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MG MGA - replacimg lifters and push rods?

I plan to replace my lifters and push rods soon. I purchased Kent Cams lifters and Crane push rods. I seem to have a problem locating any step by step instructions on the subject.Can anyone out there give me a hand?
Terry B

You should really be doing this only when you also change your cam.

You aren't going to gain one iota of advantage with the new pushrods (unless yours are bent or worn) and lifters (unless yours are worn, in which case you HAVE to change the cam or have it reground.)
Bill Spohn

Wwen I purchased the car I was told it had a high street cam instaled I even have the old cam in a box. The problem comes from the previous owners mech. And I use the term lightly. He was charged for quite a few things which were clearly never even touched! My problem is I cant quiet my beloved A down past tractor noise. I figured the best course of avtion would be to replace lifters and push rods. If there is any truth to the fact my cam might only have 2000 mi. on it should I just chuck it? Dont get me wrong,if its best for the A I'll pay for the best.My little car is my hobby it's my friend in many respects.
Terry B

Are your clearances set absolutely correctly ?? Set them to .015 inches on a hot engine and that means after at least 20 mins driving and if possible set with the engine at a slow idle. Then we can all pass judgement on the valve train.
Iain MacKintosh

Get rid of the original lead sinkers (cam followers)and change to the 18v MGB hollow cam followers and longer 18v pushrods.
The combined length of both is about 5mm less though, but it's well worth the efficiency saving as the total mass is about 1/3 less.
I've found this extends the valve crash limit by almost 500 Rpm also.
If you do change to the mini / 18v cam followers, make sure you use the one's with the drain hole in the side, as some don't come with this, but it makes the cam last a little longer...
Cheers <MARK>
Mark Hester

No, no, no - your problem has nothing to do with tappets and pushrods (probably) but likely has everything to do with the usual thrashed rockers and shaft.

Leave the followers and pushrods alone and remove the rocker shaft and have a really good look - 90% of the time, wear up there is the culprit and a new set of bushes and shaft and refacing (or replacing if need be) the rockers will quiet things down.

If you really feel driven to do so, you can replace the pushrods without causing any mischief, but leave the followers alone unless they are worn, in which case you'd be looking at a new or reground cam as well.
Bill Spohn

I agree top end wear is quite sevear on these engines, not 90% though... cam's and lifters don't last forever.
My philosophy is pulling apart the engine is both costly and time consuming.
So changing a cam follower at £3 each is really cheep and helps the cam last longer, as they become concave and the surfaces begin to pit, thus wearing out the cam faster.... you will notice this as the tappets adjustment will become more frequent and the gaps increase.
When new, if placed on a flat surface they are slightly convex and will rock.
I've heard the theory that cams and followers should be matched and yes you should not remove the followers and place them back in other holes, but installing new followers should at least remove 50% of the ware, but obviously they will not last as long as they are now running on an old surface.
My race engines go through about 3-4 sets of followers before I eventually get around to rebuilding the engine and regrinding the cam.
Much the same applies to big end bearings... keep replacing them and you don't need to grind the crank as often as the tolerances are much tighter and the metal in the bearings softer.
As for pushrods, once changed to the later type I've never really changed them, just polished them and checked for cracks... Carbon Fibre of hollow alloy VW one's are next though.
I also run offset bushes in the rockers to increase the ratio in one engine and roller rockers in the other.

I think we have got off the topic though, as Terry was looking for instructions.

Terry.
Without removing the head it's tricky.
You will have to slacken off all the rockers as much as you can.
Remove No.1 & No 8 rocker altogether... Not easy as you will have to rotate the engine.
the others you can compress the springs towards the middle and remove the pushrods.
Label the pushrods 1(front) to 8 (rear)
remove the engine side covers... not easy with the carbs in place (I have a Webber so very easy)
stick your fingers in and remove the followers ... you can buy a magnetic tool for this if you really get stuck, or very pointy pliers.

Reassemble in reverse, but use plenty of cam lube with new followers.

Hope this helps...
Cheers <MARK>
http://freespace.virgin.net/marka.hester/
Mark Hester

I can't tell you how much your help has been to me. It realy makes one happy to know there are fellow MGA nuts like myself. As for you boys across the big pond....Thanks a million.
Terry B

I still come back to my point of checking the valve clearances first before moving on. Much of the other comments are carrect save the one saying it is difficult without removing the head. This is not needed.

Slacken the head bolts one by one and retorque to 20ft lbs then remove the four holding the rocker shaft posts and then the complete rocker shaft assembly. At that point it is your call asto what you want to do with the pushrods and buckets but I too think that the problem is at the top end.

Reassemble the rocker shaft tightening the nuts to 20ft/lbs then in sequence tighten them all to 40ft/lbs I think.

Believe it or not there is no need to drain the cooling system !!
Iain MacKintosh

Sorry Ian,
But I would never recommend anyone try that.
I've been racing since 86 and blown a few head gaskets in my time and I now know how to make them last longer. Painting them in silver paint or similar also helps, so does recessing around the base of each stud.
This is why race engine builders charge much more.

Once there on there on and once there off there in the bin... Head gaskets that is...
It's 60Ft/Ibs and no more unless your using competition studs, but certainly do it in stages.

What if the radiator still had pressure in it, as do the oil galleries some times. You just force the oil out into the gasket, especially if the head has become slightly warped.


What I didn't mention however is that sometimes you need a long strong screwdriver or similar to sometimes compress the spring and depress the valve... usually 1mm is about enough... if the tappet adjusters don't unscrew enough that is.

Cheers <MARK>
Mark Hester

Sorry Mark but it is just not necessary to remove the head to change a rocker shaft. Race engines may be one thing but the normal MG engine is another. We must assume first that the head gasket is not leaking and I think we would be well aware it it were in which case it would be a head off job anyway. It would be common sense to release any pressure in the cooling system and pressure in the oil ways dies down a few seconds after stopping the engine so that is irrelevant.

By removing the shaft the way I have described will ensure that the nip still remains on the gasket at all times and that it is never too much in any one area so as to warp the head.

60lb/ft is too high a torque for MGA head studs, you will strip them for sure. The B has a max of 50ft/lbs which can also sometimes be problematic unless OEM studs are used (once again I refer to standard parts and not race.)

It is for this very reason that I questioned my own figure of 40ft/lbs which meant of course - check the manual. I agree that if the head were removed and also the studs, that it is essential to use a rosebud bit before installing new studs but in this thread we are neither talking about race engines or removing the head from this near standard one....yet at least.
Iain MacKintosh

The information I have outlined above is fairly standard procedure but I've just looked the original BMC manual for rocker shaft removal and it clearly says to slacken all 11 cylinder head bolts. Under these circumstances it also says to drain the cooling system first to prevent leaks into the cylinders but it then goes straight back to refit the shaft and all bolts. There is no suggestion of removing the head and I would caution against even accidentally moving it. If you use the method I have suggested there is no risk of this and the torque figure is low enough to obviate warpage. In addition you can if you wish leave the water in the system but release the pressure cap.

However the torque figure quoted for the early B is 45/50ftlbs and I seem to remember that the A was 5ft/lbs less so please check as the studs are near their limit
Iain MacKintosh

This thread was discussed between 27/11/2005 and 30/11/2005

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