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04-21-2018, 08:14 PM | #1 |
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Flat tappet lifters
Hi all
Looking for advice on solid flat tappet lifters for a maximum effort sbc 311" with factory cast iron heads restricted to a maximum tappet diameter of 0.904" and mushroom tappets are not allowed as per class rules (Australian Superstock). Whilst we have used Schubek/Smith lifters in the past with one failure (what a mess) were looking at going a different way. Given the rpm (8500-9500) and the aggressiveness of a newer style camshaft we are running (Cup style cam) we are looking to get some recommendations on lifters. I have read in some older forums that racers have had good results with DLC tool steel lifters. So i would just like to get some feedback and past experience with these and if they require any special break in or oil to be run with them. The cam shaft is a steel core 55mm cam with all the latest surface treatments for increasing surface hardness. Any input would be highly appreciated. |
04-21-2018, 09:29 PM | #2 | |
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Re: Flat tappet lifters
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Your choices are NASCAR Nextel Tool Steel lifters with the DLC coating made by Trend, PPPC and Ferrea. The PPPC tool steel lifter can be sent back to PPPC for resurfacing later on. For your application, make sure to get a lifter for an AMC application since they have the proper pushrod oiling for a Chevy engine. Both Trend and PPPC make the oiling modification. Ferrea already has a modified lifter under P/N LF1004. http://trendperform.com/b-94213-1149...rformance.html https://www.pppcenter.com/06Catpgs/C5.pdf |
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04-22-2018, 05:46 AM | #3 | |
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Re: Flat tappet lifters
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04-22-2018, 06:21 AM | #4 |
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Re: Flat tappet lifters
Yes, you can run DLC coated tool steel lifters on an 8620 steel core camshaft. I strongly suggest the high end finish that Comp Cams has recently introduced. I use and sell only Trend lifters. I suggest you ask your lifter supplier about motor oil, as certain DLC coatings do not always work with just any motor oil.
We use the Trend tool steel lifters (without DLC) with as much as 550# open pressure on 0.842" lifters. We do this on nitrided cast iron core cams, and we do not use the EDM oil hole.
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04-22-2018, 07:28 AM | #5 | |
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Re: Flat tappet lifters
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04-22-2018, 08:45 AM | #6 | |
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Re: Flat tappet lifters
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We're not using DLC coated lifters, we may try them in the future. The guy to talk to at Comp is Dave McCarver. The new finish is one actually developed for the LSx series roller cams. However, the idea behind it is to provide the smoothest possible surface, so that more of the roller contacts more of the lobe. The gain for a flat tappet application is that the breaking is pretty much a process of burnishing and polishing. So the more polished a surface is to start with, the easier it is to finish the break in. Realize that DLC is just like the foot on a Schubeck in that it absolutely does not tolerate impact or abrasives. That's the reason DLC does not work on cast iron, cast iron is a really nasty abrasive.
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04-22-2018, 09:06 AM | #7 | |
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Re: Flat tappet lifters
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04-22-2018, 09:20 AM | #8 | |
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Re: Flat tappet lifters
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04-22-2018, 02:15 PM | #9 |
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Re: Flat tappet lifters
Both the Trend and PPPC lifters operate well with high spring pressures and the DLC coating is a plus to prevent wear. DLC coatings have improved and most of the high end solid and roller lifters are DLC coated including, Jesel and Morel.
My Boss at my place of employment, was the engine shop manager for 30 years in several NASCAR teams. He used and we continue using both the Trend and PPPC, DLC coated lifters with no issues. As regards to the engine oil and DLC coating compatibility, a few have experienced issues with the Driven oil. My recommendation would a synthetic oil such as Mobil 1, Lucas or Amsoil. There are many SAE Engineering papers that have tested the compatibility and it appears that the recommendation for best wear is to use 5W-30 weight synthetic oil with DLC coated parts. Last edited by SSDiv6; 04-22-2018 at 02:20 PM. |
04-22-2018, 07:44 PM | #10 | |
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Re: Flat tappet lifters
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Thank you for the response, starting to get a lot more confident with this type of setup. Given your Boss' past experiences within NASCAR would you be able to comment on a camshaft specific question? My question relates to cup style camshafts being apparently designed to loft the lifter and hence giving the valve additional "dynamic" lift whilst running. Is this something that you or he has encountered and if so how would a DLC coated lifter hold up in this scenario? As Alan mentioned above you don't want a DLC lifter bouncing around so to speak because it will have the same result as a Schubeck, thus it seems strange to want to design a camshaft to loft the lifter with this potential catastrophic result. Any input would be highly appreciated. |
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