1959 Atom Skier Gray Marine 4 knocking
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=48739
Printed Date: October-05-2024 at 4:16pm
Topic: 1959 Atom Skier Gray Marine 4 knocking
Posted By: Linbarr
Subject: 1959 Atom Skier Gray Marine 4 knocking
Date Posted: May-26-2020 at 3:55pm
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New varnish on my boat this winter. Running great this year THEN... Last weekend I was cruising to the boat ramp when she started knocking and loosing power. Oil pressure dropped to zero. Shut her down immediately. Problem was a ruptured line to the oil pressure gauge. Repaired and replaced the two lost quarts of oil. Restarted engine. Ran quiet and smooth as before with 40lbs oil pressure on trailer with siphon. Launched. Ran quiet and smooth as on trailer. BUT, over about 2,000 rpm she starts knocking and loosing power. Oil pressure stays at 40 lbs. Please tell me something other than to rebuild the engine. I do not have those skills.  ------------- Barry Smith |
Replies:
Posted By: 8122pbrainard
Date Posted: May-26-2020 at 4:12pm
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Barry, Sorry to say but the knock could be a blown main or connecting rod bearing. The only way to really tell is pulling the engine and pulling the oil pan. The varnish job looks fantastic. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: 56-Atom
Date Posted: May-26-2020 at 4:50pm
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My 56 Atom, 70hp, had a similar issue last season. On the first fire up the engine ran great up to 3000+ rpms. Then it suddenly capped out at 2400 RPMs. Tried to re-set timing, fuel/water separator filter, rebuilt generator, carb adjust and the same. At end of season a gentleman at the dock suggested a new spark advance spring. Did so, and rpm shot up to 3400. If you open your distributor cap you should be able to assess the spring, should be fairly tight, hard to pull on with your fingernail. It is a cheap fix attempt. If you get the same, then at least you have a spare set of points/spring for after the motor gets looked at. ------------- 56-Atom https://www.facebook.com/media/set/edit/a.1729455880510267/ |
Posted By: zwoobah
Date Posted: May-26-2020 at 5:09pm
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If it's knocking after running low on oil, you have a lower end bearing problem. Do not run the motor or you risk scoring the crank and requiring a full rebuild. Pull the motor, pull the oil pan, pull the bearing caps and inspect the crank surface. If it's still shiny and you can't feel any scratches with a fingernail, you might be able to just throw in new bearings and run it. Also, get rid of that live oil feed line and run an electronic sender gauge. ------------- 1968 Mustang 16 - 351W powered |
Posted By: 8122pbrainard
Date Posted: May-26-2020 at 5:16pm
What? An oil line is just a sound as a fuel line. They do not rupture. I suspect a loose fitting after the varnish job? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
zwoobah wrote:Posted By: Linbarr
Date Posted: May-26-2020 at 6:38pm
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I would be foolish to not check this out. thanks, ------------- Barry Smith |
Posted By: Linbarr
Date Posted: May-26-2020 at 6:41pm
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There was a six inch long rubber/fiber line that connected to the copper line under the floor board. Pretty rotten on both ends. My bad for not seeing and replacing it when I had the floor out. ------------- Barry Smith |
Posted By: 56-Atom
Date Posted: May-26-2020 at 7:20pm
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Mine blew at the gauge seal and leaked all over the dash. Are you still running a 6 volt and how is your dash grounded? The reason I ask is my 56 originally grounded via the copper oil pressure line. ------------- 56-Atom https://www.facebook.com/media/set/edit/a.1729455880510267/ |
Posted By: Linbarr
Date Posted: May-27-2020 at 3:52pm
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I am thinking a lower bearing problem. I have discussed the issue and fix with my boat mechanic. He is ready to pull the motor next week and check it out. I will be getting the parts. Where do I find the right bearings? My assumption is that all should be replaced. What do I need to order the bearing? Do I need a different size from the stock? Is it a good idea to replace the oil pump since I have the opportunity? Any coaching you can provide is greatly appreciated. ------------- Barry Smith |
Posted By: 8122pbrainard
Date Posted: May-27-2020 at 4:03pm
Barry, Your mechanic needs to determine the sizes. If the crank needs grinding, then that too will govern the size. The Gray is based on a Industrial Continental block so he should have a source for parts. If not, then http://www.vannessengineering.com/" rel="nofollow - Van Ness will be a good source but they will want more $$$. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: 8122pbrainard
Date Posted: May-28-2020 at 10:18am
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Barry, One additional thought and that is your mechanic should also check the cam bearings. I believe with those Continental blocks, the oil goes to the cam first and then to the main bearings/rod bearings. So, the cam bearings would see the lost oil first. Speaking of oil, what have you been running in it? Hopefully an oil with a good ZDDP content. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Linbarr
Date Posted: May-28-2020 at 10:52am
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I have been running Shell Rotella with zinc additive, non detergent oil. Thanks for asking. Should I replace the oil pump while the engine is out? ------------- Barry Smith |
Posted By: zwoobah
Date Posted: May-28-2020 at 12:47pm
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Yes, I'd replace the pump. May want to replace the timing set as well. Cheap insurance. Your mechanic will likely recommend replacing all the usual seals - front and rear mains, oil pan, etc. It's smart to do while everything is accessible. Don't order bearings until the engine is apart. If it has been rebuilt in the past it may already have oversize bearings and you will need to order the matching size. If the crank is scored and it needs to be turned, you'll also have to order a different size. Unfortunately this will slow down the rebuild by a few days, but there's no way to know what is in there until you can measure. ------------- 1968 Mustang 16 - 351W powered |
Posted By: Gary S
Date Posted: May-28-2020 at 1:00pm
On the plus side of all this it will give you a chance to clean the insides out and you can start using a detergent oil  Also measure the pumps clearances it may be ok and a new one close to unobtainable. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: 8122pbrainard
Date Posted: May-28-2020 at 4:27pm
Plus 1 on the pump and the oil ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Linbarr
Date Posted: May-28-2020 at 4:59pm
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thank you for the coaching and information! ------------- Barry Smith |