Os Speed quick question
 

whats stock shimming on speed? and secondly if preffered what would you run, magnesium or aluminum head in 80* heat? thanks

Stock shimming is one copper .1mm and one silver .2mm for a total of .3mm.

Aluminum head ALWAYS unless you're trying to keep heat in. The Mag heads don't cool as well.;)

thanks Jammin, now sorry but i forgot, which is the aluminum the circle one or the black and red cut one? sorry there both sitting here just curious

The circular one is the AL, the red and black one is the mag.;)

much appreciated! and is the aluminum really a better cooler? i have them both in hand and the mag feels much lighter. the person i bought this from said run the mag in hot, aluminum in winter as it holds heat. but i respect your posts on here so any advice is well recieved

I've never run the mag head, but the reason they switched back to aluminum was because it cools better. No body really uses mag heads anymore. They are lighter, but not as good for cooling.;)

The mag head was a failure, thats why they discontinued it. It wont hold enough heat in the winter and gives you a false sense of security in the summer. Stick with aluminum.

So it cools too well? Maybe that was it. I have it backwards. Anyway, Mag heads don't work well. Stick with aluminum.:nod:

yep, made it hard to tune correctly. i have some new left over os speed mag heads if anybody wants to trade for new aluminum speed heads;)

Ah I see.:nod:

The Mag head did not diddipate heat as well. Magnesium, being less dense than aluminum was a great tuning tool as it lowered the weight of the motor at the highest point (the head). Unfortunately, magnesium's lower density was its downfall. Materials that are less dense DO NOT conduct heat as well. If you temp'd the Mag head motor, it may read 245*F, but temp it at the case and you would get 310*F. The mag head just didn't dissapate the heat. Most people abandoned the Mag head in favor of the Aluminum version. If you temp the aluminum head, you would get 245*F, and about 260*F at the case. Much better:)

Magnesium actually cools so well you can’t keeps heat in the motor, only to be used in extreme OAT’s. Besides it doesnt have the strength of the Aluminum head.

And you dont temp the Head, you Temp the button that why the temp guns are made to fit right above the glow plug. All the cooling head is there for is to help dissipate the heat from the engine.