cam replacement proceedure

[chrisdurham]

ive ordered the cam kit from power for my 4.3 - am wondering when i install it - are there any precautions i should take - a special oil for example? should i fill the followers with oil? best way to prime the oil pump?

any pointers appreciated

[debaron]

Hi Chris,

to answer your questions - be very very careful removing the old cam - cam bearings are difficult to replace if you damage them!!

Have you got a new timing chain in with this cam kit? For a few quid it's false economy not to do the timing chain as it's got to come off anyway and they can stretch a fair bit once old.
Make sure the new cam is very clean when it goes in - a bit of grit or muck in the bearing(s) would be bad.

Definitely lube the cam when fitting. Is it a standard 430 cam or are you upgrading?
Reason I ask is that we've got to deal with the nasty subject of preload....

It really should be checked - even if you are doing a like for like replacement. I won't go into it here - there is plenty of info about it onPH and on the web in general.
Suffice to say that there are so many different manufacturers of parts these days it's possible for tolerances and hence the valve preloads to be out.
If you are doing the preloads - they need to be done with the followers EMPTY of oil and on the heel of the cam - i.e. 180 deg off it's lobe for each cylinder.

The pre serp pump should be packed with vaseline or similar on reassembly - others say the serp pump should be too. You can also fill the oil filter with oil before screwing it down - this will also help.

Good luck - I'm sure you'll be fine! Give the forum a shout if you get stuck - we'll try and help!

[chrisdurham]

cheers mate for the info -

So, in terms of cam removal - whats the safest way? just pulling it slowly? im assuming you cant support it from the other end?

Im getting the kit from power so yes, its got chain and sprockets etc

So just lub with normal engine oil - ive seen a few threads I need to really look at re which oil!

I think its the power 885 cam - so a bit of an upgrade - tbh ive not even considered preload etc :+(

yeah ive read the vaseline thing - cant think why it will work though?

[phazed]

So, is yours a pre serp?

[chrisdurham]

yes its a pre serp

[phazed]

Buy a special cam lube and liberally cover the lobes and journals.

Pack the pump with vasoline if disturbing it.

Some people take the dizzy out and with an extension through the dizzy hole, spin up the pump till oil pressure is gained.

Pre serps can be a bugger to build pressure once disassembled!

Order a shim pack to pack up the rocker pedestals to adjust the preload, it's unlikely what you have will work.

[carsy]

Chances are your pre loads will be ok but best check. Theres a good right up on the proceedure on V8D website. I`d be surprised if TVR did this anyway.

When you withdraw the cam just be ready to take the weight when it comes out of the bearings. Just saves the lobes crashing into the bearings. Slowly does it and you will be fine.

Once your happy with pre loads. Pull the followers out and force oil into them with an old fashioned oil can with trigger type pump. This will save clatter on start up.

Vaseline in the pump just allows the pump to pull the oil through. If its clean and just air in it, it will never pull the oil through. Vacuum, suction type of thing.