Cam selection

« **Reply #25 on:** August 06, 2014, 12:04:51 AM »

Quote from: GT Jets on August 05, 2014, 11:59:21 PM

Motor full of fine metal shavings.... Pull it down and measure everything... JMHO.. Also check the front thrust surface of the block behind where the cam sprocket rides.

GT

my motor skills aren't that refined

...not sure how to pull it down and measure or check the front thrust surface.....

« **Reply #26 on:** August 06, 2014, 12:15:45 AM »

How much work has been done to your engine?

That XM 278 H is the cam we ran in the marathon motor... Very nasty, requires some work to get it right. It ran good in the race boat, pulled 5,200-5300 with a cleaned up stainless AA impeller with a 10.75:1 468 big block.

Not saying it wont run, quite the contrary, but she will be pretty snotty.

You will have to have the heads worked on, likely have the valve guides cut down for the seals to fit.

I guess it all depends on how the rest of the engine is set up...

Still think the motor has to come completely apart. Which is why I recommended a roller cam. It wont happen again.

GT

« **Reply #27 on:** August 06, 2014, 12:25:29 AM »

Not sure what has been done....this is the first time I've taken it this far apart....it's a 396 bored .30 over (I think) ,don't know the clearances, "A" impeller. From some research I'm guessing the compression is 10.25-1....

« **Reply #28 on:** August 06, 2014, 12:29:22 AM »

Quote from: Roadrunner on August 05, 2014, 07:43:33 PM

Her is a pic of my cam card and a video of what it sounds like. I bought the matching springs with the cam. I also have 049 heads. I am very pleased with the performance of my boat. The torque through the powerband is outstanding. Sounds bitchin' too.

Sent from my iPhone using SoCalJetBoats

I was looking at this one but was wondering if I could step up a little bit to the xm278h.....

« **Reply #29 on:** August 06, 2014, 12:38:39 AM »

Quote from: mayhem35 on August 06, 2014, 12:25:29 AM

Not sure what has been done....this is the first time I've taken it this far apart....it's a 396 bored .30 over (I think) ,don't know the clearances, "A" impeller. From some research I'm guessing the compression is 10.25-1....

Is the motor still in the boat?

It is my feeling that she needs to be put on the floor and inspected for excessive wear.

At least pull the pan and pass a magnet through it... bet you get that shocked face...

« **Reply #30 on:** August 06, 2014, 12:43:05 AM »

Yep....and I've already had the shocked FML face many times thru this little adventure and I've somewhat enjoyed it in a twisted jet boat owner way!!!😨😨😨

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« **Reply #31 on:** August 06, 2014, 02:18:10 AM »

Quote from: GT Jets on August 05, 2014, 11:22:19 PM

Well, then let me know before you buy one and I will sell you mine at a discounted rate... I have the whole kit, brand new in the box. I am ordering a roller and want to put another motor together to potentially run CJ next year.

I can't remember the exact grind, but it is the XM series from comp.

I assume you already built the rest of the motor? That metal went somewhere...

Glenn-

Goin racin'?

I wanna know

Dan'l

Boat is still down side up, shoe is gittin' fitted

« **Reply #32 on:** August 06, 2014, 07:33:01 AM »

Quote from: mash on it on August 06, 2014, 02:18:10 AM

Glenn-

Goin racin'?

I wanna know

Dan'l

Boat is still down side up, shoe is gittin' fitted

Man, I do this to myself every year.

I have nearly everything I need to put a boat together except the time necessary.

I am staring at a potential job change in February that will likely free up some of my time and allow a much more flexible schedule.

I figure on putting together a boat and a motor this winter and see what happens.

There will be a thread if I start...

It is so much fun, if you get the opportunity, get involved.

GT

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« **Reply #33 on:** August 06, 2014, 09:19:26 AM »

Quote from: GT Jets on August 05, 2014, 11:57:26 PM

Do you know how nasty that cam is?

GT

It will be even more so in a smaller engine.

« **Reply #34 on:** August 12, 2014, 06:40:26 PM »

Quote from: mayhem35 on August 06, 2014, 12:04:51 AM

my motor skills aren't that refined ...not sure how to pull it down and measure or check the front thrust surface.....

what he means is, the motor will have to removed from boat, if installed, and taken apart and inspected. by inspecting, i mean measuring the bearing surfaces on crank and rod (bearing journals)...basically any part that requires oil and rotates has potentially been exposed to fine metal shavings/dust/powder if you will. which acts like an abrasive and can grind down surfaces so that they are out of tolerance...usually resulting in poor oil, low oil pressure...excessive wear, etc. also, it would be wise to have the block's oil passages cleaned...after all, contaminated oil has passed thru them...you wouldnt want any remnants to find its way into the fresh oil of your new build.... dont forget to check/clean oil pump. good luck, keep us posted.

mayhem35

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GT Jets

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mayhem35

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mayhem35

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GT Jets

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mayhem35

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mash on it

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GT Jets

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Flusher

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JARVIS

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