Valve guide install - My take
Posted: Tue Jan 30, 2024 3:35 pm
I was installing new valve guides today so I took a few pictures of my process. In a previous thread I did make a few generalities to how I do it and misspoke on the spacers I use.
So first of all I am replacing cracked stock guides and removed them. The process I use is to cut the guide flush on the chamber side of the guide. I use a piloted counter sink (sorry no pictures). Then I put in oven and heat to 450F use "finch" tool to remove old guides hitting from inside the chamber towards the outside. I find I have had better success than going into the chamber.
Once removed I use gage pins to measure the diameter of the guide holes in the head. .5155 is what this head was. I then ordered oversize guides and on my lathe turned them down to .518.
Here are the items I used for install. The specifications for a 140 head calls for the guide to be inserted and stop .96" from the chamber surface. (if you zoom in on the pic you will see the specifications) and the exhaust 1.05"
I made two aluminum stops one for the intake and one for the exhaust. This way when I am inserting the guides they will stop at the correct amount. I put the guides on the freezer over night and then just before I install them I put them in a cup and use air duster ,held upside down to discharge liquid refrigerant into the cup to keep the guides as cold as possible.
I could not take pictures of the actual process because you have to move fast, before the head cools. Remove 450F head from oven and put on heat proof surface. Take a guide and put on finch tool with hardened washer to act as stop. Spray guide with a bit of lube and insert till it contacts stop.
You will notice that there is a difference in height between the intake and exhaust guides they are not all the same height.
You might also notice I have an old valve on the table, I use that to sometimes drive the insertion tool out from the guide because of the interference fit of the guide causes it to pinch a bit on the tool. The old valve is place in the chamber to pop it out.
The guides still need to be reamed to final size for best fit.
If you have any comments or improvements please share.
Thanks
Tom
So first of all I am replacing cracked stock guides and removed them. The process I use is to cut the guide flush on the chamber side of the guide. I use a piloted counter sink (sorry no pictures). Then I put in oven and heat to 450F use "finch" tool to remove old guides hitting from inside the chamber towards the outside. I find I have had better success than going into the chamber.
Once removed I use gage pins to measure the diameter of the guide holes in the head. .5155 is what this head was. I then ordered oversize guides and on my lathe turned them down to .518.
Here are the items I used for install. The specifications for a 140 head calls for the guide to be inserted and stop .96" from the chamber surface. (if you zoom in on the pic you will see the specifications) and the exhaust 1.05"
I made two aluminum stops one for the intake and one for the exhaust. This way when I am inserting the guides they will stop at the correct amount. I put the guides on the freezer over night and then just before I install them I put them in a cup and use air duster ,held upside down to discharge liquid refrigerant into the cup to keep the guides as cold as possible.
I could not take pictures of the actual process because you have to move fast, before the head cools. Remove 450F head from oven and put on heat proof surface. Take a guide and put on finch tool with hardened washer to act as stop. Spray guide with a bit of lube and insert till it contacts stop.
You will notice that there is a difference in height between the intake and exhaust guides they are not all the same height.
You might also notice I have an old valve on the table, I use that to sometimes drive the insertion tool out from the guide because of the interference fit of the guide causes it to pinch a bit on the tool. The old valve is place in the chamber to pop it out.
The guides still need to be reamed to final size for best fit.
If you have any comments or improvements please share.
Thanks
Tom