LC) proper flow. Worked much better but the boost pump could be weak link.
FMC canceled the project as not cost effective, as well as, having questionable engineering area's.
FMC added perimeter aluminum shields aft of radiator to the inside of rear grill. BIG IMPROVEMENT!!!!
(FMC Parts Manual, “Deflector” Fig.13-1.Item 11, “Panel” Fig.13-2,Item 20. LC)
Also, added aluminum (? My #120 shield is steel. LC) shield between aft engine cross member to bottom of radiator.
This provided protection from gravel bouncing up into the engine fan and helped air flow.
Also adjusted radiator tilt to position engine fan 2/3 of cross section of blades into shroud.
Replaced OEM supplied 180 thermostat with now obsolete 160 Chrysler thermostat.
Also changed radiator cap to 7 lb. (From what ? LC)
End of cooling problems unless oil leak plugged air passage (radiator fins LC),
or lower hose was replaced with hose without spring inside or molded into hose allowing hose to collapse.
(Gates Green Stripe Hose has molded spring inside and is smooth inside. LC)
The next problem was OEM radiators supplied. Approx. (100 total had LC) 90+ of the 190 total plugged with solder.
Subject problem was found and corrected.
After FMC #646, Chrysler derated their engines due to CA smog from 8.9 to 1 in 1973-74 to 7.9 to 1 in (1975 ? LC) 1976,
and removed some head gasket holes to raise cylinder head temp, changed cam grind, changed distributor curve.
All of these modifications reduced power and caused the FMC motorhome to enjoy (? LC) elevated coolant temp.
NASA Ames asked RVS to assist with an engine temp study by installing 9 heat sensors in the engine area connected to a graph recorder. (No OTHER TEMPS/Locations mentioned LC)
At 65 MPH on I-5 w/l00 ambient temp, the engine compartment exceeded 350, above the carburetor.
Reduced temp in engine area by replacing Donaldson muffler with dual exhaust.
Engine compartment temp down to 160 to 180. (Above the carb ? LC) The Donaldson was a big heater.
RVS has also been usng 6-row radiator cores when replacing bad cores with great success for many years as guided by FMC engineering.
(FMcs have 6 core frames, but came with 4 core Radiators. Look thru shroud/fan at side of Radiator FRAME. 1" to 1-1/2” space between frame fan side and inside row of core = 4 core. LC)
The correct FMC motorhome waterpump is not a shelf item (obsolete JB).
Factory remanufactured available. Correct impeller is 4-3/8 OD with 8 blade paddles. (Unique to FMC 440s. Other 440 powered Motorhomes have car type water pump. LC)
Also, note: Do not over lubricate water pump. NEVER A POWER GREASE GUN. 1/2 pump made 2 times year. (regardless of USAGE ? LC)
Most engine water pump failures are caused by OVER lubrication.
JIM
Jim Black's Entries on the Yahoo FMC Website will no longer be AVAILABLE after Dec 14, 2019 - https://help.yahoo.com/kb/groups/SLN31010.html?impressions=true
Lou #120
Edited by hemi354az 2019-11-09 6:11 PM
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Jim Black RVS on FMC Engine/Coolant System on YAHOO
