Oil to the timing chain area
Discussion
Pulling the cover off to hopefully stop an oil leak that (I think) comes from that area, I started to wonder about how the oil gets in and out of the timing chain area.
Haynes says it enters via the front cam bearing, so presumably by leaking out the edge of the bearing. How does it get out the timing chain area? Via the hole (about 20mm dia.) mid way between the two chain wheels back into a cavernous area within the block?
If so, the oil level in that area is a lot higher than the general sump level even when not running which could explain the quantity of the leak when standing.
Any help greatfully accepted.
Tony H
Haynes says it enters via the front cam bearing, so presumably by leaking out the edge of the bearing. How does it get out the timing chain area? Via the hole (about 20mm dia.) mid way between the two chain wheels back into a cavernous area within the block?
If so, the oil level in that area is a lot higher than the general sump level even when not running which could explain the quantity of the leak when standing.
Any help greatfully accepted.
Tony H
Think (sincerely hope) I may have found the reason for the original leak.
The lowest two of the smaller threaded holes have been strained, possibly by the screws going too far in and pressing against the block/gearbox.
the result is a raised area around the holes almost a like a boss. This may have stopped the cover fitting properly.
The engine is built up from two and whilst I thought I had used the best front plate, maybe I hadn't....
The lowest two of the smaller threaded holes have been strained, possibly by the screws going too far in and pressing against the block/gearbox.
the result is a raised area around the holes almost a like a boss. This may have stopped the cover fitting properly.
The engine is built up from two and whilst I thought I had used the best front plate, maybe I hadn't....
I had a look yesterday and it does seem as thought the oil comes out of the cam beaqring end and comes through the hole in the block as a 'mist'. So it's sort-of splash feed in that area. Those timing covers are a real pain sometimes. I've seen so many leak through having a non-flat flange, or throught the bolts being over-tightened and splitting the gasket. the 1/4" bolts on the timing cover should be tightened to 6 lb.ft and the 5/16" ones to 14 lb/ft. Unfortunately most torque wrenches don't go down that low. Mine starts at 20 lb.ft. It's a question of judgement then. Use Hylomar as well.
phumy said:
Just find a decent "flat" surface and hammer it flat again, should be too difficult
it's still on the engine in the engine bay.....good file works just as well if slow.the cover is actually a bit distorted too, now that i can hit!
Peter, 6lb/ft never seems enough does it!
Thanks all
Tony H
Skyedriver said:
phumy said:
Just find a decent "flat" surface and hammer it flat again, should be too difficult
it's still on the engine in the engine bay.....good file works just as well if slow.the cover is actually a bit distorted too, now that i can hit!
Peter, 6lb/ft never seems enough does it!
Thanks all
Tony H
Useless bit of information: Did you know that Hylomar was originally developed by Rolls-Royce to cure the oil leaks on the Merlin engine? Take a look at a photo of the underside of an early mark of Spitfire. Covered with oil. And you think a Mini can be bad!
Cooperman said:
It always worries me. I usually use a bit of 'Loctite' and use a short spanner rather than a socket and ratchet. Blue Hylomar is also good. By the way, don't forget the thrower plate before you fit the cover. I once did, but fortunately it didn't leak.
Useless bit of information: Did you know that Hylomar was originally developed by Rolls-Royce to cure the oil leaks on the Merlin engine? Take a look at a photo of the underside of an early mark of Spitfire. Covered with oil. And you think a Mini can be bad!
The thrower plate? Which way does it go back please, wasn't sure the last time I assembled the thing and the Haynes book wasn't that clear either.Useless bit of information: Did you know that Hylomar was originally developed by Rolls-Royce to cure the oil leaks on the Merlin engine? Take a look at a photo of the underside of an early mark of Spitfire. Covered with oil. And you think a Mini can be bad!
Is is concave or convex?
Always used to use Hylomar on my Imp engines, but used something called Weldseal (?? I think) when I built up this one. It was supplied by the company that did the re bore. Very runny but sticks like superglue as the hours trying to scrape it off the timing chain cover and front plate will testify.
