Das Heinkel Forum für Perle, Roller und Kabine

I am replacing the valve guides in my A2 with a pair of standard bronze guides from the Club. The newer bronze guides are slightly larger, OD about .1mm greater than the original steel ones. Is this correct? Could they be oversize ones sent in error?

Hi Max 57
i have also renewed a few of the bronze ones from the club and they also were a bit bigger/larger at the outside. I could not press them in correct so i made them a bit smaller on a turningmachine once and on an ordinary standing drillmachine with sandpaper the other time. Then i heated the cylinderhead up to about 180-200 degrees centigrade in my baking oven when my wife wasn't at home and put the bronze guides into the freezer. Then i had no problems to press them into the head. What you also need is a rheamer to widen the inside holes a bit, otherwise the valves dont fit into the new guides.I don't know if they have got any other sizes of the bronze guides but i always got the same ones as you got. I hope i could help you and you understood my bad english. Don't be shy to ask more questions.
Wish you big success
Werner Schlüter

Why are bronze guides provided by the Club? Are they considered superior to steel guides?

I dont know why they use bronze, but nearly all modern engines have bronze guides fitted. Maybe the ones they sell are modified ones from other engines??

I can push the standard iron valve guide with my thumb. So the bore is too large for standard guides. The new bronze ones are .05mm OD larger than the bore. The bore is not very smooth when I look at with a magnifying glass, but I would think that when the aluminum cools and shrinks around the bronze guides the irregularities would change to fit the bronze guide. If I heat the cylinder head in the oven, and can push the cold bronze valve guides into place with a gentle tapping(protecting the bronze guide with an improvised tool) I think that would show a correct fit, that is, the new guides are the right size for the bore. Does this make sense?

I am sure it will work if it is possible to press it in wit low power( only tapping). If you have to to use a bigger tool and hammer it in you'll destroy the cylinderhead. (read my reply on facebook)
Werner