Perkins 4108 injectors preparing a spare set

[pcatterall]

My 4108 makes a little black smoke but uses little oil. There is plenty of air getting in. I thought it would be useful to change/check the injectors.

I bought a used set and they look to be in good nick.
is it sensible to have them checked/refurbed so as to have them as spares and probably in fact to exchange them and keep my old set as spares.
I see a speciallist firm does an exchange deal for about £40 each. Is it worth doing this?
Is the actuall changing process simple for an average DIY guy?
Many thanks as allways!!
　
　

 

[sailorman]

How often do you check those in your car ?

 

[Heckler]

My 4108 makes a little black smoke but uses little oil. There is plenty of air getting in. I thought it would be useful to change/check the injectors.

I bought a used set and they look to be in good nick.
is it sensible to have them checked/refurbed so as to have them as spares and probably in fact to exchange them and keep my old set as spares.
I see a speciallist firm does an exchange deal for about £40 each. Is it worth doing this?
Is the actuall changing process simple for an average DIY guy?
Many thanks as allways!!
　
　

Pete
Angola, Saudi Arabia mid 70s, Lincoln welding sets, Perkins 4108 engines. Unbreakable except for the water pumps. We were 3 months down a suplly line in Angola, I ordered a set of injectors and pump. I left in 92, they were still in the stores! We never needed them! I have changed similar injectors back in the UK. Undo the spill pipes, undo the injector pipe, undo the two nuts and lever them out. They are supposed to slide out, but get carboned up. There is a copper washer in the bottom of the hole, make sure you get it out and anneal it.
S

 

[pcatterall]

How often do you check those in your car ?

Never is the answer you want. But I think that the operating conditions are different? my car doesn't smoke either

 

[PlankWalker]

When I rebuilt my 4108 25 years ago I had 5 injectors serviced,
the extra one was raped up in an oily rag put in a plastic bag and put in the spares locker.
I have never needed it and presume it's still there.

Plank

 

[danielefua]

Pete
Angola, Saudi Arabia mid 70s, Lincoln welding sets, Perkins 4108 engines. Unbreakable except for the water pumps. We were 3 months down a suplly line in Angola, I ordered a set of injectors and pump. I left in 92, they were still in the stores! We never needed them! I have changed similar injectors back in the UK. Undo the spill pipes, undo the injector pipe, undo the two nuts and lever them out. They are supposed to slide out, but get carboned up. There is a copper washer in the bottom of the hole, make sure you get it out and anneal it.
S

I was interested in the same question of the OP and I am quite satisfied of the reply but... how am I expected to anneal those copper washers? Heat and fast cooling, I guess, but foolproof practical operative advice are very welcome.

Daniel

 

[sailorman]

I was interested in the same question of the OP and I am quite satisfied of the reply but... how am I expected to anneal those copper washers? Heat and fast cooling, I guess, but foolproof practical operative advice are very welcome.

Daniel

heat & naturally cool

 

[Heckler]

I was interested in the same question of the OP and I am quite satisfied of the reply but... how am I expected to anneal those copper washers? Heat and fast cooling, I guess, but foolproof practical operative advice are very welcome.

Daniel

Dangle on a bit of wire, heat on the gas stove till cherry red, drop in a cup of water, job done.
S

 

[Sarnia]

My 4108 makes a little black smoke but uses little oil. There is plenty of air getting in. I thought it would be useful to change/check the injectors.

I bought a used set and they look to be in good nick.
is it sensible to have them checked/refurbed so as to have them as spares and probably in fact to exchange them and keep my old set as spares.
I see a speciallist firm does an exchange deal for about £40 each. Is it worth doing this?
Is the actuall changing process simple for an average DIY guy?
Many thanks as allways!!
　
　

As you have seen most 4108 owners have rarely if ever changed injectors. I has diesel commercial vehicles, two with 4108's, (now a boat with an old but reliable one) my local diesel engineers would always insist it was better to re-furb or test the injectors as a unit using the hp injector pump with them on the test bench, as professionals I am sure they had good reason to. Replacing injectors not to difficult a DIY job, refitting the hp pump rather more technical to remove and replace as it has setting marks to reset to.

 

[Tranona]

My 4108 makes a little black smoke but uses little oil. There is plenty of air getting in. I thought it would be useful to change/check the injectors.

I bought a used set and they look to be in good nick.
is it sensible to have them checked/refurbed so as to have them as spares and probably in fact to exchange them and keep my old set as spares.
I see a speciallist firm does an exchange deal for about £40 each. Is it worth doing this?
Is the actuall changing process simple for an average DIY guy?
Many thanks as allways!!
　
　

Have you checked that you are not overpropped. Black smoke is a symptom of overfuelling, not of defective injectors. Common on overpowered boatss like yours to overprop to keep cruising revs down as you do not need full power to achieve hull speed. Trying to get full revs results in overfuelling and black smoke.. One solution is to reduce the pitch on your prop, another is to keep revs below the point at which it smokes. Your fouled prop only makes it worse by overloading the engine.

As others have suggested, rarely do injectors need changing or refurbishing. Deal with the other potential causes first.

 

[danielefua]

heat & naturally cool

Dangle on a bit of wire, heat on the gas stove till cherry red, drop in a cup of water, job done.
S

??????
They sound pretty different...

