Shorter push rods for a 1275??
Discussion
You can buy shorter push rods.
Alternatively fit packing pieces under the rocker shaft to raise it by the necessary amount. To work out how much to raise it, just meassure a standard head for thicknerss, then your new one and the spacers need to be the difference. Make sure the packers are groung both sides and drilled to match not only the studs, but the oil feed hole as well.
There must have been a heck of a lot machined off the head and/or block for the rods to be that much too long.
Alternatively fit packing pieces under the rocker shaft to raise it by the necessary amount. To work out how much to raise it, just meassure a standard head for thicknerss, then your new one and the spacers need to be the difference. Make sure the packers are groung both sides and drilled to match not only the studs, but the oil feed hole as well.
There must have been a heck of a lot machined off the head and/or block for the rods to be that much too long.
The head was very high comp when it was first measured so has had more taken out of the chambers to drop the compression to a reasonable amount. It also looks like the top of the head may have been machined at some time as the 12G940 text has the top of the casting missing. Is there any benefit to doing this or would it just be to get all the gasket faces clean?
I have fitted standard rockers for the time being which have about 1-2 turns spare when adjusting the valves but I would like to use the 1.5 rockers, what is the best option? Shorter push rods or packing? Also do you know where I can get either?
I have fitted standard rockers for the time being which have about 1-2 turns spare when adjusting the valves but I would like to use the 1.5 rockers, what is the best option? Shorter push rods or packing? Also do you know where I can get either?
Don't do that. They should be case-hardened at the ends and grinding will remove the hardening. You might get away with it for a short while. The end shapes are quite critical as well. Try measuring a 998 push rod. It may just happen to be the right length. I've never tried this, but it's worth a look.
I still think packers are the right way to go as you can then get the angles absolutely correct. All you need to do is get a piece of mild steel plate, probably about 10 swg or 12 swg (that's 0.128" or 0.104" thick) scribe the outline of the rocker pillar onto it and simply cut around the outline. Don't forget that one of the packers must have an oil feed hole in the right position. I put the hole in all of them, cause at my age I might get them mixed up. De-burr the edges, check that the surfaces are very smooth and flat, get them surface ground to the exact thickness you need if possible, and jobsagoodun.
I still think packers are the right way to go as you can then get the angles absolutely correct. All you need to do is get a piece of mild steel plate, probably about 10 swg or 12 swg (that's 0.128" or 0.104" thick) scribe the outline of the rocker pillar onto it and simply cut around the outline. Don't forget that one of the packers must have an oil feed hole in the right position. I put the hole in all of them, cause at my age I might get them mixed up. De-burr the edges, check that the surfaces are very smooth and flat, get them surface ground to the exact thickness you need if possible, and jobsagoodun.
Paul, I'm with Peter on this, don't try to grind down your pushrods. If you check them closely you'll see the cam follower end is slightly domed, which you won't be able to replicate without a special cutting tool in a lathe, and you will still have to harden them up again.
Check out the 998 rods, I seem to remember they are slightly shorter due to shorter block deck height of the 'thou. Might be just the job.
The "proper" way is as described; get some idea of how much material has been removed from head and block and make some rocker pillar spacers.
I can't think why someone would want to machine off the top face of the head.
Check out the 998 rods, I seem to remember they are slightly shorter due to shorter block deck height of the 'thou. Might be just the job.
The "proper" way is as described; get some idea of how much material has been removed from head and block and make some rocker pillar spacers.
I can't think why someone would want to machine off the top face of the head.
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