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miike
06-07-2013, 04:46 PM
Well I had a 502 that I bought off craigslist in January. Finally I got it put in, did a cam break in, and started other testing and tuning. I was having problems with it idling and such. I had to get towed in twice. It was the second time that it locked up. Because it wasn't originally built for marine use, I was a bit skeptical about water reversion. One day after it shut down unexpectedly at the ramp, I pulled the boat out and pulled a manifold off. There was no sign of water reversion. Being quite happy about that I set out to fix some other ignition and starting issues. That took another week and I was delighted to have the boat out on the lake until it shut down at 2400 rpm. I tried to restart and heard metal slapping around so I figured I threw a rod. After that I contacted the builder and he agreed to take a look at it. I towed it down to his place 2 hrs away yesterday and he began to diagnose the issue. We pulled a manifold to get to the valve cover. Two pushrods dropped into the cam. We pulled the intake and saw the cam was grenaded. From that point I worked for a few hours to pull the drive and ultimately the motor. The builder isn't sure why it blew up. It had hardened pushrods and a hardened cam that was originally a Comp Cam and was reground. We are having more marine friendly cam ground for it now. It was at 108* LSA and we are putting the new one at 114* and going with 3/8s hardened pushrods. The heads are coming off and all the rod bearings will be checked. I'm pretty happy the guy is willing to fix it at his cost. He believes he can get the cam warrantied because it may not have hardened properly after the regrind. Fairly lucky for a craigslist purchase, but I sensed honesty in the guy while I was buying it otherwise I may not have gone through with it.

The cam was 598 lift and 296 duration at 108 LSA. We are going to keep the big lift and duration and only change the LSA. The builder is confident the rest of the valvetrain will hold up to prolonged use and that it is well built with the best parts that will take it. 1.72 roller rockers are in it. It is a solid lifter flat tappet cam in a Gen VI 502 block. Apparently it has Gen V timing parts to accommodate for the difference in Gen VI and V cams.

He will break in the cam with me and tune my carb and timing, which I am really happy about because I don't feel confident with my tuning skills.

Lots of members have been really helpful, most notably Mr. Fixx. He has taken my calls at all times of the day, even while I'm troubleshooting at the boat launch. He was the one who finally got me idling well by changing plugs and gap and an overheat ignition module. He and Madpoodle are the nicest guys who have helped me. They haven't belittled my engine or skills like lots of guys do who try to get you to buy stuff from them or have them work on your boat. Carl C advised me to call these two from the start. And JayZ has helped me while he performs almost the same project, a 502 in a King Cobra boat. So big thanks to Mr. Fixx and the others who have helped out!

It'll be a week before we get everything back together. I'll head back down and drop the motor in and go for a ride on the lake and see how it all goes.

I'm not sure if we can balance the thing with the flywheel on it. Does it need to go to a machine shop for that?

f_inscreenname
06-07-2013, 04:58 PM
I'm not sure if we can balance the thing with the flywheel on it. Does it need to go to a machine shop for that?

yes
Sorry for you woes.

Donzi_Dude
06-07-2013, 07:02 PM
sorry to hear about your troubles. reversion is not an issue at 2400rpm. sounds like maybe a bad cam and thats why it wouldnt idle but it could be a million things.

hope you get it sorted.

Conquistador_del_mar
06-07-2013, 07:08 PM
This would be a good time to consider installing a roller cam. My two cents, Bill

miike
06-07-2013, 07:11 PM
Ya that's what I hear... Since the guy is fixing it for free and he's really proud of his solid lifter set up, I think I will keep it. I like the idea of solid lifters because it's old school and bad ass. Not sure if that had anything to do with it coming apart. Since I bought it that way, it's tough to ask for it to be changed, even though I'm positive it's getting new lifters.

