Turn up 4020 Injection pump

[David G]

Can someone tell me how to turn up the pressure on an early 4020 injection pump?

Thanks,

 

[tim s]

There is not much that you can do, if you know where the leaf spring screw is you can tighten it some to gain a 'little', but you will need to send it to a pump shop to get a bigger increase in power, send the injectors with it.

 

[JDemaris]

There isn't anything inside the injection pump to turn up the injection pressure. That can only be done by adjusting the injectors themselves.

Turning in the head-screw in the injection pump makes the pump plungers travel further, and thus increases the amount of fuel injected at each stroke. Flow increase, not pressure.

 

[Anonymous-0]

You can take the pump to a injection shop and have the injection shop install a fuel screw that will allow you to adjust the fuel amount.

 

[tim s]

The leaf spring screw is not outside, it's in under the shut-off linkage, takes an Allen wrench to tighten, we ust to mess with them on the dyno, you would get about 10 percent increse in HP, not much, not enough to hurt anything eather..

 

[Mike Aylward]

But if you use a 7-4 or -5 spring instead of the stock -1 or -2 and remove the shims under it you can make it purr.. Mike

 

[Anonymous-0]

10% is a nice incresse and puts a 4020 at a solid 100 hp and it will live a very long time set this way any bigger incresse and you realy start to shortin engine life Kent

 

[Anonymous-0]

1/8 of a turn will realy wake up a 4020.

1/4 turn and a turbo will make about 150 hp.

 

[tim s]

I work on about 175 diferent 4020's in my area, is see all the bad that can and does happen to the from being over-fueled and over-worked, it makes you sad and makes you proud at the same time, these old work horses are still working,,some of the I have o/h 3 and 4 times over the years, the threads are virtualy wore out in some of them, I keep a good supply of helio-coil just to keep them stiched together, they are an amazeing machine..

 

[Anonymous-0]

I agree with you Tim. I didnt realize how far mine was turned up until it was on a dyno. I only use the extra power for reserve but still plan on turning it back down a bit.

 

[165Massey]

Any pictures of where to find this screw ? I’ve got a 67’ 4020

 

[used red MN]

Any pictures of where to find this screw ? I’ve got a 67’ 4020

If you don’t know where the screw is, that lack of knowledge tells me you should probably not be messing with it. Just my personal opinion, your MMV! (your mileage may vary)