Replace camshaft 4.6 V8 (Within RANGE ROVER P38)

[keithdixon]

I am looking to replace the camshaft, push rods, hydraulic lifters, timing chain, rockers & rocker shaft.

The engine is still in the car and drives ok (With tappet noise)

Does anyone have any advice regarding how this can be done with the engine in situ?

What parts are worth while replace whilst doing the above?
What is likely to break when i make room for the cam to come out?

thanks in advance

[RoverP6B]

All that you listed can be removed and replaced with the engine remaining within the Range Rover.

Depending on how long it has been in situ, the waterpump could be replaced as well.

Depending on the mileage covered and how often the engine oil has been changed, the camshaft bearings may require replacement, however this would require removal of the engine.

Ron.

[keithdixon]

Thanks Ron,

What needs to be stripped down to make space?

Just the radiator / grill?

[RoverP6B]

Hello Keith,

Grille and radiator, air conditioning radiator and of course the inlet manifold has to come of along with the rocker covers.

Clean all the bolts and apply an antiseize lubricant to the threads, covering totally. Loctite make such a product.

Torque them as per specification, not more nor less.

Be sure to follow the camshaft manufacturers instructions to the letter.

You can guarantee that you will have hours and hours, spread over at least 2 days of fun and excitment, and if you are not used to swearing, you soon will be!

Best of luck,
Ron.

[keithdixon]

thanks again Ron,

With your experiance what tends to go pear shaped whilst doing this?

(So that i can get the replacement parts ready!)

rgs

keith dixon

[RoverP6B]

More likely than not, is that the tappets or lifters if you prefer won't be removable from the top, so you will need to extract the camshaft first, paying particular care not to damage the bearings which remain within the block.

Withdrawing the lifters downwards is now possible, but not by hand as you cannot reach them. Tap them gently through, and then with the sump off the bottom of the engine, if you are lucky they will fall straight through.

Best of luck,
Ron.

[sidecar]

Fitting the new cam in without scraping the bearings with a cam lobe is pretty hard. I wrapped each lobe with some gaffer tape, you can then push the cam home and remove the tape with some pliers once the cam is in place. The tape did a good job of stopping the lobes scratching the bearings.

Also fill the sump with oil before you fit the valley gasket, or even before you fit the cam, use a funnel and try NOT to get the oil on the cam. You can then lube up the cam with the special lube. Doing this avoids the normal oil just washing all the special cam lube of the lobes as it runs down the valley and over the cam. (Lube the cam bearings when fitting the cam).

Run the cam in and have a hosepipe ready to cool the rad, it is very likely to overheat without the hosepipe blasting the rad.

If you have any probems just kill the motor, don't leave it ticking over.

I ran my cam in for 20 minutes at 2-2.5Krpm. You may get away with not running in a standard cam in if you are using standard valve springs...it's up to you! I run a piper 285 with RealSteel dual springs and standard lifters. My old 3.5 lump had a typhoon cam fitted by the previous owner and I'm not sure what he did but 3 lobes were knackered in 5000 miles.

According to RPI the market is flooded with dodgy Rover lifters, (they were made under licence by a company that sounded like "Bere").

The problem was that they were not machine correctly and many have failed. RPI sell standard spec ones from a manufacturer in the States. Personally I do not like the Rhoads bleed downs or any others that promise all sorts of wonderful things!

If your cam is worn out you should be checking the rest of the valve train at the same time.

The chain and sprockets are likely to be knackered and you should have a close look at the rockers and rocker shafts, you should not feel any play in them.

If you can feel play then both the shafts and the rockers will have to be replaced. The shafts are what shows as having wear on them but the rockers will have hard bits of metal embedded in them and this is what wear the shafts out. Old rockers will eat a new shaft very quickly. Fit the new shafts the right way round, the oil holes point in and down towards the valley area.

All the the valve gear will cost a fair amount of dosh but not to change worn out bits is asking for trouble! (Pushrods seem to fair pretty well so should be OK)

Pete

[keithdixon]

thanks guys,

Pete, Why "Run the cam in and have a hosepipe ready to cool the rad, it is very likely to overheat without the hosepipe blasting the rad"?

I plan to replace the chain / sprocket and also the rockers / shafts

[sidecar]

thanks guys,

Pete, Why "Run the cam in and have a hosepipe ready to cool the rad, it is very likely to overheat without the hosepipe blasting the rad"?

I plan to replace the chain / sprocket and also the rockers / shafts

Not sure if your question is "why run the cam in" or "why run the cam in and have a hospipe blasting the rad"

1. Cams that use flat followers need the cam run in as the cam is actually open-pored and quite rough when its brand new. The followers and the lobes have to be run in to polish off the surfaces. The engine needs to be run at 2 to 2.5k RPM as there is actually less load on the nose of the cam at this RPM. The main load on the cam at low RPM is due to the valve springs, this load is reduced by the inertia of the valve train as the RPM rises. (At very high RPM the inertia totally overcomes the springs and the cam follower "floats" off the lobe!).....If this wasn't the question, sorry!

2. The hose pipe blasting the rad is required because in my experiance the engine will quickly overheat as there is no real airflow through the rad, the fan can only do so much. (i.e pull enough air to stop the engine overheating at 800-1000 RPM). Then again my 4.6 lump was brand new with new bores so that might not have helped!

Some people reckon that it is all bull 5hit about running cams in, but then others have knackered cams to prove that it's not bull! I guess it depends on the cam and the springs.

The problem with trying to run the engine straight up to 2k rpm is that the coolant system is likely to be full of air, its a bit of a pain to keep the revs up, have the rad cap off so that you can top the system up and gauge when to fit the cap back on, keep an eye on the temp gauge, AND blast the rad at the same time!

If it starts going pear shaped, kill the engine, let it cool down, top up the rad then fire up the motor and start the clock from where you killed the engine.

Changing the rockers and shafts is a good idea, the downside is that it will cost a fair bit!

Good luck with the overhaul.

Pete

[kiwicar]

sound advice, whatever you do don't be tempted to start it and leave it at idle for a minute while you sort yourself out. Start it, straight up to 2 to 2.5 k and run it between the two for atleast 10 minutes, if anything happens kill it straight away, sort the problem then start it again and straight up to running in revs. If you leave it at idle at start-up there is not enough oil flying about the place for a new cam, virtually all of the lubrication for the cam lobes is from oil mist and splash off the crank. If it is at idle there is very little mist and splash hence you take the nose off the lobes. The hardened surface treatment is only a few thou thick, you can be through that in seconds if there is not enough lubrication (hence the assembly lube you slap all over the lobes as you put it together).
Mike

[keithdixon]

thanks guys, makes sense now,

Can you advise upon "assembly lube" which type and where to get?

[sidecar]

thanks guys, makes sense now,

Can you advise upon "assembly lube" which type and where to get?

Real steel sell it but any good cam manufacturer should provide you with a tube along ith the cam.

V8 Tuner (on this forum) will probably sell it too!

Pete

[keithdixon]

thanks pete,
will check the camshaft kit box to see if there is some in there