Joel Sell wrote =
. I have checked the =
archives on these
questions, and have read conflicting answers.
1) I've read that the =
1.4
rocker arms are good to use, but I've also read
that the "ramps are =
too
steep" and can cause valve damage.
Which statement is
true?
Joel =
I think that both =
statements are true.
You need to a stronger spring to keep the valve from free falling =
back onto
the valve seat because of the increased valve speed the ratio =
rockers
offer. I have seen the guides close around the valve due to the retainer =
striking the guide when ratio rocker are used on bug
engines
Bob
2)It appears that =
Type 1 rocker
arms are the way to go, but do I need to
buy just the rocker arms, or =
the
whole shaft and assembly? Will the T1
rocker arms just slide on my =
waterboxer
rocker shafts? I'm also planning on
getting the swivel foot
adjusters.
The type 1 rockers would be needed =
to use the
8mm swivel foot adjusters and the shaft size is the
same &nbs=
p;
my dyno testing of =
ratio
rockers on stock bug engines showed that the engine gained 6 hp =
with stock
springs above 3000 rpm and lost 1/2 of that when the heavy duty =
springs
where added. The vanagon engine does not need top end horse power it =
needs low
end and mid range increases the higher air flow at lower lifts provides
that.
I posted this back =
in june you
can see what the extra lift will give you in air flow then compare that =
to the
heads with the bigger valves.
I have been building a 2.1 engine for my =
own 85
camper and along with the usual upgrades of the reground OEM cam with =
more
duration, a little more piston skirt clearance and some major head work. =
I
decided to try a set of 3mm larger valves and larger harder valve seats. =
After
all the work to get larger valves and seats into a pair of AMC heads and =
doing
the high flow valve job I sent the heads out to have them flow tested on =
a flow
bench. The flow bench measures cubic feet of air moving threw each port =
at a
given valve lift. Some of you might recall that I had some flow =
testing
done when I started doing high flow valve jobs on stock heads =
with varying
degrees of porting work.
Flow bench test results
1 stock AMC head intake port
2 ported and polished AMC head stock valve =
intake port
3 Boston Bobs big valve AMC head minor =
porting now in
Bobs camper
=
CFM.
------------------------------------------------------------=
------- =
Lift &n=
bsp;
NO.1intake NO.2 intake NO.3 =
intake
.050 &n=
bsp;
24.8 &nb=
sp;33.0 =
34.8
.100 &n=
bsp;
47.1
52.2 &nb=
sp;
57.3
.200 &n=
bsp;
89.6
91.4 &nb=
sp; 108.4
.250 11=
5.4 116.=
7
132.8
.300
125.3
128.5
145.8
.350
137.6 14=
5.3 &nbs=
p;171.4
.400 =
; 144.9 &nbs=
p;
158.8
181.3 this is above stock =
lift
.450
147.8 17=
4.1
186.0
.500
154.6
179.0
190.6
Bob Donalds
as always all right reserved