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#41
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Real, according to the FT break in procedure since forever, to raise RPM to lubricate lobes during break in. Now once broken in, are we saying that the lube running down over the cam from the top end return, is enough to lube the flat tappet cam for extended operation below 1800 RPM? Remember, the FT cam (and the pontiac engine) had mostly gone away by the time the first OD transmissions came out.
As for cam recommendations, choose based on lowest expected cruise RPM at OD with converter locked. You want a cam that establishes good port velocity at that RPM, not still in "hot for teacher" reversion that will buck at that low loaded RPM. I'm thinking 068 to 2801 territory. The Lunati 702 may be the biggest you want to use. A small roller might get you a broader powerband and still smooth it down low. Its the stock converter and lockup behavior you gotta watch for. Late model motors like LS can increase the lockup speeds, use higher stalls and stretch the shift points when the cams get frisky. Harder to do without a computer controlled transmission.
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I could explain all this to the girl at the parts store, but she'd probably call the asylum. White '67 LeMans 407/TH350/Ford 3.89... RIP Red '67 LeMans. 407/TH400/Ford 3.25 |
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#42
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SKU 66056X3 .0025 Groove from the oil band to the lifer face for reduced lobe wear Heavy Duty Snap Ring
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Ed 1968 GTO (Thanks Mom) 2006 Silverado 2007 Cadillac SRX 2015 Chevy Express ![]() 2024 Cadillac LYRIQ |
#43
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FWIW…If the engine operated much above 1200 RPM cruising in OD I doubt you could see lubrication issues with the cam. Most continuous duty industrial engines usually operate at around 1760 RPM (basically every American V8 has been used for irrigation pumps here in the Midwest). They don’t have much trouble with cams versus anything else, probably actually have less trouble versus in a vehicle.
We have found small cams do not necessarily make the engine super efficient at pulling vehicles with overdrives. I think it is because some of those smaller cams you end up with unexpected pumping losses. You can actually add a lot of cam with some hot for the teacher idle and still get good fuel economy. I recall Richard Guido’s turbo charged 1400 HP 500+ cid Pontiac getting over 20 mpg on his long trips from Canada to the drag and drive events. Last I knew that had a Bullet SR cam in it in the 240*s @ .050” on a wider LSA. My pump gas TA usually gets the lower 20s for fuel economy with 3.23s, it is an 11:1 461 with a 245*/253* 114LSA @.050” Bullet roller cam. It has a hot for the teacher idle like a RA4 cam. The roller cams definetly can help with the average low end power. I often see guys want all the power in by 5000 with an overdrive to get good fuel economy, but it does not always work like they think it will. Part throttle does odd stuff. My TA is just starting to go when it hits 5000. |
#44
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"....are we saying that the lube running down over the cam from the top end return, is enough to lube the flat tappet cam for extended operation below 1800 RPM? "
One observation.... "You'd be amazed at how much oil naturally comes out the bottom of the lifter bore, and floods the cam lobe. It's a solid column of oil, completely around the lifter, dumping onto the cam. Just prime an engine without the valley pan on, and you'll see what I mean. It dumps quite a bit with a cold 20/50, so you can imagine how it comes out when the oil is hot." Paul Carter Carter Cryogenics Koerner Racing Engines .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) Best time 5.13 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
#45
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Yup, I even have a video of it on my YouTube channel, of a Pontiac engine no less. It's massive amounts of oil that just floods out around the lifter, so much so it's amazing any of it actually makes it through the push rod and to the rocker arms.
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#46
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Where would one look to having a cam nitrited?
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#47
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I am happy with old faithful and newer Comp 857's. A little ticky when it is fully heat soaked but hasn't blown up yet. Will report back when it does.
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#48
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There are multiple places in Michigan that offer nitriding processes.
Start here...... https://www.ahtcorp.com/services/nit...urizing%20(FNC). https://sunsteeltreating.com/#:~:tex...to%2030%20tons. Ordering a new cam from Comp ? COMP Cams has proven their technological leadership by becoming the first aftermarket valve train company to own and operate a Pro Plasma™ Nitriding service in-house. .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) Best time 5.13 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
#49
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Which newer Comp HR lifters? 857S or the cartridge style?
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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule. |
#50
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not the evolutions, the older newer ones, if that makes any sense.
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#51
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The older before the Evolutions were the ones made by Shaver Engineering in So Cal for Comp.The Evolution looks the same except it has the cartridge.Tom
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#52
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I've been having Comp do it.
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#53
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The problem is that there doesn’t seem to be a clear consensus on which roller lifters are good for a basic mild build without buying the most expensive Johnson’s so it’s almost a pick you poison on a HFT or roller.
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#54
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As far as I'm concerned there's only one pick whether it's a mild build or not, and that's the Hylift Johnson's with pin oiling. Yeah they are expensive, last set was $1400 for a sbc build I did just recently and I've seen the price as high as $1600, but I've never had or seen a set fail as in breakage, they run perfectly quiet, and I've had them in engines for many years without a problem. While others run cheaper brands and have issues with link bars, bleed down rates, noise, broken wheels, etc..... The problem though is price (understandable) and the fact that they are hit and miss as far as availability, they seem to go through stints where they are hard to get for months.
Probably a very close second would be the new evolutions, but even those are $700 which most here will consider too expensive as well. I'm actually going to try a set in another build I'm doing. At least if you get a noisy one you can swap out the cartridge for minimal cost. They have pin oiling and they've made the bodies thicker/stronger than previous versions from Comp. So it has potential. |
#55
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Last edited by Jay S; 12-20-2024 at 05:29 PM. |
#56
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It’s almost 2025 & we’re dealing with either paying stupid money for lifters, guessing from a large manufacturer or worrying about flat lobes, no wonder guys switch to LS motors, what a sad state of affairs for us as Pontiac lovers. |
#57
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#58
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I have 5,000 miles on an older set (2010 ) of morels from Bullet and I don’t think that make any excessive racket . Makes about as much noise as a stock 5.3 LS that I had .
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#59
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Final drive of 2.38 to 1 in OD.... the 702 cam should be a faster rate with good lift for stock/mild heads. I like the 9.25 cr to be safe with todays gas.
I feel your already on a good plan... I would suggest Good lifters...and light springs for a camshaft break in...just to be as safe as possible. And as always oils, for us old flat tappet people. |
#60
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Retro rollers will be OK for low mileage applications that get a lot of attention. Failure rates support support this fact.
Solves some problems causes others that have not been resolved. Buy buy buy they will sort it out... |
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