28Eliminator's Overlap on his camshaft
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28Eliminator's Overlap on his camshaft

  1. #1
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    Default 28Eliminator's Overlap on his camshaft

    Dave,
    Sorry we had to talk on such bad news. I ran some numbers on the seat duration to see what overlap numbers looked liked as we did take in account on this build that you wanted a sound build that could use the short risers.

    Mercury Mag 502 engine with cast iron manifolds has 57 degrees of overlap
    HP500 Carb Engine and the shorts has 68 degrees of overlap
    28Eliminators cam has 59.5 degrees

    I called a ex Crane guy that was at Crane during the 90's and asked him about 60 degrees overlap and injesting water. He said 60 is no issue.
    Chris Straub
    Straub Technologies

    3HP is an A$$ Whooping!!! JW

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    cfm
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    Quote Originally Posted by cstraub View Post
    Dave,
    Sorry we had to talk on such bad news. I ran some numbers on the seat duration to see what overlap numbers looked liked as we did take in account on this build that you wanted a sound build that could use the short risers.
    Mercury Mag 502 engine with cast iron manifolds has 57 degrees of overlap
    HP500 Carb Engine and the shorts has 68 degrees of overlap
    28Eliminators cam has 59.5 degrees
    Bold and in red above is incorrect. You've stated the overlap at .004" with the HP500 cam instead of at .006" like the Mag Cam and 28 Eliminator's cam. The HP500 cam has 60º overlap at .006". Your statement is 8º high.

    From my notes, here are the specs on the Mag Cam and HP500 cam. Seat/overlap #'s at .006" as is 28Eliminator's.

    Notice the overlap at .050" as I'll get into why on very next post.

    Merc Mag Roller
    Merc# 431-850478 / GM#12551622
    .006" 288º/288º Overlap 57º
    .050” 225º/225º Overlap -6º
    Lift .483”/. 483”
    ICL 109º
    LSA 115.5º

    Merc HP500 Carb
    Crane Gen VI#169611 Grind#HR-284-2S-10IG
    276º, 284º At .006” 60ºOverlap
    222º, 230º At .050” 6ºOverlap
    Lift with 1.7 .576” , .598”
    ICL 105, ECL 115
    LSA 110

    Now, here : http://www.performanceboats.com/dyno...ml#post1425675
    28Eliminator stated his cam specs as quote:

    Quote Originally Posted by 28Eliminator View Post

    Here it is in a nutshell;

    8.9:1, .030 over 502 GM block (Gen V). Bored and honed with Plates, plateau honed, square decked .015 - .019. Align bored. GM forged crank, micro polished only. Dimple rods, resized and shot peened. SRP 4.500 -3cc dome pistons, JE rings. Pistons are .005 in the hole. Melling HV 1077 pump, standard press. Changed bypass valve to 30# in block and remote pad

    Heads are stock 088 castings. I did an extensive bowl blend and opened up SS radius, polished the chambers, 5 angle int, full radius exh, 122 cc chambers (thanks Merc), Milled .010, .100 longer valves with 11/32 stems (REV's), 2.25 int, 1.88 ex. Flowed 358 @ .700. Morel lifters, Crane gold rockers

    Dart intake (HP500), Gil exhaust, 800 cfm Holley, MSD ignition system.

    Straub Hyd Roller (Squishy ) 650/603, 228/242
    Looking up Bullet's Lobes that are as stated by 28Eliminator above in Bold + Red

    we have the following:

    Duration at .006" 284°, 300° Overlap 68° 8° More Overlap than HP500 at .006"
    Duration at .050" 228°, 242° Overlap 11° 5° More Overlap than HP500 at .050"
    .3823" Lobe Lift .3550" Lobe Lift
    .6499" valve lift w/1.7 .6035" valve lift w/1.7
    112° LSA

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    Quote Originally Posted by cfm View Post
    Bold and in red above is incorrect. You've stated the overlap at .004" with the HP500 cam instead of at .006" like the Mag Cam and 28 Eliminator's cam. The HP500 cam has 60º overlap at .006". Your statement is 8º high.

    From my notes, here are the specs on the Mag Cam and HP500 cam. Seat/overlap #'s at .006" as is 28Eliminator's.

    Notice the overlap at .050" as I'll get into why on very next post.

