Head questions
 

I found water in my oil, and had been getting hydrocarbons in my radiator. I just removed the head on my '30 Town Sedan.

1) Can anyone tell me for sure if this is a stock head?

2) If I decide to remove some material for higher compression, how much is TOO MUCH before valve clearance becomes an issue?

Chuck

Re: Head questions
 

Attachment 257214OOPS! here is a photo.

Re: Head questions
 

Yes it is stock. I think you would have to remove too just to get a significant increase in compression.

Re: Head questions
 

Valve clearance won't be a problem, Stock pistons protrude about .030 out of the block. Machine the head until you have about .030 counterbore left and the thickness of the head gasket will be your clearance.
It peps it up pretty good. I have this setup on my 30 coupe.
On my 28 with aftermarket pistons that don't protrude I was able to machine it until the counterbore was completely gone, about .125.
Bill

Re: Head questions
 

be careful of the fit of a head gasket in the valve area if you start cutting. Look closely at the valve area of the head. The sides of the chamber are concave for less valve shrouding. As you mill the head, you are widening out the head opening in the valve area. Lay your gasket on there and see how much you can widen out before the fire ring begins to hang into the chamber. I have seen several expensive heads ruined because this mistake was made

Re: Head questions
 

If you want more compression buy a high compression head. Milling the stock head won't make that much difference. Mill it enough to make it flat and stop.

Charlie Stephens

Re: Head questions
 

Milling doesn't add much compression, but it can change the quench/turbulence and you will notice that.

Re: Head questions
 

Might check for cracks?buy high comp head you'll be happy you did!

Re: Head questions
 

Thank you all for the good input. So far, I'm just doing a quick fix and had to ask about cutting the head down, while it still can remain simple and cheap. When I have time (& $$$) to pull the engine and see what the mains and the crank look like, I'll decide what to do with the head at that time. It will depend on what I am doing down under. I believe I still have old babbit, and if turn out to be as worn as my stock valve guides, I'll be doing some more serious work, and probably get a 5.5 head at that time.

Meanwhile, I'm also doing new stock valves (and lapping), springs and guides, adjustment, and throwing her back together. I promised a young couple to be their chauffeur at their wedding in March. (So with a full time job, I'm pushing it!)

Re: Head questions
 

Ok, I tried looking up "quench/turbulence", and it looks complicated. So HOW will I notice that effect? Is it positive or negative from a driving standpoint? Changes in advance/retard? Changes in mixture? Faster burn or slower? You piqued my interest.

Re: Head questions
 

If you are going to pay some one to mill the head, why not put that money towards a good 5.5 or 6 head. I have milled a stock head to the max. It did help but not as good as a 5.5 head.

Re: Head questions
 

Look at your picture in #2 and notice that the small coolant hole under the water pump is right next to the edge of the combustion chamber. Milling this head could be a waste of money. I'd just buy the 5.5 head now, so you save money in the long run.

Re: Head questions
 

Have you checked the flatness of the deck of the engine or checked the engine for any cracks ? Look closely for cracks in the area between the valve seats and the cylinders.

Re: Head questions
 

Just read this. That water hole IS very close. I took my head in to the shop straight after work to head shop to just clean it up, blast it and check for level. I did NOT tell them to mill it down; just enough to level it.

Re: Head questions
 

Not sure if deck is flat. I didn't pull the studs yet. Isn't it unusual for the block to warp?

Re: Head questions
 

If that was my head and I was going to use it, then I'd tap the hole with fine threads and screw a fine thread bolt into the hole with locktite on it. Let it set up for a day, then cut the bolt and file it down flat with the head, and drill a new hole about 1/8" closer to the front of the head. Actually this should have been done before leveling the head, but still can be done as I described.

How does the head gasket line up with that small hole? I'm wondering why it's so close to the edge?

Re: Head questions
 

Tom, Here is a closeup of that hole. I will get my head back by Thurs or Fri. Then I will examine if the head gasket lines up with it. It is a bit close. Thanks for pointing that out. I could still opt for purchasing a 5.5 head.

I just pulled my oil pan for the first time since I owned it (I've only put 700 miles on her).
The engine is still in the car and I wasn't planning on rebuilding the whole shebang yet. I will start another post regarding doing the rings while I'm at it. I'm afraid to look at the babbit. It may fall to pieces. Then I AM stuck with a full rebuild, and I'll miss this wedding for a friend. Oh well. It is what it is! Can I rebuild it in IN THE CAR?

Re: Head questions
 

Dang, the pic again!Attachment 257456

Re: Head questions
 

Were your cylinders bored with a shotgun? :D

What is the bore? It might be time to sleeve them back to standard.

It isn't too bad to pull the engine, and for the work you want to do that's the way to go.

Rering or rebuild is much easier and better with the engine out of the car. You might get lucky and have good babbit.

Re: Head questions
 

Since you're under the gun timewise, just get the head fixed and back on. Threading and plugging that hole may well fix the whole problem anyway. Since it was running OK except for losing water it will surely last just fine through its wedding duties.