Camshaft sprocket.

[olonas]

Not sure if this should come under "Mechanical" or not?
However, there seems to be an unobtanium shortage of timing chain camshaft sprockets. Particularly those with the strange (useless?) tensioner rubber rings.
There is availability of rubber less sprockets which are described as not requiring the "tensioner" rings.
I would rather use what is already there than risk the alternative.

[svenedin]

If you need to change the camshaft sprocket due to wear it might be an opportunity to fit a duplex kit? I certainly don't miss my rattling timing chain since doing this!

Stephen

[philthehill]

If you want a qualified 'Risk Assessment' opinion then the risk is greater with a simplex chain than the duplex chain.
You can reduce the risk even further by using a duplex chain with tensioner.
The simplex chain with rubber tensioner rings starts to fail soon after fitment.
You can go halfway to the duplex set up by using a 'A' Plus simplex chain with tensioner.
To alleviate any risk to my engine I have used a steel duplex set up with 'A' Plus tensioner.
BMC/BL fitted the duplex without tensioner and simplex with tensioner with good reason -
the simplex set up is c?ap.
Phil

[olonas]

Did you encounter any issues when countersinking the two holes to accomodate the two supplied screws, brake drum securing, 1/4" U.N.F. (same part number), which fit through the front engine plate Stephen? If not, what did you use to countersink the holes?
I have seen a video on the old Youtube when someone had to remove the front plate and braze/weld some extra to allow for the countersinking.
i.e. those two holes look very close to the opening to allow a countersink.

front plate1.jpg (71.61 KiB) Viewed 2037 times

[philthehill]

Removed as duplicate post to that below.

[philthehill]

If the countersinking is undertaken with care then there will be no problems encountered.
I have countersunk many front engine plates over the years and never had a problem.
The countersink should be 82 degrees for a UNF screw but a 90 degree countersink will suffice.
Use screws that require a Allen key to fit and remove. The screws should be secured with Loctite loc and secure fluid.
The screws just need to be nipped up.
Below is a photo of me countersinking a 'A' Series front engine plate with a 82 degree countersink:-

Front plate counter sink 1.jpg (51.69 KiB) Viewed 2025 times

Below is a photo of the finished product:-

Front engine plate countersink 7.jpg (73.03 KiB) Viewed 2024 times

The R/H screw has been faced off to give a bit more clearance. the L/H screw was also faced off.
Below is a photo of the countersink I use. The multi-face cutter removes any chatter encountered when undertaking the countersink. It also provides a better finish to the countersink.

Front plate countersink 2.jpg (72.75 KiB) Viewed 2025 times

This is the link to the screws I use:-
https://www.minispares.com/product/Clas ... o%20search
The camshaft sprocket may require machining to give the required 0.007" camshaft end float.

[svenedin]

Did you encounter any issues when countersinking the two holes to accomodate the two supplied screws, brake drum securing, 1/4" U.N.F. (same part number), which fit through the front engine plate Stephen? If not, what did you use to countersink the holes?
I have seen a video on the old Youtube when someone had to remove the front plate and braze/weld some extra to allow for the countersinking.
i.e. those two holes look very close to the opening to allow a countersink.
front plate1.jpg

I have to confess that ESM did it for me. They had the engine out at the time as the gearbox was being replaced.

Stephen

[Guildbass]

Not sure if this should come under "Mechanical" or not?
However, there seems to be an unobtanium shortage of timing chain camshaft sprockets. Particularly those with the strange (useless?) tensioner rubber rings.
There is availability of rubber less sprockets which are described as not requiring the "tensioner" rings.
I would rather use what is already there than risk the alternative.

Yes, I broke mine removing it a week or so ago. I didn't realise the 'edges' were so thin and cast iron brittle...Pro tip, don't pry them off from the back....!!!
Couldn't find another but a duplex kit with both sprockets and obviously the chain was not a lot more money than the 'out of stock' single row sprocket'. The ESM kit includes a couple of countersunk screws to replace the two bolts that sit under the crank pulley as they would otherwise foul the new deeper crank pulley and you also need to apply a light countersinking to the plate on those two holes for the screws to sit in well enough. 30 secs with a big drill bit did that fine!
The new kit has all the same marks for so an easy upgrade AND solution to cack handed 'mechanics'.

[philthehill]

If you are fitting a duplex kit you will need to use the later flat oil thrower plate instead of the concave plate.
The plate is marked with a 'F'' which should face forward.
https://www.moss-europe.co.uk/oil-throw ... soc=154478
The timing gears need to be aligned and can be adjusted by adding or removing one or more shims located behind the crankshaft sprocket.
If you have the felt timing chain cover seal it now would be a good opportunity to replace the timing cove with a cover that has the neoprene lip seal.

[olonas]

Thanks all for the input.
I fitted the existing chain, crankshaft sprocket and camshaft sprocket about 20 years ago. I considered a duplex set up at the time but felt a bit wary of countersinking the holes with the front plate insitu. Only because of the possibility of metallic bits entering the engine. Yes, the holes can be filled with grease, as can the bit have some grease added.
A few months ago I replaced the cover lip seal and the chain is slack compared to when fitted. I should really have replaced it then. I didn't, I should have checked the condition of the sprockets' teeth for wear too.
I can't fully confirm which type of oil thrower is fitted, but do know it has a "F" stamping.
I'm still leaning towards the status quo and a simplex replacement. Yes, I agree it's not the best and is a really "cr?p design.

[olonas]

After much deliberation I have opted for the duplex kit from E.S.M..
The two short countersunk screws they supply do have a hex. socket head for Allen key/hex. key tightening. That makes it easier to apply a sensible/correct torque. I think they are high tensile too.
Three questions Phil, if you don't mind.
1. What diameter 82 degrees countersink bit do you use? The set I have include a 3/8" and 1/2".
2. Would I be correct that the threaded holes in the main bearing are "blind"? i.e. not drilled through into the crankase.
3. Do you know what torque, lbf ft or Nm, is correct for them? There are tables online for generic tightening, but they only refer to 1/4" UNF in general and varying degrees of tensile strength.
Would it be possible for this thread to be moved to mechanical by admin.?

[philthehill]

I would use the 1/2" dia 82 degree countersink. The head of the countersink of the screw should fully fill the countersink in the front plate. See photo above.

The 1/4" UNF bolt holes are blind. Check the length of the screw is not too long before final tightening. It should not bottom out before it becomes tight.

The countersunk screws should be torqued to no more than 8 lbf ft.

[olonas]

Thanks Phil, much appreciated.
"The 1/4" UNF bolt holes are blind." Thanks for confirming what I was hoping. That was my primary concern with regards to any metallic particles entering the crankcase/sump.
The screws provided with the ESM kit are short and probably of the required length.
That tightening torque agrees with most of the figures suggested in the online tables for a 1/4" UNF bolt/screw.
Those Mini Spares screws look to be the same as those from ESM.