Series 3 Camshaft replacement

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Simon Perks

Simon Perks

Active Member
Posts
318
Location
Switzerland East
New years greetings from the Alps folks.
My series 3 2.25 petrol performance has noticeably deteriorated over the last few months even after the usual regular service valve clearance settings plus being fitted with a new SU carb, 123 electronic dizzy new plugs and leads, regular oil changes and the like.

Historically I replaced the timing chain 2 years ago but have never since buying the car been able to get the engine timing to be correct when working off the marks on the pulley (the marks are correct when i check TDC but it runs at like 20deg!!) so have relied on the strobe gun and what I hear, she ticks over really nicely and actually runs with out humpy bumpy rough running problems but there is a point in top gear where it's just all over and hill pulling is a regular up n down the gear box range.

Having discussed this with my local garage it has been suggested that there could be two things.
1. the camshaft is now so worn that the valve timing is out
2. the timing change has stretched ( yes it is a Britpart kit)

So thoughts on this please.
Never dome a camshaft, how hard is this? should i get an upgrade part like the ACR power plus model.
Timing chain, what about getting a sprocket with variable positions to get the chain tight.

Thanks folks
take care out there

Simon
 
You don't say how many miles your landy has done or more crucially how many miles since the timing chain change. If the new chain had stretched so much it affects the timing, I would have though it would be rattling like mad, is it. When was the oil filter last changed? Don't bother timing it with a strobe, just do it by ear. Apparently, new carbs aren't as good as the originals. I don't think I've come across a series 3 with a SU carb, they are usually zenith or Webber.

Col
 
Simon Perks said:
New years greetings from the Alps folks.
My series 3 2.25 petrol performance has noticeably deteriorated over the last few months even after the usual regular service valve clearance settings plus being fitted with a new SU carb, 123 electronic dizzy new plugs and leads, regular oil changes and the like.

Historically I replaced the timing chain 2 years ago but have never since buying the car been able to get the engine timing to be correct when working off the marks on the pulley (the marks are correct when i check TDC but it runs at like 20deg!!) so have relied on the strobe gun and what I hear, she ticks over really nicely and actually runs with out humpy bumpy rough running problems but there is a point in top gear where it's just all over and hill pulling is a regular up n down the gear box range.

Having discussed this with my local garage it has been suggested that there could be two things.
1. the camshaft is now so worn that the valve timing is out
2. the timing change has stretched ( yes it is a Britpart kit)

So thoughts on this please.
Never dome a camshaft, how hard is this? should i get an upgrade part like the ACR power plus model.
Timing chain, what about getting a sprocket with variable positions to get the chain tight.

Thanks folks
take care out there

Simon
Click to expand...
I would think there are a number of other things worth considering before changing the camshaft.
Is the advance retard mechanism and vacuum pipe in good order.
And is the newly fitted SU properly jetted for that engine, as it must have come off something else originally.
 
Colthebrummie said:
You don't say how many miles your landy has done or more crucially how many miles since the timing chain change. If the new chain had stretched so much it affects the timing, I would have though it would be rattling like mad, is it. When was the oil filter last changed? Don't bother timing it with a strobe, just do it by ear. Apparently, new carbs aren't as good as the originals. I don't think I've come across a series 3 with a SU carb, they are usually zenith or Webber.

Col
Click to expand...
Hi Coll,
I would guess it's about 60k (km) 180k on this engine ( it's a 5MB ) and in mountain terrain, oil filter last march.
The original Zenith was a nightmare, running on and when it was hot not starting, did the surface grinding and replaced all the seals to no effect, the replacement copy was just crap and so i opted for the ASR upgrade manifold and SU carb which made a huge improvement to fuel consumption and smoother running.
The timing chain could be just one tooth out according to my mechanic.
 
