camshaft turbo and non turbo
camshaft turbo and non turbo
(OP)
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
viv





RE: camshaft turbo and non turbo
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.
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RE: camshaft turbo and non turbo
thanks
viv
RE: camshaft turbo and non turbo
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.
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RE: camshaft turbo and non turbo
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
RE: camshaft turbo and non turbo
viv
RE: camshaft turbo and non turbo
RE: camshaft turbo and non turbo
viv
RE: camshaft turbo and non turbo
RE: camshaft turbo and non turbo
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
www.retallickeng.com.au
Was told it couldnt be done, so
i went and did it!
RE: camshaft turbo and non turbo
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/
RE: camshaft turbo and non turbo
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.
RE: camshaft turbo and non turbo
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.
RE: camshaft turbo and non turbo
RE: camshaft turbo and non turbo
RE: camshaft turbo and non turbo
viv
RE: camshaft turbo and non turbo
RE: camshaft turbo and non turbo
RE: camshaft turbo and non turbo
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!!
RE: camshaft turbo and non turbo
Don Redmon
Replika Maschinen, Inc.
RE: camshaft turbo and non turbo
About my previous statement. The engines I talk about always run at the same RPM, Unloaded or fully loaded, the RPM remains the same.
When you alter the rpm of the engine evenly with the load, it can change everything. I don't know for sure.
RE: camshaft turbo and non turbo
looking for trouble. Your compression ratio will surely be different and pumping the inlet with a turbo will quickly destroy your bus engine. Loosing your marine block along with cam surely implies further component loss. You may want to implant your normally aspirated buss engine until you come across a wrecker.