Cannot get hold of hylomar up here, was going to use "instant gasket" stuff as it is a bit thicker than the last stuff. Hope it holds up. Not getting much done at the moment because a) looking after 2 y-o son and b) there's 6 inches of snow outside.
Merlin engined Mini, now that would knock the spots off an R1 or V-Tex ...
It goes on with the 'dish' towards the chain. i.e. it's concave on the chain/sprocket side. I think if you put it the wrong way round, the outer diameter can hit the timing cover.
Anyway, I'm off out now in my Grandson's lovely 1061 cc Mayfair+ to get some bits from the DIY shop, then i'll take mt 'S' out to blow the cobwebs out of it.
Anyway, I'm off out now in my Grandson's lovely 1061 cc Mayfair+ to get some bits from the DIY shop, then i'll take mt 'S' out to blow the cobwebs out of it.
Skyedriver said:
The thrower plate? Which way does it go back please, wasn't sure the last time I assembled the thing and the Haynes book wasn't that clear either.
Too true. My Haynes says "concave side faces forward" but the picture shows the concave side facing backwards (the correct way)Mr Edd said:
I am sure some will correct me but most parts like this are stamped with a hint.
It is if I only opened my eyes!!!!!Edited by Mr Edd on Sunday 3rd February 10:55
Do you ever wish you hadn't started something....
Where there was a ground mark on the inside of the case (where there was an area pressed in (near to the crank seal, where I guess a sensor has been at sometime) and which I tapped out to clear whatever was catching it (still with me) has a split in it (ever so tiny but still it is holed. So out with the MIG and it is so thin I burn the split into a hole.......
Of course the split could have always been there and THAT was where the oil was leaking out of....
Still we'll get there in the end.... and at least the snow has gone now, the rain has washed it away.
Tony H
On the timing cover topic, may I remind anyone interested that if, or rather when, you change later cars to a duplex timing chain you have to countersink the holes in the front engine plate to accept the wider crank sprocket and fit 1/4" UNF x 5/8" long socket head countersunk screws. Also you delete the nasty chain tensioner as you are moving to the original Cooper 'S'-type arrangement. However, the later timing covers have a flange inside which hits the duplex chain and this must be ground away almost completely or the timing chain won't go back on.
This weeks tip: If you are going to time the cam in accurately using either offset woodruff keys or a vernier sprocket, set the initial cam timing about 2 degrees advanced from manufacturer's recommended settings. This allows for the initial wear on the chain which settles down after about 1000 miles to give accurate cam timing for much longer. If you just set to recommended, within about 1000 miles the chain stretch has retarded the cam about 1.5 degrees.
This weeks tip: If you are going to time the cam in accurately using either offset woodruff keys or a vernier sprocket, set the initial cam timing about 2 degrees advanced from manufacturer's recommended settings. This allows for the initial wear on the chain which settles down after about 1000 miles to give accurate cam timing for much longer. If you just set to recommended, within about 1000 miles the chain stretch has retarded the cam about 1.5 degrees.
Getting one of me heads here.....
It's an A+ 1300, MG Metro possibly, with a timing case that has a "chimney" on it to go to a breather (not connected).
I have a duplex system with NO tensioner, and there is nothing inside the cover worthy of removal, save for a bit of gunge before refitting, unless there's something else I have done wrong......
I have tapped out a small indentation near the crank pulley and removed a welded on bracket for a sensor(?) and removed the inner steel part of the lower pulley as it wasn't doing anything and catching on the weld (see above).
Think I'll try Rocket Science it'll be simpler
It's an A+ 1300, MG Metro possibly, with a timing case that has a "chimney" on it to go to a breather (not connected).
I have a duplex system with NO tensioner, and there is nothing inside the cover worthy of removal, save for a bit of gunge before refitting, unless there's something else I have done wrong......
I have tapped out a small indentation near the crank pulley and removed a welded on bracket for a sensor(?) and removed the inner steel part of the lower pulley as it wasn't doing anything and catching on the weld (see above).
