Tech FAQ's
 |
Here at CB Performance Products, we get thousands of emails every
week. And since we can't ever seem to have time to answer each
one individually (although we try!), we put together some of the
most Frequently Asked Questions.
Please take the time to see
if your question has been answered, before proceeding to the contact
page. |
Q:
How do I adjust my valves?
A: Adjust your valves with the engine cold and the cylinder at
top dead center. Clearance between the rocker arm and valve stem should
be .006in (.15mm).
Q: I have just bought a new set of points, what should I set them
at?
A: The breaker point dwell should be set at 44' to 50'. If you
don't have a way to check dwell, set the point gap to .016in to .020in
(0.40 to 0.50mm).
Q: What is the best way to synchronize my dual carburetors?
A: Purchase a Weber or
Dellorto Tech Book, which you
can find available in our online VW
Library Warehouse. Complete tuning instructions are included.
Q: What should I set my ignition timing at?
A: Street applications range from 28' total advance to 30' total
advance. Off road applications will vary from 28' total advance to 34'
total advance.
Q: What type of oil filter is needed for a CB Performance filter
type oil pump #1791?
A: Our #1703
Oil Filter will fit, but if you need to get the part ASAP, then
head to your local Auto Parts Store and purchase a FRAM #PH-3600.
Q: How much more horsepower can I expect by installing a CB Performance
Turbo Injection Kit?
A: With a moderate amount of boost, 8-12 lbs, you can DOUBLE
your engines horsepower.
Q: What can I expect to gain by installing a CB Performance Ultra
CFI Injection Kit?
A: You will gain increased throttle response, improved low-mid
and high end RPM horsepower. We, on average, see about 10-15% horsepower
increase over a comparable size of dual carbs.
Engine
Specifications and Torque Recomendations
| Crankcase
nuts
Crankcase 12mm nuts . . . . . . . . . . . . . . . . . . . 25
ft/lbs.
Crankcase 8mm nuts . . . . . . . . . . . . . . . . . . . . 15
ft/lbs.
Cylinder head nuts
Stock 8mm studs . . . . . . . . . . . . . . . . . . . . . .
. 18 ft/lbs.
Chromoly 8mm studs. . . . . . . . . . . . . . . . . . . . 23
ft/lbs.
10m studs . . . . . . . . . . . . . . . . . . . . . . . . .
. . . 25 ft/lbs.
Connecting Rod Bolts
Stock T-1 . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . 25 ft/lbs.
UniTech. . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . 29 ft/lbs.
Uni Tech HD w/ARP 3/8" bolts . . . . . . . . . . . . 45
ft/lbs.
CB H-Beam/ARP Bolts . . . . . . . . . . . . . . . . . . . .
29 ft/lbs.
(consult with other mfgs)
Generator Pulley. . . . . . . . . . . . . . . . . . . . . .
. . 40 ft/lbs.
Spark Plug. . . . . . . . . . . . . . . . . . . . . . . . .
. . . 25 ft/lbs.
Oil Drain Plug . . . . . . . . . . . . . . . . . . . . . . .
. . 25 ft/lbs.
Rocker Arm Shaft Nut. . . . . . . . . . . . . . . . . . . .
22 ft/lbs.
Clutch Pressure Plate. . . . . . . . . . . . . . . . . . . .
22 ft/lbs.
Stock Gland Nut. . . . . . . . . . . . . . . . . . . . . . .
.250 ft/lbs.
Racing Gland Nut. . . . . . . . . . . . . . . . . . . . . .
.350 ft/lbs.
Valve Adjusting Nut . . . . . . . . . . . . . . . . . . . .
