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2.5NA (12J) timing belt / pump timing Q.'s


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I'm in the middle of my 1st timing belt change on my ex-MOD 110 - following Les' excellent tutorial from the tech archive

Q1: the inside of mine was EXTREMELY MUCKY - is this just a bad crank seal, or something more sinister? The little sieve in the wading plug housing was all gummed up too.

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Q2: I locked the flywheel using the special tool in the housing - the crank sprocket timing mark looks spot on but the cam mark seems about 1/2 a tooth out (i.e. the dot is on the point of a tooth, whereas the arrow aligns with the next valley). Is this correct or should I try to adjust it when fitting the new belt?

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Q3: The crank sprocket came off OK but anyone have any tips for prying out the crank seal?

Q4: the water pump spins freely and has no obvious bearing play but the wheel has a good deal of surface rust - problem? Should I try to clean it up?

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Q5: Before removing the belt, I attempted to check/set the injector pump timing using the special tool in the pump housing and rotating the pump. I could see the pin bobbing up and down but it never really engaged positively - is that normal? Also the set point seems to require the pump to be rotated almost fully clockwise i.e. it seems to be almost out of adjustment travel - again is this normal and if not what should I be doing about it!

Thanks again in advance

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It's very common for the inside of the timing case to be gunked up. Even with a new gasket there isn't a perfect seal - use rtv sealant along with the new gasket. Changes in temperature can cause water etc to be sucked through the timing cover dust seal. It might be worth replacing the camshaft oil seal if it's suspect.

You should find that the new belt once fitted will locate the crank and cam timing marks in the right position.

Use an old screwdriver or similar item to remove the seal - don't lever against the alloy casing - use a bit of wood or similar item to protect it.

Rust inside the engine is an indicator that anit-freeze either hasn't been used or that it was too weak a mixture. Anti-freeze is also a rust inhibitor.

The Injector pump setting tool doesn't lock into place or even go in very far - a couple or so mm is enough. You need to maintain pressure on it and 'feel' it sink.

Les.

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Thank you sir!

The gasket didn't seem to be in great shape - there were some bumps of previous material especially around the boltholes. I will be replacing both the crank seal and the front dust seal.

There is also a M8x1.25 tapped boss near the top of the cover - should this have a plug in it?

Any comment on why the pump timing seems to be so retarded - or is it me :D

John H.

--

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There is also a M8x1.25 tapped boss near the top of the cover - should this have a plug in it?

Is there? You don't happen to have a picture do you?

Retarded timing would have produced a lot of smoke/difficulty starting/invalid carriage-type top speeds/BHP figures as low as Mr Troopers inside leg measurement :D

You do know there are two timing marks don't you? (bet you didn't make a note of which one it is) :P

Les.

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Is there? You don't happen to have a picture do you?

Here you go. The 2 upward facing ones are for the 24V alt bracket (it was an FFR - there are 2 corresponding ones in the top of the inner cover, which I've kept plugged with the original bolts - yes they DO go right through into the case so I plan on replacing them with short set screws just to be 100% sure they don't ever get wound down onto the belt).

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Retarded timing would have produced a lot of smoke/difficulty starting/invalid carriage-type top speeds/BHP figures as low as Mr Troopers inside leg measurement :D

Those are certainly the symptoms it came with B) - I had a go at timing the pump back in April but it didn't seem to be far off, and in the end I convinced myself it was dodgy fuel - after disposing of which the smoke cleared up and it pulled OK all summer.

You do know there are two timing marks don't you? (bet you didn't make a note of which one it is) :P

Les.

The 'dot' not the 'F'? Care to enlighten me what the 'F' the 'F' is for :D ?

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Here's how it finished up.

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I had a bit of trouble with the belt ballooning off the pump sprocket when I slackened it off for the re-tensioning step (almost didn't notice at first because it had teeth engaged on both the camshaft and tensioner sides of the sprocket - but there was a whole extra tooth's worth of belt tucked up around the outside).

Just a few observations:

- crank seal was TIGHT and hard to get a good angle to pry on - snapped the handle off a 10" screwdriver and had to go medieval on it with a 24" one

- the back end of a hub nut box wrench is just about the right size to drift the new crank seal in

- it's easy to be fooled by parallax when judging whether the cam sprocket is on the mark, you really have to get your head (or camera) down level with it

Thanks again for keeping me on the straight and narrow Les.

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