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3.1 to direct injection

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3.1 to direct injection

Postby moseswal2 » Wed Mar 02, 2011 10:03 pm

Hi I know this has been posted before.

We should be able to do this and I'm determined to find a way.The 3.1 pic I found on the net.

The other picture is from a 2.5 which is the same as a 2.8 exept for the shape of the hole shape in the piston and stroke.In the 2.5/2.8 head the glow plugs and injectors are longer and more centered.

So I was thinking that if you put the 3.1 glow plugs and injectors in a 2.5/2.8 head but they are short and will not stick out the head.So why not machine a cylinder type hole in the head as per my drawing.The 3.1 has a flat piston so buy using the same short injectors and glow plugs they will not touch the pistion.

any thoughts guys.
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Re: 3.1 to direct injection

Postby geeves » Thu Mar 03, 2011 12:15 pm

The direct injection engines have the combustion chamber in the piston. The indirects have it in the head. Other people have looked at this and given up as you cant get the correct pistons to fit the 3.1 as direct injection. Your idea is different though and might work.
Things that may cause a fail.
Machining head. Where are the water jackets?
Fuel map will need to change. This is mechanical on earlier engine
Injectors are different on indirect engines
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 3.1 to direct injection

Postby moseswal2 » Thu Mar 03, 2011 9:05 pm

Thanks Geeves

It's mechanical injection.
I was goint to put 2.5 tips etc on the 3.1 injectors and use a 2.8 injection pump if I have to.
The water jackets are on the edges of the head, at the center of the head it should be solid but there is only one way to find out.The drawing was only to show the idea, the machining is going to be much smaller and finer than that. I still need to measure the head injectors etc.

I dont want to change any rings or pistons etc.
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Re: 3.1 to direct injection

Postby geeves » Fri Mar 04, 2011 2:56 pm

There will be a water jacket above the combustion chamber. If it wasnt there the head would melt.
Its worth a crack but the cost of machining a head to find it doesnt work is quite high. Im not holding much optimism of success.
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Re: 3.1 to direct injection

Postby moseswal2 » Fri Mar 04, 2011 5:03 pm

I see what you mean there is not much to work with and if the material between the water jacket and combustion chamber is to thin it will cause it to over heat or crack.I also see that the injectors are completly different.
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Re: 3.1 to direct injection

Postby moseswal2 » Fri Oct 07, 2011 4:17 am

Hi

Please see my drawing, I have an idea, I did no calculations or anything yet just wanted to run it by everyone and to hear your thoughts.
I wanted to machine a space in the head to about 7mm deep so I can move the injector 7mm up to prevent the piston from knocking against it. I will also serve to reduce the compression ratio from 20:1 to 18:1. Again I still need to work out the volume that needs to be machined out to achieve this. I also need to work out what compression ratio will work best with this bore and stroke. I want to use the 3.1 glow plug because it is short.(maybe to short)

I have an old 2.8 engine so I was going to use the pump, injectors, head etc.
I want to use the 3.1 cam but the cam timing will be for indirect injection. Can I just take off the pulley and use a 2.8 pulley. Will the 2.8 pulley make the timing to direct injection timing.
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Re: 3.1 to direct injection

Postby pig75 » Fri Oct 07, 2011 6:46 am

It might be easer using a head of a 4JH1
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Re: 3.1 to direct injection

Postby superturbocompound » Fri Oct 21, 2011 9:10 am

i can see what you're trying to do and from my understanding the purpose of the indirect injection is to improve the quality of the turbulence and you have just removed that,so it'll be noisy and smoke badly,direct injection injectors have nozzles specially designed for a piston and cumbustion chamber,i read that an injectors that is out a few degree will result in smoking and noise aswell,and the reason DI are more efficient the IDI is because of the lower area exposed to the combustion and less heat loss through the cooling system,i hope i don't sound to negative...
p.s. diesel are a complicated engine in terms of their combustion process,lotsa reading needed to be done...
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Re: 3.1 to direct injection

Postby geeves » Fri Oct 21, 2011 1:36 pm

Nothing is impossible but in this case I cant see any way that the gains will be worth the effort. There are gains to be made but the payback would be slightly longer than forever
Sanding your knuckles before starting work can help. That way you cant skin them
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