2.25 diesel head rebuild - help!!!

Oldseadog · Jan 6, 2014

If you use an epoxy you will need one which has been specifically developed for cast iron!

You could then, once the holes is perfectly clean, put a dab in the bottom of the hole and screw into it.

Once it has been left to part harden, remove the bolt and it should be OK.

However, you would be cheaper to buy all the bits and use a helicoil!

divie · Jan 6, 2014

Helicoil, yes they are expensive if you buy a kit that includes the drill,tap,insertion tool and helicoil inserts. Cheaper option to take it to an engineering company to be done.
In this respect I am fortunate in having my own lathe and milling machine but am to far away to offer any help.

jamesmartin · Jan 6, 2014

you can other kits ,recoil are good

Freetime101 · Jan 6, 2014

Will pop over to Turner Engineering and get them to have a look - will hopefully be cheaper than buying a helicoil kit

Turboman · Jan 6, 2014

Freetime101 said:
Will pop over to Turner Engineering and get them to have a look - will hopefully be cheaper than buying a helicoil kit

Take the head along too and they will tell you if it needs skimming, and maybe check the swirl chamber protrusion too

Freetime101 · Jan 6, 2014

That's the plan

Hope they're open Saturdays...

nrgserv · Jan 6, 2014

trax said:
Just a thought, don't know if this is a good idea or not.

Since the torque is pretty low, I wonder if you could chop the head off and epoxy it in as a stud, using the existing threads as a guide should mean it is straight. then use a nut on the top.

once used a redhead in a stat housing for studding, as a field bodge.
worked and carried on working so left it..
(redhead also known as wedge anchors)

joe27979 · Jan 7, 2014

what's a hot spot look like? sounds like a quiz show question

Blackburn · Jan 7, 2014

558168 CYLINDER HEAD HOT SPOT | shop | www.lrseries.com spot&page=1

that's them in place on 2.5 15J [Sherpa engine] below valves diesel is injected above them and ignites from the compression and the heat in the hotspot , indirect injection engines.

joe27979 · Jan 7, 2014

top explanation thanks Blackburn

:nothingtoadd:

Turboman · Jan 7, 2014

joe27979 said:
what's a hot spot look like? sounds like a quiz show question

Blackburns pic shows the hotspot in the head, here it is removed.

The fuel is injected into the chamber and is meant to swirl around the little pegs, which will be very hot, to give a very complete atomisation of the fuel before it goes into the cylinder through the little rectangular port.
Because of this they are also known as swirl chambers, or pre-combustion chambers. This is only half of the chamber, the top part is formed by the recess in the head.

divie · Jan 7, 2014

Having had a hotspot break up and do lots of engine damage I am very wary of them now. Does anyone know of a supplier making hotspots with an oversize fitting diameter? Once the head is worn the options to bore and bush to standard are not very practical, I did look at making a new Hotspot but it is to much work to reproduce.

Turboman · Jan 7, 2014

divie said:
Having had a hotspot break up and do lots of engine damage I am very wary of them now. Does anyone know of a supplier making hotspots with an oversize fitting diameter? Once the head is worn the options to bore and bush to standard are not very practical, I did look at making a new Hotspot but it is to much work to reproduce.

I think you have been quite unlucky, I have seen a few fall out in pieces from the head when removed, and also had them angle down and start tapping on the piston crown, but I havent seen them do a lot of damage.
Im not sure if OS would work, as the recess in the head would probably not be perfectly circular. Usual remedy is to fit an insert in the head.
They would be very tricky to make, not only a complex shape, but they are made of a very hard metal, which expands more than the head to lock the chamber into position as it heats up.

jamesmartin · Jan 7, 2014

divie said:
Having had a hotspot break up and do lots of engine damage I am very wary of them now. Does anyone know of a supplier making hotspots with an oversize fitting diameter? Once the head is worn the options to bore and bush to standard are not very practical, I did look at making a new Hotspot but it is to much work to reproduce.

hot spots arent std cast iron ,and arent supposed to be over tight fit though usually are when new as they shrink slightly , its the protusion above head face thats supposed to hold them in

Freetime101 · Jan 7, 2014

Well I measured the piston heights tonight...

Knowing how small the tolerances on engines are I used a straight edge and feeler gauges - what a noob!

1, 3 and 4 are between 0.022" and 0.025" - piston 2 is 5/16ths! Obviously used a ruler not a feeler gauge for that last one...

So I guess I've bent a con rod - balls

Is this an engine out job? Bad news if so

jamesmartin · Jan 7, 2014

Freetime101 said:
Well I measured the piston heights tonight...

Knowing how small the tolerances on engines are I used a straight edge and feeler gauges - what a noob!

1, 3 and 4 are between 0.022" and 0.025" - piston 2 is 5/16ths! Obviously used a ruler not a feeler gauge for that last one...

So I guess I've bent a con rod - balls

Is this an engine out job? Bad news if so

yep ,as long as bore and crank are fine it can be done by removing sump ,jacking chassis away from axle helps , piston comes out of top ,be caerfull of rod bolts when pushing it up past crank journal, journals mark easily, rods only fit on piston one way round so check when fitting to piston, both v in piston and anti rotation notches in rod and cap go to cam side

Freetime101 · Jan 7, 2014

Nice one, cheers - bit of shopping to do now then...

Other than a torque wrench do I need any special tools?

Cabbie · Jan 7, 2014

Why not let Turner Engineering overhaul the head professionally for you. At least you will know it is right and all the faults will have been addressed.

Freetime101 · Jan 7, 2014

I called them today and he said I was looking for faults in the wrong place - said it was best to check the con rods before rebuilding the head.

I'm not scared of getting my hands dirty and actually quite enjoy it - all part of land rover ownership

Turboman · Jan 7, 2014

Freetime101 said:
I called them today and he said I was looking for faults in the wrong place - said it was best to check the con rods before rebuilding the head.

I'm not scared of getting my hands dirty and actually quite enjoy it - all part of land rover ownership

Good on you Ft, that is the spirit, you will get lots of help with that attitude

If the head is straight and not cracked, there is nothing you cant do if you are careful and have decent tools. Measurement and advice from the pros is always helpful, but by DIYing you will save a lot of money and you will find it interesting too. Working on em is half the fun

2.25 diesel head rebuild - help!!!

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