Hello people,
I have a few questions about my cyl head and I was wondering if people could help me.
1) is my cylinder head unleaded or not?
Unfortunately I haven't figured it based on the casting number, it's a 12G940 but next to the thermostat it says 22K6 so I haven't found any info based on that. It only popped up in a dutch forum but no info there.
IMG_6515.jpg 62.53K 0 downloads
I also read on a post here that a fair indication is whether the oil gallery plug near the thermostat housing is brass or riveted and in my case it is brass (you can see it in the photo). Does that mean it is leaded?
2) Is it normal for exhaust guides to be recessed in the boss?
I am attaching a picture for reference.
IMG_6511.jpg 41.7K 3 downloads
This definitely doesn't look normal to me. I did check the installed height and it seems within specs.
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3) What is the best time to do modifications?
I will be taking the head to a machine shop to change out the valve guide (got the manganese bronze ones), install unleaded seats if necessary and skim the head to get the desired CR.
At what point is it best to modify the head? Would it make sense to punch out the current valve guides myself and work on the head (which would give me more space as well and make it easier to form the boss) and maybe once it is back from the machine shop I could do some touch up work?
Thanks,
Nik