    Merc Mag Roller
    Merc# 431-850478 / GM#12551622
    .006" 288º/288º Overlap 57º
    .050” 225º/225º Overlap -6º
    Lift .483”/. 483”
    ICL 109º
    LSA 115.5º

    Merc HP500 Carb
    Crane Gen VI#169611 Grind#HR-284-2S-10IG
    276º, 284º At .006” 60ºOverlap
    222º, 230º At .050” 6ºOverlap
    Lift with 1.7 .576” , .598”
    ICL 105, ECL 115
    LSA 110

    Now, here : http://www.performanceboats.com/dyno...ml#post1425675
    28Eliminator stated his cam specs as quote:



    Looking up Bullet's Lobes that are as stated by 28Eliminator above in Bold + Red

    we have the following:

    Duration at .006" 284°, 300° Overlap 68° 8° More Overlap than HP500 at .006"
    Duration at .050" 228°, 242° Overlap 11° 5° More Overlap than HP500 at .050"
    .3823" Lobe Lift .3550" Lobe Lift
    .6499" valve lift w/1.7 .6035" valve lift w/1.7
    112° LSA
    Wrong lobes Scotty. The engine shows not sign of reversion. If had reversion the tops of the pistons would be clean along with the chambers. The engine dropped a seat and the water entered then.
    Chris Straub
    Straub Technologies

    3HP is an A$$ Whooping!!! JW

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    cfm
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    Quote Originally Posted by cstraub View Post
    Dave,

    I called a ex Crane guy that was at Crane during the 90's and asked him about 60 degrees overlap and injesting water. He said 60 is no issue.
    I have a copy of Crane's Newsletter on this very subject. They actually talked about overlap at .050" not seat overlap. Not just this article, but many of their other newsletters as they talked about the HP500, 500EFI, and 525EFI on many occasions.
    Crane Article on Marine Camshafts
    Tech Tip

    If you’re planning on trying to improve the performance of your boat this spring or if you have a customer just rebuilding his engine, check these few things first. When choosing a cam for a marine engine, the first thing you need to know is the type of exhaust that is being used.. There are several different types of marine exhaust systems which determine how big a camshaft you can use. If you have exhaust logs or underwater exhaust, you must use a cam with no overlap at .050? lift because of the back pressure created by the water in the exhaust system. If you have a through hull or above water exhaust system, you can choose a cam with up to 4 - 6 degrees of overlap at .050" lift. If you have double wall or water jacketed pipes that mix the water and exhaust at the end of the tailpipe, you can usually use any cam that would best match the compression and RPM that you want to prop the boat to at maximum speed. So make sure before you or your customer choose a camshaft, that you know what type of exhaust is in the boat. You don’t want to end up with water in your engine.
    Here (again) are the three cams mentioned by the OP. Check out the .050" duration numbers this time.

    Quote Originally Posted by cfm View Post
    Merc Mag Roller
    Merc# 431-850478 / GM#12551622
    .006" 288º/288º Overlap 57º
    .050” 225º/225º Overlap -6º
    Lift .483”/. 483”
    ICL 109º
    LSA 115.5º

    Merc HP500 Carb
    Crane Gen VI#169611 Grind#HR-284-2S-10IG
    276º, 284º At .006” 60ºOverlap
    222º, 230º At .050” 6ºOverlap
    Lift with 1.7 .576” , .598”
    ICL 105, ECL 115
    LSA 110

    Now, here : http://www.performanceboats.com/dyno...ml#post1425675
    28Eliminator stated his cam specs as quote:

    Looking up Bullet's Lobes that are as stated by 28Eliminator above in Bold + Red

    we have the following:

    Duration at .006" 284°, 300° Overlap 68° 8° More Overlap than HP500 at .006"
    Duration at .050" 228°, 242° Overlap 11° 5° More Overlap than HP500 at .050"
    .3823" Lobe Lift .3550" Lobe Lift
    .6499" valve lift w/1.7 .6035" valve lift w/1.7
    112° LSA

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    cfm
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    Quote Originally Posted by cstraub View Post
    Wrong lobes Scotty. The engine shows not sign of reversion. If had reversion the tops of the pistons would be clean along with the chambers. The engine dropped a seat and the water entered then.
    I went by what was posted by the owner of the engine, 28Eliminator. See the link:
    Now, here : http://www.performanceboats.com/dyno...ml#post1425675
    and what I quoted above.

    Where did he get that info from ?

    If indeed incorrect, could you post the specs because I can only go by data that is given.

    Thanks.

