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Boxer timing belts

10K views 34 replies 8 participants last post by  LurntWubber 
#1 ·
hi all.just stripping down my spair engine and want to take the old belts off as i need to send the cams away to be reprofiled.Has anyone got any info or data on doing the timing belts.or timing the lot fro scratch.it looks rather more complex than a standard inline.would i be able to get away with marking each bank of cams to each other and then those marked against the crank.and anyone know of a maintainence manual for the 33. Mines a 1.7i 16v.many thanks for any input.
 
#3 ·
If you are wanting the standard timing positions its quite simple. you do each head seperatly. Make sure the engine is tdc obviously, but on number 1 piston not number 4 (very easy to do) As the flywheel mark says top at both positions. Once you are certain that part is correct then the standard cam pullys have marks on them. one pully has one mark on the face (its a line) the other pully has 2 lines.

One pully will rotate by hand to the correct position the other needs to be turned and held as its under tension so use a 17mm spanner on the cam nut. you need to have the lines all pointing towards each other so they look like this =- the single line has to be in the middle of the double line. once in that position pop the belt on. ensure that the belt is tight on the opposite side to the tensioner so that when you release the tensioner it makes both sides tight.

Hope im not telling you how to suck eggs and it helps.

Paul
 
G
#11 ·
they are tensioned by a spring to set the correct tension but then locked in place by the central nut, unlike on say a jtd engine where it us constantly under spring tension and moveable.

hope that makes sense :confused:

that's for the 8V eninges anyway, presume the 16's will be similar??
 
#12 ·
If it's anything like the sud's It's a spring caught in the tensioner casting, inserts into the block and you wind on the tension.

I found the easiest way was to force it back against it's own tension and pinch it up with the holding nut, time the belt then release to tension. :thumbs:
 
#18 ·
As i know these springs can't be ordered anymore, and they are not part of the
belt tensioner or the complete cambelt+tensioner set either.
Probably you still have the factory ones.

The force of the tensioner spring in my '92 and '94 33s is not enough anymore to set
the necessary belt tension by itself. I have tested springs from a '96 146 1.6 boxer,
but those was weak too, i have to "override" the spring loaded belt tension while i was
tightened the nuts.

(Just a note: in many cases there's no need to replace the tensioner arm,
just the caster. Some cash can be saved because you can get a caster with
SKF bearing about half of the price of the complete tensioner arm.
But i agree, it's much easier to replace the whole tensioner.)
 
#17 ·
No , thats too much and it will slip a tooth in a bad moment. Ussualy , what they say generally about tensioning cambelts is to be able to put a pen in between.
I took the cover off a couple of weeks ago just to investigate (being a curious beginner), and I think the belt was looser than that of what you describe Lonewolf.

Have to recheck for sure.

So a pen should be able to fit in between the belt and tensioner pulley?
 
#21 · (Edited)
(Just a note: in many cases there's no need to replace the tensioner arm,
just the caster. Some cash can be saved because you can get a caster with
SKF bearing about half of the price of the complete tensioner arm.
But i agree, it's much easier to replace the whole tensioner.)
Also another question in addition to the pen space:
Which part is the caster and arm?
Looks like 1 piece with the pulley on the end.

Sorry I'm a total beginner when it comes to this area of the car so far.:p

mmm..pic has come out a little small. Can you see that?
 
#28 ·
That is brilliant.

Just what I needed to understand the workings.

I can remove these easily and inspect the springs no? And even manually tighten them a bit more if the spring has lost it's tension somewhat.

This won't have any effect on the timing position I assume.

:thumbs::thumbs::thumbs::thumbs:
 
G
#32 ·
twisting the belt 90degrees used to be the standard way of tensioning a belt before we got all the silly amount of pulleys for them to go across.
if you can just, and only just turn it that amount i would leave it at that. the boxer engine has a very simple route for the belt and the pulleys have a good level of teeth in mesh at any time, not like modern cars that can only have a quarter of a given pulley in contcat.
if you get them too tight then they will squeal and wear out prematurely.

not too sure where the pen thing goes though :confused: not heard of that method before :confused:

do you put it length ways, nib to top between the teeth? if so what make of pen, i have several that are differing lengths :lol:

would be interested to hear about that one though, always keen to learn new techniques :thumbs:
 
#33 ·
The messiah has spoken... ("He's not the messiah, He's a very naughty boy!")


(If that quote was lost on you please visit: YouTube - He's Not The Messiah)


I can't remember the reference but it was a technical writeup of sorts: It was suggested that if the tensioners don't provide enough tension from the spring it is acceptable to force tension onto the tensioner before torqu'ing up the holding nut.

However: This is coming from a guy who only pinch tightened his front wheel nuts before driving it to work... :eek:
 
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