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Serpentine Pulley Kit
Slipping Belt Problem on your Perkins 4.236 Solved

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     With more & more electronics being used on boats, the demand for more DC amperage is increasing. If you are using a high output alternator on a Perkins 4.236 with a standard belt, you already know the problem. Belt dust due to slippage and the constant worry of re tensioning the belt. The danger being, a slipping belt has a reduced life and could fail leaving the engine without the function of the fresh water circulating pump.

     Over tightening the belt is not the answer as you will find out below.


    Caution: An over tightened belt, operated over a period of time, can cause metal fatigue on the front section of the crankshaft.

     This can result in failure, breaking the crankshaft at the #1 journal. This generally occurs when owners have over tightened their belt in an attempt to stop or reduce slippage.

     The serpentine belt will not slip using the same recommended tension as used on the “V” belt shown in Figure 2 below.

The Solution: Trans Atlantic Diesels Inc. can supply an easy to fit serpentine pulley kit (6 groove) for the Perkins 4.236. With this kit you can achieve in excess of 150 amps DC, (providing your alternator has the capacity).

Contact us for highly competitive prices on Balmar Products.
 Perkins 4.236


  • Water Pump Pulley # 336236W

  • Crankshaft Pulley #336236C

  • Crank Pulley Mounting Bolts 4 x 7/16” x 1 Ό” fine

  • Belt # 060514

  • Puller to remove water pump pulley

  • Alt Bracket Spacer 3/4” plate.

  • Alan bolts to mount alt. spacer plate to block 2 x 3/8 x Ύ fine., Loctite required on these bolts.

  • Alt. bracket mounting bolts 2 x 3/8 x Ύ fine

  • Alt. adj. arm spacer 3/8”

  • Alt adj. arm bolt 3/8 1 Ό fine

  • 24-12704 Bush 1620 (Optional)

  • Serpentine Pulley for alternator. (17mm bore) Fits Balmar 60, 70 and 90 Series and most common Delco Alternators and others

  • Tube of Red High Strength Loctite for Alan Bolts

When placing your order:
We recommend ordering an additional spare belt.  Let us know which alternator you have to ensure we supply you with the correct size pulley, as these will vary between manufacturers. We cover the most commonly used sizes.


The following instructions are for installation guidance only.
All normal safety precautions should be followed.
     1. Alternator Bracket Spacer - First, disconnect the battery supply to the engine. You will now remove the alternator from its existing mounting bracket. Next, remove the mounting bracket itself, you will be fitting behind it an Alt. Bracket spacer to position the alternator further forward. Remove the 2 mounting studs, if you don’t have a stud remover you can use 2 x 3/8 fine nuts locked together or Vice Grips as you will be replacing these studs with special bolts supplied.

     Caution: These stud holes align with the timing gears, it is very important to use the correct length bolts supplied, to avoid seriously damaging the gears.

     Having removed the old alternator bracket, you will now fit the new spacer adaptor. Start by cleaning out the threads that held the bracket in place, they must be free of oil because you will be using Loctite to retain the replacement bolt. We recommend the use of brake cleaner or similar solvent. Remember these are not blind holes, they go through and align with the timing gears.

     Place the two 3/8” x Ύ” long Alan head bolts through the countersunk holes in the Alt Bracket spacer, apply Loctite to the threaded area of the bolts. The spacer should be orientated with the two vacant holes facing forward of the engine. Tighten the 2 Alan bolts using a 5/16” Alan wrench. You are now ready to fit the original bracket to the Alt. bracket spacer you have just fitted. Use the 2 x 3/8” x Ύ” long hex head bolts to secure the original bracket to the adaptor.

     You will now remove the Belt adjusting arm to facilitate a spacer using a 9/16” socket. Fit the 3/8” x 1 Ό” long bolt through the adj. arm, add the Alt Adj. arm spacer and refit the arm using a 9/16” socket, this can be loosely tightened until the alternator is in place, at which time the arm can be positioned to connect to the alternator.

     2. Alternator Pulley - Next, if you are using your existing alternator with the V groove pulley, remove this. An impact wrench works well. If not available some alternators have an Alan head in the shaft for holding it, most pulleys will come off without force once the securing nut is removed. Fit the New Serpentine Alternator pulley to the alternator, reversing the sequence for the removal.

     3. Water Pump Pulley - Now remove the Fresh Water pump pulley, remove the securing nut with a 15/16” socket. Using the puller supplied in the kit, using a ½” socket, screw the puller bolts approx ½” into the pulley then using a 9/16” socket, turn the center bolt in to the water pump shaft to remove the pulley.

     Caution: Do not try to pry the pulley off from behind as it is constructed of cast iron and will easily break.

     There is a key in the water pump pulley shaft, be sure this stays in place. Now fit the new pulley being sure the key way lines up correctly. You will use the securing nut to pull on the new serpentine pulley on the water pump shaft. (An impact wrench works well for this)

     Next, fit the supplied Crankshaft pulley on to the existing crankshaft pulley. Be sure that the mounting surface is clean, if not the pulley will not register correctly and will run out of true. Using a 5/8” socket fit the 4 x 7/16” x 1 Ό” long bolts.

     4. Alternator Pulley - Replace the V pulley on the alternator with the serpentine pulley. An impact wrench works well for this. Some alternators have a provision in the end of the armature shaft for an Alan wrench to hold armature from turning while tightening with a wrench. Torque may vary according to your alternator manufacturer.

     5. Serpentine Belt - Fit the new serpentine belt. Check for alignment. There are slots in the alternator bracket that will give you some adjustment if required. Once the belt is fitted and good alignment is achieved, Tighten the belt adjuster arm. Both bolts, the one on the alternator and the one at the mounting point of the arm where the spacer was fitted.

     Belt Tension should be, so that without undue pressure, the belt can be depressed 3/8 of an inch at the center of the longest span as shown in the image below.

     NOTE: The new belt will require re-tightening after a loaded run period of approx. 2 hours. Continue to check tension until the new belt no longer stretches. Following this procedure, periodic checks should be made checking condition and tension. Carry a spare !



The instructions detailed above are for installation guidance only.
All normal safety precautions should be followed.


To ensure our Serpentine Pulley Kit will work with your 4.236 engine, please identify which set up your engine currently has, as not all will accept the kit.

Figure 1 4.236 European Low Line Tank

Shown in figure 1 is the 4.236 European Low Line Tank. This tank WILL ACCEPT our Serpentine Pulley Kit.

Figure 2 - 4.236 Bowman Manifold Assembly
Shown in Figure 2 is the Bowman Manifold Assembly. This configuration WILL ACCEPT our Serpentine Pulley Kit.
Figure 3 - 4.236 North American Manifold
Shown in Figure 3 is the 4.236 North American Configuration Manifold. This WILL ACCEPT our Serpentine Pulley Kit.
Figure 4 4.236 European Bowman Front Mount Tank & Heat Exchanger Configuration
Shown in Figure 4 is the 4.236 European Bowman Front Mount tank and heat exchanger configuration. This WILL ACCEPT our Serpentine Pulley Kit.

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This Page Last Updated June 01, 2020

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