Just fired up used 5.7 and some problems

[DAMIEMARIAH]

I have just fitted a used 97 volvo penta 5.7gs engine. The owner siad he had bought it for his boat a couple of years ago but then decided to go diesel so it has been sat around since.
I drained the fuel and it smelt really bad as it was so old, when i looked at it the engine turned over on the starter ok and there was plenty of oil in it.
I have now fired it up, it took some time but with some easy start it fired up, first on 7 cylinders then after a few minitues all 8. but i am now left with a tapping noise from the port cylinder head and both rocker cover vents are chuffing smoke, this is a fine white smoke looks a bit like steam and smells of fumes/petrol.
When i rev the engine the tapping goes away a bit but comes back at idle, the engine is very responsive and idles ok but sometimes it needs a bit of throttle to get it started again.
a mechanic has looked at the engine running and suggested its the rings a bit stuck in and the noise is possibly a stuck valve? he suggested a engine reviver additive to flush through the engine, then change the oil he said this should free off the stuck components.
Does anyone have any experience and advise on the 2 problems.
I was let down on a new engine and found this one, but i hope its not a pup though!

 

[Bondo]

Re: Just fired up used 5.7 and some problems

Ayuh,.... I'd start by changin' the oil, 'n doin' a Compression test, 'n leak-down test, to see what it's general health is...

I'd skip the snake oil treatment...

 

[RogersJetboat454]

Re: Just fired up used 5.7 and some problems

Lifters may be bleeding down, and allowing the valve train to get loose. What was the oil pressure reading, especially at idle? If it's low, chances are the lifters are being starved for oil.
If the oil pressure was acceptable, the lifters with some cleaning, and fresh oil, may come back to life. If it doesn't go away, they may need to be replaced.

The smoke/steam is probably moisture in the engine burning off. Did you do an oil change before running the engine?

Have your mechanic check compression. This will tell you over-all health, and may pinpoint problem cylinders.

 

[DAMIEMARIAH]

Re: Just fired up used 5.7 and some problems

Oil pressure at idle is 30 psi and rises to over 40 when revved, fresh oil before start up. do these engines have hydraulic lifters?

Lifters may be bleeding down, and allowing the valve train to get loose. What was the oil pressure reading, especially at idle? If it's low, chances are the lifters are being starved for oil.
If the oil pressure was acceptable, the lifters with some cleaning, and fresh oil, may come back to life. If it doesn't go away, they may need to be replaced.

The smoke/steam is probably moisture in the engine burning off. Did you do an oil change before running the engine?

Have your mechanic check compression. This will tell you over-all health, and may pinpoint problem cylinders.

 

[RogersJetboat454]

Re: Just fired up used 5.7 and some problems

do these engines have hydraulic lifters?

Yes they do.

 

[DAMIEMARIAH]

Re: Just fired up used 5.7 and some problems

Thanks Rogers jetboat.
I ran the engine for around half an hour, switching off and on a few times, i wonder if the lifters will free themselves off while it is sitting over the next few days. Just got to look at the petrol smelling white smoke from the breathers, i would have thought after 30 mins of running and engine nice and warm that if it was water in the engine it would have evaporated in that time?

I think i will do a compression check, does anyone know what psi range i should be looking for?

 

[RogersJetboat454]

Re: Just fired up used 5.7 and some problems

The lifters aren't going to get any better by sitting. Like I said, it sounds as though they are bleeding down. Sometimes they get gunked up, and bleed off oil too quickly. Other times they are just plain damaged. Could also be related to the oil being thinned out by fuel, which is covered below.

As far as the smoke, with fresh oil, and running it that long, it should have diminished. You say you smell fuel in the oil. Could be that the rings are allowing some blow-by.. Or another possibility is if you have a mechanical fuel pump, the fuel pump diaphragm may be ruptured and leaking fuel into the crank-case via the fuel pump boss. May want to have a look at the fuel pump.

Another possibility for the smoke is if there is a water leak into the crankcase. May want to have your mechanic rig up a way he can test the cooling system for leaks. Usually blocking off passages, and pressurizing it to 10-15 PSI does the trick.

As far as compression figures, that's when there may be a broad range of acceptable numbers. It all depends on the compression ratio of the engine, and the general condition of the engine. The main thing you want to check for is that all the compression readings are within 10% of one another. Check the compression, and post your numbers. I'm sure there will be plenty of people on here to critique them...

 

[jerome radtke]

Re: Just fired up used 5.7 and some problems

You may want to try using a vacuum guage. they can tell you many things.

How to Use and Interpret a Vacuum Gauge

 

[Silvertip]

Re: Just fired up used 5.7 and some problems

Head to your local auto store and buy a quart of RISLONE. It's in a yellow container in the engine additives (some refer to these as snake oil) aisle. Rislone has been around for decades and does wonders at cleaning up an engine and freeing stuck rings and valves. There is obviously no guarantee this will solve the problem but there is no harm in trying and the most you are out is a little time and a five bucks. Add the additive to the engine oil and run the engine as long as you can, above the point where the noise goes away. Two things affect lifters: 1) they stick in which case they make noise all the time. 2) They have a high bleed down rate in which case they make noise at idle. I'm sticking my neck out hear but I'm guessing this engine is not in as good a shape as the seller contended. It won't hurt to do a compression check, remove the valve cover to see what is going on with the valve train, and before doing any major work, try RISLONE (regardless how anyone feels about that). That product as saved a number of diesel and gas engines for me over the years and as a result put a fair amount of money in my pocket. It will NOT save a worn out engine. Only a rebuild will do that. While inspecting the running engine with the valve cover off, oil will spurt all over so cover the push rod end of each rocker arm with heavy duty aluminum foil to control the mess. Use a thick feeler gauge between the rocker and valve tip to determine which lifter is making noise. Somtimes a quick rap with a rubber mallet on the push rod end of the rocker arm will dislodge a stuck lifter. You are not driving fence posts here -- I said a rap! With the engine off, you can do the same thing on the valve end of the rocker to see if a stuck valve comes loose.