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rvtechnician, RV Mechanic
Category: RV
Satisfied Customers: 27
Experience:  31 year Technician RVDA/RVIA Master Certification
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safari serengeti: i have a 1989 safari serengeti motorhome.

Customer Question

i have a 1989 safari serengeti motorhome. it has a john deere ohskosh chassis and a carbureted ford 460 motor. it has the exhaust leak problem and is down on power and running hot. except for these issues, the motor has 37k miles, starts right up and runs good otherwise. i've replaced the following: coil, spark plugs and wires, air filter, oil filter and filled with mobil 1 15w 50 oil. instead of just replacing the broken stud, i want to explore installing headers and also, i've read about 70s timing set, which makes the motor run better. i'm interested in a little more power with no cooling issues. i plan to install new thermostat and have checked coolant levels.
also, unrelatedly, my hydraulic line(s) are leaking which operates for both the hydraulic jacks and the brakes.
access to the motor is from inside the motorhome and of course below. the driver side access is not great. i read on the that they have a header system but for some reason they say that it does not fit a john deere/oshkosh chassis, which is what i have.
do not want to spend alot of money for expensive header system however.
what do u think?
Submitted: 4 years ago.
Category: RV
Expert:  rvtechnician replied 4 years ago.
Hello, and thanks for the question. You are correct in that Gale Banks does not make a system that fits. There are some differences built into your coach chassis by OshKosh, Unfortunately, they built very few of these so parts and accessories are limited. Once Ford started making chassis again, it became much easier to deal with. There is a system we use in our shop made by Doug Thorley. The headers are part number 212Y to fit your RV. These are a heavy duty exhaust header made with 13 gauge pipe, 1/2" flanges, and an industrial chrome or ceramic finish. They are rather pricey, but there is no inexpensive way to fix this inherent exhaust problem. Please contact Doug Thorley direct to ensure you get the proper fit. They do list your chassis. I'm not certain if they will have the rest of the system back past the header flanges. You may need measurements and specific information regarding catalytic converter/converters, muffler/mufflers, and smog tubes before contacting them. Be sure to check/test your catalytic converter prior to reinstalling it. These were problematic on carbureted engines and can be the cause of overheating. Some other issues you may run into with this repair include: broken exhaust bolts and/or damaged cylinder heads. Typically we see broken bolts caused by shrinkage of the exhaust manifolds. Sideways shrinkage can snap the bolts off. These bolts typically break off flush and are extremely difficult to extract. Many times we have to remove the cylinder heads to extract the broken bolts. These are a special bolt with a rolled thread and heat treatment. They rarely can be drilled and extracted with success. We have had some removed successfully using a laser machine. Plan on possibly replacing the cylinder heads if you have broken bolts. There are also issues with the end cylinder head exhaust bolt castings. The right rear and left front castings are prone to cracking and breakage where the end exhaust bolt is located. In some cases, this is hard to see. I have had these break during tightening of the new bolts.There is no repair for this and again, the cylinder heads must be replaced. Please ask if you need more information. Please click accept if this answers your question.
Customer: replied 4 years ago.
i'm sorry, but i'm not happy bc you haven't said anything that i didn't already know or have read about.
you didn't answer about the timing set, the hydraulic lines r&r, at all.
also u don't sound like u are directly familiar with my model, bc i dont have a cat.
if prefer not to pay what do u think?
Expert:  rvtechnician replied 4 years ago.
As I stated, please ask if you need more information: So your coach does not have a catalytic converter? There are a number of different set ups in these coaches. Ford uses multiple exhaust systems including with/without cat converters, single/dual exhaust, Y pipes/non Y pipes, single/dual mufflers, with/without A.I.R. smog tubes. The timing set will only help if there is extreme stretch and wear in the current set. Advancing the cam timing in this engine is a waste of time/money in my opinion. The compression is too low. I've done this replacement a number of times and have never seen that help in either performance or fuel economy. Stick with the exhaust and possibly a cold air intake for the air box. The breathing is where this engine is really choked. What kind of hydraulic leveling system do you have? I need manufacturer, model, control panel model and description.

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