Conquistador_del_mar
06-07-2013, 07:18 PM
Ya that's what I hear... Since the guy is fixing it for free and he's really proud of his solid lifter set up, I think I will keep it. I like the idea of solid lifters because it's old school and bad ass. Not sure if that had anything to do with it coming apart. Since I bought it that way, it's tough to ask for it to be changed, even though I'm positive it's getting new lifters.

I suppose you know that you can get solid lift roller cams, too - my 572s making 800+HP came with solid lift roller cams from the NASCAR engine builder. It would cost a little more, but you would not have to break in the cam with rollers. Anyway, good luck this next time around. Bill

Donzi_Dude
06-07-2013, 07:22 PM
the only reason to go with a solid in a BBC for marine use is extreme lift/racing rpm's and i dont think your there but maybe your are.

pride can hurt you.

:wink:

ralphvc
06-07-2013, 08:30 PM
from a drag racer and part time builder. Depending on how hard it banged and locked up you may have some suspect stressed rods. Don't mean to scare you but a grenaded motor costs a lot more than a set of rods. I too would go with a solid lifter roller motor.

BUIZILLA
06-07-2013, 09:00 PM
108* LSA / 296* duration in a wet exhaust marine engine?

really?

there is no power advanatge w h a t s o e v e r under 5500 rpm to justify solid flat tappets....

since you have to get a new cam and lifters anyway, it just doesn't make logic to use a solid blank...

this is 2013, not 1973..

hdsadey
06-07-2013, 10:20 PM
What kind of oil are u using. Todays conventional oil has no zinc cause everything is roller. Solid flat tappet cams require oil with zinc for lubrication. I work in a high performance muscle car shop and we do not warranty any flat tappet motors because of todays oils. Seen cams wipe lobes shortly after break in due to lack of zinc. Just my .02.

miike
06-07-2013, 11:47 PM
Break in oil was valvoline conventional 20W-50 with comp cams break in oil

Shortly after, oil change was valvoline conventional 20W-50 with STP additive that has zinc

Cam didn't look so hot, even lobes that weren't hurt by pushrods had rough edges.

Donzi_Dude
06-08-2013, 06:25 AM
not saying this is what caused your woes but its easily checked. i would say its a 50% chance this or a soft cam.


"One of the biggest causes of hydraulic/solid cam wipe-out is the cam being too far forward in the engine. There needs to be .010" or less end-play in the cam in the engine, and I have aimed towards to .006" or less mark.
To see if this was your problem, look at your wiped-out cam.
If there is still phosphate on the FRONT of the good cam lobes, about 1/10" or so, your cam had too much end play, it moved forward, and the lifters didn't have the proper amount of spin.
The distributor gear on the cam will also show wear only on the back 3/4ths."

JayZ
06-08-2013, 08:15 AM
I recommend you use Brad Penn racing oil. Bummer about the mill, good that the guy is standing by his work. Hopefully you end up with an even better motor now. ...look at this as an opportunity.

BUIZILLA
06-08-2013, 08:22 AM
how did the pushrods damage the lobes?

MOP
06-08-2013, 08:46 AM
IMO since the fellow seems like a prince add some $$ and get a proper roller setup, you will be way ahead in the long run. Flat tappet is risky no matter how you cut it, yes you can run $12-15 a quart oil but still will have shortened life. I hope he is doing a complete tear down, fine bits and pieces can migrate throughout the entire assembly.

Phil

olredalert
06-08-2013, 09:40 AM
----Nothing to add but the fact that I too run Brad Penn oil, not only in my boats but in my old cars as well. So does Tyler Crockett and thats enough recomendation for me.......Bill S

duckhunter
06-08-2013, 09:52 AM
The whole "reground" cam is a little suspect to me. Heat treating is a pretty dynamic process and doing something as complicated as a camshaft would be easy to screw up in a non-factory environment. Solid lifters would certainly aggravate any weaknesses in the cam. I pulled a brand new high-dollar Crower cam out of a small block in three pieces for one of my buddies after a catastrophic failure.

