Is my engine toast?-gctid820035

[businessgetmoney]

Well...... i got out of the river and went up on plane and ran about 4-5 min until it started to loose power and fell off. I throttled down and it stalled, noticed my temp gauge was pegged and saw a clump of seaweed floating off my drive!!!

Many swear words later, i did get it started and cooled down asap! This has happened before but not this extreme. I always have caught my gauges when temps go high!

So im wondering if im toast or not. Seems to run fine, no knocks and it idles and performs like normal.

What makes me concerned is the water vapor pouring from the breather on one side not a good sign. Checked my oil and surprisingly there no water in it.

What do you guys think? How forgiving are head gaskets...

[Patrevan]

'Seems to run fine, no knocks and it idles and performs like normal.'

This might indicate to me you dodged a bullet. I'd be checking the impeller though. I'm thinking that clump of seaweed may have fouled your prop causing the loss of power. Once the prop was freed from that, it was away again. I don't quite understand your comment "noticed my temp gauge was pegged'. Do you mean it remained high even after you shut the ignition off? This would indicate a faulty guage to me.

[businessgetmoney]

Meaning the temp was all the way up. Gauges are fine.

Stupid rivers... lesson learned always check for debris leaving the river.

Im going to do a comp test and know for sure. Supposed to go on a big 4 day trip tuesday

[Chief_Alen]

My best guess your ok, check for water in the oil. i always check the oil before starting up my boat, meaning i lift the dog house, airs out the engine bay, start the boat, and check for leaks as the engine warms, again after i shut down, tied up last thing i do is check the engine oil.

Your case i would install a red led high on the dash, tied into you temp sender.

By the way you might not have a alarm for high temp... you should.

[businessgetmoney]

Did a comp test today, all cyls about 60psi.. one cyl at 0. Trying to interpret that info. Maybe the dead cyl is a stuck valve? Im no longer blowing any smoke out breathers. No back firing through the carb. No water in oil.

When it overheated and shut down it did not want to turn over, meaning it wouldn't move but i was able to get it going. Indicates swollen pistons to me?

For giggles I checked the same gauge on my neighbors small block it turned out 70psi.

Would bad piston rings cause low even numbers on both sides like this? Bad head gaskets would mean water in oil...

[CptCrunchie]

"businessgetmoney" post=820093 wrote:
Did a comp test today, all cyls about 60psi.. one cyl at 0. Trying to interpret that info. Maybe the dead cyl is a stuck valve? Im no longer blowing any smoke out breathers. No back firing through the carb. No water in oil.

When it overheated and shut down it did not want to turn over, meaning it wouldn't move but i was able to get it going. Indicates swollen pistons to me?

For giggles I checked the same gauge on my neighbors small block it turned out 70psi.

Would bad piston rings cause low even numbers on both sides like this? Bad head gaskets would mean water in oil...

Now, I'm no mechanic, but are you sure you don't mean 170psi? 30-60psi is a bad cylinder.

[Norton_Rider]

"businessgetmoney" post=820093 wrote:
Did a comp test today, all cyls about 60psi.. one cyl at 0. Trying to interpret that info. Maybe the dead cyl is a stuck valve? Im no longer blowing any smoke out breathers. No back firing through the carb. No water in oil.

When it overheated and shut down it did not want to turn over, meaning it wouldn't move but i was able to get it going. Indicates swollen pistons to me?

For giggles I checked the same gauge on my neighbors small block it turned out 70psi.

Would bad piston rings cause low even numbers on both sides like this? Bad head gaskets would mean water in oil...

Squirt a bit of oil in the cylinder that's zero and do a compression test. If it comes up, it's bad rings and/or scored cylinder. If it's still zero, it's most likely a burned or stuck valve.

[CptCrunchie]

Yup! I'm no mechanic. :S

[builderdude]

"businessgetmoney" post=820093 wrote:
Did a comp test today, all cyls about 60psi.. one cyl at 0. Trying to interpret that info.

For giggles [b]I checked the same gauge on my neighbors small block it turned out 70psi.[/b

Are you referring to the gauge used for the compression test? If so I'd say the gauge is inaccurate.

An overheat that causes the temp gauge to peg will likely crack cast iron. I'd pressure test the cooling system to see if it holds.

[Chief_Alen]

You need a known good screw in type gauge.

[businessgetmoney]

It was a screw in gauge. Not sure what other kind there is. I do think that gauge is screwy.. might just be wishful thinking.

Im going to rent another gauge and do a collant pressure test.

[Download_Complete]

"businessgetmoney" post=820150 wrote:
It was a screw in gauge. Not sure what other kind there is. I do think that gauge is screwy.. might just be wishful thinking.

Im going to rent another gauge and do a collant pressure test.

5.7L GM blocks typically see 130-150 psi when they are healthy. The fact that you saw 60, and then 70 on another engine, implies that either the gauge is bad or you're doing it wrong.

[2850Bounty]

[color]blue wrote:
OK..... a few things to note:

When taking cylinder pressure readings with a screw-in style hose/gauge unit, the pressure will be accumulative.

This means that you should pass through at least 3 compression strokes per cylinder reading.

(very few bother to mention this)

It is best to remove all spark plugs prior.

It is also best to open the throttle plate above idle position. (does NOT need to be fully open!)

Make sure that the gauge itself is accurate.

There should be no more than 10% variation between the highest and lowest cylinder pressure reading.

The GM built SBC for marine use should be at or above 150 psi per cylinder.

If you see low cylinder pressures, DO NOT remove cylinder heads prior to doing a cylinder leak-down test.

Once the cylinder heads have been removed, this test is no longer an option.

Adding oil to the cylinders on a V engine (with the intent to determine point of failure) is rather futile because gravity works against us causing the oil to pool at the low side.

This is "old school" and was used back when all cylinders were all vertical.[/color]

Your case i would install a red led high on the dash, tied into you temp sender.

[color]blue wrote:
An electrical temp gauge receives data from a sender that varies electrical resistance.

This style sender will not trigger a red LED light.

[/color]

.

[2850Bounty]

"Download_Complete" post=820160 wrote:


The fact that you saw 60, and then 70 on another engine, implies that either the gauge is bad or you're doing it wrong.

[color]blue wrote:
Agreed![/color]

.

[Norton_Rider]

"2850Bounty" post=820162 wrote:
[color]blue wrote:
OK..... a few things to note:

Adding oil to the cylinders on a V engine (with the intent to determine point of failure) is rather futile because gravity works against us causing the oil to pool at the low side.

This is "old school" and was used back when all cylinders were all vertical.[/color]

I disagree. This still works on a v-engine, and even a flat (boxer) engine. You need to use a squirt can and try to get the oil on the inside walls and all around. Then the test needs to be done right away. All you are looking for is a slight increase in compression. I've done it a number of times.