Sudden loss of performance and pressure

Tough summer to be one of my boats, got bad gas in the outboard earlier in the year still need to rebuild the carbs, threw a rod in the jetski a day after that, so far this summer had lost a new alternator and a new stereo in the ’83 two weeks into getting it in the water. This weekend I broke my Kevlar canoe pretty near in half during a race on Sunday, and then on Monday…

Took out the 83 (302 std rotation, edelbrock performer intake, cam/lifters/carb, 250 hours, g40p’s, scorpion pedestal mount roller rockers, dui added 60 hours ago) to go wakeboarding Monday morning was heading down the lake to the calm water thinking to myself how good she sounded and I decided to open her up, couldn’t break 42 mph at about 4000 rpms on the Perfect pass, airguides agreed. Normally with the 4 people aboard and the sacks empty I would have expected around 46 at 4550 or so. Slowed down to about 3k on the tack and continued to the spot I was headed for, when I got there I handed my buddy dan some goggles and told him to go check the underwater gear, nothing bent contorted etc. Now I was a bit worried but not terribly, till I started it back up and noticed my oil pressure was down about a notch at every rpm as well, not down to nothing but abruptly lower, a good 20 psi lower at 2800 rpm than usual. I was in vacation mode so I brought her back to the lift at about 2800 rpm (3-4 miles) no signs of trouble other than the oil pressure at 35 instead of 55 I shut her down hoisted her we took out the last remaining working boat in the fleet (not a cc) and I tried not to think about it. Well today I am going to have to go up there after work and investigate. Any guesses? I am going to compression test and go from there. I am hoping its valve train related although the only thing I can think of that would drop the oil pressure and take off the top end would involve a rod off a lifter? The performance loss seems more like a wiped cylinder, the oil pressure seems more like a main bearing issue. Hope the machine shop isn’t busy…
-Joe.

That's the bad thing Dave I believe joe just rebuilt it this spring but pulling the valve covers and looking for a flat lobe on the cam might be the root cause.

just a thought what oil pick-up did you use? there are about three different ones i believe.

Well, pulled the valve covers and two loose pushrods were discovered, on about 1/8 play, one closer to a quarter inch play right next to each other halfway back port side. Pulled the manifold and lifters on those two, on lifter is collapsed but wearing well, one was worn concave. So I need a camshaft and lifters (lobes on the camshaft felt pretty good) doesn't do me much good to worry about it beyond that. Either that will cure it, or it needs a rebuild to deal with any possible damage from the shavings and if it needs a rebuild putting in the camshaft breaking it in and seeing what happens from there isnt going to do any further damage. Anyone got any theorys?

It was a new edelbrock cam and lifter set last spring, now with 250 hours. I am not sure on the oil passage routing myself but I am still trying to convince myself that the collapsed lifter was causing my drop in oil pressure and that the 250 dollars worth of camshaft, lifters, gaskets, timing chain, etc I am about to have overnighted from summit are going to have me skiing by sunday morning.

Sorry about your troubles Joe. It's awesome you can just pull it apart, find the difficulty and work to rectify it. This would have me down for weeks while I was writing this board every step of the way. Keep pressing on!

thru bolt is out, but corrosion is pretty evident, I am trying to get this all done while the boat is in the shorestation so overhead lifting is a trick, two muffler clamps and two jacks are next on my list of remedys, hopefully it pops because my parts are here and it looks like a good weekend for working on it saturday and skiing sunday.
-Joe.

In the end the PB blaster and a big pipe wrench did it, if it was a pretty pylon there it wouldn't have been fun, but since a previous owner had already cut off the the ring and put on an extended pylon that will cover the new damage its no tragedy.

Didn't get enough time without rain to complete the repair this weekend, had a few hours to dissasemble and start scraping the gaskets probably another hour or two of surface prep left before I can put it back together...

This motor has seen nothing but Mobil 1 15w-45 except for the first two break in oil changes after rebuild that were conventional mobil oil.

Thanks for the compliments Jimbo, I bought the exhaust manifolds from 79nautique and polished them (need a touch up at this point but I did have them to a mirror finish) just a standard edelbrock performer intake... anyway everything was dry today and I started her up, broke in the cam and went for about a 13 mile cruise at 20-25 mph. Tomorrrow I dump the dino oil from the break in put the mobil one back in and see how she runs. My oil pressure is back where it should be though so I am hoping for the best. -Joe.

Joe that mobil 1 maybe the issue, I guess if it happens again we'll know for sure.

My buddy used it in all of is stuff RV, super comp & super gas drag cars, generator, personal car until he smoked the bearings in one of the race motors.

Edelbrock is recommending a 10w-30 conventional oil and GM EOS engine oil supplement for at least a few oil changes before switching to synthetic. Would have been nice to know about the EOS before the intial break in but live and learn I guess I will hold off on the synthetic for a year or so and check and see how its going at that point.

Glad to hear you found the source of the problem Joe. Now lets see some pics of that beast all shined up!

Tim I got your pictures right here...
No laughing at my temporary square wooden motor box, the vinyl covered one that matches the seats wouldnt fit over the 302 because of the water pump location. We have actually come to love the big flat carpeted box in the middle of the boat for jumping off, siting on, holding boards while getting in etc. I am thinking of dying it blue and leaving it.


















-Joe.