MSD 84811 Installation

MSD Cap and Rotor

for GM LT-1 Engines 1995-1997

PN 84811

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Parts Included:

1 - Cap
1 - Rotor
1 - Isolator
2 - Rotor Screws
2 - Seals

IMPORTANT: Due to the number of applications and years that the LT-1 Cap and Rotor are used

on, it is highly recommended to have the Service Manual for your vehicle during this
installation.

DISASSEMBLY

1. Disconnect the negative battery cable.

2. Locate the radiator petcock and drain the coolant from the system.

3. Disconnect the MAF and IAC sensors. Remove the air intake ductwork and the MAF sensor.

4. Once the coolant is drained, remove the upper radiator hose from the thermostat housing.

5. Loosen the three bolts that secure the crankshaft pulley/hub assembly. Do not remove them
entirely at this time.

6. Remove the accessory drive belt by moving the spring loaded idler pulley. Use caution as this
pulley is spring loaded! The belt will slide off the pulley system and the idler pulley will settle
beyond its installed position.

7. Once the belt is removed, proceed with removing the pulley from the crankshaft hub by pulling
the three retaining bolts.

8. It may be necessary to remove the cooling fan. This is done by removing the four bolts and
disconnecting the wiring connection.

9. Disconnect the air pump power wires and remove the
air pump from its mounting brackets.

10. Disconnect the coolant temperature wiring sensor
located on the water pump.

11. Loosen the lower radiator hose clamp and the two heater
hose clamps at the water pump. Coolant will generally
still pour out of the hoses and water pump.

12. To remove the water pump, the power steering pump
may need to be removed. With a shorter extension, the
water pump bolt should be able to be accessed. There
are six water pump bolts. Once again, more coolant may
spill out.

13. At this point, you should be able to access the distributor
cap! Mark the location of each spark plug wire before
removing them.

14. Remove the vacuum lines (if equipped) and the distributor

4 - 3.5mm x 6mm Phillips Screws
1 - 8-32 x 1.125 Phillips Screw
1 - Clamp-Block
1 - Removal Tool

Figure 1 Removing the Original Cap.

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2 INSTALLATION INSTRUCTIONS

connector.

15. Using the supplied special tool and a 1/4" wrench, remove
the four screws that hold the distributor cap to the engine
and pull the cap off (Figure 1).

16. Remove the two rotor screws and pull the rotor off. At
this time, the isolator assembly will slide off the housing.

INSTALLATION

1. Locate and install the distributor-to-isolator seal then
position the isolator in place on the distributor (Figure 2).

2. Install the new rotor with the supplied hardware. The rotor
only installs one way. Make sure it sits squarely on the
shaft.

Note: It is recommended to use a threadlocker like Loctite

Blue on the two rotor screws.

3. Make sure that the Isolator-to-Cap seal is installed on the
isolator, then install the cap using the supplied Phillips
head screws (Figure 3).

4. Locate four metric Phillips screws that retain the cap
assembly. There is also a standard, slightly larger and
longer Phillips screw. This screw is used with the Clamp­Block that goes in the cap tab located between the wiring
harness and the coil wire tower (Figure 4).

5. Note that the Clamp-Block has two different thicknesses
(Figure 5). Some distributor housings have a machined
surface while others are cast. Determine which side works
best in your application to secure the top mount of the
cap. Once the direction is achieved, slide the Clamp-Block
into position and screw the standard Phillips screw into
position (Figure 5).

6. Connect the distributor connector followed by the coil
wire and spark plug wires. Ensure that each wire is in the
correct location (Figure 6).

7. The distributor is assembled. Reinstall all of the
components in the reverse order. It is recommended to
follow along with your vehicle’s service manual.

Figure 2 Installing the

Distributor-to-Isolator Seal.

Figure 3 The Isolator-to-Cap Seal.

CLAMP BLOCK
LOCATION

Figure 4 Clamp-Block Mounting Boss.

M S D   •   W W W . M S D P E R F O R M A N C E . C O M   •   ( 9 1 5 )   8 5 7 - 5 2 0 0   •   F A X   ( 9 1 5 )   8 5 7 - 3 3 4 4