Cooked V8

**101RRS** · 12th April 2020, 05:47 PM

I have been running a couple threads on thermostat issues I have been having in my top hatted 4.6 RV8 with carbs.

In September last year I wanted to check a few things with the engine hot and the thermostat housing stayed cold so did not open and the engine got hot.

I have started the engine a few times since without getting it hot and all was OK. I changed the thermostat this weekend and ran it yesterday and all was good – got up to normal operating temp again with no issues.

Today I started the engine up and really heavy white/blue smoke came out of the exhaust – so thick it was smoking out the neighbourhood. I didn’t get any pics but later I went out and restarted to get something – this time the smoke was no where near as thick but is still there. Here is the vid (click of the pic to open).

VID_20200412_163943

So it looks like when it got hot last year I did something to the engine that has not manifested itself until now.

Oil is nice and clear, coolant does not have any bubbles or oil.

Dip Stick.jpg

Heavy thick oil is coming out from exhaust joints on both banks of the engine.

Exhaust Joint.jpg

Exhaust drip.jpg

My thoughts are that with the engine getting hot – there is at a minimum a ring issue – clearly oil is being burned. When I have had similar symptoms in other engines in the past, broken/melted rings have been the cause.

At this stage I am thinking of pulling the 4.6 and putting the 3.5 back in so that at least I can use the vehicle and sort the 4.6 out on the engine stand in slow time.

Happy to take ideas and/or thoughts.

Thanks

Garry

**Pedro_The_Swift** · 12th April 2020, 06:18 PM

Thats a lot of oil forced into the exhaust ,, its a wonder it still fired...

**Graeme** · 12th April 2020, 06:40 PM

How are the crankcase breathers?

**ian4002000** · 12th April 2020, 06:43 PM

I would get the motor hot and take it for a drive to see what happens.
It looks like valve stem seals need changing.
Dont give in yet

Ian
Bittern

**PhilipA** · 12th April 2020, 07:50 PM

First thing would be to have a look at the plugs.

They should show where the oil is coming from.

Next thing I would look down the cylinders with a borescope.
I can't think where you would get that much oil!
maybe your exhaust valves are so loose it has been running down when stopped assuming you don't have stem seals.
Regards PhilipA

**101RRS** · 12th April 2020, 07:55 PM

Originally Posted by Graeme

How are the crankcase breathers?

They are actually open to the atmosphere at the moment with the sucker pipes not connected - the sucker pipes on the side of the carbs are blanked off - like this pending the final configuration.

Originally Posted by ian4002000

I would get the motor hot and take it for a drive to see what happens.
It looks like valve stem seals need changing.
Dont give in yet

Thanks Ian - I hope it not the valve stem seals as the engine was recently rebuilt with new everything but is something to look at. The nice clean oil you see is the running in oil and the engine has only covered about 100km but the vehicle with this engine has not been driven in a year. I might try a run tomorrow in case it is something sticking.

Cheers

Garry

**101RRS** · 14th April 2020, 02:16 PM

Just to close this thread.

Went for a drive around the block yesterday and this was the result (click on pic to see vid)

Vid Uphill with Smoke

Got back home and went for a second run (click on pic to see vid)

Vid Uphill no Smoke

The two vids were taken only about 5 minutes apart. Smoke now completely gone - so engine definitely not cooked.

Today started first up no smoke and drove about 40km round trip to get my annual LPG safety certificate and no smoke at all.

Where the truck is parked it is on a slight sideways slope and all I can think off is that oil had built up in the rockers and got down into the combustion chambers when the engine cooled - however when parked overnight in a different position there was no smoke at all.

Garry

**PhilipA** · 14th April 2020, 02:33 PM

Yes it sounds like it was missing at first then finally cleared.
The exhaust probably had a lot of oil in it.
Congratulations!!!!
Regards PhilipA

**Eevo** · 14th April 2020, 02:36 PM

**101 Ron** · 14th April 2020, 03:15 PM

A lot of motors will burn oil just after being filled with fresh oil, especially if the oil was thrown in quickly.
condition of valve stem seals and type of seal matters too.
Also note that a motor if boiled ...over heated, but not boiled dry or steam jacket pockets ,cannot over heat enough to hurt the motor as boiling water cannot exceed 100c .
also if you have been playing breather pipes and PVC valve ect and fill the motor with oil, it can make the motor burn oil until it sorts its self out.
If you really want to stop this problem happening again you can fit a side valve motor which never have valve stem seals ect……...I would be happy to take the 4.6 litre bent 8.
Ron

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