Sudden loss of performance and pressure
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=4510
Printed Date: November-23-2024 at 8:33pm
Topic: Sudden loss of performance and pressure
Posted By: JoeinNY
Subject: Sudden loss of performance and pressure
Date Posted: August-15-2006 at 1:40pm
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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. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Replies:
Posted By: David F
Date Posted: August-15-2006 at 5:16pm
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...or a camshaft failure that sent metal through the engine and took out the bearings hence the loss of oil pressure. With a camshaft worn down, the engine losses guts and does not idle very well. Hope I am wrong, but if not, a complete rebuild is required. ------------- |
Posted By: 79nautique
Date Posted: August-15-2006 at 5:20pm
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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.
------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: JoeinNY
Date Posted: August-15-2006 at 5:41pm
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Yeah rebuilt it last fall, new heads rockers dui this spring, the cam has 250 hours definitely a possibility. Still runs and sounds pretty good, I am hoping for the best and expecting the worst at this point, should have a pretty idea later tonight as I am goin up after dinner. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: 79nautique
Date Posted: August-15-2006 at 5:52pm
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just a thought what oil pick-up did you use? there are about three different ones i believe. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: JoeinNY
Date Posted: August-15-2006 at 5:57pm
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The oil pan and pickup are from a 1967 289 interceptor its a monster oilpan with deep rear sump, drain in the back dipstick port side center. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: JoeinNY
Date Posted: August-15-2006 at 9:05pm
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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? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: 79nautique
Date Posted: August-15-2006 at 9:29pm
I'm assuming you used new lifters with the used cam when you re-built it this past spring. Not sure on the actual oil passage routing but heres a thought. When the one lift wore most likely do to poor heat treatment from the factory, it restricted the oil flow to the other lifter causing it to lose it's prime and collasping it...... That's my story and I'm sticking to it damn it ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: JoeinNY
Date Posted: August-15-2006 at 9:37pm
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.
 ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: JoeinNY
Date Posted: August-17-2006 at 8:05am
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Hopefully a night soaking the in blaster does a little bit to change that attitude of that pylon because that sucker took all the hammering, pulling, heating, twisting etc we could throw at it last night with a laugh. Anyone have a magic pill we were overlooking?
-Joe. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: The Dude
Date Posted: August-17-2006 at 9:17am
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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! ------------- Mullet Free since 93 http://www.correctcraftfan.com/diaries/details.asp?ID=717&sort=&pagenum=1&yrstart=1991&yrend=1995 - 95 Sport |
Posted By: Munday
Date Posted: August-17-2006 at 12:32pm
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Joe I had the same pylon trouble when I changed cam this winter.I was all alone too.I rigged a comealong over pylon and put some tension on it tapped with mallet it came up slowly,looked like some heavy grain sand had gotten in the cup over the years and married everything together,you pulled out the thru bolt right?
Good luck Munday |
Posted By: JoeinNY
Date Posted: August-17-2006 at 4:30pm
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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. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: 79nautique
Date Posted: August-17-2006 at 6:12pm
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Soak the bottom in liquid wrench or something simular then try rotating it before pulling it up and don't forget about the slight bend in the pylon towards the base. So if you are trying to pull it up from the top your going to be loading it at an angle and draging against the socket in the hull and the wood floor. Take a hammer and try ringing the socket in the base to free of the corrosion and around the wood floor. Good luck
might try and get underneith and catch the bottom lip of the pylon and pry against the socket, not a lot of room to work but if you could get a good sized prybar and someone else pulling up might help. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: JoeinNY
Date Posted: August-21-2006 at 11:19am
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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... ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: boat dr
Date Posted: August-21-2006 at 12:23pm
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not to beat a dead horse on the oil subject,but what type and brand of oil were you running ? sure does sound like an oil related failure. my cam and motor guys(race engines builders)have seen a rapid increase in flat tappet cam and lifter failure....Rotella or any of the other premium diesel oils. their reasoning behind the rash of failures is the removal of the zinc and the other heavy metals by the oil co's.they are not needed w/roller cams in todays motors.my new 331 stroker will only have Rotella straight 30w,just info i have gained on the subject........boat dr ps cause and effect if you dont fix the cause the effect will be the same..... ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: JoeinNY
Date Posted: August-21-2006 at 1:19pm
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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. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: jimbo
Date Posted: August-23-2006 at 12:26am
| Nice looking engine! Nice exhaust and speed boat intake. Hope you get it straightened out soon. I guess you just shot holes in my argument to get a second boat! |
Posted By: JoeinNY
Date Posted: August-23-2006 at 11:28pm
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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.
