Gaetke wrote:
>
> I guess I've found an opportunity to show my ignorance. I know
>little to
> nothing about cylinder heads, and their various options. I guess this is
> the time to learn, being in the market for one, so here goes:
>
> What are the advantages of (and what type of driver should get):
>
> bronze guides?
>
The bronze guides are a more generic term for the guides that are found
in your car. I'm not exactly sure what the various types are, but
typically, you rebuilder should be familiar with the content of the
guides. The Porsche motors I'm familiar with use the premium guides,
because heat is such a problem. The silicon bronze phosphorus, or just
phosphorus bronze guides are high wear, long life guides, and are
designed with self-lubrication in mind. You should be able to get these
guides for around $10 or less each. You may not have to replace the
guides. You should be able to lift the valves a few mils off the valve
seat and rock the valve stem tip back and forth. Your better MGB
manuals will have the max play listed. Or, you can take the heads to a
TRUSTWORTHY machine shop and they will do the diagnosis for you.
> hardened seats?
>
Earlier MGB engines ( someone may know the exact year(s) ) used seats
that were designed with lead containing fuel to be used. Now, someone
on the list might be more proficient on this topic (I'm sure there is),
but I believe that the problem with the original seats is that you had
problems with seat regression, where the seats wore away ??? The seats
on my engine are original with 70k miles on them. No problems yet. You
have the hardened seats installed when you have the heads rebuilt, so
you can use the unleaded fuel.
> stellite exaust valves?
>
Last longer than standard valves, but you may not need them. If you
valves are fine, reuse them. The water pumper cars are not bad on the
valves/guides/etc.
> Do valve seals just cut oil consumption, and do they require any of
>the
> above modifications to be made practical? Worth it?
>
Definitely get new valve seals when you get work done. They are cheap
and prevent smoke at startup. The seals basically prevent too much oil
from getting down the stem and eventually into the combustion chamber.
These items do wear out, and especially when the car is not used much.
> What does one do to a head to make it ready for unleaded fuel?
>
The hardened seats are all you need for safely running unleaded fuel.
Some question the use of the hardened seats and say regular seats are
fine with unleaded fuel.
> If the main advantage to all of these things is a longer time between
> valve jobs, how long does a valve job with none of these features last?
> with all of them?
>
The durability of the valve job is, in my opinion, more related to the
quality of the work. I had some work done on my brother's Rover V8.
Horribly ground seats with varying seat width. We took the heads to a
better shop, paid more, and got a superb three angle valve seat job and
workmanship to last a LONG time. The valvetrain is not under great
stress, given the fact it is not a horsepower monster, and lift is not
insane, but I could be wrong here.
> If it matters, I'm not going to put a ton of miles on this car each
>year,
> but those miles will include four drives of 900 miles to and from school,
> so my primary concern is failure during a long drive. In fact, that will
> make up a large part of the mileage put on the car each year. How does
> that effect what I should be done to my head?
>
Nothing. You either have the head built up right or you don't.
Shortcuts don't pay. I would not think that a cylinder head is
something that plays greatly in the reliability game. Find a reputable
shop and they will build up a head that will last, oh, a good 75k miles,
I guess. Get the 3 angle valve seat job, and do what they recommend as
far as replacement and refurbishing is concerned.
> I want long and detailed answers! :) I know some of you have to be
> passionate about cylinder heads... I feel like I need my own head
> magnafluxed (couldn't resiste the pun).
>
Don't know if heads necessarily need to be magnafluxed, but I have heard
of heads cracking. They are made of cast iron, so they're pretty tough,
but magnaflux wouldn't hurt.
Like I said before, I can't emphasize how important it is to get the
work done right. You can spend $200 on new guides, valves, seals, etc.,
but done improperly, you will find yourself doing the job over again. A
good shop may be able to use your valves again, save you money, and
you'll never hear a peep out of the heads.
Jay
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