flat tappet cam in magnum motor?

Small Block Mopar Engine

  1. tobysoldblue

    tobysoldblue tobysoldblue

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    Will this work? or is the block not accept a flat tappet hydraulic cam?
     
  2. 388dart

    388dart Well-Known Member

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    it will work - but pushrod clearance in the heads needs to be checked and an LA front cover is required to run a mech fuel pump.
     
  3. tobysoldblue

    tobysoldblue tobysoldblue

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    Cool!Ill still run an electric fuel pump,so do i still need to use the old style timing cover?
     
  4. fishy68

    fishy68 Tyr Fryr's Inc. FABO Gold Member

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    Yes you still need the old style cover because the magnum cover is for a reverse rotation water pump and has channels that won't work with a old style pump.
     
  5. 375inStroke

    375inStroke Well-Known Member

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    Why? Is there an advantage to this? I would think this would be a step backwards?
     
  6. Bill Dedman

    Bill Dedman bill dedman Legendary Member

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    Please forgive me if you already know all this....

    There are oiling issues when you replace roller lifters with flat tappets. The top end pieces (rockers, etc.) on a Magnum-head motor get their lubricating oil from the pushrods, which get it from the lifters. Unlike the L-A motor, there are no oil-supply passages in a Magnum block to transfer oil to the heads from a hole in the block, through the head gasket to matching holes in the head, with oil for the rockers going up through the head to the rocker stands.

    BUT, I've read several places where you can use Jeep flat-tappet hydraulic lifters and longer pushrods (the roller lifters are taller) and still oil the top end that way.... through the pushrods. Seems the Jeep flat tappet lifters have the required oil holes in the pushrod cup to feed oil to the pushrods.

    Be aware that the lack of zinc in motor oil these days has created longivity problems of monumental proportions for flat tappet cams. This can be dealt with by using ZDDP additives and/or buying oil that still has anough zinc in it, but it's not always easy to find out which oil has what. Ignore it, and your cam may develop flat lobes sooner, rather than later...

    I'd think twice before going to a flat tappet cam, with the oil problem that exists today. Hydraulic rollers are maintenance-free and have profile capabilities (because of the rollers) that you can't duplicate with a flat tappet setup. No, they're not the ticket for full-race motors, but for a street/strip car, they have a lot of good points, I think, one of which is that the zinc problem doesn't affect them... at all.

    Good luck with this.

    Bill
     
  7. 70aarcuda

    70aarcuda Master Hoader of SBM FABO Gold Member

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  8. tobysoldblue

    tobysoldblue tobysoldblue

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    Thanks for the info.I understand about the roller versus hydraulic cam debate.My problem is the price of the roller cams.I havent looked a lot,because the ones ive seen are @300.00 or more.I can buy 2 or 3 flat tappet cams for 300.00!Are there some cheaper roller cams with good specs for under 200.00?Also,most of the guys i know just reuse the factory roller lifters.Dont they ever wear out?I would think anything that rolled for 150,000 miles would be pretty much wore out?How hard is it to redrill the non magnum intakes to the correct angle for magnum heads?Ive seen the magnum intakes are quite expensive too.
     
  9. needsaresto

    needsaresto Well-Known Member

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    You could regrind a stock one and get a custom grind at the same time..for much less.

    Other than the cost factor it makes no sence to go hydraulic when you could have more power and better mileage AND less maintenance with a roller cam.

    Auto makers have gone roller for good reason.

    Save your bucks up for the roller,or investigate a reground stock one.


    Someone here will chime in on where you could have this done by a reputable grinder.
     
  10. 70aarcuda

    70aarcuda Master Hoader of SBM FABO Gold Member

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    dont think you can redrill the intake manifolds since there is not material to support the new holes..

    everyone redrills the cylinder heads....which you can compare the cost vs a professional product crosswind intake which fits both heads...

    new magnum roller lifters can usually be had for about 100 bucks on ebay...hydraulic roller cams are not cheap...but sometimes you can find a used one for about half price..

    i just sold a used hydraulic roller cam for 75 bucks..it came out of a 360 hp crate motor...so they are out there...

