peening magnesium

blabla914 · 03-04-2008, 07:43 AM

I've done several searches on the oil spray jets and their installation. I had these jets installed by a machine shop in the area and two jets fell out in about 10000 miles. I don't want to go into the details of what's going on with the shop. It is being handled. In the mean time I am fixing my motor. The case is a mag 1R case from a '69 E motor.
How would you handle peening these jets in? You can see what the machine shop tried to do. They gave it one shot where the counterbore in the case is even with the squirter.

Obviously, this didn't work so well. I can't make it look like factory because my case doesn't have the boss for the squirter. It looks like the factory boss was peened in with a tool. Since I don't have the boss I couldn't do that even if I made a tool since the case web isn't flat.

Thank you to Henry Schmidt of Supertech for posting that photo.
The good news is I'm not going to rely on peening 100% to keep them in. I will also be holding them in with loctite sleeve retainer and primer as recommended in the factory bulletin. I know some machine shops don't even peen them these days relying only on the loctite. I'm not convinced there isn't some value to a mechanical method as a backup. The problem is I'm afraid I'm just going to bust off a chunk of the mag over top the squirter. I mean it's mag. It doesn't bend so good. Do you think I could use a punch with a flat tip in 2 or 3 places about 0.100" away from the hole just to close the top of the hole a bit to tighten the fit?
Any other suggestions are certainly welcome.
Thanks for your help.
Kelly

MatthewBrum · 03-04-2008, 10:02 AM

I peened my AL case with a small round punch in three spots evenly spaced. You just have to make sure that you remove any burrs or flakes that may occur from the peening process. Another thing to consider is the fit between the piston squirter bore and piston squirter. I believe it should be a slight press fit where you can almost push the squirter in by hand. When the proper fit is used only slight deformation is needed to keep the squirter in. If there is a lot of clearence I would peen a little more to ensure the squirter is captured.

cgarr · cgarr's Garage

How did you know they fell out, Oil pressure tip you off?

blabla914 · 03-04-2008, 01:22 PM

The oil pressure made a fairly big and sudden drop. One day it went from easily 1 bar/1000 rpm hot to just 10 psi/1000 rpm. I also noticed that there was now a much larger difference between idle oil pressure and oil pressure at 2000 rpm. An engine oil analysis came back clean which told me all the bearings were OK. At this point I suspected a squirter had fallen out. Then I found a squirter in the sump during an oil change.
Not long after that oil pressure suddenly dropped again to under 10 psi/1000 rpm. Idle oil pressure hot was not measurable on the gauge, but the light didn't come on. Turbo banjo fittings with the reduced hole got things back to 10 psi/1000rpm for the rest of the summer. Another engine oil analysis also came back clean.
When I tore it apart I found two squirters had fallen out. One is still MIA.

Kelly