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Topic: 1997 PowerTech Isuzu 8KW Generator Radiator Modification (Read 1130 times) previous topic - next topic

1997 PowerTech Isuzu 8KW Generator Radiator Modification

This is a recap of my 1997 PowerTech 8000KW Isuzu 3 cylinder generator radiator modification and service. The generator shut down from coolant loss at the beginning of a 8,000 mile trip last summer. The radiator core partially separated from the bottom tank due to excessive vibration. Based on articles in the Beam Alarm technical archive I decided to modify the radiator mounting system. I also needed to replace my generator box insulation, so I chose to remove the generator with its sliding tray to have full access to the generator.

General Notes: Generator mostly metric, framing SAE; used plastic baggies to label all bolts and fasteners by assembly; photographed all connections before dismantling; labeled wires with blue masking tape and permanent marker, a few also with wire ties and tags.

Removal: 1. Removed bottom sound barrier and frame; 2. Disconnected house battery ground; 3. Disconnected positive lead from generator starter and covered it with a piece of old hose; 4. Disconnected flexible exhaust pipe at exhaust manifold on engine; 5. Disconnected multi-plug control wiring harness for generator at control box; 6. Opened control box and removed two hot leads from circuit breakers and ground connection; 7. Removed nut holding conduit to control box and carefully threaded wires out of control box and wire tied flex conduit to frame; 8. labeled and removed two fuel lines to generator using bolts and hose clamps to stop flow of fuel, secured same to body; 9. Pulled generator tray out to stopping point and attached engine hoist with large safety links to lift points on engine (could not use engine tilt bar, used short link of heavy chain instead), raised up on hoist to provide neutral balance on rollers; 10. Removed top roller bolts and rollers (one per side) from slide tray which in my case required cutting bolts with 4 1/2 inch angle grinder with cut off wheel since bolts were too long to remove (major pain and required full protective face mask); 11. With an assistant, slide generator assembly out of compartment to help balance assembly; 12. Moved assembly to garage and set on four heavy duty safety stands.

Repair and Service: 1. Removed radiator and found an old school radiator shop to re-core radiator. Garland Radiator Repair, 508 W. Ave D, Garland, TX 75040, 972-494-5810 $395. 2. Parts ordered from Power Tech: IDL 8-10 Isuzu Upper Radiator Hose, 03HSIDL10U, $35.95, (Gates 8247); Isuzu Thermostat Gasket 3&4L Series 2 ½" 03GKT4LTHM, $10.36;  Isuzu Thermostat 3&4L Series 2 ½" 03THM4LS, $58.36; 3&4 L Series Isuzu Fan Belt 038F3LB (Dayco Top Cog 15335), $22.36; Isuzu Engine Mount (Green Dot) 09MNTGRN, $39.95 x 4; radiator isolator mount with8 3/8" stud, 09MNTIS38HM, $12.95 x 2; IDL Model Isuzu Lower Radiator Hose, 03HSIDL10L, $27.96 (Dayco Length Code E No. 71203 which required trimming); exhaust manifold gasket not available, reused. 3. Generator tray wire brushed with angle grinder, primed with Rustoleum Rust Converter and sprayed with silver paint. 4. Replaced main fuel filter, Isuzu OEM Filter is 8-9413247, crossed over to Baldwin BF7648, WIX 33386, Donaldson P550057; 5. Replaced Onan fuel pump filter, Cummins 1491353 Onan Fuel Filter (Amazon), my generator has an Onan No. 149-2331-02 low pressure fuel pump, does not appear OEM; 6. Replaced bad fan shroud isolator, W Winco 351.1-19-19-1/4-55 Series GN 351.1 Rubber Cylindrical Vibration Isolation Mount with 2 Threaded Studs, Inch Size, 0.75" Diameter, 0.75" Height, 1/4-20 Thread (Pack of 5 purchased on Amazon); 7. Fuel Hose 30R7 5/16" I.D. 7 Feet USA w/ 4 Clamps by The Stop Shop (Amazon); 8. Clamps: 10x HPS (14mm-16mm) Stainless Steel Fuel Injection Hose Clamp SAE 15 by HPS Performance (Amazon); 9. Replacement rollers for generator slide tray, half were damaged, Koyo YCRS-20 Yoke Roller, Sealed, Inch, Steel, 1-1/4" Roller Diameter, 3/4" Roller Width, 3/8" Inner Diameter, 13/16" Overall Width (Amazon, these are sealed unlike originals); 10. Insulation, Dynamat 11905 Hoodliner 32" x 54" x 3/4" Thick Self-Adhesive Sound Deadener (3 rolls required).

