camshaft turbo and non turbo 1

[captviv]

hi , i have 2x navistar/international 1993 , 7,3 litre 444 cubic inch turbo diesel engines in my boat . would like to know if it is possible to use a non turbo camshaft from the same size motor and use it in my turbo motor ? if yes , would i be loosing any horsepower ? thank you
viv

 

[patprimmer]

Do you know the specs for the turbo and non turbo cams. Sometimes there is no difference.

I don't know about your engine, but in general, sometimes there is a difference in cams for engines designated for different applications, ie stationary, truck, car, marine.

Regards

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[captviv]

no , dont know specs . checked on the numbers punched on each cam , and they are different . was wondering if the angle and length of the lobes would be different , and if then that would cause loss or gain in power of engine ....

thanks

viv

 

[patprimmer]

Is lift different.

Most likely difference is lobe centres.

Lift is easy to measure. Lobe centres requires a lot of work with a dial indicator and a degree wheel.

A cheap degree wheel is the ring gear. Divide 360 by the number of teeth for how many degrees per tooth.

Remember there is 720 degrees per engine cycle.

Regards

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Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Fabrico]

You won't loose power. You don't need to change the cam.

Bank's has an article on turbocharging the earlier IH engine.

http://www.bankspower.com/im_TB_Dec96.cfm

 

[captviv]

thank you fabrico , you see my problem is ..... have blown the block and camshaft on one engine , and can only find a non turbo replacement block and camshaft. therefore wanted to know if possible to use it in a turbo application , as rest of parts still ok . thanks
viv

 

[Fabrico]

I was only referring to turbocharging a non-turbo motor and not loosing power in the process. Not loosing power is not the same as making the same power. You should avoid configuring something that is not in balance with the other engine. Unless you monitor EGT between the two you may loose another motor. Surely there must be more sources for repair parts.

 

[captviv]

unfortunately not ..... i am a diplomat in cuba and it will be difficult and costly to import a new motor . the non turbo motor is used here in old buses , and looking at it , looks like all i have to do is bolt on my turbo and exhaust manifold ( cause water cooled ). but , still not sure if merely bolting on my turbo to the "new" engine will give me same performance as my existing motor in boat .... whats your thoughts ? thanks
viv

 

[boatmotorgod]

Marine engines need to make more power at higher rpms then std. engines. Boats have to turn more rpms to go faster and therefore see increased load with increased speed. When the bus gets up to speed you let up on the throttle and cruise. To opperate the engine at close to WOT all day long; the marine engine is balanced better, usually has windage trays in the oil pan, usually has larger valves and utilizes a different camshaft. Turbo motors can utilize slightly lower compression ratio's too since the turbo is forcing more air into the engine. The camshaft is the brains of the valve train, it is optimised for turbo, non-turbo, compression ratio, and marine/higher RPM use. Don't expect to get the same power with the bus engine. however you might be able to rebuild the bus engine utilizing the cam,head, and oiling system from the marine engine and get decent results. Or you might have to lower your expectations and make due with what you have availible or can afford. This might entail reducing prop pitch to achieve decent results with less power. Good luck!

 

[kenre]

captviv,

One other thing you need to look out for is some engines used for turbocharging have oil squirters in the block, to cool the piston crowns. If the non turbo one doesnt have these and there is no provision to fit them i would be very cautious
to add the turbo. Oil pumps may be different to compensate for the squirters. Hate to be stuck a long way from land with
pistons full of holes.

Ken

http://www.retallickeng.com.au

Was told it couldnt be done, so
i went and did it!

 

[Fabrico]

That's right on the duty cycle for boats, and cooling the pistions on some engines. Some also use different crank bearings and oil coolers for the turbo'ed application.

Anyway there are several forums that talk of nothing but Powerstroke engines. Some there should be exactly familiar with your situation. Try a search under "powerstroke forum".

One is

http://www.powerstrokeforum.com/

 

[jbthiel]

Typically a turbo cam has less overlap than a non-turbo cam. But putting a turbo on a NA engine will work - it just might not be as efficient or powerfull as it could be. There are many diesel engines out there that are made in NA, turbo and turbo aftercoold configurations with few differences in the base motor. They just put a turbo cam in a NA engine.

As for cost, I can't imagine that getting just a cam shipped to you would be too expensive. And I would carefully inspect the block for any differences mentioned above.

 

[patprimmer]

I have seen factory turbo options in cars where cams are different and also where they are the same. Same deal for blocks, rods, cranks and pistons.

I have seen marine versions of auto engines that have some std parts and some heavy duty special parts.

We are all guessing unless someone can be specific about the NA bus motor vs the turbo marine motor.

The factory engineers will normally only upgrade to more costly components if testing proves it necessary, so it depends on how much reserve capacity there was in the original NA design.

If the vast majority of production were turbo they might not get a cost saving when buying smaller quantities of a lower spec part, so they might use the turbo part in the NA version. We simply don't know unless someone here can give specific information on both engines.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[captviv]

thanks patprimmer .... the "people" who marinised my engines are "starpowr" , but have not managed to get it touch with them . cant seem to find anything on web regarding them ..... hope there is someone who can help ?

 

[merritr]

I sent a quick message to a friend who works for International Diesel. At the moment he can't look up the parts to be sure the cam is the same between the turbo and non turbo motors, but he believes they should be. I can get a more solid answer tomorrow.

 

[captviv]

thank you merritr , have managed to find a block , so info would really be appreciated
viv

 

[merritr]

Word is that the part numbers are the same: International p/n 1805072c92

 

[merritr]

That last post was just the part number for the normal (non marine) diesel motor service assembly. The marine assembly p/n is 1821361c91 and the cam p/n is 1821321c1. They are the same numbers between turbo and non turbo engines.

 

[CapeNor]

For marine diesel engines (500rpm 4stroke)

A turbo camshaft differs greatly. The inlet valve opens a lot quicker and the overlap is bigger. This is because:

The inlet valve can open when the pressure in the cilinder is lower than the boost air pressure. With a turbo, this can be earlier.

The Turbo will increase the exhaust manifold pressure. So the exhaust gassen leave the cilinder less fast.

The overlap is bigger. It seems negative, but the turbo is NOT usefull for better scavenging, it's to bring more mass of air in the cilinder, so more fuel can be added.

For marine diesel engines, 5000 kW and 500 RPM 4stroke, it can differs as much as 25 degrees crank angle (camshaft angle is half of it).

The lift of the valves is not changed, because this is determent by the design of the cil head and the piston (clearance between the piston and the cil head)
The speed of the lift, the initial angle of the cam, can be changed, but I don't know if they do that a lot. If you increase these things, the stress on all parts are increased a lot!!

 

[DonReplika]

While I do not know your specific applications. In automotive usage a turbo and N/A camshaft are quite different. To keep this simple. A forced inducted engine requirse less degrees of camshaft duration. It simply takes less time, this is where the the forced part comes in, to fill the cylinders. Hence a smaller camshaft for the N/A engine. Contact a camshaft specalit about a proper camshft for your application. Mixing and matching components that were not designed for the application is simply looking for trouble.
Don Redmon
Replika Maschinen, Inc.