Perkins 4.236M Injectors Help...

[NahanniV]

One of my winter projects is to refurbish the injectors on my Perkins 4.236M engine. I have been getting some white smoke and some fuel sheen on the water at the exhaust.

I suspect the injectors, but have also tried to rule out any other cause.
Oil is new and correct level. Filters are clean. Fuel pressure is good. I am not using any coolant or oil. Exhaust system is not obstructed.
I did a blowby test with the boat in the water and the results were good.
Since removing the injectors I have done a compression test and a leakdown test and the results were good for a 35 year old engine.

I had planned to exchange the injectors for rebuilt ones, but, I've run into a slight problem; One of the injectors is different than the other three. Three look as though they have never been removed since the engine was built in 1978 (paint on threads was intact). The other one is a different number and the injection pipe looks like it was replaced as well.

Original 3 injectors:
BKBL67S5151 ZV Des.No.5217419 CU (170atm Per. manual)

New Injector:
BKBL67S5299 XI Des.No.5281626 FC (195atm Per. Manual)

The companies that I have talked to will not accept my mismatched injectors for a core refund, they want 4 identical ones.

I could go to a local diesel shop and have them rebuilt, but the prices quoted are not firm and are the same or more than buying re-manufactured injectors including the core charge.

So, I am leaning toward getting a new (remanufactured) matching set of four.

My question is: which ones ?

It looks like the one that is readily available is "FC" like the new one that I have, but the opening pressure on that is different than the ones that came with the engine, about 300psi higher, will that make a difference ?

I don't know if the new injector opening pressure was adjusted to match the old ones.

I am also wondering if I can CrossRef to tractor injectors, which seem to be considerably cheaper.

Any thoughts would be appreciated.

Cheers,
JM.

[Tiki2]

our friends with a 4108 had white smoke after rebuilding the engine and it was because the timing was slightly out. A small adjustment in the position of the injector pump resolved the smoke entirely. The 4236 is the same set up and so have you considered adjusting the timing. Mine is a '92 model 4236 and has markings that we used as a guide when we replaced out injector pump and so imagine yours is similar.

[NahanniV]

Originally Posted by Tiki2

our friends with a 4108 had white smoke after rebuilding the engine and it was because the timing was slightly out. A small adjustment in the position of the injector pump resolved the smoke entirely. The 4236 is the same set up and so have you considered adjusting the timing. Mine is a '92 model 4236 and has markings that we used as a guide when we replaced out injector pump and so imagine yours is similar.

Thanks,

I have the injectors out now, so I will be either refurbishing or replacing them; They are well overdue. The injection pump shows no signs of ever being touched. My understanding is that wrong injector opening pressure can also change timing, so I will make sure the injectors are working correctly before I think about changing the injection pump timing.

Cheers,
JM.

[shakey doug]

You can have your odd injector rebuilt to the same specs -new spring nozzle/pintle ete as the others the holder will allow that. In your post #3 you have hit the nail right right on the head.

[NahanniV]

Thanks for the advice,

I called around to all the local diesel shops and finally found one that had some used injectors of the same spec as the originals for my engine.

Had them all rebuilt plus got a spare with all the washers and seals at a reasonable cost.

Now just need some warmer weather to install them.

Cheers,
JM.