496HO engine problems.

[yeller]

On my first run of the year, boat was way down on power.
I discovered I had developed a hole the supercharger's intercooler and as a result, was sucking a a decent amount of water through the intake. When I saw how much water was entering the intake, I was surprised the boat even ran. There was enough water that some blew past the rings into the crankcase. Probably about 1/4 to 1/3 of a quart.


Once at home, I changed the oil.
After installing a new cooler, I took the boat out and my oil pressure gauge was reading low. About 5lbs at idle and 20psi at about 3500rpm. Interestingly, the Guardian system monitors oil pressure and it did not go off.
I ran back to the dock at about 2500rpm (about 10 minutes).

Parked the boat for a couple weeks before I could look at it again. Put the muffs on the drive and fire it up. This time oil pressure reads 20psi at idle, but will only go to about 30psi at 3500~3800rpm. I figure I'll change the oil again, so I leave the boat idling to warm the oil. After a bit, the Guardian system goes off. I'm only guessing, but I think it was from overheating. My temp gauge went to 180 and I've never seen it go over 160 before. I also notice that I'm not getting the same volume of (raw) water exiting that I'm use to seeing. This is the first time I've ever put muffs on the Blackhawk drive though, so I'm not sure if the muffs deliver the same amount of water through the drive as when on the Bravo1.

In any case, I figure I'll change the pump impeller. Rip the pump apart and impeller is near perfect (150hrs). Damn. I was hoping that would be my water problem. Change the impeller anyways and back flush the system. Water flows great. No restrictions. Out of curiosity, while the pump is off, I put the muffs on the drive and turn on the water. Absolutely no water flows through the drive and out the open intake hose. So I connect the garden hose to the intake hose and water easily flows backwards and out the drive muffs that are still in place. Connect the hose to the muffs and no water flows out the intake hose. What gives? I can't think of anything that would stop the water flow. Why would the water flow in only one direction?

Anyways, I reinstall the water pump and fire up the boat. With the engine running, the pump is able to suck the water through the drive. (Still confused about why the garden hose couldn't push the water through the drive). With the new impeller, there is still not very good water flow through the cooling system. Probably half what I'm use to seeing with the Bravo.
I idle the boat for a bit and Guardian system goes off. Boat isn't to temp this time but exhaust manifolds are getting mighty warm. I'm guessing due to poor water flow.

Before firing the boat up I had installed a mechanical oil pressure gauge for verification, and oil pressure was still the same. 20lbs at idle, to a max of about 30lbs.

Shut the boat down and decide to change the oil/filter again. I usually run straight 40w, but because of the low oil pressure, I thought I'd try 20w-50 this time. Fire the boat up and 25lbs at idle. Ran it up close to 4000rpm to test the pressure and only saw a tad over 35lbs. (Water flow through system did increase with the rpms, so the pump is working. Just doesn't seem to be using as much of the hose water as it should).

I'm hoping to take the boat to a shop tomorrow and get a scanner hooked up to check the alarms, but in the meantime, I have a couple questions:

1) Anyone with BH experience know if they flow less water (on the muffs) than a Bravo?

2) I use to have great oil pressure. Any thoughts on why it's low now?

I really don't think I took on enough water to cause premature bearing wear, (which would result in low oil pressure).
I had a cracked block on my old boat and it took on a fair bit of water. I ran it for about 50-60hrs with the cracked block. I figured I'd run it till it died. Every couple times out, I'd have to drain about a quart of oil/water. Every 4th or 5th time, I'd change the oil. It never did die. When I stripped the motor down, bearings were still good.

Just looking for different opinions. Let me know what you think.

[gcarter]

Just curious......have you ever pulled the end caps off the heat exchanger?

[BUIZILLA]

On my first run of the year, boat was way down on power.
I discovered I had developed a hole the supercharger's intercooler and as a result, was sucking a a decent amount of water through the intake. When I saw how much water was entering the intake, I was surprised the boat even ran. There was enough water that some blew past the rings into the crankcase. Probably about 1/4 to 1/3 of a quart.

this was salt water being sucked through?