+1 for adding the roller setup while you've got it apart, along with a more realistic factory ground marine cam. Definitely do a good detail cleaning of the entire motor & oil system (don't forget oil pump, remote filter head, cooler, lines, thermostat, etc). I would probably do bearings as well just for piece of mind.

Might as well throw some money and time at it to get it right. Then go boating with peace of mind.

joseph m. hahnl
06-08-2013, 10:17 AM
I highly doubt the cam was soft. that's a reach. :cistineb:. I'm sure it had a Brinell /Rockwell hardness test done before they finish ground it.. I'll bet it even had a X-ray to check for porosity, if it was a cast cam. it was most likely an assembly issue. Reversion can happen at any Rpm, Harmonic reversion which is what some marine engines suffer from at idle , goes away once the resonance changes, the sound wave drives the water out. But full fledge reversion which comes from a late closing exhaust and early intake combined with a low static compression ratio will never go away and gets worse as the rpm increase. It has been noted that it can blow all the way back through the carb. On a high lift marine cam, the exhaust lob is advanced at closing " Closes sooner" as well as lob separation angle being greater. Duration can be misleading, You need static CR and you need the cam card with the opening and closing angles to truly set it up correctly. also note that as you increase the duration the exhaust closes later and the intake opens earlier .With out knowing the start or end of the valve cycle I find the duration # useless. as the exhaust could close from 13 degrees to 30 degrees the separation angle will always be the same regardless. When you think about it it's the cam being advanced or retarded is what makes it a marine cam:p

Donzi_Dude
06-08-2013, 12:22 PM
P to V clearance can take a cam out. i would suspect that before it being enough of a reversion issue to take the cam out.

miike
06-08-2013, 12:37 PM
how did the pushrods damage the lobes?

When we pulled the valve cover, two pushrods were missing from the same cylinder. They fell down into the cam. It may have been the lifters that screwed all that up.

Didn't look like cam walk. Although the lobes weren't in great shape, it looked like the lifters were riding square on top.

miike
06-08-2013, 01:40 PM
I don't know if the pushrods broke first or the cam. I think the cam is in at least three large pieces. The lower end is still intact but the bearings are being checked.

joseph m. hahnl
06-08-2013, 02:40 PM
The whole "reground" cam is a little suspect to me..Yes! Merc throws away there flat tappet cams in there remanufactured engines and they regrind the roller cams:biggrin: I suspect 2 loose rockers and they pooped the pushrods out

Donzi_Dude
06-08-2013, 02:56 PM
Yes! Merc throws away there flat tappet cams in there remanufactured engines and they regrind the roller cams:biggrin: I suspect 2 loose rockers and they pooped the pushrods out


i imagine that might play hell with the idle too.

boomr
06-08-2013, 10:57 PM
Bummer, sorry to hear about the trouble. It's never any fun have something like that happen, but it sounds like the engine builder is trying to make it right for you.

I still know where you can find a decent 22 for sale (joking with ya).

When you get it back together, are you running it out of Coulon? If I still have the boat, we could meet, and I'll try to keep up.

Good luck,

Mike

miike
06-09-2013, 02:52 PM
Was that your pro charged 502 boat at lakeside?

boomr
06-09-2013, 07:21 PM
Was that your pro charged 502 boat at lakeside?

Yep, stored at Lakeside, but Vortech on a 502.

miike
06-09-2013, 07:57 PM
I launch at Mercer Island and will be doing so quite often this summer once the stupid bugger runs. Damn I want my boat working now. I've never spent so much time during the spring on my boat to have it ready in the summer, with one exception, I refinished and recarpeted the cabin of my 20 ft Grady I used to have one spring when it got a new motor. But it worked after that!!!!!!!!!

wwahl
06-09-2013, 11:55 PM
I am located just NE of Mercer Island north of Chism Beach Park in Bellevue. Look for a testarossa 18' Donzi on a lift.
Willie

CHACHI
06-10-2013, 07:03 AM
What kind of oil are u using. Today's conventional oil has no zinc cause everything is roller. Solid flat tappet cams require oil with zinc for lubrication. I work in a high performance muscle car shop and we do not warranty any flat tappet motors because of today's oils. Seen cams wipe lobes shortly after break in due to lack of zinc. Just my .02.

