I've been told that some camshafts are hollow. I have NO idea of what brand or years this might apply to. Can someone enlighten me please? Note: I'm just looking for education here.
For some reason I want to say that Crosleys (Croslies?) used a hollow camshaft. Why does this kind of stuff get stuck in my brain? Also found it interesting that at least some Briggs & Stratton engines use a plastic camshaft. Wonder what kind of break-in process those require?
Had 89 Pontiac transport minivan with 3.8 v6. wife said car died. When I got it running it was only firing on 2 cylinders and no oil pressure. Cam snapped in 2. It was hollow. Sent from my SM-G965U using The H.A.M.B. mobile app
The 2.3 ford engine had a hollow camshaft, but that helped oil the rocket arms as it was overhead cam
Did a head gasket on my O/T, BMW E36, OHC a few years back.. It had a hollow cam, the manual said to use a SST to remove it, or the cam would break.. I just left the last two bearing caps on with the valves under pressure in between, then removed the cap nuts evenly on each cap to release the pressure..
Many motorcycle cams are hollow. Especially the high rpm engines. I'd bet that if the NHRA rules allowed it, the Pro Stock cams would be hollow too. But the NHRA is trying to cut the Pro Stock costs as much as possible, so that's out. "Gun drilling" is a common practice. The core of a round bar of most any material is all but useless. There is very little radial strength in the center. Look at a Top Fuel / Funny Car rear axle...it's a piece of tubing. Pro Stock axles are "gun drilled" also. The axles on MOST drag race cars have been gun drilled (if the owners can afford the extra cost of having it done) to remove a few...well some weight..! Mike
So, to recap (at least until more replies are given): Crosleys seem to be the only H.A.M.B. friendly engines that have hollow camshafts. Not that it matters inasmuch as I'm only looking for information and education, but that's the way it appears to me so far.
Splined lobes would be cool. If they were a 36 or 72 spline, you could play with the cams duration 5 or 10 degrees at a time.
Atcha I'm glad you asked the question because I didn't know that either. It is true, you do learn something new every day. Pat
You wouldn't be playing with duration though....just lobe separation angle , lobe centerline, and overlap. Since the cam turns at half speed, that also doubles the amount of change per spline when measured at the crank...72 spline would be 5° at the cam but 10° at the crank....36 spline would double those numbers. You'd need 144 spline for this to be a useful feature.
I wonder if one could be modified for this. I hope we still have room for an occasional laugh on this board?
Supercharged Miller engines ran the supercharger drive through a drilled camshaft as the blowers were rear mounted (usually in the ****pit with the driver)..
That is no joke. Some of the very big prime mover engines (really BIG) have a cam ***embled like that except the lobes are taper keyed to the shaft. Sometimes you have to knock the keys loose and move the lobe over several inches to fit in the grinder. These cams are over 10 ft. long.
The Ford ****** 1.9 four cylinder used a very hollow camshaft, with a plastic stick thingy inside that took up most of the volume. For amu*****t I researched the plastic thingy part number and found it's an available Ford service part!
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