Head dowels damn tight

[rmcdonnell]

Hi Folks,

After a year or so of not fixing the car: (it got cold and dark) I've started on the fun of replacing the head. I offered the head to the block without gasket, to check alignment on a hole near the water jacket, but the dowels that locate the head seem to be extremely tight: and it's rocking on them, even if I push down with a fair amount of weight: is this normal?

Do I have to bolt the head down to get these dowels to go in...?
I remember it being a pain to get the head off, but that seemed fair at the time. With clean parts I thought the head would be a "snug" fit on the dowels, not need pounding on!

Any reason why the dowel holes in the head cant be relieved a tad.? Do these pins come out of the block readily?

Cheers
Rissole

[ditch68]

Yes, they should come out. Shoot some PB Blaster or other penetrant, and use a vice grips with a piece of leather to turn them without marring them, there may just be some corrosion on them or cooked oily gook.

Clean the bores with a brass brush (like a rifle bore brush on a drill) and clean the dowels and grease them and they should be better.

Jeff

[rmcdonnell]

I don't think I need to get them out of the block, and the dowels are clean, I wiped around them with very fine oiled sandpaper (400 grit), and put a spot of clean oil on them. They measure 8.0 dia. They have a 45 degree chamfer at the very top.

I've got the head clean, and the mating dowel bores look clean and measure 8.02mm. Wondering if I should ream them out to 8.05 or 8.1 even.

Can't quite see why the alignment dowels need to be such a close tolerance, as long as the gasket can't creep about, I'd of thought that the exact position of the head wouldn't matter within say 10 thou, and once it's locked down, it's not going anywhere...

cheers
R