engine change

bryhp · Feb 17, 2009

How hard is to change a 4.6 litre engine in a P38 Auto?

Also how heavy does an engine weight?

Bry

Beast o Bodmin · Feb 17, 2009

thee quite light weight engines for their size.disconnect all the gubbins and label it as you go then reomve gearbox studs and then engine mounts and jimmy may out she may!!!

Irishrover · Feb 17, 2009

Allow 3 days if you are reworking the cylinder heads. You will need an engine crane to ensure that it goes in nice and straight. Guess a full engine weighs about 400lbs.

classic kev · Feb 17, 2009

Don't know about 4.6l but I read somewhere a fully dressed 3.5 weighs 235kg. So 400lb not far wide of the mark.

Irishrover · Feb 17, 2009

I used a crane with the jib fully extended and it lifted it no bother with heads, sump,front cover & manifolds on.

bryhp · Feb 18, 2009

Before i jump in at the deep end and buy a second hand engine, was wondering if my engine is salvagable?

The noise is defo metal noise very like piston slap, engine runs but feels under powered sound is coming directly under inlet manifold.

Just don't want to rush into buying another engine if there is a cheaper option, the oil pressure light comes on suggesting oil pump failure, coolant level is not changed and there is no coolant or oil mixed. I thought it was bottom end but sounds as i say like piston slap has anyone had similar? Could be a bent valve?

Have noticed a touch of metal in the oil.

Any help would be appreciated

Irishrover · Feb 18, 2009

I would think VERY carefully about buying a second hand lump, you could be travelling into uncharted waters. If you can live without the motor for a week or two, pull the lump out and strip it down to see what's what and make the call on what you find and price up the parts. The V8 is a nice engine to work on and if you are armed with the Overhaul Manual from RAVE you can't go wrong.
You say the noise is like "Piston Slap", could be pre-ignition (Pinking)-doubtful, broken rings-thought it would be burning oil, or a worn Small End (Gudgeon pin). Hopefully all will be revealed if you decide to strip it down.
At the end of the day, the cash and the choice is yours................

bryhp · Feb 19, 2009

How do you diagnose Pinking? and whats the cure?

Thanks

Irishrover · Feb 19, 2009

Pinking is a term for pre ignition which is caused by either the timing being too far advanced-unlikely on the P38, excessive carbon build up in the combustion chamber which gets hot and ignites the fuel before the spark plug, or used to be caused by using lower grade-say 2 star in the old days, petrol-it's all the same grade now.

Irishrover · Feb 19, 2009

Do you think it could be timing chain rattle???

brnocz · Feb 19, 2009

you dont say the history of the engine ie fuel type/ e ngine milage as what as already been said in the replys you have had the other thing that as not been mentioned is worn valve guides also cause pinking, as you stated the noise seems to be from the manifold area. it could also be a loose or bent pushrod if fitted ie incorrect valve clearance, this would also explain the lack of power.as for piston slap i think if this was the case and you can hear it then you would also use a lot of oil, i would be tempted to remove the rocker cover first and check the valve clearance.then move on to a compresion test.

bryhp · Feb 20, 2009

Think i'm going to take engine out and check the big end shells. Then go from there, as more i think the more i think its the same noise as my last big end failure on another car. Car has 123k miles on it full service history and since i've had it its only run on shell petrol. And only good quality oil used as i tend to change oil every 5kmiles

Irishrover · Feb 20, 2009

No need to pull the lump out to check the big end shells. Drop the sump off, you will have access to all the big end caps. Far easier and less time consuming.

bryhp · Feb 21, 2009

Can I replace the shells from underneath to? As i Haven't done work on this engine before how do you remove the baffle in the sump?

zzr1200 · Feb 21, 2009

Years ago I owned a V8 110, that decided to immediately turn from a perfect running engine, in to an engine that sounded like it had dropped a big-end and punched a hole in the side of the engine, with no signs of damage at all.

A hydraulic cam follower had totally collapsed and combined with some camshaft lobe wear wouldn't open the exhaust valve, as soon as the inlet valve opened on this cylinder the fuel/air mixture in the manifold ignited causing the banging....recheck your cam and followers...

Also before stripping the vehicle, test the oil pressure with a pressure gauge, against the stated pressure in the workshop manual.

bryhp · Feb 21, 2009

Will take rocker covers off, will this be visible under the camshaft?

Thanks for the heads up,

Is there an easy fix?

cheers

zzr1200 · Feb 21, 2009

bryhp said:
Will take rocker covers off, will this be visible under the camshaft?

Thanks for the heads up,

Is there an easy fix?

cheers

The camshaft and follower are under the inlet manifold in the bottom of the V, you should be able to remove the rocker covers, inlet maniflod, rocker shafts and then the push rods. Then remove the cam followers for inspection, idealy they should be flat but very slighty dished bottoms due to wear is ok (if worn through to the oil chamber inside the follower its possible you could loose some but not all oil presure), the camshaft should have no real sign of wear on the lobes, but you"ll usually find at least one lobe is worn.

If worn,the camshaft comes out the front of the engine after removing the radiators/timing cover/gears/chain a fairly simple job, just time consuming.

I haven't pulled an engine out of a range as yet, but had a loads of others out of Land Rovers.

Rover V8's have always suffered from low oil pressure, my first tool is always a pressure gauge to check for the actual pressure when hot, start with the facts then look for the answers.

bryhp · Feb 21, 2009

Been out at the car since i got home from work and started on the top end, I am now certain its the bottom as there is play on bottom pulley. Is it possible to replace shells from underneath with the sump removed?

Beast o Bodmin · Feb 21, 2009

If I were to have a nackered bottom i would take the engine out and do a proper rebuild and even fit a 5l stroke kit......

bryhp · Feb 23, 2009

Next question is where is the oil pump on the 4.6?

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