According to what I already vaguely knew I think I will follow skipper_stu advice but... that's all?
Daniel

 

[pcatterall]

Have you checked that you are not overpropped. Black smoke is a symptom of overfuelling, not of defective injectors. Common on overpowered boatss like yours to overprop to keep cruising revs down as you do not need full power to achieve hull speed. Trying to get full revs results in overfuelling and black smoke.. One solution is to reduce the pitch on your prop, another is to keep revs below the point at which it smokes. Your fouled prop only makes it worse by overloading the engine.

As others have suggested, rarely do injectors need changing or refurbishing. Deal with the other potential causes first.

The plan to change the injectors was really because that seemed a simple thing to do so that at least one possible issue was resolved and could be crossed off the list.
The over propping idea has merit in that I think my prop is just right so that with a clean prop she can reach max revs and speed (7 knots). Certainly a fact that currently the prop has a massive amount of barnacles, she will hardly make 5 knots and produces vile oily ‘smoke’ until I throttle back to revs which match that speed. Clearly the engine is unable to burn the fuel being supplied. A bit of diving and scraping called for before we go anywhere!!
I will have the injectors ‘tested and set up’ just in case they are needed, they can then go into my spares box correctly labeled until called for.
Thanks for all the tips!!

 

[sailorman]

??????
They sound pretty different...

According to what I already vaguely knew I think I will follow skipper_stu advice but... that's all?
Daniel

i was taught to anneal one lets the item naturally cool
to harden quench

 

[sailorman]

The plan to change the injectors was really because that seemed a simple thing to do so that at least one possible issue was resolved and could be crossed off the list.
The over propping idea has merit in that I think my prop is just right so that with a clean prop she can reach max revs and speed (7 knots). Certainly a fact that currently the prop has a massive amount of barnacles, she will hardly make 5 knots and produces vile oily ‘smoke’ until I throttle back to revs which match that speed. Clearly the engine is unable to burn the fuel being supplied. A bit of diving and scraping called for before we go anywhere!!
I will have the injectors ‘tested and set up’ just in case they are needed, they can then go into my spares box correctly labeled until called for.
Thanks for all the tips!!

my 4108 maxed @ 3k giving 7.5kts driving an 18" MaxProp
it will go to 4800 ish to give > 48hp but that would be very noisy indeed

 

[macnorton]

The plan to change the injectors was really because that seemed a simple thing to do so that at least one possible issue was resolved and could be crossed off the list.
The over propping idea has merit in that I think my prop is just right so that with a clean prop she can reach max revs and speed (7 knots). Certainly a fact that currently the prop has a massive amount of barnacles, she will hardly make 5 knots and produces vile oily ‘smoke’ until I throttle back to revs which match that speed. Clearly the engine is unable to burn the fuel being supplied. A bit of diving and scraping called for before we go anywhere!!
I will have the injectors ‘tested and set up’ just in case they are needed, they can then go into my spares box correctly labeled until called for.
Thanks for all the tips!!

What do you call "max revs", that engine should reach 3800 (ish) in gear and 4200 out of gear.

 

[Heckler]

i was taught to anneal one lets the item naturally cool
to harden quench

That is for steel. IIRC aluminium put some soap on it, heat until soap goes brown then let cool naturally, copper as I said.
S
PS I used to be in maintenance, this was part of the day job.

 

[macnorton]

That is for steel. IIRC aluminium put some soap on it, heat until soap goes brown then let cool naturally, copper as I said.
S
PS I used to be in maintenance, this was part of the day job.

30 years back as a diesel engineer apprentice I was taught to heat copper washers until cherry red then cool in air, the washer are soft and pliable after like new ones are. quenching creates a hard surface (like the crust on bread) and is better for stubborn manifold bolts so they don't round after heating, but both methods would work.

 

[ean_p]

dont think that it matters for a non ferrous material like copper and aluminium....though for steels it is essential that the 'structure' is 'frozen' at specific points to provide the correct degree of temper....

 

[Heckler]

30 years back as a diesel engineer apprentice I was taught to heat copper washers until cherry red then cool in air, the washer are soft and pliable after like new ones are. quenching creates a hard surface (like the crust on bread) and is better for stubborn manifold bolts so they don't round after heating, but both methods would work.

We will agree to differ! Manifold bolts? or nuts? Steel?
S
PS Just found this on an education site
"Experimental process
1. Prepare lengths of copper wire, 6 to 10 inches long, or tubing, 1 to 1.5 ft in length.
2. Ask selected class members to slowly bend the copper—careful not to cause
crimping.
3. Once bent, ask another class member to unbend the copper.
4. Discuss why the copper cannot be fully unbent due to work hardening.
5. Now work harden the copper more by hammering the copper into a flat rod.
6. If available, anneal the tubing at a high temperature (400C or 700F or higher)
7. After annealing, remove from the furnace and quench in water to cool
8. Re-bend and note that the material is soft again."

 

[Sneaky Pete]

heat & naturally cool

Copper you heat dull cherry red and quench in water. This will soften the metal. To harden copper you need to work it or if it is used as a gasket it will naturally harden itself with vibration.