All of today's oils contain zinc and phosphorus. Unfortunately the levels that the API mandates is no where near what they were 5 years ago. The typical automotive product has some where around 900 parts per million of zinc.

I am kind of partial to this one. http://www.spectro-oils.com/motor-guard/

My .02.

Ken

Ed Donnelly
06-10-2013, 10:41 AM
Have to agree about Spectro Oils ...Ed

miike
06-10-2013, 12:45 PM
I am located just NE of Mercer Island north of Chism Beach Park in Bellevue. Look for a testarossa 18' Donzi on a lift.
Willie


Ahh I never noticed that boat along there. I usually swing wide around that swimming area. Part of the shoreline I never get closed to and you guys probably like it that way.

I live up in Medina and like to hang out in Meydenbauer.

miike
06-11-2013, 07:48 PM
Ok so it looks like we are going to a roller cam and hydraulic lifters. The builder recommends Howard lifters. Cam will be ground from a blank I believe.

Also I will put in a this timing set: single roller 520 pitch chain with ductile iron gears


And it will go to a machine shop for balancing with the flywheel on.

Donzi_Dude
06-11-2013, 09:48 PM
sounds like your looking to twist this thing over 6 grand.

:biggrin:

miike
06-11-2013, 09:57 PM
I doubt it will because 5500 rpm with a 25 Mirage is 84 mph and I dont have the running gear for that.

Just Say N20
06-11-2013, 11:07 PM
Boats need torque. Outdrives “generally” like to live below 5,500 rpms. Engines that develop lots of hp, but at rpms higher than 5,500 rpms are generally better in cars than boats.

Most “car” engine builders don’t build great boat engines for this reason; they build engines that produce big hp numbers at rpms that are never achieved in a boat. When run at boat rpm ranges, they are generally considerably down on torque and hp, and the boat performance is less than expected.

miike
06-11-2013, 11:44 PM
power is from 1500-6000

I think peak is 5500

JayZ
06-12-2013, 09:14 AM
power is from 1500-6000

I think peak is 5500

...maybe you should dyno tune and break in the motor this time around.

JayZ
06-12-2013, 09:21 AM
power is from 1500-6000

I think peak is 5500

also, Have you considered that the stock OMC oil cooler may be too small for your new beast?

joseph m. hahnl
06-12-2013, 05:54 PM
Ok so it looks like we are going to a roller cam and hydraulic lifters. The builder recommends Howard lifters. Cam will be ground from a blank I believe.

Also I will put in a this timing set: single roller 520 pitch chain with ductile iron gears


And it will go to a machine shop for balancing with the flywheel on. Mine is Internally Balanced :propeller:

miike
06-12-2013, 06:49 PM
also, Have you considered that the stock OMC oil cooler may be too small for your new beast?

I had a new one built which is approx the same size, maybe an inch longer. What I find by reading Oso is that oil cooler need to be bypassed with a thermostat kit because the oil gets too cold in the cooler. Did you make a new oil cooler?

miike
06-12-2013, 06:50 PM
...maybe you should dyno tune and break in the motor this time around.


The engine builder is tuning it with me this time. Not sure there is going to be a need for the dyno but I have been thinking about it. The roller cam won't need a break in.

JayZ
06-13-2013, 11:33 AM
I had a new one built which is approx the same size, maybe an inch longer. What I find by reading Oso is that oil cooler need to be bypassed with a thermostat kit because the oil gets too cold in the cooler. Did you make a new oil cooler?


I think the stock OMC cooler is kind of small but i used mine. I am going to shoot mine for temps next time out.

CHACHI
06-13-2013, 11:36 AM
I think the stock OMC cooler is kind of small but i used mine. I am going to shoot mine for temps next time out.

Make sure you are at least 180-200F