Randall,
How do you know which heads you have? Did the have casting numbers as
american cars do or do you just measure from the port to the block?
Thanks,
Mike
> From: "Randall" <ryoung@navcomtech.com>
> Reply-To: "Randall" <ryoung@navcomtech.com>
> Date: Tue, 18 Apr 2000 10:28:29 -0700
> To: "Triumphs (E-mail)" <triumphs@autox.team.net>
> Subject: RE: Head modification
>
>
> Michael :
>
> I think I saw a post saying you were talking about a TR3...
>
> There are actually about a half-dozen different head castings, Kastner's
> warning applies primarily to the very early "low port" heads (at least 2
> different castings of these). If you have one of these, and want some
> performance, my suggestion would be to find a later head and intake
> manifold. The TR4A head, curved tube intake manifold, and HS6 carbs
> (required to make it all fit between the fenders on a TR3) are supposed to
> be good for 5-10 mid-range horsepower all by themselves, even with the lower
> CR ...
>
> According to an article written by Ken Gillanders at BFE, the stock
> high-port heads measure between 3.325" and 3.330" from the valve cover
> surface to the head gasket surface. He says to never remove more than .150"
> from these heads.
>
> However, well before you go that far, you will need higher octane gas than
> you can buy at the pump. My suggestion would be to only take .080" or .090"
> off the head, then use one of the thin .020" head gaskets available from
> BFE, Moss, etc. That way, if you find your CR is too high, you can go back
> to the .060" stock head gasket. Note that a change in head gasket thickness
> has a bigger effect on CR than shaving the head, because the area of the
> opening is larger. You should also grind the edges of the combustion
> chamber out to match the head gasket, as shown in Kastner's book, as
> otherwise the exposed sharp edge will increase the tendency to knock.
>
> I assume you're putting in hardened exhaust seats all around, another
> worthwhile modification is to switch to the later exhaust valves with the
> smaller stem. There are special "changeover" valve guides available to do
> this.
>
> Don't forget to check that the head still clears the water pump housing, and
> the intake manifold still clears the edge of the block, after milling the
> head.
>
> Randall
>
> Michael Thompson wrote :
>>
>> Hello all,
>> I have burnt an exhaust valve seat and while the head is off
>> I would like
>> to do a little work on it, primarily shaving it down to increase the
>> compression. I have two heads, so I'm not too worried about
>> not being able
>> to go back to stock.
>> I have a good fast road cam installed and 87mm liners and
>> pistons. Both
>> heads I think are earlier versions. My main question is how
>> can I tell how
>> far to go with the plainer? Kastner's prep manual warns of
>> making the water
>> jacket weak on the earlier heads. Where can I measure this?
>
>
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