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Turbo Charging An End 673


willyb42

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Willy,

This has been an ongoing discussion here for several years.

Look into the old forums, and you will find a lot of information

about retro-fitting a turbocharger to your NA 673.

The general consensus is that the engines were not set-up to

accept a retro-fit turbo, but in some instances there have been successful

installations. (There have been plenty of meltdowns too)

The early turbocharged 673 engines may not have had the oil cooled pistons,

and were also limited in their rated power (205 hp, I think).

The later units were rated up to 250 hp, and had the oil cooled pistons and

other modifications to handle the charge air pressure.

Regardless - the engine is not a good basis for a hot-rod motor.

If you can go back and buy the whole E-7 engine, it might be a better starting point!

Actually, by the time you are done with the retro-fit, if it's done properly you will have spent

a small pile of money and a big pile of time.

You might consider purchasing an early Maxidyne 237, 250 or 285 hp, and probably will be much better off.

I don't mean to be the bearer of bad news - but the retro-fit turbo route is a tough path to be on.

Paul Van Scott

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Willy,

This has been an ongoing discussion here for several years.

Look into the old forums, and you will find a lot of information

about retro-fitting a turbocharger to your NA 673.

The general consensus is that the engines were not set-up to

accept a retro-fit turbo, but in some instances there have been successful

installations. (There have been plenty of meltdowns too)

The early turbocharged 673 engines may not have had the oil cooled pistons,

and were also limited in their rated power (205 hp, I think).

The later units were rated up to 250 hp, and had the oil cooled pistons and

other modifications to handle the charge air pressure.

Regardless - the engine is not a good basis for a hot-rod motor.

If you can go back and buy the whole E-7 engine, it might be a better starting point!

Actually, by the time you are done with the retro-fit, if it's done properly you will have spent

a small pile of money and a big pile of time.

You might consider purchasing an early Maxidyne 237, 250 or 285 hp, and probably will be much better off.

I don't mean to be the bearer of bad news - but the retro-fit turbo route is a tough path to be on.

Paul Van Scott

Thanks for the Info. I have thought about the 237 route, but the 673 i have was completely overhauled less than 10k ago and kinda want to keep it. would b nice to have a little more umph on the hills though! But thank you very much for the input, The truck is still a real blast to drive around. maybe I will just leave it alone. thanks

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I can tell you first hand, it didn't work for us !! I bought the truck with a freshly overhauled 673-P....that was supposed to be built for a turbo. Hell...I ain't a Mack mechanic and didn't know the difference.....learned a lot in a big hurry though LOL

Over the years....I've talked to three other people, that experianced the same thing with the same results...funny thing about it...the engines all ran less than a 1000 miles.

We knew something wasn't quite right...but didn't think we'd hurt much...just bob-tailing around. WRONG.. But it sure run like raped ape for a short while.

If you look in my gallery...there's a picture of one of the two pistons that broke.

Anyone that needs a good block, brand new turbo or anything off of that old engine...let me know. We're getting sick of that motor in the way all the time. It would just about kill me to scrap it..but no one seems interested. All seem to be doing what we did....go with a newer Maxidyne

John

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My 711 is was retrofitted to turbocharging in 1966 with a Mack kit after burning valves. It still runs very well, but the truck is shot due to rust.

Maybe the usage of a lower volume turbocharger would up the power but let it live.

Rob

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

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  • 1 month later...

I installed a turbo on my old 673. It is not on the road yet so I do not know how it will hold up. One BIG!! difference between the turbo and non turbo engines is the use of the Syncro-Advance on the injection pumps. I installed a pump from a turbo engine, NO Syncro-Advance.

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