Black flaky stuff...

General Chat About Exhaust, Cylinder Heads, Fuel Systems And Intake

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timnutt
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Black flaky stuff...

Post by timnutt »

Hi,

I'm refurbishing a 3.9 Rover v8 and when I lifted the rocker covers to check on the state of the rockers, etc. I find that everything is covered with what can only be described as black flakes. It's as if the oil has been burnt. Is this a sign of overheating or very infrequent oil changes, or what?

I'll replace the rockers, etc. and give it a good clean, but any idea what could be causing it?

Thanks!
TimN


Quagmire
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Post by Quagmire »

You said it already, lack of oil changes! Black cornflakes that smell of burning right?

Fairy power spray is your friend if you stripping it all down for a rebuild...
1974 Rover 3500s
1984 3.5 90
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timnutt
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Post by timnutt »

Yup - little black cornflakes is a good description. They crumble in your fingers like ash.

Here's hoping that lack of oil changes hasn't worn anything too badly. I guess I'll know more once I get the heads off.

Fairy power spray...! Good tip. On my last build (2.0 pinto) the forum had a poll set up for "How many people had put engine parts in the dishwasher to de-grease/clean them....... and got away with it!!" LOL!!

Cheers!
TimN
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ChrisJC
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Post by ChrisJC »

The black stuff is basically combustion products that have sneaked past the head gasket into the valley, and been washed down into the sump. That is one reason that the RV8 has such short oil-change intervals.

That particular issue was fixed by going from 14bolt to 10bolt head fixings and composite gaskets.

Chris.
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Series IIA 4.6 V8
R/R P38 4.6 V8
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sidecar
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Post by sidecar »

Were any of the 3.9 lumps 14 bolt heads?
unstable load
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Post by unstable load »

timnutt wrote: "How many people had put engine parts in the dishwasher to de-grease/clean them....... and got away with it!!" LOL!!
When 'er Indoors' dishwasher had it's door handle break, it found itself in the garage even before the replacement was bought..... :lol:
Cheers,
John
timnutt
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Post by timnutt »

sidecar wrote:Were any of the 3.9 lumps 14 bolt heads?
Yup - mine is, early 1990 engine. I've only found 1 place that stocks the full 14 bolt replacement head bolts so far: RPi. Any other suggestions.

TimN
P.s. Still thinking how to get the dishwasher into the garage....neat idea!
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Post by sidecar »

timnutt wrote:
sidecar wrote:Were any of the 3.9 lumps 14 bolt heads?
Yup - mine is, early 1990 engine. I've only found 1 place that stocks the full 14 bolt replacement head bolts so far: RPi. Any other suggestions.

TimN
P.s. Still thinking how to get the dishwasher into the garage....neat idea!

You only need to replace the bolts if they are stretch bolts, if they have a loose washer then they are not stretch bolts so you can just re-use 10 of them. If you are using stretch bolts be very careful of dodgy one ones on ebay. A chap on this forum tested a load and they were crap!.

I use ARP studs because I don't like the idea of torquing up against an ali thread whilst turning against the thread. Some people have still had the threads pull out with ARP studs, mine have been OK at 75 ftlbs, you could just go to 70 though. (The clamping force is still higher than with the standard bolts due to the fine pitch thread, unfortunately this is the same force that is pulling on the ali threads). The main problem with ARP studs is the cost!
unstable load
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Post by unstable load »

You don't need to move the dishy from the kitchen. Wait until you know madame is out for the time it takes to run 2 cycles, then stick the bits in and clean them, followed by an empty cycle with detergent only to clean the dishy, and it's job done.
Just make sure you remove all evidence you were there and remember, Deny, Deny, Deny if you get bust!! :twisted:
Cheers,
John
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