. 18 ft/lbs. |
How
to calculate Deck Height in CC's
the
inch system
Forumla
- Bore (in.) X Bore (in.m) X Stroke (in.) X 12.87 = Deck in CC
Example - 90.5mm = 3.563" X 3.563" X .060"
X 12.87 = 9.80cc
1mm = .03937
or
the Mm system
Forumla
- Bore (mm) X Bore (mm) X Deck Height (in.) X .01996 = Deck in CC
Example - 90.5 X 90.5 X .060" X .01996 = 9.80cc
|
Deck |
Piston - Deck Height in CC's |
85.5 |
87 |
88 |
90 |
90.5 |
92 |
94 |
.030 |
4.36 |
4.51 |
4.62 |
4.83 |
4.88 |
5.04 |
5.27 |
.035 |
5.16 |
5.34 |
5.47 |
5.72 |
5.78 |
5.97 |
6.24 |
.040 |
5.79 |
6.00 |
6.13 |
6.42 |
6.49 |
6.71 |
7.00 |
.045 |
6.71 |
6.95 |
7.11 |
7.43 |
7.52 |
7.77 |
8.11 |
.050 |
7.28 |
7.54 |
7.72 |
8.07 |
8.16 |
8.43 |
8.80 |
.055 |
8.03 |
8.31 |
8.51 |
8.90 |
9.00 |
9.30 |
9.71 |
| .060 |
8.72 |
9.03 |
9.24 |
9.66 |
9.77 |
10.09 |
10.54 |
.065 |
9.46 |
9.80 |
10.03 |
10.49 |
10.60 |
10.96 |
11.44 |
.070 |
10.15 |
10.51 |
10.75 |
11.25 |
11.37 |
11.76 |
12.27 |
.075 |
10.90 |
11.28 |
11.55 |
12.08 |
12.21 |
12.62 |
13.17 |
.080 |
11.64 |
12.06 |
12.34 |
12.90 |
13.05 |
13.48 |
14.08 |
.085 |
12.33 |
12.77 |
13.06 |
13.76 |
13.82 |
14.28 |
14.91 |
How
to calculate Engine CC's
Forumla
- Bore (mm) X Bore (mm) X Stroke (mm) X 3.1416" = Engine cc
Example - 90.5 X 90.5 X 69mm X 3.1416 = 1775cc
(to get the Volume of 1 cylinder in CC divide by 4)
Example - 1775 ÷ 4 = 443.75
|
Bore |
Stroke - Engine Displacement
in CC's |
64 |
69 |
74 |
76 |
78 |
82 |
84 |
77 |
1192* |
1286* |
1378 |
1415 |
1453 |
1527 |
|
83 |
1385 |
1493* |
1601 |
1644 |
1688 |
1774 |
1818 |
85.5 |
1496 |
1584* |
1699 |
1745 |
1791 |
1882 |
1929 |
87 |
1521 |
1640 |
1759 |
1806 |
1855 |
1949 |
1997 |
88 |
1556 |
1678 |
1799 |
1848 |
1898 |
1994 |
2044 |
90 |
1628 |
1755 |
1882 |
1933 |
1985 |
2086 |
2138 |
| 90.5 |
1646 |
1776 |
1903 |
1955 |
2007 |
2110 |
2160 |
92 |
1700 |
1835 |
1967 |
2020 |
2074 |
2180 |
2232 |
94 |
1776 |
1915 |
2052 |
2109 |
2165 |
2275 |
2332 |
*1192 = 1200cc
Engine |
*1493 = 1500cc
Engine |
*1286 = 1300cc
Engine |
*1584 = 1600cc
Engine |
How
to calculate Compression Ratio
| Forumla
- |
Head
cc = Deck cc = 1 cylinder volume |
Head
cc + Deck cc |
| Example
- |
69mm
X 90.5mm engine size = 1775 ÷ 4 = |
|
| |
.060"
Deck = |
|
| |
Head
= |
|
| |
|
|
|
|
Compression
Ratio Chart
1300, 1500, 1600cc Type I, II & III
Single & Dual Port Heads CC in Head - Depth of Flycut
| Bore
X Stroke |
37cc
.140 |
39cc
.120 |
41cc
.100 |
43cc
.080 |
46cc
.050 |
51cc
stock |
Engine
Size |
| 85.5
x 69 |
9.68 |
9.31 |
8.98 |
8.67 |
8.25 |
7.64 |
1584 |
| 85.5
x 74 |
10.32 |
9.92 |
9.56 |
9.23 |
8.78 |
8.13 |
1699 |
| 85.5
x 78 |
10.82 |
10.41 |
10.03 |
9.68 |
9.20 |
8.51 |
1791 |
| 85.5
x 82 |
11.32 |
10.86 |
10.49 |
10.12 |
9.62 |
8.90 |
1883 |
| 87
x 69 |
9.91 |
9.54 |
9.20 |
8.88 |
8.45 |
|
1640 |
| 87
x 74 |
10.56 |
10.16 |
9.80 |
9.46 |
9.00 |
8.33 |
1760 |
| 87
x 78 |
11.08 |
10.66 |
10.28 |
9.92 |
9.43 |
8.73 |
1855 |
| 87
x 82 |
11.60 |
11.16 |
10.76 |
10.38 |
9.87 |
9.13 |
1950 |
| 92
x 69 |
10.76 |
10.36 |
10.00 |
9.66 |
9.19 |
8.52 |
1835 |
| 92
x 74 |
11.46 |
11.04 |
10.64 |
10.28 |
9.78 |
9.06 |
1968 |
| 92
x 78 |
12.02 |
11.57 |
11.15 |
10.77 |
10.25 |
9.49 |
2074 |
| 92
x 82 |
12.59 |
12.12 |
11.68 |
11.28 |
10.73 |
9.93 |
2180 |
_______________________________________________________
If you dont see it here you may always email our tech department at
techdept@cbperformance.com. |
