Camshaft
Location .........Right-hand side (thrust side) of engine
End-float ........0,06 - 0,13 mm (0.0025 - 0.0055 in)
Number of bearings ....... 4
Material .................Steel shell, white metal lined
inspect camshaft bearings
6. Measure thc internal diameter of each camshaft
bearing at several points using an internal
micrometer. A comparison of the bearing
diameters with those of the respective camshaft
journals will give the amount of clearance. The
bearings should be renewed if the clearance
exceeds 0,0508 mm (0.002 in). Or, in any event, if
they are scored or pitted. This work should only be
entrusted to line boring specialists.
That's what the good book says ....
CharlesY
Well Steve, I have to say I would be very tempted. What's to lose?
The idea of line-boring is that all 4 camshaft journals will bear in the shells all the time, thus making sure that the VERY considerable down-thrust hammering from working the valves does not cause any bending moment in the camshaft which would eventually cause a fatigue failure.
But, assuming your front three bearings are OK, which I think they will be, I would go for it.
Can you get a bearing shell? IF it is a SPLIT SHELL (pray it isn't) it will be tricky to work out how much the shell will close in when you tap it into the block. If it's a solid shell find another camshaft from the same model engine and try-fit it to the rear journal. You may find that you don't need to touch the shell at all, so long as it has SOME clearance. I reckon the job's a runner.
Watch out if oil holes need to be lined up.
CharlesY
Charles/anyone - do you know what the camshaft journal diameters should be? - my haynes gives every dia apart from the cam journals! I will ask a nice man at work to attempt to bore out a new shell to suit if i can find the dimension - they are a rolled steel shell, white metal coated with like a dovetailed joint so will prob need to bore out a collet to suit,
thanks
steve
thanks
steve
Before you do that ....
Is your camshaft out?
The bearing shell may not need to be reamed. But it sounds like it's a split shell bearing.
You'll need to be extremely careful tapping it into the block.
You must not tap it so it goes skew-whiff. It must go in dead straight.
Make sure you have a drift large enough JUST to slip into the block and no more, and use that to drive the shell into place, dead square.
Are you thinking about doing this with the camshaft in situ?
I'm not sure that would be a good idea, unless you can be certain (a) it's all well oiled and (b) the bearing does have clearance on the camshaft journal.
Worrying .... tense moments.
CharlesY
Is your camshaft out?
The bearing shell may not need to be reamed. But it sounds like it's a split shell bearing.
You'll need to be extremely careful tapping it into the block.
You must not tap it so it goes skew-whiff. It must go in dead straight.
Make sure you have a drift large enough JUST to slip into the block and no more, and use that to drive the shell into place, dead square.
Are you thinking about doing this with the camshaft in situ?
I'm not sure that would be a good idea, unless you can be certain (a) it's all well oiled and (b) the bearing does have clearance on the camshaft journal.
Worrying .... tense moments.
CharlesY
I have hunted high and low but can't find that data anywhere.
For all that's involved, you may be safer taking the camshaft out.
It really MUST have enough clearance to permit a lot of lube oil to flow.
Too tight and it will pick up, and spin the shell again.
CharlesY
thanks for your time Charles - ive drawn a similar blank so my planof attack now is: Drain oil and remove vac pump and skew gear (no need to drop sump i believe), strip front end off engine, remove rocker box and rocker shaft, tip engine on its side, rotate crank to push cam followers as high as poss - AND hopefully withdraw camshaft. I can then inspect and measure, check housing bore and fit new shell (loctiting in place if I deem necessary) i can then ream out the shell to suit the journal (i have found a range of adjustable reamers at work) - your opinions please!!
thanks
steve
thanks
steve
Do it. Fit the bush, and do everything possible to drive it in square.
But, BEFORE you attack the rear bush with the reamer TRY FIT the camshaft the wrong way "round". See if your luck is in, by trying GENTLY to fit the back journal of the camshaft into the new bush from the back of the engine. You never know your luck, and it is still quite possible in my opinion that the new shell is finished to size. Line boring MAY only be needed when all four shells are new (new engine or all replaced) not because they are too small, but simply to align a passageway clean through all four shells.
In your case you know the first three are OK - it's only the rear one you need to think about, and with a tad of wear in the first three the camshaft may glide into place.
Remember to oil the bearing shells before you shove in the cam.
My bet? 50-50 it fits without needing the reamer.
CharlesY
Hi there,
I have the same problem and have just tried to fit the bearing without success,
seemed like there was interference on the camshaft journal I`ve looked through the manual but can not find a size for the camshaft journal. Does anybody have a camshaft lying around to measure the journal diameters.
Also to take the camshaft out do you need to remove the cylinder head to get the cam followers out?
I have the same problem and have just tried to fit the bearing without success,
seemed like there was interference on the camshaft journal I`ve looked through the manual but can not find a size for the camshaft journal. Does anybody have a camshaft lying around to measure the journal diameters.
Also to take the camshaft out do you need to remove the cylinder head to get the cam followers out?
jamesmartin
Well-Known Member
head needs to be off to remove follower assemly,cam bearings need to be fitted very accuratley with a special dolly ,there are allways split, those with jigsaw shape split are a much better finished fit than straight split,ensure hole line up with oil ways especially no1 as it has head feed at the top of bearing as well as bottom
range17
New Member
Hi ,i have recently rebuilt my 200tdi completly ,including camshaft bearings and camshaft ,the bearings were from turner engineering and did not need line boring BUT they MUST be pressed in totally square to the housings in the block which requires the block to be stripped down to go under a press or large pillar drill which it what i used .
Hope this helps .
Rob .
