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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: jmblake on October 02, 2012, 06:12:48 PM

Title: 8V71 swap to 8V92
Post by: jmblake on October 02, 2012, 06:12:48 PM
Well I have been planning on turboing my 71 Detroit this winter when I got a lead on a 92series about 30 mile from home. It was in a 78 MCI 8, It was installed in 04 when it was totally rebuilt with 70,000 miles on it now, He is installing a 50 series in his bus now. It is pretty much complete including the cradle, alternator powersteering pump, Jake's,and aircompressor. I already have the big radiators installed and I would have to change my muffler and air cleaner anyway. I know I would be much happier with the power of a 475hp 92series over the turbo 71. I should be able to pick this engine up for $3500.00 do you guys think this would be a good decision to do, and what am I missing that I may need to switch to the 92 series. Thanks Jason
Title: Re: 8V71 swap to 8V92
Post by: kyle4501 on October 02, 2012, 06:32:09 PM
Isn't the cooling system on a MCI 9 limited to 435 HP even with the oversized radiators?
The 2 strokes need to dump a LOT of heat.
If you go with 475 HP, you will probably need more cooling capacity to take full advantage of it.

GOOD LUCK!  ;D
Title: Re: 8V71 swap to 8V92
Post by: jmblake on October 02, 2012, 06:49:41 PM
Kyle,
Not sure about that, He had it in his 8 and didn't have any problems, I could also get the smaller pully for the fan drive to help out.
Title: Re: 8V71 swap to 8V92
Post by: Geoff on October 02, 2012, 07:01:00 PM
I think if the previous owner had no problems with his 8V92TA he wouldn't be thinking about going with a Series 50.  To keep an 8V92TA cool in an MC8 you need a good radiator water spray system.

I would pass on this deal unless you paid core price and took the 8V92TA apart to check for overheating damage.
Title: Re: 8V71 swap to 8V92
Post by: jmblake on October 02, 2012, 07:06:03 PM
He got a good deal on a wrecked transit bus at the local salvage lot with the 50 series, He thinks he will also double his milage over the 92.
Title: Re: 8V71 swap to 8V92
Post by: luvrbus on October 02, 2012, 07:21:39 PM
If you have heating problems turn it down to 435 hp there are tons of MCI's on the road with 8v92 engines in the 400 hp range they do fine I maintain 2 that are set at 400 hp one has 435,000 miles on the engine came from MCI at 400 hp

Just have it checked for heat damage one way you can do yourself is pull the air box covers and look for black streaks inside the liners you see those it has been warm fwiw
Title: Re: 8V71 swap to 8V92
Post by: jmblake on October 02, 2012, 07:32:28 PM
I would have liked to have heard it run but he already has it out and putting the 50 series in. I will be taking my mechanic friend with me to look at it, he has been working on these old detroits all his life, he is now 74 years old. Thanks for the replys, I just think I would be much happier with the 92 vs turboing the 71 with a lot less work.
Title: Re: 8V71 swap to 8V92
Post by: hargreaves on October 02, 2012, 07:32:50 PM
Unless he is only getting 4 miles per gal with the 8v92 he won't double his milage with the series 50. Cheers Gerry.
Title: Re: 8V71 swap to 8V92
Post by: luvrbus on October 02, 2012, 07:36:14 PM
Yep and he will miss the 1300 to 1500 lbs of torque from the 8v92 me I am a huge fan of the 8v92
Title: Re: 8V71 swap to 8V92
Post by: jmblake on October 02, 2012, 07:42:56 PM
Gerry,
Thats what I thought but Ill let him believe what he wants.

Cliff,
I to am a fan of the 8v92s my dad had them in his trucks back in the day, and my mechanic friend keep him going for years.

If it checks out does $3500.00 seem like a fair price?
Title: Re: 8V71 swap to 8V92
Post by: Nick Badame Refrig/ACC on October 02, 2012, 07:49:39 PM
Hi Jason,

My 102C3 started out life with an 871. It was converted to an 8V92T in 2003'

If you say you have the Big 92 rads installed, I wouldn't worry about cooling issues.

At most, you may have to install the radiator air scoops that R&M sells.

Good Luck
Nick-
Title: Re: 8V71 swap to 8V92
Post by: kyle4501 on October 02, 2012, 07:52:48 PM
Quote from: jmblake on October 02, 2012, 07:42:56 PM
If it checks out does $3500.00 seem like a fair price?

I would think so since it comes with the goodies you need for your coach.

I don't remember ever having too much power.  ;)
I also think fuel mileage is overrated  :o   Especially when you heed just a little more power.