Think I'll try Rocket Science it'll be simpler
The trouble is that there were so many different configurations produced by BMC/BLMC/ARG/Rover that it's difficult to know where you are unless you have all the pieces in front of you. I didn't think the Duplex arrangement was used after the end of the Cooper 'S' in about 1971/2, but I could be wrong.
The timing covers for the cars with slide-type tensioners are a different shape from all the earlier ones and have a 'bulge' for the tensioner. Some have the oil guide flange inside which needs to be ground off if a Duplex is to be fitted, but not all covers seem to have this.
My personal preference is for the 'S'-type duplex arrangement without any tensioner - it's so simple and reliable. Of course the chain goes a bit slack after, say, 10,000 miles (less on a full competition car) but it's easy to change with the engine in-situ and I think the tensioners wear badly is really high revs are used as on a race or rally car. Remember, chain stretch won't alter the cam timing less with a tensioner than without since the chain is always 'pulling' the cam from the crank sprocket when normal revs are being used, so the chain is tight on that side (if you see what I mean).
I think I know what I mean here!!!!
The timing covers for the cars with slide-type tensioners are a different shape from all the earlier ones and have a 'bulge' for the tensioner. Some have the oil guide flange inside which needs to be ground off if a Duplex is to be fitted, but not all covers seem to have this.
My personal preference is for the 'S'-type duplex arrangement without any tensioner - it's so simple and reliable. Of course the chain goes a bit slack after, say, 10,000 miles (less on a full competition car) but it's easy to change with the engine in-situ and I think the tensioners wear badly is really high revs are used as on a race or rally car. Remember, chain stretch won't alter the cam timing less with a tensioner than without since the chain is always 'pulling' the cam from the crank sprocket when normal revs are being used, so the chain is tight on that side (if you see what I mean).
I think I know what I mean here!!!!
Cooperman said:
The trouble is that there were so many different configurations produced by BMC/BLMC/ARG/Rover that it's difficult to know where you are unless you have all the pieces in front of you. I didn't think the Duplex arrangement was used after the end of the Cooper 'S' in about 1971/2, but I could be wrong.
The timing covers for the cars with slide-type tensioners are a different shape from all the earlier ones and have a 'bulge' for the tensioner. Some have the oil guide flange inside which needs to be ground off if a Duplex is to be fitted, but not all covers seem to have this.
My personal preference is for the 'S'-type duplex arrangement without any tensioner - it's so simple and reliable. Of course the chain goes a bit slack after, say, 10,000 miles (less on a full competition car) but it's easy to change with the engine in-situ and I think the tensioners wear badly is really high revs are used as on a race or rally car. Remember, chain stretch won't alter the cam timing less with a tensioner than without since the chain is always 'pulling' the cam from the crank sprocket when normal revs are being used, so the chain is tight on that side (if you see what I mean).
I think I know what I mean here!!!!
Understood.The timing covers for the cars with slide-type tensioners are a different shape from all the earlier ones and have a 'bulge' for the tensioner. Some have the oil guide flange inside which needs to be ground off if a Duplex is to be fitted, but not all covers seem to have this.
My personal preference is for the 'S'-type duplex arrangement without any tensioner - it's so simple and reliable. Of course the chain goes a bit slack after, say, 10,000 miles (less on a full competition car) but it's easy to change with the engine in-situ and I think the tensioners wear badly is really high revs are used as on a race or rally car. Remember, chain stretch won't alter the cam timing less with a tensioner than without since the chain is always 'pulling' the cam from the crank sprocket when normal revs are being used, so the chain is tight on that side (if you see what I mean).
I think I know what I mean here!!!!
Looking at my cover, it has a breather chimney and the lower part is enlarged. There is a flange around the cam sprocket area and that has been ground away. Did I do this under your advice when I built the engine??? memory not what it used to be!
I am using a duplex without a tensioner, new less than 2k miles ago.
Anyway it's going to go back together to see if it still leaks, either from the joint or the repaired small split in the case.
Fingers crossed
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