Geared camshaft drive.

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philthehill
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Geared camshaft drive.

Post by philthehill »

Arrived today - vernier adjustment geared camshaft drive - replaces the camshaft sprockets and timing chain.
Been after one of these set ups for some time.
cam drive gears 1.jpg
cam drive gears 1.jpg (17.39 KiB) Viewed 2770 times

callyspoy
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Re: Geared camshaft drive.

Post by callyspoy »

That looks like a fun bit of kit.
I had the vernier belt drive on a Mini before, it was pretty good. Not a patch on this though of course!
I'm trying to visualise how it mounts up, can you explain?
philthehill
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Re: Geared camshaft drive.

Post by philthehill »

The intermediate gear assembly bolts to the front engine plate/block using the two holes previously used by the 'A' Plus simplex timing chain tensioner.
Any movement of the intermediate gear assembly block is alleviated by two fitted pins which pass through the gear assy and into the front engine plate/block
The benefit of using the gear drive is that there will be no chain stretch so no variation in camshaft timing.

Phil

philthehill
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Re: Geared camshaft drive.

Post by philthehill »

Here is a photo of the 'A' Plus simplex set up. If you can imagine the chain tensioner removed and replaced by the intermediate gear assembly.
100_2206.JPG
100_2206.JPG (1.86 MiB) Viewed 2757 times
The 'A' Plus timing chain cover is required with the geared drive set up.

Will post further photos of the set up as progress in fitting is made.

Phil

RobThomas
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Re: Geared camshaft drive.

Post by RobThomas »

Hello Phil.

Quite jealous. I assume that splash lubrication is enough? The Vedette sump extends forwards so the bottom pulley is exposed to far more oil, if that helps? Just thought it worth mentioning. :D
Cardiff, UK
philthehill
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Re: Geared camshaft drive.

Post by philthehill »

Rob
Thank you for pointing out a possible issue - lubrication of the straight cut teeth should not be an problem; good oil pressure will ensures that there is plenty of oil circulating within in the timing chain case directed from the front camshaft bearing oil feed which is how the timing chain is lubricated.
Phil

philthehill
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Re: Geared camshaft drive.

Post by philthehill »

Rob
As I have been timed out of the above post I will add here:-
The intermediate gear has a caged needle bearing running on what appears to be a surface hardened and ground pin so should not require lots of oil to run satisfactory. As the intermediate gear is straight cut there is no considered need for thrust bearings with any gear float held against the internal walls of the carrier.
Slowly working out how it all goes together - next task is to fit a front engine plate to the spare 1275cc Midget block and go from there. I will have to drill the front engine plate and possibly shallow drill the block for the holding/location pins.
Phil

philthehill
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Re: Geared camshaft drive.

Post by philthehill »

I have had quite a good couple of days in the workshop.
Started getting my 1400cc MG Midget engine back together incorporating the geared camshaft drive.

Here is a current picture of the geared drive.
geared cam drive 1.JPG
geared cam drive 1.JPG (1.71 MiB) Viewed 2500 times
Phil

pgp001
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Re: Geared camshaft drive.

Post by pgp001 »

Phil

Is there any way of fine tuning the cam timing with that setup ?
Does it have any vernier adjustment or is back to stepped keys.

Phil

PS
Ignore the question, I have just re read your original post......Duhh
philthehill
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Re: Geared camshaft drive.

Post by philthehill »

The cam gear is fully adjustable and the cam timing can therefore be set precisely.
Note the vernier holes in the cam gear in the first photo.

Declan_Burns
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Re: Geared camshaft drive.

Post by Declan_Burns »

Phil,
Who makes that kit?
Regards
Declan


Regards
Declan
philthehill
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Re: Geared camshaft drive.

Post by philthehill »

Declan
As regards the maker - currently I have no idea - I picked up the kit S/H off 'e' bay for a very reasonable price.

If anyone out there has any information it will be gratefully received.

I have seen this kit or similar advertised but at the moment cannot remember where. Possibly Slark Race Engineering.

The kit does take some fitting though as I am finding out. It came with no fitting instructions so having to take it step by step and work it through.

As the front engine plate is not located by dowels to the front of the block as per the rear engine plate it can move slightly about the front engine plate mounting bolts. To eliminate any movement and add security of location of the front engine plate and intermediate gear carrier I have drilled through the front engine plate and into the block by about 8mm (thankfully no oilways in that area of the block).
I will be fitting longer 1/4" diameter rolled split pins to locate the parts. Currently awaiting the new longer rolled split pins.