[MOP]

Some will disagree but on the muffs except for short bursts it is not good to run over 1200, I have seen quite a few impellers go south during the spring wake up at our marina.
Now a thought on the water issue, years back a few buds and I fooled around with water/alcohol injection. The right mix and it will give a reasonable boost, but let it get too much and you can raise cane with head gaskets and the rod bearing. Two things I would do in your situation is do an oil sample and a leak down test, it may have pounded the bearings giving you the lower oil pressure water can be some destructive. Note the links below mention the damage that can occur.

Phil

http://www.rallycars.com/Cars/WaterInjection.html
http://rusubaru.com/water/
http://blizzard.rwic.und.edu/~nordli...ies/raydorman/

[Donzi_Dude]

oil pressure sounds low...

[Rumblefish]

On my first run of the year, boat was way down on power.
I discovered I had developed a hole the supercharger's intercooler and as a result, was sucking a a decent amount of water through the intake. When I saw how much water was entering the intake, I was surprised the boat even ran. There was enough water that some blew past the rings into the crankcase. Probably about 1/4 to 1/3 of a quart.


Just looking for different opinions. Let me know what you think.

Sorry to hear .. but as you know water doesnt compress very well so time for a leak down...

Also big block chevys usally have .002-.0025 clearance in the bearing depending on who built the engine. and with a small amount of water in the oil ran for a period of time you can loose the babbitt facing and give that much up in clearance and lose alot of oil pressure..

on the upside like you said it may continue just fine if the bearings dont spin and the leak down is good. sounds like you corrected the cause already so Minor rebuild and you still have plenty of summer left.

[yeller]

Just curious......have you ever pulled the end caps off the heat exchanger?

George, I backflushed the system and flow wasn't an issue. Although I didn't take the end caps off, I'm positive there is no obstruction.

this was salt water being sucked through?

Yes.

Some will disagree but on the muffs except for short bursts it is not good to run over 1200, I have seen quite a few impellers go south during the spring wake up at our marina.
Two things I would do in your situation is do an oil sample and a leak down test, it may have pounded the bearings giving you the lower oil pressure water can be some destructive.

I know I shouldn't wind up the motor on the muffs, but I needed to check the oil pressure and an oil sample wouldn't help because it's been changed twice already. Also, I'm not concerned about compression, I'm concerned about 1 - oil pressure, and 2 - water flow (so a leak down test is wasted time for me at this point).

....Minor rebuild and you still have plenty of summer left.

3 months of summer left for me (at the most). Any type of rebuild would probably kill it for me, because I have very limited on free time.


Thanks for the feedback guys.
I do realize that everything points to excessive bearing clearance. Based on how much water I ran in my old motor (and for how long), I'm just having a hard time believing that the amount that was in this motor would kill the bearings so quickly. I literally ran well over a quart of water (fresh and salt) for hours on end in the old boat and the bearings held up fine.

Before I even started this thread, I knew the motor would have to come out. I just thought I'd throw my problem(s) out there to hear others opinions.


I am still curious as to why no water would flow through the drive until it was "sucked" through by the pump. I can't think of any reason except for physics and how the water exits the muffs in relation to the drives water pick up.

[mrfixxall]

just my o2!

when you injected water through the inner cooler it probably filled the cylinders with water,cylinders could not handle it and forced the water past the rings into the crank case..from all the water being injected and being forced past the piston rings it most likely pounded the bearings out the the rods..

i would not run the engine like it is or it could cost more to fix..if it indeed pound the rod bearings you may also have a few bent rods..

do a compression test to verify,low compression in some of the cylinders will be the tell tail to which cylinders are most likely have the bent rods and crushed bearings..

contact haxberry , it shouldnt be but a week or 2 to fixx it..

[VetteLT193]

as far as the water flow, it's simply a gravity thing. Water is heavy and the seal on the muffs is loose. it will simply run out the drive before forcing its way to the engine.

