Robsscooby

iTrader: (1)

Hi there
My00 scooby turbo 2000
has started knocking after 400mile of me rebuilding the engine.
Reason behind rebuild was due to carbon build up and failed a leak down test at scooby clinic.
so ripped motor out and started stripping.
thought while its stripped will change crank bearings.
so replaced with acl race bearings
fitted brand new oil pump genuine scooby 1.
had all heads skimmed pressure tested and shims set
new piston rings
full engine gasket set
car ran perfect for the first 300 mile
then started knocking.
so out with engine again
and all bearings are chewed up
looks like oil starvation.
please be kind
any one have any ideas
cheers

scubbay

iTrader: (61)

damaged bearings are caused by oil starvation. Plain and simple. An error in the build perhaps? or faulty pump.

Robsscooby

iTrader: (1)

Someone else wreckons its the fact I might not of built oil pressure correctly

merlin24

iTrader: (1)

What did the oil clearances come out at on the big end and main journals when you built it?

Mick

**jay**

iTrader: (1)

was it the same crank from the original engine or did you replace it?

RICHARD J

iTrader: (4)

Did you check the bearing clearances with plastagauge? This may be the issue. Also new builds can be a pig to build up oil pressure before starting up & if you don't have good oil pressure before you fire it up then oil starvation is inevitable.

FMJ

iTrader: (2)

How does one build up the pressure? Turn over with no spark as you do when you disconnect the crank sensor for an oil change?

Robsscooby

iTrader: (1)

I did check with plastigauge
cant remember the readings
and what should they be
and ye whats the best way of building oil pressure

edsel

iTrader: (2)

Before initial start up, fill the oil filter with oil. The filter material soaks oil so it will need topping up as it absorbs. Fit filter.
With the crank position sensor disconnected (so it doesn't fire) crank the engine several times till the oil light goes out. If you have an oil pressure gauge make sure the pressure builds.
Assembly lube will only protect the engine for a very short time.

This way you're trying to eliminate a dry start up. I follow this procedure when changing the oil as well.

Robsscooby

iTrader: (1)

Does anybody no the clearances between the crank and shells
for the oil

Robsscooby

iTrader: (1)

Whats the tolerance I mean

Bob99

These are from 2002 factory manual but I would have thought they would be the same for your engine.

Crankshaft bearing oil clearance is 0.010 - 0.030 mm (0.0004 - 0.0012 thou)
Limit = 0.040 (0.0016)
Thrust clearance is Standard 0.030 - 0.115 mm (0.0012 - 0.0045 in)
Limit = 0.25 mm (0.0098 in)

These are obtained when the parts are at 20 deg C and the correct torque has been used.

Bob99

Connecting rod oil clearance: Standard = 0.020 - 0.046 mm (0.0008 - 0.0018 in)
Limit = 0.05 mm (0.0020 in)

Connecting rod side clearance Standard = 0.070 - 0.330 mm (0.0028 - 0.0130 in)
Limit = 0.4 mm (0.016 in)

Robsscooby

iTrader: (1)

That main bearings and conrod bearings clearances

Bob99

First message is the main journal and thrust bearing.
Second message is for the con rods to crank.

TH3_5T1G

iTrader: (15)

An idea I've always adopted too, when disconnecting the crank sensor and priming oil supply to a new engine, remove the plugs so it will turn over quicker to build higher pressure sooner. But obviously making sure the filter is filled first

Steve001

iTrader: (7)

surely cranking the engine could be done before the engine is fitted back into the car?

Steve

FMJ

iTrader: (2)

It could be... but why bother rigging up the starter and a battery and stuff when you can just fit it and disconnect a plug? Also I would feel more comfy having the engine firmly mounted in the car when its turning over and the starter does shake it around a bit.

Steve001

iTrader: (7)

food for thought

however, it would not be too difficult to secure an engine on good/substantial bench?

benefits I can think of are:-

Oil pressure built up with no chance of engine starting
Checks for initial oil leaks would be easy, especially crank seals etc
Cam belt/timing check easy to do
much easier to remove/replace plugs and a basic compression test
AND if something is wrong, its out already

jason_2013

Initial oil priming is very important as said. Especially with acl race bearings as they are thinner than standard because they don't put the final layer on that duraglides have. The best way is fill oil filter as discussed. With the engine together but cambelt removed (for access) remove the oil pressure relief valve and fill the oil pump up. Fit everything together except spark plugs. Then loosen the turbo oil feed banjo and crank engine until oil spurts out. Refit the lot and start the engine after confirming there are no oil leaks.

You can safely do the engine test before fitting if you like. You'll need to fit the gearbox or a bell housing and starter motor. You can test oil pressure and cylinder compressions or leak down test if you want.

Also on previously failed crank bearings it is very difficult to remove all the fine swarf from the sump. Even if you think its completely clean put a bit of petrol in there and swish it about. You'll see it in there.

Also skimming the heads is OK unless you don't use a thicker head gasket to keep the compression ratios standard. Too high compression without mapping to compensate will put more load on the bearings.

Blue by You

iTrader: (23)

This is essential to avoid cylinder compression loads on new bearings until the oil system is fully primed.