1996 Volvo Penta 302 5.0 FL ticking

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Dec 5, 2017
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Hello, I have a 1996 Volvo Penta 302 5.0 FL (carbureted) and I believe OMC partnered up to build the motor. My outdrive is a Volvo Penta SX. I can get serial number upon request. The motor has about 350 hours on it and it runs wonderfully. My motor runs at roughly 175-190 Fahrenheit whenever at the lake or on the muffs. Recently I ran my boat on the muffs and I am hearing a ticking sound which I believe is coming from the the left/stern area of the motor (spark plugs 1-4). My fuel is fresh 91, spark plugs are brand new (OEM Volvo plugs) and gapped correctly with a brand new distributor and cap (OEM Volvo Distributor and cap), fresh oil change with Mobil 1 full synthetic 5w-30 and wix oil filter , brand new impeller (OEM Volvo Impeller) and new fuel filter. The motor has never been opened nor have the intake manifolds or risers been replaced which makes these items on the motor 21+ years old. I recently did a compression test with all of the plugs removed and my numbers are as fallow Cylinder #1 (127 Cold/PSI -- 127 Hot/PSI) Cylinder #2 (125 Cold/PSI -- 125 Hot/PSI) Cylinder #3 (139 Cold/PSI -- 145 Hot/PSI) Cylinder #4 (135 Cold/PSI -- 139 Hot/PSI) Cylinder #5 (125 Cold/PSI -- 130 Hot/PSI) Cylinder #6 (119 Cold/PSI -- 119 Hot/PSI) Cylinder #7 (135 Cold/PSI -- 140 Hot/PSI) Cylinder #8 (140 Cold/PSI -- 141 Hot/PSI). I was curious if it was worth doing a leak down test and or adding a little oil into each piston then doing another compression reading. Other than that I'm not sure what to do, I've had an authorized Volvo Penta shop tell me the motor is done and needs to be rebuilt, he also mentioned most machine shops will not touch an engine that has eternal water cooling next to the pistons? Any suggestions are gratefully appreciated.
 
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Dave-R

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I had the same Ford fuel injected engine in a 1997 boat. It's the lifters. They were noisy . I tried oil changes and even transmission fluid to try and quiet them. I guess you could change out the hydraulic lifters. If your thinking a rod nock, that usually sounds deeper in the engine. Maybe someone else will have an idea. That what I suspect your noise is. Let us know what you find. Dave-R
 
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jimmbo

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Cylinder #6 is of concern, it is considerably lower than the highest. You could try the oil and recheck compression on that cylinder. The coolant temp sounds too high for a raw water cooled engine, by chance has the original thermostat been replaced by an automotive stat? Is there a chance the ticking is a snapping sound from a spark? If the noise is indeed a lifter, there is a chance there is a bit of dirt/varnish in that lifter. A good additive like GMs EOS might help, if the engine is not a roller cam, the additive will certainly add needed additives to protect the cam lobes, something that todays oil are not good at. It may also loosen up any sticky piston ring.
 

Horigan

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Is 5W-15 the recommended oil for that motor? My '95 recommends straight 30W. Maybe a higher viscosity oil will quiet it down.
 
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From what my maintenance manual says describing the ticking sound one would assume that it is a lifter. It almost seems to go away when I steer the steering wheel. I do have a power steering fluid leak I need to fix.



Cylinder #6 is of concern, it is considerably lower than the highest. You could try the oil and recheck compression on that cylinder. The coolant temp sounds too high for a raw water cooled engine, by chance has the original thermostat been replaced by an automotive stat? Is there a chance the ticking is a snapping sound from a spark? If the noise is indeed a lifter, there is a chance there is a bit of dirt/varnish in that lifter. A good additive like GMs EOS might help, if the engine is not a roller cam, the additive will certainly add needed additives to protect the cam lobes, something that todays oil are not good at. It may also loosen up any sticky piston ring.

Yeah Cylinder #6 is definitely low and with those number readings I am >10% which I've read is not okay. So if my compression number raises after adding oil into cylinder #6 I basically have something wrong with the piston, ring or possibly the cylinder head correct? I don't think the ticking sound is from the spark, I did pull all the plugs one by one on the distributor cap and noticed the sound did go away after pulling ( I forgot which ones) two different ones. One plug wire basically made the ticking go away completely and the other wire made the ticking a bit more faint. When I'm at Lake Havasu up river or in the early or late season I do notice my temps dip into the 160's due to what I can assume is the colder water. I have had my thermostat replaced once after I overheated my engine a few years ago (due to impeller breaking) and I cannot recall if its an automotive stat. Is there anyway one call tell if its an automotive? Would GMs EOS go directly into the oil and be ran for a season or just temporary? I'm not sure if the engine is a roller cam. My manual does call for straight 30W oil, which I would assume a full synthetic like mobile 1 5w-30 is equivalent to, correct me if I'm wrong. I was also thinking of going up to a 5w-40 but that seems quite a bit heavy.
 

