At 05:19 PM 7/12/99 -0700, you wrote:
>Jim,
>
>The date would be handy in case some of the recommended substitute parts become
>invalid, we know how old the info was. Also easier to track if we get any
wiser
>as we age. Doubtful. Through it in, or approx. if it's a combo.
Will add the dates back in, I removed it on the first half until I got
to thinking---.
>
>On your valve seals. Just had an estimate for 'doing' my 260 heads (or my
289's,
>if there is much of a difference. Just the casting edges at the exhaust
side are
>open on the 260's. The valves and chamber volume are the same. The
springs are a
>little lighter, but they would be replaced anyway.
>
>
>In discussing this with the machinist I learned a lot. I had asked for valve
>seats for the exhaust, 10 deg keepers, larger stainless valves with chromed
>shafts, silcon-bronze guides, uncertain about the push rod guides, as my
heads all
>have the non-rail guides.
On my Tiger II original 289 Heads there is a small hole that the pushrod
passes through. This is the "guide" for the pushrods/rockers. The later model
heads had bigger holes and required "rails" on the tip of the rocker to locate
the rocker to the valve.
Be careful of adding extra guide plates if you have non-rail
rockers. You may
have interference between the added guide and the original hole. May have to
bore the
hole bigger.
The old heads had hardened push rods to allow the cast iron hole
"guide" to
be used. The later model with rail rockers had soft push rods. You MUST use
hardened push rods with guide plates.( Otherwise the push rods wear into after
about 15k miles)
He likes a set of split guides under the new screw-in
>ARP studs. They get welded together after mounting because the centers are
not a
constant. Be sure that the guides are the correct size, some aftermarket
racing guides are designed for 3/8 push rods which are sloppy for the stock
5/16 push rods.
I hope he uses a TIG only, as a MIG or stick welder will cause a lot
of slag
to get on the new heads. Need to clean REAL good. If this welding happens
after
the valve seals are in then you need very good luck to prevent damage to the new
seals due the sparks/slag.( and maybe a few chunks of metal stuck to the
valve stems
and springs.
> Thinking of my roller-tip Cranes (not needle bearings/no added
>height).
I use Harland Sharp roller rockers on my 351C. I have been completely
happy with this brand. Just examined all the rockers the other day. No sign
of wear. I did have to modify the sheetmetal insert around the 351C valve cover
breather to prevent interference with two of the rockers. Not sure about the
smaller 260/289 valve covers and roller rockers clearance.
In discussing seals he recommends stem seals (teflon/steel inserts in
>the head machined pocket) for the intakes, as that's were the vacuum is.
For the
>exhaust he uses the umbrellas only to get the oil back on the guide. Don't
need
>both.
Both seals on the same valve will not work as I noted in my problem
on my 351C. I will never use steel/teflon or rubber/teflon again. The
umbralla seals work fine and are easy to change at low cost.
>One on intake, one on exhaust. Pocket clearance the exhaust, polish
>chambers, magna flux first, heavier springs and light flat cross section
springs
>in the center for stabilizing.
The flat springs are dampers and work, however they add a lot of heat
to the oil as they work by friction. Get a set of Titanium springs for $3000
and you do not need a damper.
Not really dual springs. He cleans out the and
>runners too, and some other goodies like he has a huge plate he bolts the
heads to
>for a flat finish cut. Cute.
Sounds like a good idea if a plate is used when the valve seats are
ground.
A good 3 angle valve grinding helps HP a bit as well.
>
>Bill ran the same as buying a new set of Edelbrock or Twisted Wedge.
>$1,000/pair. What you think?
>
If you are going to spend $1000 plus then go with the new heads,
there are numerious brands available, most with bigger valves as well.
If you want to go cheap and still improve your breathing then
get a pair of rebuilt 351W heads, D00Z-6050C or equivilent. I did that
on my 289 (pre 351C time). Carfully measured the CC of each head and then had
the pair machined down so both heads had similar CCs. This was also to
raise the compression a bit as these are open chamber heads. Bought a tool
and did the screw in stud mounting on a drill press. Used PAW studs ( NEVER
AGAIN) that were shit! After 5K miles a stud broke and I noted that the rockers
had worn most of the other studs almost half way through. Changed to
Mister Gasket and no more problems. Used cast pop up pistons (from PAW) to
make the
compression 10.4 to 1. Worked well with 93 octane gas. The open chamber
heads do
not ping as easy as the closed chamber heads. The total head bill including the
tool to do the screw in studs was under $500. Had much bigger valves as well.
I did a slight port clean up with a router containing a grinding
bur. Cost more
at the eye doctor to remove the steel from my eye than the heads cost, but
insurance
covered most of the doctor bill.
Used Marosco push rod guides and 271 Red LockTight for the studs.
Used new
hardened push rods as the push rods need to be a little longer for the 351W
head.
The valve stems and springs are taller than the 260 or 289.
The least hassel is to use Winsor Junior or similar after market heads.
Save your originals in case you have a restoration nut buy your Tiger sime day.
>Steve
James Barrett Tiger II 351C and others
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