cams needed 4.2

[pulsarboby]

hi guys
started stripping the car down today to do the startermotor and thought i would reshim her too.....what a bh of ajob to get at the startermotor lol

anyways after ripping the rockercovers off i found that both the camshafts have huge amount of wear and cracking on the main profiles which im quite shocked to find considering its onl done 30 odd thousand with history

anyone got any good cams for sale for the 4.2? if so give me a shout please as waste of time shimming till i fit the cams
also need a good startermotor too but i may just buy a new one seeing as its such a bh to get at

[spongy]

How hard is it to remove the cams etc,just toying on doing my shims if the garage have not done em.Was happy for garage to do em but time is becoming an issue now.Did my scooby engine years back with no probs,and have rebuilt many engines but never a v8,i know the same rules apply but would like an idea.

[pulsarboby]

like you mr spongy i normally only do jap crap so all new to me aswell.
ive not got the cams out yet as i wondered if theres a timing chain tensioner on there but from what i can see its just a case of unbolting the hex bolts on the sprockets then undoing the cam caps and lifting cams out

can anyone of the techies confirm if theres a tensioner which needs removing....if so where is it please

[spongy]

I think you just slide the front pullys forward bud.there is a tvr tool to hold pullys in the correct position when doing the cams etc.dont think the are any tensioners you need to worry about ......but i may be wrong

[ukkid35]

You really do need the sprocket retaining tool, otherwise you will be in for a world of pain.

Even with the tool you will only be able to remove one cam at a time (you need one tool per bank).

Check the 'Adjusting Valve Clearances' procedure in the service manual for details.

[spongy]

bud did you buy the retaining tool or did you make one

[pulsarboby]

cheers for the heads up on that
will it spring off the tensioner if you havent got the tool? or is the tool just to stop the chain coming off the sprocket?

dont suppose you have a link to a manual with the info do you as ive got no manual or info on it at all, thanks in advance

[ukkid35]

pulsarboby said:

cheers for the heads up on that
will it spring off the tensioner if you havent got the tool? or is the tool just to stop the chain coming off the sprocket?

dont suppose you have a link to a manual with the info do you as ive got no manual or info on it at all, thanks in advance

http://www.thetvrsite.com/cerbera/workshop-manuals

Engine Manual section C

Without it you will loose the cam timing, and probably the sprocket down the front of the engine - that means pulling the engine to retrieve it.

Edited by ukkid35 on Sunday 25th March 00:44

[ukkid35]

spongy said:

bud did you buy the retaining tool or did you make one

Neither, my half arsed attempted at cam timing was done with the timing cover removed, so no need for the tool.

[spongy]

ukkid35 said:

Neither, my half arsed attempted at cam timing was done with the timing cover removed, so no need for the tool.

[pulsarboby]

thanks for that il have a good read up before removing the sprockets then lol

just found out that kent cams do new profiled cams for around £140 a piece which i guess may be worth getting
anyone used these before?

they call the things clatter cams but think they should change that to shatter cams judging by the state of mine...il try post a pic of them tomorrow there in a terrible state, no wonder the poor little booger was noisy as hell on the topend

[ukkid35]

Modern oils destroy cams in flat tappet engines, because they have very low ZDDP levels to protect Cats. Make sure you use a high ZDDP oil.

[DuncanM]

ukkid35 said:

Modern oils destroy cams in flat tappet engines, because they have very low ZDDP levels to protect Cats. Make sure you use a high ZDDP oil.

That's a very interesting piece of info!

Do you have any examples of high level ZDDP oils? I have looked through the tech data available on a few oils on Opie and I can't see how you'd tell?

Other than that it is additives I guess?

Regards

Duncan

[pulsarboby]

funnily enough i was quite shocked to see that theres no real oil feed or spray bar to keep the cams lubed, it seems they just rely on whats sitting in the well below them, you think they could have fitted a spray bar which was bolted to the caps so the cams had a constant feed of cooled oil.
are these type of cam failiures common place as i guess it would not be hard to take a tapping from oil gallery with direct feed to a spray bar

yes some info on oil would be great if you dont mind as i was gonna use 10w/50 fully synthetic

[scotty_d]

I am at 54k on my 4.2 and the cams are in good order i am moving on to 10-50 fully synth this year i was on 5-40 but i never really use it in winter so i think this is better for my usage plus the oil get done at a max of 4k any way

[TVTrev]

I' looked into the ZDDP rate of oils before filling mine up. I found a site saying that for the engines with flat tappets you need at least 1200 ppm to stop wear of the shims.

I bought Mobil 15w 50 which is available at Halfords in 5 litres for about £40 at the moment.

Have look at the Mobil chart for comparison.

http://www.mobiloil.com/USA-English/MotorOil/Files...

There are other makes that contain more that 1200ppm of ZDDP such as AMISOL, have aloof at their PDF on the subject.


http://www.amsoil.com/techservicesbulletin/motoroi...

Trev.

[pulsarboby]

has no one got any good secondhand cams for sale please?

cant really do the shimming till i locate some cams as mine are well and truly boogered!

[pulsarboby]

just bought a couple brand new cams and a set of rocker buckets.....nearlly a grand for that lot plus i need to sort the startermotor out certainly not cheap to work on are they!

will be attempting to fit all this and reshim her this weekend which i can honestly say im not looking forward to

has anyone ever just attempted to remove the chain from the sprocket and hold the chain up by some means or other?
that way you could remove the hex bolts without fear of dropping them down the timing cover.
would have thought that if you marked the sprocket to corresponding link plate on chain then it cant be out....or am i barking mad lol

hopefully given a week or two after owning the thing for almost a year, il actually be able to drive it

[Tanguero]

Do NOT remove the chain from the sprocket!!!! Cable tie the chain firmly to the sprocket. Stuff a rag well into the opening in the timing cover under the sprocket and click a magnetic pickup tool onto the side of each bolt as you undo it. Slide the sprocket onto the retaining tool or whatever bit of tube/extension bar you have bolted to the cover and away you go.

It honestly isn't that difficult. I think you are seeing problems where none exist and will realise how painless it is once you have done one side.

[ukkid35]

In my opinion, although no one else seems to agree with me, you need a single modified shallow cam cap in order to safely remove and refit the cam without placing undue strain on it. The standard cam caps don’t rise high enough before you run out of thread.

As has already been said, you will be taking them in and out several times each during the exceptionally tedious shimming process.

I would gladly pay to have the heads modified to use hydraulic tappets (although I am in no hurry to take them off ever again).