[yeller]

just my o2!

when you injected water through the inner cooler it probably filled the cylinders with water,cylinders could not handle it and forced the water past the rings into the crank case..from all the water being injected and being forced past the piston rings it most likely pounded the bearings out the the rods..

i would not run the engine like it is or it could cost more to fix..if it indeed pound the rod bearings you may also have a few bent rods..

do a compression test to verify,low compression in some of the cylinders will be the tell tail to which cylinders are most likely have the bent rods and crushed bearings..

contact haxberry , it shouldnt be but a week or 2 to fixx it..

Thanks Fixx. This is the best explaination of why the bearings could have failed. I kept thinking of the water in the oil as being the instigator, but it does make more sense that it was the pistons trying to compress the water that hurt the bearings.

No need for the compression test though. If the motor is coming out, it will be getting new forged rods/pistons from Raylar.

I'm sure Haxberry could get me running quickly, but I'm the type of guy that hates paying others to do what I can do myself. I enjoy assembling my own motors.

....and thanks for the drive water explaination. I was sure it could be explained by physics. I just needed someone to confirm it for me.

[MOP]

If you read up you will find out it is the water/fuel mix produces extreme combustion that hammers the bearings, if you had enough water in the cylinders to stop a piston it would hydro lock and either not turn over or bend the rods.

[mrfixxall]

Thanks Fixx. This is the best explaination of why the bearings could have failed. I kept thinking of the water in the oil as being the instigator, but it does make more sense that it was the pistons trying to compress the water that hurt the bearings.

No need for the compression test though. If the motor is coming out, it will be getting new forged rods/pistons from Raylar.

I'm sure Haxberry could get me running quickly, but I'm the type of guy that hates paying others to do what I can do myself. I enjoy assembling my own motors.

....and thanks for the drive water explaination. I was sure it could be explained by physics. I just needed someone to confirm it for me.

i just read that mop also stated a good point!

when you get it apart and if you have a dial indicator pur it on the deck of the block and find tdc of that cylinder,measure the deck and then the top of the piston, subtract that number and write it down..do this to all the cylinders and see if they vary from each other..the ones with the bigger numbers inspect the cylinder walls..when compressing water it will rock the piston in the cylinder walls and could put a hairline crack in it..if you cant see anything it may be wise to have the block and cylinders magnafluxed to make sure..

If your going to change the rods and pistons go with srp or j&e. a good rod would be a k5 hbeam from crower or if you can afford oliver that would be my first choice..you may as well get rid of tha cast crank as well and go with a forged one.. wineburg,Bryant or a luniti would be my choices..

good luck

[Buddyc]

Or just put a 525 in it like Carl did and sell the 496... Really sorry to hear about your misfortune

[Carl C]

Or just put a 525 in it like Carl did and sell the 496... Really sorry to hear about your misfortune

I was thinking the same thing about feeling bad for Glen after all the trouble he's had and boating season just getting rolling. Good luck with it. I don't know what else to say....

[silverghost]

If this was my boat & engine I would disconnect everything needed to lift the engine out of the boat.
Pull the oil pan and start to pull the rod bearing caps & actually inspect the bearings & cranshaft bearing journals.
I would also pull the main bearing caps.
Do this while your engine is still assembled & cylinder are heads still on.

If you then see no damage or scoring on the crankshaft bearing journals; or and discoloration from heat, I would replace both the rod & main bearing shells with new STD. size bearing shells .
Use Plastigauge to check new bearing shell clearance.

You need not pull the entire engine apart to do this bearing shell swap.
Re-assemble &
Drop the engine back in your boat and see what your oil pressure situation then is .

This may salvage your summer boating season as well as your engine.
IF~ the bearing shells were just hammered out of shape & size.

On the oher hand IF you see crankshaft bearing journal scoring and heat damage you will then know that the saltwater/oli mix ruined your oil's film thickness that your crankshaft rides-on between the bearing shells to prevent direct metal to metal contact on the crankshaft bearing journals & bearing shells.

Then you will finally know for sure that a complete engine re-build is now in order.

This inspection/repair should only take a few evenings at best.~~~If it's just your bearing shells that were hammered out of shape.
It's worth a shot .

I would not run this engine now as it now sits with low oil pressure.