Turboman said:
I would think there are a number of other things worth considering before changing the camshaft.
Is the advance retard mechanism and vacuum pipe in good order.
And is the newly fitted SU properly jetted for that engine, as it must have come off something else originally.
Click to expand...
HI Turboman,
the SU is brand new and has the jet from ASR, I did enquire if I needed another due to altitude but the techs at ACR said not, I also had a leaner jet (needle on an SU) for the swiss MOT but it was much worse with no power at all but the emissions were ok (switzerland is really hard core on this)
 
Simon Perks said:
HI Turboman,
the SU is brand new and has the jet from ASR, I did enquire if I needed another due to altitude but the techs at ACR said not, I also had a leaner jet (needle on an SU) for the swiss MOT but it was much worse with no power at all but the emissions were ok (switzerland is really hard core on this)
Click to expand...
Also, you still haven't said what mileage the engine has done?
 
I ignored the timing creeping over a few months and unfortunately the Britpart chain eventually snapped.

Get the thing out and fit a proper one. o_O
 
Renewing the cam shaft is a pretty involved process. More so if the bearings need changing.
At on time I ran my 2a with an SU and it went fine on normal roads but once steep slopes were encountered [ off road ] it just did not run well so went back to a Zenith [ were available at the time ]
 
Have you done a compression check? If your valves are burning out due to lack of leaded fuel (or lack of additive) that would affect power and running.
 
wireman said:
Have you done a compression check? If your valves are burning out due to lack of leaded fuel (or lack of additive) that would affect power and running.
Click to expand...
My thoughts too. A compression test only tells you so much though, a leak test would be better. I would think the cam followers would wear long before the camshaft, it would be easier to inspect them, although the head will need to be removed in any event which would be a good time to fit a composite head gasket and new valve seals.

Col
 
The other thing that shocked me was the dent in the rocker face. No way I could get anywhere near with a feeler gauge. Naturally I didn’t know this until the rocker shaft was removed.
If your taking the head off you can remove the tappets and rollers then have a butchers at the cam for wear from above. It could be as simple as the rollers are a bit goosed.
 
Last edited:
Colthebrummie said:
My thoughts too. A compression test only tells you so much though, a leak test would be better. I would think the cam followers would wear long before the camshaft, it would be easier to inspect them, although the head will need to be removed in any event which would be a good time to fit a composite head gasket and new valve seals.

Col
Click to expand...
Hi Coll,
i did the head gasket when I did the timing chain, if I do the head off and valve seals, would it pay to do new valves?
 
Bobsticle said:
The other thing that shocked me was the dent in the rocker face. No way I could get anywhere near with a feeler gauge. Naturally I didn’t know this until the rocker shaft was removed.
If your taking the head off you can remove the tappets and rollers then have a butchers at the cam for wear from above. It could be as simple as the rollers are a bit goosed.
Click to expand...
Bob, is that a tricky job, getting the rollers out? .. I just wonder if like the valves I should just replace em anyway ... so like i do the vales and seals plus the rollers and a new composite head gasket ..
I mean if i'm also destined to do the timing chain, how much more of a job would it be to put a new camshaft in at the same time ?
 
Simon Perks said:
Bob, is that a tricky job, getting the rollers out? .. I just wonder if like the valves I should just replace em anyway ... so like i do the vales and seals plus the rollers and a new composite head gasket ..
I mean if i'm also destined to do the timing chain, how much more of a job would it be to put a new camshaft in at the same time ?
Click to expand...
It is a fair amount of hassle. And that is not a huge mileage to wear out a camshaft, assuming the oil has been changed at the right intervals.
I would just check the followers, and have a look at the camshaft, and if it is OK, put it back together.
Likewise the valves, they are unlikely to be worn out, just check the guides, change the seals, and see how you go.
There is no point in spending money to change parts that are not worn out, and it may be that none of these things are causing your issue with the way the engine runs anyway.
 
Is it not possible to inspect the cam shaft and rollers by taking the small side plates off ie petrol pump one [if mechanical pump] and oil filler
 
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