New heads after water ingress, but lots of smoke from rocker cover breathers.

[loco]

Hi all,
So, I have a 4.3 v6 vortec. We had (salt!) water ingress from a leaky inlet manifold. Unfortunately it took a while to get the engine out, and the mechanics found some of the valve seats were shot from corrosion. So, we replaced the heads, the engineer removed the sump to clean it, then put the engine back in after blasting out all the oil channels etc.

Compression is good, and the engine starts and idles well.

We took it out for a run and after a couple miles at speed, the engine choked out and stalled. We had loads of fumes in the engine bay. It seemed to be ticking as if it was running hot. Concerned we were burning oil, we added a little at sea and thought we could hear a hiss as we did.
Looking at the gauges, it didn't appear to be running hot, with the the temp read out right in the middle (assuming I can trust it).

We limped back just above idle. The engineer suggests it must be the big end or crank bearings that have corroded and are tight which is causing the oil to cook and cause the fumes.

Thing is, the engine starts on the button and idles fine, with no noticeable rumbles or noises.

Someone I know suggested the cooling system (impeller, etc) but I'm doubting that. I might go and test the temperature of the coolant hoses.

Any other ideas what to test at this point? Current thinking is to just buy a new long engine, but I really would like to avoid the expense!

Thanks in advance!

 

[Scott Danforth]

start with the impeller

if you heard a hiss while dumping oil in, the engine temp was well over 300F

 

[loco]

Thanks - I’ll try that. Should those impellers be packed with water based lube each time they’re taken apart? I always do when I change them so they prime themselves. I’m thinking since the engineers had the engine out, it would have all been drained dry, so if it needs packing, that could be the whole problem.

Temperature sensor wouldn’t have read the high temperature as the system would be dry, and it was just reading the heat soak from the block.

 

[Lou C]

Was the engine drained of salt water right away? You had water in the oil (typical if the intake leaks because it goes right in the cam valley) but did you have salt water in the cyls as well? Because if it didn’t smoke from the valve covers before if you had salt water in the cyls for ant length of time it could have rusted the cyl bores. The thing to when this happens is to get the water out as soon as you can and change the oil, then spray figging oil in the cyls to prevent rust. Had a similar problem caused by a blown head gaskets and was able to save it by draining it quick and changing the oil a few times & fogging it....

 

[loco]

Yeah I think the cylinder bores might have an issue.

I took the impeller out and it looked just fine. Replaced it with a spare, re-lubed and re-packed with grease.

Reading the sheet from the engineer, it mentions a seized cylinder. They say that saved it and got good compression, but I wonder if it’s got a faulty piston ring. I’ll do a compression test on all the cylinders. It surprises me that, having taken the heads off, they wouldn’t have identified any other issues with the cylinder bores.

That said, if it had a faulty ring, wouldn’t that be evident right from when it started? Smoke from the exhaust, and constant blow-by (and therefore fumes in rocker cover breathers) right from a cold start? As it stands now, the engine looks to run absolutely perfectly from cold. It seems the issue is only obvious when it’s under load.

A real head scratcher.

 

[Lou C]

I got the salt water out of mine right away, and sprayed fogging oil liberally in the cyls and cranked it over, then repeated...
I let it sit then from end of Oct to Feb when I took it apart (winter in Long Island not fun for doing mechanical work) then got a warm spell that Feb and got out the impact gun and took off the heads, the fogging oil was still in the cyls and nothing was rusted.