Engine - Accelerated Camshaft Wear Prevention
GROUP 11Engine
Bulletin Number
11 07 88 (1767)
Montvale, NJ
December 1988
Technical Dept.
SUBJECT:
Camshaft Wear
ENGINES:
All Motronic M30
Situation:
Accelerated camshaft wear can occur for the following reasons:
^ Loose oiler pipe "banjo" bolts.
^ Incorrect engine assembly.
^ Infrequent oil service.
^ Excessive engine oil dilution.
^ Severe engine duty cycles.
Loose Oiler Pipe Banjo Bolts
It is absolutely essential that all available oil pressure be concentrated in the cam oiler pipe.
Whenever the headcover is removed, the banjo bolts should be checked for proper tightness. If the bolts are found loose, the sealing crush washers above and below the oiler pipe must be renewed prior to banjo bolt retorquing. Reoccurrence can be avoided by cleaning the banjo bolt and supply bore threads and applying a small amount of blue Loctite(R).
Engine Assembly
During cylinder head installation, care must be exercised when installing the valve train oiler pipe. Prior to installation, lay the oiler pipe with the oil spray holes facing up (inverted). Verify that located between one intake and one exhaust cam lobe. Install the oil direction.
Caution:
The M30 oiler pipe is not symmetrical! Incorrect installation will result in severe and rapid camshaft wear.
Oil Service
Engine oil services must be performed in strict accordance with specified intervals whether it be fixed mileage increments or the service interval indicator. Under severe driving conditions it is strongly recommended to increase the number of oil services.
The correct grade and viscosity for the prevailing season must always be used. Correct viscosity/temperature information can be found in S.I. 11 15 84 (939).
Oil Dilution
When an incident of camshaft wear is encountered, the engine should also be inspected for conditions which promote abnormal oil dilution.
For example, a leaking fuel injector or cold start valve is a constant dilution source during periods of shutdown. Further, unapproved modifications to the coolant NTC sensor circuit can result in cold running enrichment in excess of the required (useful) amount. Conditions such as these prevent the motor oil from properly lubricating the camshaft and other internal engine parts.
Severe Duty
Frequent cold starts and short distance traffic conditions without achieving operating temperature, or extended periods of high rpm with perhaps high load constitute the most common types of severe engine duty. These and other extreme conditions can promote and accelerate camshaft wear.
When replacing the camshaft of a Motronic M30 engine which is subjected to severe duty cycles, it is now possible to install a camshaft having a special "blued" hardening treatment which extends the components durability under continuous, adverse conditions.
Availability of the hardened camshaft will be provided via the Regional Technical Department. As the need arises contact your facing Regional Technical Department for the camshaft, using the part numbers listed in the Parts Information section below.
Regular M30 camshafts can be ordered in the standard way through the National Parts System.
After installation of the special hardened camshaft, we would appreciate the completion and return of the enclosed: "M30 Hardened Camshaft Evaluation" form.
Parts
Information:
The special severe duty camshafts are available through the regional offices, using the following special part numbers:
733i/A 9/81 - 1/84 11 31 9 061 216
733i/A after 1/84 11 31 9 061 217
735i/A 11 31 9 061 218
Please do not attempt to order these part numbers thru the National Parts System. The numbers are frozen and will be superseded to the conventional camshaft part number.
Warranty
Status:
Information only.
Warranty
Status:
Covered under the BMW New Car Limited Warranty of 3 Years/36,000 Miles.
Defect code: 00 00 61 49 00
Labor operation: 00 50 168
Labor allowance: 11 FRU