jimmbo

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1) marine thermostats are usually about 140 - 150 degrees
2) oil added to cylinder may improve compression if there is a problem with the rings or minor scuffing. It generally doesn’t help if the valves are burnt, or not seating
3) GM has stated EOS is an occasional use product
4) if the Oil spec is SAE30, DO NOT use 5w-30, 5w-40, 10w-30, 10w-40, those oils are SAE 5w or 10w oils with a pile of Viscosity Index Improvers added to keep the oil from thinning out less than a SAE 30 or 40 when hot. If you want to use a multi grade, Mercury and Volvo market excellent 15w-40 oils. Marine engines operate in a different environment/parameters than auto/light trucks do, so oil designed for cars/trucks, gas or diesel, may not be the best choice for a marine engines(that comment should start a war).
5) lifter ticks have nothing to do with ignition spark. If the tick went away when the spark plug was pulled, it is not a lifter. Things that come to mind are, connecting rod bearing has too much clearance, piston pin loose, oil too thin.
If the noise went away when the steering is moved, then more troubleshooting is needed to determine where the tick is coming from. There may be a stiff or worn u-joint on the output shaft, or an issue with the gimbal bearing
 
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Scott Danforth

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5w-30 oil is canoe oil.....really close to water.

SAE 5W-30 is specifically for a car with roller valve train that is lightly loaded, not for a boat motor that is loaded like a dump truck driving up-hill in sand all the time. your car only need 5hp to maintain 60mph. your boat uses all 200hp to maintain 40mph

your oil spec is SAE 30 straight weight for cold temps and SAE 40 for warm temps. you can use 20W50. running thin oil in a boat motor is a fast way to destroy the bearings. when in doubt, run an oil with zinc. not to turn this into an oil thread, however I run Rotella 15W40 diesel oil in everything except the wife's VW, and after the warranty period, it will probably go in there too.

Jimmbo has you on the right path with tick diagnosis. if it is a bearing, time to pull the motor.

do a leak down test to determine if its rings or valves that is causing the low compression.
 
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So my boat definitely seems to be running warm. Could that be possibly due to the weight of the oil? I had no idea that multi weight oil was not good for boat motors but it makes sense when you put it into that context. I have ran 5w-30 for 5 years now changing it twice a season. Could running a higher viscosity oil such as SAE 40 or 20w-50 help add compression? You mention the tick could be from such thin oil as to what I'm running (5w-30), do you recommend me changing the oil to my actual oil spec for the engine before I do a leak down test? So the plan of attack at this moment would be to troubleshoot the steering, how is it possible that the steering could be making a ticking noise in which the noise seems like its from the engine? I plan on taking a look at the boat tomorrow afternoon.
 
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jimmbo

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Use an Oil, SAE 30 or 15-40, I would also recommend it meets NMMA specs as well. Once you have a more suitable oil in the crankcase, run it and see if it is quieter
 
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I changed the oil to a SAE 30 Sierra Full Synthetic Marine Engine Oil and the motor is still just as loud. I am doing a leak down test and where I believe TDC is does not seem accurate? I am running at 90 PSI on my 33 gallon air compressor and 90 PSI on the leakdown and my leak down is running at about 60 PSI for the leak down.
 
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Okay, I figured out a litte bit more but I swear my piston was not TDC when I got these readings. I used a drinking straw to find out when the cylinder was highest and when I took the readings they were around 20 PSI, I then would slowly crank the engine by hand and find where it was hardest to crank and I would get my highest readings. All readings are with the compressor at 90 PSI and 90 PSI on gauge. Engine was warm with all plugs out. Cylinder #1 - 72 PSI // Cylinder #2 - 59 PSI // Cylinder #3 - 89 PSI // Cylinder #4 - 80 PSI // Cylinder #5 - 71 PSi // Cylinder # 6 - 61 PSI // Cylinder #7 - 79 PSI // Cylinder #8 - 82 PSI. I thought for sure cylinder #6 would have the lowest reading due to the compression test reading being lowest at #6.
 
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Dec 5, 2017
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Any help whether I should buy an entire new motor or have this one rebuilt would be helpful. I don't know anything about motors and would like to have her running healthy without worrying about the motor failing on me out on the lake.
 
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