    maybe i sold it too cheap...LOL
     
  11. tobysoldblue

    tobysoldblue tobysoldblue

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    dang,75.00 was cheap,but i guess if you didnt need it,better to let it go cheap than let it collect rust.I had heard about the cross wind intake,but when i mentioned it on fabo a while back,a lot of guys treated me like i was slapping them in the face.I guess because its a chinese? made intake.Any way,id buy one,im sure theres other chinese parts on my car some were,yall just havent caught me yet,lol
     
  12. 70aarcuda

    70aarcuda Master Hoader of SBM FABO Gold Member

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    you watch your tv and use your computer..and guess where it was made...LOL
     
  13. Bill Dedman

    Bill Dedman bill dedman Legendary Member

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    I was degreeing my cam in and wanted to buy a spare hydraulic roller lifter to modify for the purpose of using it with a dial indicator during the degreeing-in process. I was going to make a flat surface on top, where the pushrod cap goes to set the dial indicator pushrod on.

    Went to my local Dodge dealer and asked for ONE hydraulic roller lifter. "That'll be $25.00, plus tax," said the parts man.

    I said, "No, no, no, no, no.... I only need ONE."

    He said, "That IS for ONE!"

    I said, "Surely, you jest...."

    He said, "Nope.... no joke; twenty-five smackers." With a straight face, yet.

    I said, "Does that computer have internet access?"

    "Yep, it does."

    I said, "Go to www.hughesengines.com," a place NOT NOTED for their low prices.

    I said, "Go to Magnum engines, then "lifters."

    He said, "Okay; I'm there."

    I said, "How much are their lifters?"

    He said, "$8.75 apiece."

    I said, "And yours are HOW MUCH???"

    He said, "Twenty-five dollars."

    I said, "Can you tell me why I should pay twenty-five dollars for an item that can be bought elsewhere for $8.75?"

    "Nope."


    I went home and called a friend of mine who was a parts man at a Dodge dealership in another city (Las Vegas.) I asked him to look up the price of one hydraulic roller lifter.

    "Twenty-five dollars," he said. I said, "ARE YOU SURE???"

    "YEP."

    Then, I told him the story of what had just transpired at the other dealership's parts department. He had no explanation....


    A set of 16 of these lifters will run you (16 X $8.75) $140.00 from Hughes, which is, as I said, not usually a place to go for bargain prices. I bought my cam there, and am very happy with the cam, and the service I've gotten from Hughes, but they are not cheap... but, that's okay with me. I'd rather have the quality service and products.

    Their reground hydraulic roller cams are, for the most part, $199.00, but you have to supply a core. If you can't supply a core, it's another $100.00.

    They don't do any Fords, Pontiacs, or Chevys... just Mopars, so they are familiar with what we need.

    This sounds like a commercial for Hughes, and it's not... I just happen to think that if I were going to buy a roller cam, that is one place I'd look.

    You said, "I can buy three flat tappet cams for the price of one roller, and I don't dobt that, but with this ZDDP (zinc) issue with the oil, right now, you may end up buying three flat tappet cams... not a good thought. Cleaning up an engine after a cam lobe has been machined off by a lifter is not a fun job.

    Just food for thought.

    I cn't imgine why Ma wants to hold us up so badly on the roller lifters. That is $400.00 for a set of 16... Wow.. who can afford that???????

    No wonder they are hurting for customers.

    Bill, in Conway, Arkansas
     
  14. Petzschler

    Petzschler →Welcome back←

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    the lack of ahem..ZINC... is only a problem for people who

    A. do not know how to properly break in a cam, or
    B. use way to much spring pressure and wipes some lobes out.

    once the cam is broken in properly, any lack of ZINC is a non issue.
    cheers
     
  15. Bill Dedman

    Bill Dedman bill dedman Legendary Member

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    Every Saturday morning, I go to breakfast with a group of Buick turbo guys, all of whom have 1986-'87, 3.8-liter Grand Nationals or T-Type Regals ("Grand Nationals" that are not black.)

    Those cars came with flat-tappet, hydraulic cams. They also have notoriously bad engineering on their rocker shaft hold-downs, utilizing only four 5/16" bolts (they MAY even be quarter-inch; I'm not sure, but they're way too small for the job, in any case) to anchor the rocker shafts to the heads. That, alone, keeps them from running much valve spring pressure; but the weak crankshafts in those cars also keeps them from turning over 6,000 rpm, if they want reliability at all...

