Camshaft question

[mattyguk1]

Hi all, I’ve been browsing the forum for a while whilst slowly bringing my recently acquired minor back to life. I’m just in the middle of rebuilding the engine (1098) and have refitted crank and pistons, I have been turning crank after fitting con rods etc to make sure everything is turning freely and all seems well. My question is....with the timing chain removed is it possible for a lobe on the camshaft to foul with the big end cap/ con rod or have I done something wrong? I know it can’t happen once the timing chain is fitted but just checking before I continue!

[philthehill]

There should be no possibility of the con rod big end fouling the camshaft.
My question to you is - have you fitted the con rods the right way round and to the right big end?
See wksp man illustrations AA.16 & AA.24 for details of con rod orientation.

A picture of the crank/con rods as is now would be appreciated.

[mattyguk1]

Hi Phil and thanks for the reply it's much appreciated, I thought there must be something wrong. The con rods and big ends appear to be connected in the correct pairs, the numbers 1-4 match. I'll check that they are fitted correct way around after work tomorrow and get back to you. I'm having trouble loading a picture at the moment, not sure how to! I'll keep trying Thanks again matt

[mattyguk1]

Phil hope these shed some light on the problem, the second picture was before I stripped it and the first is now. Not great pictures I’ll try to get some better ones today

[philthehill]

Thank you for posting the pictures.

Everything seems to be as it should be.

Is it the actual con rod big end or the locking tab washer that is hitting the cam shaft?

I have a part stripped small block 'A' Series engine and some time today I will check on the clearances in relation to the crankshaft/camshaft.

I have just checked the clearance between big end and camshaft lobe - turning the crankshaft there is adequate clearance between the two with the camshaft disconnected from the crankshaft and the lobes purposely position towards the crankshaft big end.

As I hinted to above if the locking tap is not turned over and locking the big end cap bolt the tab will foul the camshaft lobe.

Phil

[oliver90owner]

Rods and big end caps must always be kept as pairs and in the correct orientation. The convention adopted was to mark each unit with the cylinder number - usually by dot punching - and always marking on the timing side.

If this convention is followed, it makes rebuilding idiot-proof, in regard to repositioning pistons, rods and big end caps, one hopes. Main bearing caps are treated similarly, although there is often differences between caps on three bearing cranks and only the centre bearing cap is remotely likely to fitted the wrong way. Some have dowels fitted to avoid the possibility, but usually the crank thrust bearing makes it plainly obvious to all those excepting the ones mentioned above, of course!

[mattyguk1]

Thanks Phil I’d appreciate that, I’ve had an unexpected day off work so have just had another look and taken some pictures. The lobes are actually hitting the con rod not just the lock tabs.

[mattyguk1]

All the caps and con rods are numbered 1-4 and are paired correctly number 1 being at the timing chain end. The numbers are facing the manifold side of the engine?

[philthehill]

The big end cap should not hit the cam lobe as shown in the picture.
That big end cap does not look to have been fitted right.
The big end shell bearings have a tab and that has to fit in the tab slot of the bearing cap.
Can you please strip off the big end cap shown and post a picture on here.

Has the camshaft been fitted with the thrust washer and cam gear as you may be pushing the camshaft into it non natural/running position?

The big end caps are fitted at an angle onto the rod and the slope should face towards the camshaft.
Are they sloping towards the camshaft?

The camshaft appears to have the twin identification rings so not a standard Minor camshaft.

[martin418]

the offset of the rods looks wrong . in your first two pictures are the engine blocks the same way round as the sump bolt holes are in different place in relation to the rod centers , in picture 2 before it was stripped the timing chain would be to your left the fuel pump blank is on top and the cam is above the crank if the rebuild looks the same it can only be the rods. the rods can be confusing .i have built a few a series and i always double check
the b

[philthehill]

Martin
The two top pictures have the block the same way round - look at the crankshaft web markings both are H 12.
Phil

[martin418]

i saw that but the sump holes are way out and the curve of the sump flange by the center main looks different

[mattyguk1]

Camshaft is fitted with thrust washer one end and oil pump the other. Should the numbers on the rod and cap be facing the exhaust side Phil? I’ll see if I can spin the piston and conrod to see if that makes a difference.

[mattyguk1]

The shorter shoulder on the con rod is facing the exhaust side also Phil, is this correct?

[martin418]

could we have a picture showing the whole engine

[mattyguk1]

I problem Martin thanks for the input

[paul 300358]

It may be worth fitting the timing chain and then looking.

[philthehill]

Thank you for posting the additional pictures.

The big end shell have been fitted correctly with the tag inserted into the tag slot of the rod/cap.

Looking at your pictures you appear to have the rods the right way round but to make sure:-

The off set of the con rods is as such - starting from the front/timing chain end.

No:1 - offset to the front main/front of the engine.

No:2 - offset to the centre main.

No:3 - offset to the centre main.

No:4 - offset to the rear main/rear of the engine.

Phil

[mattyguk1]

Like this Phil?

[philthehill]

The offsets are correct.

As suggested above - put it all together including the timing chain/gears and turn the engine over very carefully and see what happens.

Whilst you have it all down fitting a duplex chain set up will give a long term benefit as the simplex chain with two rubber ring tensioner is not known for long life.

Phil