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#41
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If you want to use a HR for a fraction of the cost I have very nice used HR set up with HLJ lifters that is close to size as the cam you were running (275DEH). |
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#42
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Sorry Paul I did not notice your post when I pecked out my reply.
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#43
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We had a cam/lifter failure on the dyno about 2 years ago. Engine had about 1 hour of running time on it. Ford small block. A 260 CU In stock engine restoration for a Falcon Sprint. So low valve spring pressure, very careful assembly, loaded up with break-in lube on cam and break-in oil. Melling cam and lifters, stock grind. One lobe went away fast. Short answer to "where does the metal go?". Answer, everywhere. It was incredible where that iron paste and tiny granules end up. Specifically, quite a bit in the piston ring lands and around the rings. Also packed up behind the dead end oil gallery plugs, in the oil pump, in the links of the timing chain, in the fuel pump cavity, rocker arm pivots, inside push rods, just everywhere. On this engine, we cleaned absolutely everything with solvent and spray wash cabinet. Surprisingly, we were able to use the rings and bearings over. But remember we are talking about 1 hour run time. The owner decided to go the hydraulic roller route he was so spooked. That was against my recommendation, but it made him feel more secure. I really think these occasional cam failures are just pure bad luck in many cases.
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#44
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Like Mgarblik said, I really think these failures are just bad luck with a few other reasons mixed in, many of which aren't the cams fault. |
The Following User Says Thank You to Formulajones For This Useful Post: | ||
#45
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Very possible they have always failed at the same rate they do now .... it's just that now, with the internet, each failure is amplified as thousands of people read about it. 30 years ago you said awww shucks, went to the store and bought new parts and no one heard about it.
And of course you never hear about the hundred thousand that broke in fine and have worked for years.
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The Following User Says Thank You to dataway For This Useful Post: | ||
#46
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Exactly my thoughts dataway. Only difference between then and now is that now the information highway lets everyone know about it.
Sometimes I think everyone would be better off putting the computer down and just get back to building cars again. Spread info the old fashion way by getting these cars out and drive them, mingle with the car crowd Last edited by Formulajones; 01-25-2024 at 06:31 AM. |
The Following User Says Thank You to Formulajones For This Useful Post: | ||
#47
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Before Hy-lift Johnson there was just Johnson. They had one of the best lifters on the market. Every lifter they sold had been hardness checked. Around 1990 they stopped this process. It makes sense to me they performed this QC test "for a reason". I'm doubting it was to keep an extra person employed.
Now after thirty years of excuses we know that most lifter failures are due to soft lifters. FWIW |
#48
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i wiped a 327/300 cam in a chevy 350, around 1995. engine had been built in the mid-80's. every now and again a flat tappet loses a lobe, no getting around it ...
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The Following User Says Thank You to i82much For This Useful Post: | ||
#49
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Yup
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#50
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The Following User Says Thank You to Ram Air IV Jack For This Useful Post: | ||
#51
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I think people just like to complain more than ever before lol
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#52
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"Bad luck"? No.
SOMETHING(S) are responsible. The problem is figuring out "what" the problem(s) are. There's so many possible causes of failure that it's hard to count 'em all. And there may be some number of small issues combining to produce a failure that any one single issue wouldn't have caused. We've mentioned metallurgy including the hardness of the cam lobe and lifter bottom. We've mentioned the surface finish of both parts--ground correctly, proper taper, appropriate spherical radius. Valve spring pressure--too high, or too low. Oil and additives including assembly lube. Oil system variables--windage trays reducing oil splash, grooves and holes in lifters or lifter bores to supply additional lube to the lobe/lifter bottom interface. There's a likelyhood of "modern" cams being more-succeptible to failure due to the higher-intensity lobes compared to mild lobes of years ago. I don't remember talking in this thread about oil temperature, or OEM machining of lifter bores out-of-position. Chevy big-blocks are kinda infamous for having the lifter bores moved out of position due to sloppy machining at GM. There's a potential for harmonics in the various vibrations the valvetrain is subject to, to provide unexpected, instantaneous loading at a certain critical speed. On boosted engines especially, popping-open the exhaust valve against residual cylinder pressure can cause enormous stress on the valve, rocker, pushrod, lifter, and cam. I don't think we've talked much about sloppy assembly procedures leading to dust/dirt/sparrows/gravel being left in the engine during assembly, although we've discussed the debris created when the cam/lifter failed. |
#53
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Back in my day, wiping a cam was like wiping your butt ... everybody did it, most people didn't feel the need to talk about it in public ...
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The Following User Says Thank You to i82much For This Useful Post: | ||
#54
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#55
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Many shops will not build an engine using a flat tappet set up.... Shops maintain this policy "for a reason". |
#56
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Ive got one to break in when it gets warm again, I put new but weak Erson 1.58 IH valve springs on my round port E'heads for break in, but it is a old school NOS 284281 crane cam Rhoads extra lube lifters @.600 lift with 1.65 Harlans
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If your not at the table you're on the menu A man who falls for everything stands for nothing. |
#57
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I'd bet about 90% of those shop builds are 100+ hp over stock figures and using pretty aggressive cams.
The demands on HFT components have increased, while the materials used have remained static, a logical consequence would be more failures. I'd think if it was a matter of no one making quality lifters then failures would be universal, they would all fail within a few thousand miles. If it was only certainly manufactures then that would have become evident almost immediately. I suspect it's a combination of demands being made on geometry and components they were never designed to withstand ... and I have a feeling a lot of clapped out old equipment is being used to machine these components ... how much high quality HFT cam grinding equipment is being made now? I think the tolerances for lobe taper and lifter crown are way looser than they were 50 years ago. You get a cam with taper 0.0005 off, and a lifter with crown 0.0005 too low and combine them ... failure no matter how hard the lifter. There is no cam manufacture out there now pumping out millions of HFT cams for OEMs that require a minimum failure rate .... so the quality slides, the machines are not worth replacing, the market gets smaller and smaller ... all this leads to sloppiness.
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#58
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"There is no cam manufacture out there now pumping out millions of HFT cams for OEMs that require a minimum failure rate .... so the quality slides, the machines are not worth replacing, the market gets smaller and smaller ... all this leads to sloppiness."
I agree sloppiness will also add offshore productions i put a higher value on new old stock components that were probably manufactured before the mayhem for instance there is a juicey SFT General Kinetics cam on ebay currently that i would consider if i needed one, Its alot harder to tell with lifters the last set i bought was Rhoads, they were newer but i know they would sweat the source and quality more than Autozone
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If your not at the table you're on the menu A man who falls for everything stands for nothing. Last edited by Formulas; 01-26-2024 at 08:58 AM. |
#59
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HFT + 1.65:1=poor man's roller. HRT+1.5:1=rich man's FT.
Cats out of the bag on the roller stuff and I keep hearing "this new version solves the problems" but they never do. Also, a shop with a policy on my money is a NOGO. Pay me now or pay me later either way I'm getting paid. |
#60
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