help exhaust cam nipping up

[GOZ]

hi chaps, im replacing my exhaust cam 6,5,4,3,2 carrier torqued up everything is fine,when i tighten No 1 cam locks up,am i missing something here,any help would be great :annoyed:

[DeJi]

did you smear oil over the bearing journals?
Is the cam really locked? Isn't it in the middle of a lift?

[Jeffers_S13]

hi chaps, im replacing my exhaust cam 6,5,4,3,2 carrier torqued up everything is fine,when i tighten No 1 cam locks up,am i missing something here,any help would be great :annoyed:

I may be misinterpreting this but are you tightening the caps up fully starting at the back ? if you are you will be bending the camshaft and possibly damaging the caps and bolts. You need to work round in a sprial starting at one end, then the other, then the other, then the other etc etc and work your way to the centre doing about 1 turn on each bolt at a time, as per the manual. Then when they are all about starting to bind, torque them up to the 12Nm specified.

If you are doing it this way then take them all off again and have a look at the cap and cam for nicks in the bearing faces of the metal work on the head and the cam or a piece of grit.

[Fudgeass]

if you have torqued them up like jeffers s13 said, then it could be just that the cam is between open and closing the valves, so it will be ahrd to turn and prolly not doable by hand

[Jeffers_S13]

if you have torqued them up like jeffers s13 said, then it could be just that the cam is between open and closing the valves, so it will be ahrd to turn and prolly not doable by hand

Yeah, if you are trying to turn it by hand just using the pulley then it will be goddam hard to turn as you will be tring to push a couple or four valve open. Get a couple of spanners on the flats positioned along the cam shaft to turn it, do it progressivley and in a controlled manner. It will sort of 'flick' between equilibriums as valves open and close.

[GOZ]

they were torqued in sequence,if i tighten No1 cam will not turn at all, loosen it and the cam turns

[Jeffers_S13]

they were torqued in sequence,if i tighten No1 cam will not turn at all, loosen it and the cam turns

So in a spiral fashion ? and the cam shaft was slowly pressed onto the valves in as equal way as possible along its length ?

Id say you either :

a) have some grit between the cap and the cam shaft or head and cam shaft.
b)the cap is somehow disfigured
c)the cam or the head or the cap has a small nick in it which is causing it to bind.

Take the cam off, re-install all the caps and check for roundness on the cap causing grief. You are gonne need a special tool for this though.

or

d) one of the lifters is sticking (just occured to me) again a piece of grit or a nick stopping it sliding in the head, check they all slide nicely.

[GOZ]

i have took cam out ,checked for grit,debris but there is nothing,also have tryed 3 different No1 caps still locks solid,yes i did tighten in 2 or 3 stages doing them in a spiral

[GOZ]

also took followers out all moving freely

[Stewb]

When you say you've tried 3 no1 caps what exactly do you mean? The caps are line bored with the head as an assembly - you can't swap caps from one head to another or from one position to another. The clearances are tiny & any slight deviation during machining will give the symptoms you describe (hence the line boring process in the first place). If you can identify the original cap off the cylinder head in question then make sure you have it in the correct orientation as that will give the same effect. If the cap was damaged/lost then it pretty much renders the head scrap unless you have the cam bearing bored out & fitted with a bearing / bush to get the correct clearance. Swpping between inlet & exhaust is obviously the same.

Stew

[Pete C]

^^^ What he said :nod:

You'd better hope you can identify the original caps!

[GOZ]

even with origanal caps it still locks solid

[SLAP TURBO]

my 2 ds worth sound like you have over torqued them :( try checking the end caps make sure the seals are not binding
also is the pistons ATDC valve could be against piston

[Jeffers_S13]

Have you the tools to hand to measure the cam journal and the inside diameter of the cam cap if you assemble it with no cam in place ? do it at 3 or 4 places to get an idea of how round both are.

[Fudgeass]

good point about the piston a TDC, dont try and force it cos you can bend the valves, done it before even by turning by hand lol

was the missus clio tho hahaha

and you MUST use the original cam cap otherwise the head will be srap mate :(

[Stewb]

As Jeffers says - check the diameter of the cam journal & the i/d of the cam bearing with the cap torqued down. (not only for actual diamter but for out of round too) As it's only the cam that has changed (??) then i'd guess you have an oversise bearing joural on the cam. It is unlikely but not impossible. Motorbike engines have used the same idea for years & i've stripped & rebuilt loads before I had a torque wrench that went that low (they are notoriously unreliable at low values anyway) & never had a problem with distorting caps. The main problem is usually stripping the threads in the head! I'd also double check that you have got the corrct cap for that location as I don't think i'd be able to choose the correct one out of three apparently identical caps! Without the cam in put the cap on & feel for a ridge between the top of the head & underside of the cap on the bearing surface. If there is a lip or a step then its not the right cap.

As an aside - The engine didn't overheat / blow a head gasket did it? I've seen cooked cylinder heads so banana'd that the cams nip up in their bearings before (Not CA18DET). You have the gaskt face skimmed flat but the upper face & the bearings are all out of true. Just a thought.

Stew

[GOZ]

got it sorted:thumbs: ,i was using the wrong cap:annoyed: ,put on original cap and hey presto cam turns thanks for the info guys great help:clap:

[Fudgeass]

you were lucky then mate, could have done some damage if you wernt careful!

:D