Flat vs Dished Camshafts - And which Oil Pump do you need?

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In the world of engine rebuilding, you can never have enough knowledge. Here is a quick tech tip on the difference bewtween Flat and Dished camshafts, and which Oil Pump you will need for your Type 1 engine.

For aftermarket and horsepower enthusiasts, a camshaft swap is the staple for modifying engines. If you've swapped cams, or want to add oil cooling & capacity to your engine, swapping the oil pump is a necessary upgrade for engine longevity.

  • So which oil pump do I need?

To keep it short - For a flat camshaft, you'll need an EARLY style oil pump. Dished camshafts require a LATE style oil pump.

  • Whats the difference?

Early style (single-port, up to 1970) engines used a flat-faced camshaft, which is easily identified by the 3 rivets (or bolts) holding the cam gear. These were used until 1970 in most any single-port engine. One key element, all aftermarket cams are of the flat-faced camshaft variety. This means regardless of your engine build, if you put in an aftermarket camshaft you'll need an early-style oil pump to match.

Flat camshaft - early


Late style engines (dual port, 1971 and later) use a dished-faced camshaft, identified by the deep dish on the camface and the 4 rivets holding the cam gear. These were used on all dual port engines 1971 and on. Dished camshafts require a late-style oil pump, which has a longer oil pump drive tab.

Late - Dished Style cam

  • How do I tell which camshaft I have?

Easy! Remove your oil pump (which may require the special, but inexpensive tool P/N 5002 - Oil Pump Puller) and look through the hole. 3-bolts/rivets and flat face means you need an early pump. 4-rivets and a dished face means you need a late pump.

  • Why aren't they cross-compatible?

The largest issue is the incompatibility between late and early cams and oil pumps. An early oil pump on a dished cam will not seat the drive tab fully, which means your oil pump will not spin to circulate oil. This can cause bearing damage and even locked engines. When reassembling your Air-cooled engine, it is always a good idea to always double check that your oil pump drive tab fully seats in the camshaft drive slot.


Thanks for reading! If you ever have questions or comments, or have information request - please contact us! You can leave a comment below, email us Sales@DuneBuggyWarehouse.com, or shoot us a call at 513-868-9543. We are enthusiasts and always enjoy hearing from fellow enthusiasts.