Radiator Mount Modification: 1. Before removing radiator made extensive measurements on the location of the radiator with original mounts, done with assembly completely removed from coach. These measurements included in reference to mounting tray, engine top and bottom, side to side. 2. Chose to mount radiator with Uni-struts on bottom using original mounts with top bracing from front fan guard and back shroud to generator tray. The only connection between engine and radiator are the upper and lower hoses. Upper braces were made with flat stock, bolts, nylocks, with angles created using bench vice, hammer and a little heat. I did not use the back half of the fan guard. This makes it much easier to adjust fan belt tension or replacement (personal choice). Front half of fan guard no longer attached to engine, but supported by long brace to back of tray positioned to allow service of fuel filters without removal. 3. Cut the original generator mount bracket from engine that extended forward to radiator. Used angle grinder with cut off wheel. At that point you have passed the point of no return. 4. Trimmed 1/4" from fan shroud to improve clearance of radiator fan in case new split mounting system added new variable to fan and shroud clearance.

Unistrut parts purchased from Amazon, two each: 1. Unistrut P2942-EG Post Base Single Channel, 2 Hole, Standard, 3-1/2" Channel; Genuine Unistrut P1325-EG 4 Hole 90 Degree Angle Connector Bracket for All 1-5/8" Strut Channel. The angle connector brackets were cut to eliminate one bolt hole from one side of each, reused as spacers. Definitely recommend the 90-degree angle brackets as they are a perfect fit for the posts.

Insulation: Worst part of the job! My insulation was still good enough to be a total pain to remove. I removed it carefully to use it as a pattern for new insulation, mostly successful. The adhesive was still in excellent shape, so it was miserable to remove. I scraped with every tool in the tool box, used all kinds of solvents and eventually sanded it off with a power sander. I used Dynamat hood liner, not equal to OEM in sound deadening or overall thickness, but maybe better thermal protection. I went to Home Depot and bought aluminum foil tape which worked well. Time will tell.

Slide Tray Rollers: I removed all rollers and all required cutting the bolts. Reused half the rollers after cleaning and inspecting. I installed with bolts in opposite direction, so it is now possible to remove them. The top rollers must be removed to extract tray, as the tray has a nipple that hits the roller to keep it from coming out too far. Installing the rollers was tedious and requires two people, one to push the roller into the slide channel and another to yell whoa, and use a Philips screwdriver to line up the hole and stab it with a bolt. Best to stick the screwdriver into the hole, when the roller hits it, remove and very gently push it down the track to capture it for bolt insertion. Recommend using a creeper underneath and keeping one's legs out from under the generator tray.

Results: The engine started first time after the pump ran for about 20 seconds. Start up has the slightest twitch force against radiator through hoses (don't know how to eliminate that), but no perceptible movement while running. The whole assembly seems much smoother, I'm thinking the four main mounts for the Isuzu were no longer doing their job. They looked fine to the eye, but the new mounts seem to make for a much smoother running engine. I am very slow and methodical stopping to think things through from many angles. I may regret not powder coating the generator tray, but touch up paint is cheap and so am I. Not too many hours on the generator since modification, but the difference is amazing.
I don't know how anybody does this in two days without prior experience. I had well over eight to 12 hours in just procurement of parts and supplies not counting reading Forum posts. I had more than two days just getting rid of the adhesive. PowerTech was very helpful along with the prior Forum posts. Also received a personal PM from a Forum member who provided important advice on the exhaust manifold gasket. If paid by the hour, I'm the most expensive RV tech in America.

Re: 1997 PowerTech Isuzu 8KW Generator Radiator Modification

Reply #1 –
Additional photo

Re: 1997 PowerTech Isuzu 8KW Generator Radiator Modification

Reply #2 –
Your presentation is better than Power Tech. Nice photos, good annotations, greaet job!

Pierce
 

Re: 1997 PowerTech Isuzu 8KW Generator Radiator Modification

Reply #3 –
Update: My generator was shutting down from over heating. This only happened underway or when running generator with access door shut. Turns out the insulation I used wasn't as thick as per original leaving a gap between generator shroud and the sheet metal surrounding gen box. The fan, which pushes air, was sending a lot of hot air from radiator back into the gen box and heating up the compartment enough to trigger shut down. I used some one inch foam pipe insulation to slip around the shroud on the box side. That did the trick, can now run generator down the road in 100 F and run while parked all night without triggering overheat.