MCI 96A3 6V92TA Swap to an 8V92TA

brettpearson67 · April 21, 2019, 05:48:07 PM

Ok, so I just bought a 1985 MCI 96A3 and it has the 6V92TA. I am planning on rebuilding the motor, but I am wondering if a swap to the 8V92TA might be worth considering?
Is it a "bolt in" swap?

If I'm going to do all the work rebuilding the 6, might I find an 8 and rebuild that instead?

Thoughts?

Thanks

buswarrior · April 21, 2019, 06:32:52 PM

8V92 set up to make big power is a raging fuel gulping furnace burning down the back that is hard to cool in those coaches.

I think you'll need a different cradle and driveshaft length.

Build the 6V92 to the 350 HP setting, life is simpler?

Smarter ones than me will chime in.

Happy coaching!
Buswarrior

DoubleEagle · April 21, 2019, 08:58:34 PM

Not smarter, but this would not be a bolt-in deal, and you would have a lot of problems to solve. Cooling capacity would have to be increased, and in the case of your coach, it would not be easy. If you have the money and time, go ahead, but you were warned.

brettpearson67 · April 22, 2019, 04:30:42 AM

If I kept the 6V92? What kind of performance upgrades can be done?
I see marine engines in the 400-425 hp range and more.
What is practical with this engine?
375-400hp?

buswarrior · April 22, 2019, 05:29:41 AM

Horsepower equals heat.

Marine engines have limitless cold water available to cool them.

Your MCI can cool a 350hp, so long as everything is in decent condition, you will have to freshen up all the seals around the fan compartment, door, and around the radiators.

Find a local busnut with this power setting and try their coach. 350 in that chassis is quite pleasant combination of performance and fuel economy.

No matter what HP you put in, they slow climbing the mountains, and won't be doing burnouts at the lights.

It takes a considerable fuel burn to get a coach closer to auto performance, and it still falls short. Many have spent a lot of money, frustrating themselves in the end.

Happy coaching!
Buswarrior

blue_goose · April 22, 2019, 05:44:51 AM

Be a good time to put in a 4cycle engine.
Jack

6805eagleguy · April 22, 2019, 06:41:07 AM

Quote from: blue_goose on April 22, 2019, 05:44:51 AM
Be a good time to put in a 4cycle engine.
Jack

Yep, but thats a lot of modification, definitely not a bolt in swap. (not that the 8v92 would be either, but it would be fairly simple)

There is no replacement for displacement but BW already said, HP = heat.

Have fun!

bevans6 · April 22, 2019, 06:50:41 AM

If you put in an 8V-92, get one on the cradle out of an MCI. The cradle is different, the bellhousing, front cover and engine accessories are unique to MCI so a truck engine will be a PITA to convert. Four stroke engines have a lower RPM range so the differential gear may need changing or go to an overdrive transmission, but the cooling problem is solved - they don't need nearly as much cooling as a two stroke, as a rule of thumb.

I'd listen to the 350 hp 6V-92 guys on this one. There's a rule of buses and life that I didn't learn until it was too late - get the one that has what you want the first time. In this case that means buy a bus that has the engine you want already.

brettpearson67 · April 22, 2019, 06:53:41 AM

I tend to creep away from the KISS principle, to my detriment.
I think I'll go ahead and adhere to it this time, rebuild the 6V and up it to the 350HP. It will be a fun project that I can share with my kids, and it won't break the bank.
Thanks for all the input
.

Gary Hatt - Publisher BCM · April 22, 2019, 09:32:51 AM

There are quite a few Series 60 engines out there now just waiting to be used. That would give you more torque, better fuel mileage, and run cooler. Also, as some folks are concerned about now, there are many more people that can work on them if you need to have it rebuilt. The Series 60 will also go many more miles between rebuild.

On the other hand the 8V92 is a really cool sounding engine. If you go that route, be sure to replace the muffler with a resonator and clean out your radiators really well and ensure your radiator fan is running at maximum efficiency and it never hurts to put air scoops on the back of your bus to draw more air into the radiators. If your radiator has louvers, best to remove those unless you need to run in the winter up north a lot.

I had an MC-7 with the same upgrade you are talking about and you really had to watch the temps when climbing. And another thing, misters would be a great help too.

Either solution will work, but most will argue go with a 4-cycle nowadays unless you are a diesel mechanic.

One guy I know that just sold his Prevost with an 8V92, he sold it with a second 8V92 that he kept as a spare in full running condition. Then if his main engine got tired or sick, he could just swap out the other engine over a weekend and keep on going.

luvrbus · April 22, 2019, 09:57:17 AM

The standard HP for the older MCI's with the 8v92 TA engine were just 360 hp because of the cooling , it is not a problem getting the 6v92TA up to 400 hp 350 hp is a good setting with 1100 ft lbs of torque FWIW the series 50 is the easiest 4 cycle to install in a older MCI like yours

brettpearson67 · April 22, 2019, 12:44:51 PM

I like the 50 series. Other than engine mounts, what would be the most difficult aspect of the swap?

Van · April 22, 2019, 02:53:28 PM

Well you will need the engine cradle the mounts, air intake plumbing to figure out. along with the CAC. And... while you are at it you might figure on the B400R trans upgrade Hydraulic pump set up Hyd lines and oh did I mention this is an electronic engine and trans sooo... rebuild what you have unless you go all in. Still interested? go buy a Gillag Phantom, it comes with most of the goodies you will need. Ps. forgot about the gear set for your differential.
I know there is more that I left out but now you know what is involved.
Good luck!
Van

brettpearson67 · April 22, 2019, 03:31:58 PM

Quote from: Van on April 22, 2019, 02:53:28 PM
Well you will need the engine cradle the mounts, air intake plumbing to figure out. along with the CAC. And... while you are at it you might figure on the B400R trans upgrade Hydraulic pump set up Hyd lines and oh did I mention this is an electronic engine and trans sooo... rebuild what you have unless you go all in. Still interested? go buy a Gillag Phantom, it comes with most of the goodies you will need. Ps. forgot about the gear set for your differential.
I know there is more that I left out but now you know what is involved.
Good luck!
Van

Whew!!!
Yeah, rebuilding what I have sounds good.
Any idea what would be involved in upgrading to the fire truck spec 400 horse version of the 6V92?

Van · April 22, 2019, 07:11:45 PM

Quote from: brettpearson67 on April 22, 2019, 03:31:58 PM
Whew!!!
Yeah, rebuilding what I have sounds good.
Any idea what would be involved in upgrading to the fire truck spec 400 horse version of the 6V92?

Injectors will be one item on the list. I am in the same camp as the previous posters (all good advice) in keeping it at 350 hp simply because of the heat factor. trust me, a freshly rebuilt mill at 350 will keep a smile on your face.
you will need to pull your radiator(s) and have them gone thru while your engine is being rebuilt other wise you'll be sorely disappointed if you over heat your fresh motor. Make do with what you have when done and if you decide you want to step up and run with the big boys in the fun lane, that will be the time for another bus with the DD60 series and 6spd B500. keep it as simple and cost effective as possible and short cut nothing on Maint.