Cylinder Block & Fittings

I'm working on the cylinder block at the moment. Having read the instructions I'm trying to eradicate the machining marks using a heavy metal block with 400 grit emery cloth attached to it. Am I doing the right thing, is there a better way and do the faces need to be perfectly free of the marks? Is a gasket the better way to go and if so how thick a piece of gasket paper will i need? Sorry there'e lots of questions here but it is my first build which I'm enjoying very much and just want to get it right.

Hi Jelk

I would recommend foliac myself, it is messy stuff, but ideal for getting into the small gaps. It isn't 100% necessary to clean off all the machine marks, but it doesn't hurt to have a good surface on it. Either way you do need some sort of sealant (be it foliac or a gasket or something else).

Many thanks

Will

Hi

I used a card joint. Never "cleaned" the machining marks and had zero issue.

Thanks Lynn

Did you use any specific kind of gasket paper?

Hi

In the old days the lads with Triumph bike used to use Kellogs cornflake packets to make there gaskets.

If you look towards the end of this thread you can see pictures of the silicon rubber gasket that I am using on my cylinder.
https://traction.forumotion.com/t3229p25-kit-11-cylinder-block-cylinder-fittings

I used Kellogs Cornflake packet. Never had trouble and the only joint to ever fail was the safeties when they were on a commercial joint.

Just have a clean and reasonably flat surface. Oil both sides of the card when applying and snug down. I always used my smallest wrench and held it in 2 fingers so not to over torque the nuts. You can feel when all the nuts are fully home and happy.

Thanks for all your help Guys

John

I have now received the cylinder fittings kit and we are progressing quite well, i.e piston rings fitted and inserted in to the cylinders, gaskets for front and rear cylinder covers made and now trying to fit the two cylinder glands as per the instructions





Prior to trying to fit the glands I have nice free and firm movement of the pistons within the cylinders. The glands slide down the piston shafts smoothly and freely. However, to get the glands to locate into their respective recesses in the rear cylinder head it does require some very firm persuasion with a rubber mallet to get them started and once started it stops any movement of the pistons at all they are firmly locked solid.

Question: which bit of the gland is  it best to relieve? The outer radius of the gland that fits into the recess or the inner radius of the gland that the piston shaft runs through, and what is the best way to do it? You can see I am very much an amateur at this, but thoroughly enjoy what i am doing so sorry to be a pain!!

John

I am sure that an expert will be along soon, but have you fitted the gland packing into the recess first ?  Also, I found that the glands must be tightened down very evenly, otherwise the hole through the gland is not absolutely parallel to the piston rod, and this will prevent them sliding nicely.
Edited to say that I abraded the outside of the gland a little, so that it went in more easily - I don’t think that will compromise the sealing as the gland packing will do that job.

Hi John

You would be best off relieving the outside of the gland that slides into the recess. I'm guessing that hammering it into place has caused the problem, as kelvin said it needs to be tightened as evenly as possible, if not then one part will dig into the shaft, and if you do have the packing in there then it will cause what you have described with the pistons going solid.

Many thanks

Will@STW

Thanks for the info, guys. I have not fitted any packing in yet as this is only the first trial fitting. I have not hammered them in any further than you see in the photos as i didn't want to do any damage. They have merely been tapped in to try and get them started. I will take Will's advice and relieve the outside radius of the gland so they fir a little more loosely.

John

Fit the outside face of the gland packing to allow easy slip in to the casting without offsetting the piston rod.
Do not alter the piston rod hole if it slips on the rod well.
You may need to tweak the holes for the studs and nuts to get good centralised fit.

Thanks Lynnr