This setup will be fine as long as you don't abuse the power.  ;D
Title: Re: 8V71 swap to 8V92
Post by: luvrbus on October 02, 2012, 07:53:37 PM
If it checks out 3500 is fair offer him less Lol the jakes are worth 1000 bucks if you could install a air to air and do away with the inter cooler that helps a bunch reducing the heat and really makes a big difference in performance on a 8v92
Title: Re: 8V71 swap to 8V92
Post by: jmblake on October 02, 2012, 07:55:56 PM
Thanks Nick
I installed the new radiators about a year and a half ago, with all new seals so it should be as good as it gets, Did you have to use the air scoops on yours? Thanks Jason
Title: Re: 8V71 swap to 8V92
Post by: jmblake on October 02, 2012, 07:58:57 PM
It does come complete since all the goodies don't fit the 50 series and he has a old cradle that he is using on the new engine.
Title: Re: 8V71 swap to 8V92
Post by: luvrbus on October 02, 2012, 08:00:29 PM
Did it have a automatic, does it have the flex plate your 71 series center will not work on a 8v92 the plate will but not the center hub
Title: Re: 8V71 swap to 8V92
Post by: jmblake on October 02, 2012, 08:03:45 PM
Yes it was a 740 like I have, I think he said that I would need a flex plate though.
Title: Re: 8V71 swap to 8V92
Post by: hargreaves on October 02, 2012, 09:09:34 PM
Hey Jason, is he keeping the transmission or does it come with the motor? If so $3500 sounds like a good deal . i just sold a 6V92 with a 740 attached for 3 grand.
Title: Re: 8V71 swap to 8V92
Post by: Nick Badame Refrig/ACC on October 03, 2012, 03:13:31 AM
Quote from: jmblake on October 02, 2012, 07:55:56 PM
Thanks Nick
I installed the new radiators about a year and a half ago, with all new seals so it should be as good as it gets, Did you have to use the air scoops on yours? Thanks Jason

No Jason!
Title: Re: 8V71 swap to 8V92
Post by: jmblake on October 03, 2012, 04:15:55 AM
Hargreaves,
He is keeping the transmission, My transmission is good it was just installed about 2 years ago, I like the idea that everything is set up for a bus and not a truck, where everything would have to be changed over if it was out of a truck. As far as price he hasn't set a price, He actualy wasn't even ready to sell it yet. My mechanic has a old restored GMC crackerbox that he takes to car shows and he ran into this guy and started talking detroits and one thing lead to another. Jason
Title: Re: 8V71 swap to 8V92
Post by: RickB on October 03, 2012, 08:51:20 AM
Jason,

I'll buy it if you don't.

Finding one that bolts right in is rare. Other than the flex plate that is.

Rick

Title: Re: 8V71 swap to 8V92
Post by: TomC on October 03, 2012, 01:06:59 PM
The in block aftercooler on the 8V-71/92 is a joke.  I turbo'd my 8V-71, mainly because it is almost impossible to install a 8V-92TA on a V730.  I used an air to air intercooler (between the turbo and blower) that Don Fairchild installed.  Don liked the setup so much, he's installed it on other buses as well.  My engine has 7G75 injectors for 375hp and 1125lb/ft torque.  My bus weighs 31,000lbs.  Last month climbed the Grapevine, which is 6% grade for 5 miles in second gear turning 1800 (not fully floored) at 45mph with no smoke out the tailpipe.  Quite satisfied with that performance. 
If you install 9G80's in your 8V-92TA, you'll have 400hp and 1200lb/ft torque-that's 50% more torque then the natural 8V-71N!  Then the engine will last a bit longer and you'll most likely get better fuel mileage.  Good Luck, TomC
Title: Re: 8V71 swap to 8V92
Post by: akroyaleagle on October 03, 2012, 02:38:33 PM
I agree with Geoff and Clifford. Only a fool wouldn't!

I don't know much about MCIs.

I installed a re-manufactured 8V92T in my Eagle in 2000 and would never go back. By the way, the fuel mileage is the same now as it was with the 8V71N. For those that don't believe that, I have kept a fuel record since the first tank I put in. I know exactly how much fuel I am going to use virtually anyplace I have been before. Maybe it's all in how you drive it. I have a very light foot. I only needed power in the mountains so the truckers would quit saying "Shoulda spent less on paint and more on power". I can out climb any truck I have ever seen now and they say "bring my doors back".

Mine was guaranteed by Reliabilt at 525hp. I have 9A90 injectors. It doesn't smoke ever and has LOTS of power. I have a very large radiator.

As the guys said, have your friend or someone else knowledgeable about 92s inspect it for you. They should be able to easily verify the condition for you.

If the inspection covers are removed and the cylinders check out, you have the steal of probably your lifetime. Grab it up before the guy changes his mind.

When you get started installing it, ask questions here. There are many of us that have helpful info for you and a few like
Clifford, Geoff and TomC, that will answer the technical stuff for you.

Good Luck,
Title: Re: 8V71 swap to 8V92
Post by: jmblake on October 03, 2012, 05:39:37 PM
Thanks for all the replies, I hope this engine really does check out OK, and I can make a deal with this guy. I don't think my MPG could get much worse so I might as well have power to match the MPG. I will go next week and check this baby out. Thanks again Jason