I have also added a threaded hole (6mm x 1.0) central between the rolled split pin holes to enable the intermediate gear carrier to be removed without having to resort to force.

I have also replaced the original 5/16" UNF cap headed screws with longer items and of a better tensile (10.9) strength.

I will keep adding to the thread as I work through the fitting.

Phil

pgp001
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Re: Geared camshaft drive.

Post by pgp001 »

If the link works there is something along similar lines here.

https://www.google.com/search?biw=1920& ... QJTnOVZFDM:

Phil
Declan_Burns
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Re: Geared camshaft drive.

Post by Declan_Burns »

Phil,
Locating the front plate with pins is a good idea. I think setting the backlash on such a system could be just as critical as in setting CWP backlash in a diff.
Regards
Declan


Regards
Declan
philthehill
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Re: Geared camshaft drive.

Post by philthehill »

Declan
The meshing of the teeth is a challenge especially as there are three sets of teeth to mesh.
I have come to the opinion that so long as I can get the gears/teeth to run free with the minimum of backlash all will be ok - thankfully one of the benefits of having straight cut gear teeth unlike the CWP hypoid skew teeth.
Gear noise will not be a consideration as it will be drowned out by the S/C gears in the gearbox. :wink:

pgp001

Thank you for the link.

Phil

oliver90owner
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Re: Geared camshaft drive.

Post by oliver90owner »

The usual method of adjusting the two meshes for backlash is to run suitable thickness paper between each pair of meshing spur gears. Slower speeds and larger tolerances on our hobby lathes, but the same principal when changing wheels for different screw thread pitches?
philthehill
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Re: Geared camshaft drive.

Post by philthehill »

oliver90owner
Thank you for reminding me about the paper thickness test.

Whilst not a camshaft gear train the same principles apply.

http://www.rccoh.com/rc.how-to/set.spur.mesh.html

Phil

philthehill
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Re: Geared camshaft drive.

Post by philthehill »

Update:-

The gear drive has been fitted but unfortunately I am not happy with the meshing of the teeth.

The intermediate gear carrier was fitted and had two mills pins inserted through the carrier, the front engine plate and into the front of the engine block.

The meshing and amount of backlash was considered perfect (checked by feel & using the sheet of paper method) until the two 5/16" UNF cap headed screws were tightened.

Tightening the cap headed screws appears to distort the intermediate gear carrier (which is alloy) and which upsets the meshing of the gears making them notchy and not smooth as they should be and I would like them to be.

Undoing the cap headed screws returns the mesh to perfect.

I have fitted a steel washer under the head of the cap headed screw to spread the load around the screw hole and that has helped in reducing the squashing/squeezing of the screw hole through the intermediate carrier.

I have enlarged one of the mills pin holes in the block (but not the front engine plate) so as to allow some articulation of the carrier and front engine plate which has helped but still not right.

Once the gears are correctly meshed it was planned to fit a third mills pin to make sure that the front engine does not move.

I may have to start again with a new front engine plate and build in compensation for distortion of the intermediate carrier.

What does not help is fitting the intermediate carrier which has a machined contact face to a front engine plate which is manufactured from pressed plate with a non machined face.

I may put this on the back burner and revert to using a vernier chain drive.

Phil

philthehill
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Re: Geared camshaft drive.

Post by philthehill »

Been working today on trying to improve the meshing of the intermediate spur gear.

The Mills pins do not like being fitted through the intermediate gear carrier, the front engine plate and into the block.

The Mills pins when fitted only through intermediate gear carrier and the front engine plate improves the meshing to the point of being considered satisfactory.

What I have done is to enlarge the holes in the block so the mills pins are not captive in the block.
To secure the front engine plate and remove the possibly of any float I have fitted two stepped dowels into the block and drilled the front engine plate to suit. The front engine plate is now properly located with no chance of moving.

Next step is to fit the intermediate gear carrier to the front engine plate.

Pictures to follow.

Phil

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Re: Geared camshaft drive.

Post by MikeNash »

Phil,
Re using paper for gauging the gear mesh, long ago & far away I saw Rizla cigarette papers being used by RAE fitters to set up a back axle. These papers are closely controlled in thickness and vary according to the colour. Alas, I've lost my notes of what is what but it's down around 2-4 thou.
Regards MikeN.
Morris Minor, the car of the future. One day they will all look like this!
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