    So, these engines have minimal valve spring pressure, and operate below 6,000 rpm.

    Of the 9 or 10 guys who come to that breakfast, at least six of them have wiped out cam lobes since the government took zinc out of the oil. Several of them have changed over to roller tappet cams, and the others have installed new cams, and use G.M. Engine Oil Supplement (heavy ZDDP content) continuously, to try to not ruin another cam.

    But, the ones that failed had been in the cars for a couple of years, so were apparently broken in properly, since they'd had no problems up to that time.

    Of course, they're not MOPARS, but the principle is the same; the ZDDP provides the high film-strength barrier that the lifter/cam interface needs for longivity.

    G.M. quit selling that "Engine Oil Supplement" a while back, but according to "Pit Stop" in the latest HOT ROD, it's back, although now, with a different part number. Go figure...

    I have no personal experience with cam failures, so all I can do is report what I've seen happen to these Buicks.... You can believe what you want, but based on their experience, I'd say that ZDDP is needed by any flat-tappet cam, for longivity.

    Just my 2-cents.... and worth every bit of that (two cents... LOL!)

    Bill, in Conway, Arkansas
     
  16. duster harry

    duster harry Well-Known Member

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    Does any one know i the mopar engine oil supplement has a high zddp in it?
     
  17. tobysoldblue

    tobysoldblue tobysoldblue

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    i went to advance auto yesturday and saw they sale lucas oil,break in oil.It say right on the bottom it has high zinc in it for flat tappet cams.Its not a bad price.Whats wrong with running a pint of it per oil change to keep from wiping cam lobes?It says to use it for the first 1000 miles,and then use regular oil.
     
  18. tobysoldblue

    tobysoldblue tobysoldblue

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  19. Bill Dedman

    Bill Dedman bill dedman Legendary Member

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    Sounds like an EXCELLENT idea to me!!!

    If I had a vehicle with a flat tappet cam, I think I'd probably be doing exactly that! No fun trying to get all that debris out of a motor after destroying a lobe or two....
     
  20. fishy68

    fishy68 Tyr Fryr's Inc. FABO Gold Member

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    I totally agree. ZDDP is needed for the life of the engine. Not just during break-in because the that cam and lifters are allways scrapeing together with much more friction than any other part of the engine.

    An example is a buddy of mine put a comp XE268 in his 454 Chevy 2 yrs. ago. It ran fine for allmost 2 yrs. had over 7,000 miles put on it and recently it started loosing power and then lifters started clacking. He pulled the cam/lifters and 4 lobes were nearly flat. We can find no other reason that this happened other than he used oil with no zinc additive after the break-in period in which he did run ZDDP additive. BTW: The spring pressures were 105 seat and 280 open. Not much pressure there.
     
  21. JeffC

    JeffC Member

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    oops sorry didn't notice this was an old thread.
     
  22. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    So you felt the need to bump a thread that is YEARS old --from TWO THOUSAND AND EIGHT-- just to say that???

    [​IMG]
     
  23. rumblefish360

    rumblefish360 So close, yet so far away FABO Gold Member

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    Maybe so, but it at least is a good topic. Failing to comment except for the "Sorry/old thread" was the shameful part. Speak up Jeff!

    LMAO
     
  24. AJ/FormS

    AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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    I got caught that way once too. I said sorry, too, AFTER deleting my comment,cuz I said to myself,something like;" By now,the OP certainly has cured his problem,and he may even be dead."
    In this case, I agree that ZDDP is a good topic. But it has been kicked around quite a bit during the intervening years.
    And as to rollers? Well my next project will be rollered, just for longevitys sake. I had that awful sinking feeling, just one time, when 2 lobes fell into the pan, within minutes of each other, after an oilchange,on a two to three year old cam.It probably had 20,000 plus miles. Being rid of the worry alone will be worth it.
     
  25. alpha13

    alpha13 Well-Known Member

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    Summit racing has high zinc oil called classic car oil. I use that stuff always. But cant say i have 20,000 miles on an engine with it. So i suppose i am not of much help. But the oil additive is out there!
     
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