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Engine Specific Info and Questions => IDI Engine => Topic started by: rodpaslow on September 29, 2009, 01:56:24 pm
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I'm looking at trying to get more out of my NA 1.6 and I have a spare camshaft from a 1.8 gasser I used to have. I currently work for a large machine shop, so consider modifying it would be easy.
If I could stick this in the 1.6 diesel; have it machine so the slot is in the end and taper is correct for the timing gear & also ensuring once in place, that it clears the pistons - would it make more power with this cam (i believe it's a 'G' gasser cam)?
Thanks!
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If I'm not mistaken, the gasser cams have significant valve overlap and so if fit to a diesel, pistons WOULD hit the valves.
Indeed, inlet opens 6 degrees before TDC, and exhaust closes 8 degrees after TDC.... OWCH! :o
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there are a number of Gasser cams that have negative overlap, the later Gas cars were dumbed down for emissions.
I have an ABA cam that I have been considering(close to 7 degrees negative overlap) but would probably have to machine valve pockets into the piston tops to keep them from mashing.
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why would you want to do that? people take diesel cams and put them in gassers and make rippers out of them. so that sounds like it would just be a waste of time.
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Theres a guy on TDI forum that who machined the valve reliefs and installed an aba cam in his tdi and it was said to run better. Can't remember the details. It did run better than with the stock tdi cam.
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who has done that( referring to diesel cam in a gasser)???
the diesel cams have substantially less valve lift and duration than gas cams, so they should not make more power.
the ABA cam is almost identical to the early diesel cams as far as duration and timing are concerned, but have substantially more lift, which makes it a prime candidate for trying out.
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from what i have read on my journeys there is little to be had in the means of performance gains.
If you want to see gains from a cam in a diesel engine, you have to first increase its ability to move air.
There is a reason they don't make performance cams for these engines.. :P it doesn't gain anything lol
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from what i have read on my journeys there is little to be had in the means of performance gains.
If you want to see gains from a cam in a diesel engine, you have to first increase its ability to move air.
There is a reason they don't make performance cams for these engines.. :P it doesn't gain anything lol
x2
that quote right there says it all. i rest my case.
and as for the diesel cam in a gas engine, they have a hella long duration or so im told. people used to take the 1.6's and put diesel cams in them when they turbo'd them.
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There aren't many people like us who want to mod a vw diesel. PP made cams for a while but in order for him to make any money the cost of the cam was higher than most fuel miser vw diesel owners wanted to pay. Theres just not a large enough market. Plus you'd have to machine your pistons for most anything larger than stock. Most people wouldn't wanna do that.
I will not believe the stock cam is the best for power in any engine from an oem for that matter. Maybe startability emmisions are better.
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camming a diesel is just not an economic way of gaining power. as foxracer1 stated you'd have to get in to some heavy machining to make the gains possible. not to mention the insane port job it would take to get all that extra air in there. and then you'd have to worry about your bottom end.
Look at all these big power making 1.6/1.9's not many use any sort of modified internals, to a degree. Cam's are not usually found on such lists. But if you were doing a mad power build and were going to be squeezing everything the engine had, Go for it :) machine it to work.. probbaly rip some serious Siht
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The machining i'm talking about is for valve clearence on the pistons. Not all that heavy in my oppinion. Stock cams are not designed for power therefore a diff erent cam would yeild more power when emission regulations are not taken in to consideration when specing the cam. Its not as easy as dropping in the cam so its not for every body. Serious Cummins 5.9 guys are not using stock cams. Serious Tdi guys are not using stock cams. You can make lots of power with the stocker but i believe there is more to be had.
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I agree, I have an ABA cam that may work, but it is a hydro cam, so it would take lots to amke it work in my mech head.
the ABA would be a good place to start if you are running a hydro head.
I am looking into the specs of the K-Grind camshaft, used in european gasser pickups, built for low end grunt.
the lift is about .5mm more intake and exhaust than the diesel one, and duration is 20* or so more intake and exhaust.
I am trying to find out the overlap specs, but they are supposed to fall on their face above 4000RPM in the gasser, so I am thinking there is a significant amount of negative overlap, perfect for a diesel.
TechtonicsTuning has them for sale for $50, and apparently they can be had from the dealer for about the same.
I am seriously thinking about using one, I might not even have to machine the pistons much to stuff it in.
-Owen
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I'm going to send a couple different diesel cams to comp cams and have them spec them out. That way i know exactly what lift and duration is across the whole lobe. Then compare it with the ABA cam and others.
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that would be cool, the other thing that would be nice is to know how many degrees before and after TDC the valves have to close and open to not hit the piston top(with an unmodified piston)
so that one could look at cam specs and know whether the cam will work or not.
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I think I will put a degree wheel on the crank and see how many degrees before and after TDC the piston is in the way of the valves.
I will put a HG on the block and mark the cylinder wall at something like 2mm down from the top of the gasket(most cams are measured with 1mm of lift to mark when a valve opens or closes) and spin the crank.
I will note the degrees when the piston comes to this line before and after TDC, this should give us an idea of what cams will interfere and which wont(based on the cam specs for valve open and close times)
hopefully there are some cams out there that fit the bill better than the stock diesel one.
-Owen
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I feel there is one that will work better. The stock one has to comprimise to meet certain standards and such. Works good stock but not for maximun ouput.
My only issue is that cams will lower dynamiccompression so with my 1.9 head it"ll get a little more finicky depending on the cam. May try to put 1.6 precups in my 1.9 head. Than i can afford to mill the valve reliefs. I'd be happy with 20:1 or so. I also think a custom or gasser long runner would help no to low boost opereation when combined with a cam.
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I feel there is one that will work better. The stock one has to comprimise to meet certain standards and such. Works good stock but not for maximun ouput.
My only issue is that cams will lower dynamiccompression so with my 1.9 head it"ll get a little more finicky depending on the cam. May try to put 1.6 precups in my 1.9 head. Than i can afford to mill the valve reliefs. I'd be happy with 20:1 or so. I also think a custom or gasser long runner would help no to low boost opereation when combined with a cam.
I seem to recall that all of the precup inserts are of the same volume, it's the volume milled into the head that changes from engine to engine.
I was going to put 1.5 precups in a 1.9 head to be placed upon a miller-cycled 1.6 to get back up into the cold starting range, but measuring the 1.5 and 1.6 precup inserts gave me the same numbers...
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Huh that dosen't make it easy for me.