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Author Topic: 8V71 oil change  (Read 4118 times)
Prevost Proud
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« on: December 04, 2006, 06:45:41 PM »


I have owned my 1980 Prevost for 2 years and I have yet to change the oil.  I am looking at putting straight 40 in instead of my 15w40 synthetic oil that is in right now.  Is this a good idea?  How much oil should I buy if I go straight 40?


Pat    Cool

« Reply #1 on: December 04, 2006, 06:48:56 PM »

I have changed mine, and also oil filter, and it took around 8 gals.

 I just bought two cases for my trip. Good to have spares.

I also added Lucas Oil Treatment.

I use straight 40W as has been suggested.


Hero Member
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« Reply #2 on: December 04, 2006, 06:57:28 PM »

Straight 40 is what Detroit thinks we should run in our 2-strokes.  That's good enough for me.  It sticks in my head that my 8-92 takes just over 5 gallons but I may be wrong.

R.J.(Bob) Evans
Used to be 1981 Prevost 8-92, 10 spd
Currently busless (and not looking)
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Simply growing older is not the same as living.
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« Reply #3 on: December 04, 2006, 07:15:34 PM »


  I have been told that Delo 100 works great in 8v-71s.  I have an 8v-92, and I use the same.

  Mine holds alittle over 6 gal. They say 15-40wt is only good in 4 strokes.  Like the ole saying is ''If it works, don't fix it"

  Steve 5B


"It's all in the name the name says it all"
Angola Coach Conversion "Aesop's Tortoise"
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« Reply #4 on: December 04, 2006, 08:33:32 PM »

Pat -

FYI, this topic comes up at least every six months or so on the message boards, and debate often rages.  Detroit's got more experience with these engines than anybody else, why is it that folk don't follow their recommendations?

Here's a link that you should print out and keep in your engine's maintenance manual, direct from "the horse's mouth":


The section that pertains to the two-strokes is in section 2-2.

In a nutshell, you've been using the wrong oil, not an uncommon thing.  Especially since straight 40wt is not usually on the shelf at Wally World, it must be ordered.

Chevron Delo 100 and Shell Rotella T are two of the more common brands used, altho there are lots of others.  Easiest is to order from your local oil or petroleum distributor, located in your yellow pages.  Comes in gallon jugs, six jugs per case.  You'll need two cases, because the 8v71 takes seven gallons plus a smidgen more with a new filter.  You can also order it in five gallon pails and 55-gallon drums.

FWIW & HTH. . .


RJ Long
PD4106-2784 No More
S13406 1978 MC-5C Converted
S14947 1980 MC-5C Shell
Cheney WA
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« Reply #5 on: December 05, 2006, 02:52:05 PM »


    Phillips 66 super duty # 40 is also a good choice
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