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Buying 1965 detroit diesel bus conversion. How reliable is 8v71? What kind of maintenance for a diesel?


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Hi there,


I am new to this and a female so I don't know much about engines. Hubby and I are looking at a 1965 8V71 with a 4 speed Allison transmission. Electric shift (not sure what this means though?). It was rebuilt less than 10K ago. He is handy and an aircraft mechanic by trade but knows nothing about diesels or RVs for that matter. I am sure he can work on it no problem, but we just want to know what we are getting into.


How reliable can we expect this to be? I have read that they all burn oil. How much? Most ads mention how many miles "since last rebuild". How often does it need to be rebuilt? What is the general maintenance for these things? I've done a ton of research but can't seem to find anything about these items. I know that all engines have "bad years". Does anyone know if 1965 was a good year?


Is there any advice that anyone could add about inspecting this thing? I'm detailing a list, but don't want to miss anything big. Are brakes an expensive or hard job? Hubby does our brakes- so I'm guessing he could do these no problem?


Thank you in advance!

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First let me say, welcome to the Escapee forums! We have a wide range of member experiences here and most of us are willing and anxious to hep you become a successful RV owner.


For myself, I'm not the RV expert but do have many years of RV experience. I do have some experience with diesels but am not a mechanic at all. I will make some suggestions based only on my observations in past years. The first is that you need to get the bus evaluated by an independent mechanic who is not only a qualified diesel mechanic but who has bus experience. It won't be cheap but it is like buying insurance. A bad choice could be financial disaster! You also need to have someone involved who knows the bus body side of things as it is also vital to know it is sound.


As important as the mechanical/bus side of the equation is, you should also pay a mobile RV tech to go over the RV conversion for you and evaluate the appliances, and all of the RV accouterments. While the running gear side is of critical importance, the interior can also be expensive to repair and replace. You need to find out when the bus was converted to an RV and who did that conversion. I have seen bus conversions which exceed the quality standards of the highest priced motorhome builders, and I have also seen some very amateur attempts. An experienced RV owner could probably give you a pretty good evaluation of that side of things but a professional might be worth the cost.

Good travelin !...............Kirk

Full-time 11+ years...... Now seasonal travelers.
Kirk & Pam's Great RV Adventure



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It is an unusual engine in that it is a 2 stroke diesel which requires a supercharger. It is no longer supported by the factory. However it is still in widespread use especially in marine applications. It is a reliable and easy to maintain. I know of no parts that are unavailable although they may be used. 1/2 a million miles between overhauls is usual.


They are noisier than today's diesels and are prone to minor oil leaks. Make sure you have a test run where the engine is working hard eg climbing a hill and make sure you can deal with the noise. They were called screaming Jimmies by the truckers.


If it starts easily from cold without starter spray, runs without excessive smoke and maintains oil pressure when working hot then there is a pretty good chance it will run for a long long time.Expect some smoke on cold start but as long as it clears on a few seconds that is fine.


They are nice honest hard working long lived motors with an excellent rep. If I was buying something with a big 1965 diesel it would be high on my list.

FT since September 2007

Safari Trek + M/C


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They are a 'great' motor that you will either love or hate. By their very nature they use oil. They are a two stroke. We had the newer 6v92tta in ours. Had 1.5 million miles on the engine and it had never been out of the chassis. Two new heads was the only 'major' work. They have 'slobber' tubes that will drop oil on the ground. So a bit of oil on the ground is no big deal. But you do need to watch your oil levels. I always traveled with a drum of oil. Ours had a two stage manual crash box. Was fun to drive but didn't tolerate poor gear shifts. Sometimes a missed changed required pulling over and starting for granny gear!! And that jake brake. :rolleyes: Going down a hill at night would scare the chickens for miles around. And tunnels!!! But I digress.


Here's a link that may be of interest. https://www.busconversions.com/



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OK guys back off the old GM's. :P PD4106 is known as the sports car of the buses. V730 transmissionj that's the 4 speed Allison. Fuel mileage 6-7 MPG. Original air lines are all copper. All lines throttle cable, shifter control and water lines are in the center tunnel. Check brakes for lining thickness. Learn how to adjust brakes - full tight and back off a 1/2 turn, 9/16" ratchet. Fuel filters 2, primary and secondary. DO NOT RUN a Detroit 2 stroke out of fuel. Carry 5 gallons of diesel and a method for filling fuel filters to prime the engine. Any good truck mechanic can check for suspension and other stuff for problems. Call Luke at US Coach in NJ for help and parts. Engine parts are still available from various sources. Things don't break very often. Remember buses run for hundreds of hour per month and very few are parked on the side of the road.

Who did the conversion?



Bill & Lynn Baxter

MCI102A3 Conversion, Detroit Diesel S50  


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  • 1 month later...

"They are noisier than today's diesels and are prone to minor oil leaks."


Is this the one known as a "Road oiler".



Amateur radio operator, 2023 Cougar 22MLS, 2022 F150 Lariat 4x4 Off Road, Sport trim <br />Travel with 1 miniature schnauzer, 1 standard schnauzer and one African Gray parrot

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