Article 2987 - Engine Detonation

TSB #146 - August 7, 1970
SUPERSEDES TSB 133, ARTICLE 2135
(Vehicles Equipped with 429-2V and 429-4V CID Engine [Except 429 CJ and 429 SCJ] - 1970)


In cases of verified engine detonation, confirm use of premium quality fuels (per Owners Manual specifications). Once premium fuel has been assured and the detonation is still present, refer to the following three-step procedure to correct the condition.
    STEP 1. After confirming premium quality fuel usage, revise initial timing to TDC. Render the hot portion of the hot and cold induction system inoperative by fastening the air cleaner door, which is located in the air cleaner snorkel pipe, in the "down" or "heat off" position (so that carburetor air is unheated). Road test the vehicle, including high speed operation at expressway speeds. If the condition persists, proceed to Step 2.
    STEP 2. Remove the distributor from the vehicle and disassemble per 1970 Car Shop Manual, Vol. 2, Group 22-02. Reassemble the distributor using the following parts from service stock:

New Part NamePart No.Class
Primary SpringC5AZ-12192-FC
Secondary SpringC5A2-12192-FC
Vacuum SpringB7AM2192-BC
Vacuum StopC5GY-12202-AC
Cam and Plate Assembly (10°)C5AZ-12210-BB

Discard all replaced pieces. Place the newly assembled distributor in Rotunda Distributor Tester (refer to 1970 Car Shop Manual, Vol. 2, Group 22-01) and set vacuum and centrifugal advance characteristics in accordance with specifications given below:

VACUUM ADVANCE
Set test stand at 0° at 1000 distributor RPM and 0 inches of mercury.
VACUUM
(Inches of
mercury)
ADVANCE
(Distributor or
camshaft degrees)
MAX. ADVANCE
(Camshaft degrees)
50-1/29-1/2°
100-1-3/4@25"
153-5-3/4mercury
206-8-3/4
257-9-1/2


CENTRIFUGAL ADVANCE
Set test stand to 0° at 250 distributor RPM and 0 inches of mercury.
DISTRIBUTOR
RPM
ADVANCE (Distributor
camshaft degrees)
MAX. ADV.
(Camshaft degrees)
3500-1/2
5000-1/211° @
8501-31600 RPM
10002-1/2 - 4-1/2
1500
2000
7-3/4 - 9-3/4
8-1/2-11


Once distributor has been calibrated, reinstall in vehicle and set initial timing at 6° BTDC. Road test vehicle, including legal high speed operation. If condition persists, at expressway speeds, proceed to Step 3.
    STEP 3. Remove cylinder heads and replace the head gasket with a thicker gasket, Part Number C8SZ-6051-A, Class A.
NOTE: After installing thicker head gaskets, the valve lash clearance must be checked per the procedure in the 1970 Car Shop Manual, Vol. 2. Check for possible binding in intake manifold bolt holes when thick head gaskets are installed in place of thin gaskets. If necessary, open up bolt holes in manifold 1/32".

Confirm initial timing at 6° BTDC. Road test vehicle to confirm correction of complaint.

Production changes have been incorporated on engines built after November 15, 1969.



WARRANTY STATUS
STEPOPERATIONTIMEDEALER CODE
1SP-12127-A700.6 hrs.Basic Part: 6051
Code: 11
2SP-12127-A1-701.7 hrs.Basic Part: 6051
Code: 11
3SP-12127-A2-70Ford 6.7 hrs.
TBird 7.0 hrs.
Torino 6.5 hrs.
Basic Part: 6051
Code: 11

ADD FOR POWER STEERING
    Ford/Torino - 0.2 hrs.
ADD FOR POWER STEERING AND A/C
    Ford - 0.3 hrs.
ADD FOR AIR CONDITIONING
    Torino-TBird - 0.3 hrs.

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