Edge Orifice Flat Tappet Lifter

[Terry B.]

Some time ago I learned that Crower sold a mechanical flat tappet lifter that is an "edge orifice" design (#66909-16 @ $86.46). Since that is the design used by GM, I thought that would be the way to build a small block. Now I see that Crower has "improved" this design by adding a hole in the foot of the lifter to force oil directly between the cam lobe and lifter (#66909X980-16 @ $168.42). In the 50's and 60's GM got by without this improved feature but they also ended up in hot water because their cams and lifters failed in the 80's. What are your thoughts regarding the old school edge orifice lifters vs the improved edge orifice lifters? The motor in question is a 283 with a Federal Mogul CS-113R cam, VS-677 valve springs and Crane Nitro-Carb rockers (11801C-16). Thank you in advance for any and all thoughts.

[Duke W.]

Re: Edge Orifice Flat Tappet Lifter

With a Duntov cam and OE replacement valve springs, valve train loading is no worse than OE, and there were few lobe/lifter problems back then.

Also, Federal Mogul cams are made to the original GM prints including Parkerizing, which aids break-in, so I don't think there's a need for the more expensive lifters. I also don't see a problem with using the F-M piddle valve lifters, which offer greater oil flow to the valve train. These were originally developed for the big block, which has higher valve train loading. They aren't really necessary for a small block, but should do no harm as long as you don't run low on oil.

Back in the day before SCCA allowed dry sumps, the Corvette guys had to run the OE oil pan and overfilled it by a quart or two to avoid oil starvation.

Duke

[Timothy B.]

Re: Edge Orifice Flat Tappet Lifter

If I was building a engine with all new parts I might consider it because of all the engine oil issues these days.

Still trying to find a good picture but I read .024 on the face of the lifter so it's minimal but I bet it helps.

[Duke W.]

Re: Edge Orifice Flat Tappet Lifter

If I was building a engine with all new parts I might consider it because of all the engine oil issues these days.

What "engine oil issues" ?

Duke

[Joe L.]

Re: Edge Orifice Flat Tappet Lifter

With a Duntov cam and OE replacement valve springs, valve train loading is no worse than OE, and there were few lobe/lifter problems back then.

Also, Federal Mogul cams are made to the original GM prints including Parkerizing, which aids break-in, so I don't think there's a need for the more expensive lifters. I also don't see a problem with using the F-M piddle valve lifters, which offer greater oil flow to the valve train. These were originally developed for the big block, which has higher valve train loading. They aren't really necessary for a small block, but should do no harm as long as you don't run low on oil.

Back in the day before SCCA allowed dry sumps, the Corvette guys had to run the OE oil pan and overfilled it by a quart or two to avoid oil starvation.

Duke

Duke-----


The main problem with piddle valve lifters on a small block is that they supply too much oil to the rocker area, flooding the area under the valve covers with oil. This can result in high oil consumption and valve cover leaks.

The piddle valve lifters were available from GM well after the edge orifice type were discontinued. However, GM never replaced the edge orifice with the piddle valve type for SERVICE.

[Timothy B.]

Re: Edge Orifice Flat Tappet Lifter

What "engine oil issues" ?

Duke

I always use 15W40 CJ rated oil in my corvettes but I think there are people that use regular S rated oil.

[Duke W.]

Re: Edge Orifice Flat Tappet Lifter

That's a "people issue", not a product issue.

Duke

[Terry B.]

Re: Edge Orifice Flat Tappet Lifter

Duke, Tim, Joe thank you for your thoughts! Your comments have value and I believe they will make it easier to spend my money wisely. Terry---