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    This is a pretty far reach for anyone Scotty. No other cylinder shows signs of water. If it had reversion each cylinder would show signs. Water droplets just don't Choose a Cylinder to attack. You and the rest of your "I hate Straub Club" are showing what lengths you'll go to try and discredit me and it really makes you look like fools. For someone who wants the truth you sure are two faced when it comes to me. The engine ran flawlessly for 40 or so hours with no changes after it came off the dyno. It accelerated harder, had a new top speed and ran very well, then he tinkered with it. Dave told me on the phone he played with timing and changed carbs and jets in the carb. The engine dropped the seat and when it did the water got in there then.

    Please don't turn Dave's bad luck into your own personal vendetta thread. It's poor taste.
    Chris Straub
    Straub Technologies

    3HP is an A$$ Whooping!!! JW

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    Quote Originally Posted by cfm View Post
    I went by what was posted by the owner of the engine, 28Eliminator. See the link:
    Now, here : http://www.performanceboats.com/dyno...ml#post1425675
    and what I quoted above.

    Where did he get that info from ?

    If indeed incorrect, could you post the specs because I can only go by data that is given.

    Thanks.
    Please post you suppliers information on where you get your stuff.. . .give me a break.
    Chris Straub
    Straub Technologies

    3HP is an A$$ Whooping!!! JW

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    Quote Originally Posted by cstraub View Post
    The engine shows not sign of reversion. If had reversion the tops of the pistons would be clean along with the chambers. The engine dropped a seat and the water entered then.
    Major reversion will maybe cause "cleaning" of the pistons etc. small amounts of reversion will mist with the A/F and you will still have combustion, which of course will not "clean" the pistons. Last time I looked, Rust in a cylinder is caused by water.

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    cfm
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    Quote Originally Posted by cstraub View Post
    Please post you suppliers information on where you get your stuff.. . .give me a break.
    Woh, woh, woh. Hold on man.

    You started this thread and you had some incorrect info.

    Thread is about 28Eliminator and I used the camshaft specs he stated.

    Edit to be more clear: your opening post is about duration/overlap/ reversion. I did not bring up the subject. edit done:

    I have put correct data.

    You say my data on his cam is wrong. Well, I got that from him.

    So.............post the correct data.
    Last edited by cfm; 02-15-2012 at 03:46 PM. Reason: to be more clear...hopefully...lol.

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    Quote Originally Posted by tara View Post
    Major reversion will maybe cause "cleaning" of the pistons etc. small amounts of reversion will mist with the A/F and you will still have combustion, which of course will not "clean" the pistons. Last time I looked, Rust in a cylinder is caused by water.
    Bill,
    Steam cleaning doesn't take much water. Heat and pressure and small amount of water is all it takes to make steam.

    Again the engine was trouble free for 40 some odd hours. All the pistons are black and show no sign of reversion.

    How about Seat pressure slamming the valve and shattering the seat....is that for real. Do none of you know what a closing ramp is. There is another Crane article out there that has Crane testing more spring pressure on hyd rollers and the more the pressure the more stable the engine was. Higher spring pressure ensures the valve is set down on the seat.

    Your neighbor up there Bill read that one and spit his coffee out.
    Chris Straub
    Straub Technologies

    3HP is an A$$ Whooping!!! JW

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    Quote Originally Posted by cfm View Post
    Woh, woh, woh. Hold on man.

    You started this thread and you had some incorrect info.

    Thread is about 28Eliminator and I used the camshaft specs he stated.

    I have said nothing about his engine reverting. You have.

    I have put correct data.

    You say my data on his cam is wrong. Well, I got that from him.

    So.............post the correct data.
    Scotty,
    Be truthful, we know why you are here.
    Chris Straub
    Straub Technologies

    3HP is an A$$ Whooping!!! JW

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    cfm
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    Is this NOT your thread starting post ????

    Quote Originally Posted by cstraub View Post
    Dave,
    Sorry we had to talk on such bad news. I ran some numbers on the seat duration to see what overlap numbers looked liked as we did take in account on this build that you wanted a sound build that could use the short risers.

    Mercury Mag 502 engine with cast iron manifolds has 57 degrees of overlap
    HP500 Carb Engine and the shorts has 68 degrees of overlap
    28Eliminators cam has 59.5 degrees

    I called a ex Crane guy that was at Crane during the 90's and asked him about 60 degrees overlap and injesting water. He said 60 is no issue.

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    Quote Originally Posted by cstraub View Post
    Scotty,
    Be truthful, we know why you are here.
    No, you don't 'Chrissy.'

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    Scott Birmingham or CFM Tech.....whatever you want to be called.
    Chris Straub
    Straub Technologies

    3HP is an A$$ Whooping!!! JW

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