------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: GottaSki
Date Posted: August-24-2006 at 7:56am
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I think Mobil 1 still doesn't have enough zinc-d for a flat lifter cam, it has to meet the new specs.
Throw in half a can of stp to get your usda allowance of zinc or use the CC diesel spec oil. STP's MSDS sez its 1-5% zinc-d. It like chicken soup, it can hoit. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: 79nautique
Date Posted: August-24-2006 at 9:22am
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Joe that mobil 1 maybe the issue, I guess if it happens again we'll know for sure. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: JoeinNY
Date Posted: August-24-2006 at 10:07am
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Yeah lets say I would rather not wait that long for confirmation. I became a big fan of Mobil 1 after it first came out because it was tripling the life of mountain bike chains amongst my friends I tried some on a chain that was already about shot (we would get about a month and half out heavy riding out of a chain) and it lasted another 3 months since then I have used it in everything four stroke I have driven and have been very happy. I used to pull boat trailers 600 miles a shot weekly with my 94 Grand Marquis and was up to 270,000 miles before I crashed it. (drove it home my friend dan finished second with it in a local demo the engine still ran perfect). Anyway I am believer in the technology but perhaps with the pushrod engines applying the new stuff may not be the way to go, I have put in an email to edelbrock tech support to see what they recommend for oil. Turns out crane actually does recommend diesel spec oils for thier flat tappet cams... ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: 79nautique
Date Posted: August-24-2006 at 10:18am
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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. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: GottaSki
Date Posted: August-24-2006 at 10:29am
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Yup, Mobil 1 just isn't the same oil it used to be, used to run the 15-50 in my KDX gearbox, then they added friction reducers that the clutches didn't like...I run the gear lub in my axles. They are just following orders to reduce the zinc-d or take it off the shelves. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: JoeinNY
Date Posted: August-24-2006 at 10:29am
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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. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: JoeinNY
Date Posted: September-06-2006 at 9:33am
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Well just as a matter of conclusion, the source of the original failure looks to be slight valve cover interfearance with the center two rockers.
The el-cheapo chrome covers I had pa$$ed my original cover everything with a$$embly lube and turn it over and check for lube on the valve cover test but when torqued down in position it appears the center two rocker arms were rubbing on the excessively large stamped mounting screw relief. The edelbrock elite series tall valve covers appear to have solved the interfearance problem as of now. The wear patterns on the old cam and the collapsed lifter correspond to the wear marks on the inside of the valve covers so I am pretty sure that was the issue. Ran it about 3 easy hours with those valve covers installed and it took 90 hard hours to cause the intial damage so hopefully I didn't do too much damage with it this time. Either way its running good with 15 hours on the new valve covers and not coming back apart till the winter at this point. Although I seem to have lost 2 mph but I think that might have to do more with throwing the carb upside down into a bucket for a week and reusing the old carb gaskets for the 6th time.. either way I am due for a vacuum leak check and a tune session. On the plus side I finally washed and waxed the boat and she came out awesome, truely not bad for a 23+ year old boat. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: TRBenj
Date Posted: September-06-2006 at 9:37am
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Glad to hear you found the source of the problem Joe. Now lets see some pics of that beast all shined up! ------------- |
Posted By: jimbo
Date Posted: September-06-2006 at 11:02am
Glad you got it on the straight and narrow JoeinNY.
I was just laughing about those with poor troubleshooting skills -- like my brother -- who would think he needed to order Edelbrock valve covers because his oil pressure dropped a bit and it wasn't going as fast as it used to  instead of checking the oil level and doing a tune-up.
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Posted By: JoeinNY
Date Posted: September-06-2006 at 2:05pm
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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. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: TRBenj
Date Posted: September-06-2006 at 5:05pm
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Joe, she shines up nice!
I may be going with some taller valve covers as well this winter- my roller rockers should be here within a week  ------------- |