Worn cylinders?

[Welderpaul]

Took the head off the engine this afternoon.

The 3 cylinders are generally in good condition. The bores have slight wear; enough to just catch a fingernail at the top of the stroke. Is this enough to need new liners, bigger piston rings (?) or do nothing?

Wear is difficult to judge, maybe 0.5mm ish

Any other maintainence required to the pistons?

 

[brightspark]

Took the head off the engine this afternoon.

The 3 cylinders are generally in good condition. The bores have slight wear; enough to just catch a fingernail at the top of the stroke. Is this enough to need new liners, bigger piston rings (?) or do nothing?

Wear is difficult to judge, maybe 0.5mm ish

Any other maintainence required to the pistons?

if u have a maintenance manual on the engine it will give the wear tollerance u can go to for bore and ring gap other than that ask at an engine reconditioers

 

[madkayaker]

What's the rings like? How did the engine run? If you have access to one worth doing a pressure test but you will need the head back on and be able to turn it over.

 

[brightspark]

What's the rings like? How did the engine run? If you have access to one worth doing a pressure test but you will need the head back on and be able to turn it over.

that will only half tell u because the valves will be worn and leaking as well . best just get it measured

 

[madkayaker]

It's a tractor engine so as long as its reasonable then it's going to do the job!

 

[brightspark]

It's a tractor engine so as long as its reasonable then it's going to do the job!

it depends on how fussy u are. theres no point in doing half a job when its a restore project . u wouldnt even bother taking it to bits if it worked and was a workhorse

 

[Welderpaul]

Yes, its a 'fussy rebuild'. I've not got to the rings yet, the way the bolts are i need to split the engine from the rest of the lump to drop the rest of it off.
It ran ok, but the last thing i want is to find problems once its all painted and back together.

 

[madkayaker]

Measure the step and see what tolerance can be big I bet

 

[oilcooled :)]

Won't your machinist advice you on the best tolerances, normally its a new liner and piston or bore job and oversize piston in the case of a solid block . You will skim the head and and get crank turned down when your there if going all out? Or are you doing the machining yourself

 

[pedrobedro]

Hone the bores then see if the step is still there and is big enough to catch the new top ring. If it is then a rebore is going to be needed.

 

[zzr1200]

Measure the bore inline with the crank (front to back) then at right angles (to the crank) this will give you the "Bores Ovality" in the wear areas. Usually the top of the cylinder wears more than the bottom part, you can get a "Ridge Reamer" that removes the cylinder wall above the wear ridge.

I have one somewhere in the garage (in never never to be found land.., I'II have a look for it if your interested, no promises), I've used it on many Rover V8's, when just re-ringing them, then a cylinder hone.

http://www.youtube.com/watch?v=h6t4bBd4ppk

 

[jonjoe]

trust me if the engines worn rebuild it we done are tractor up left the engine when we knew it was worn blew all the seals because of blow by. oil every were and blew the rear oil seal and put oil on the clucth plate causing it to stick and then was a real brute to get into or out off gear

 

[jonjoe]

what make of tractor is it

 

[madkayaker]

Ford dexta if memory works

 

[jonjoe]

if shes not blue she'll not do but im a massey boy myself

 

[Tengtooltom]

The Dexta has a dry liner. That means that the liner is only a couple of mm thick and has a small retainer lip on the outside at the top.This is similar to the mod that is done to the Rover V8 block when it starts to leak coolant into the bores.
The Dexta and the MF 35/135(early) have very similar engines and are very cheap to reliner and fit new pistons. Complete overhaul kits are available from lots of sources http://vapormatic.co.uk/engine-part...olland&typeid=&t=&seriesid=&s=&modelid=F3.152 (Lots of dimensions here also)
Be VERY careful when chipping out the old liners as they are very brital and you could damage the block. We used an old punch/screwdriver ground off at maybe 45 degrees and chipped a slot all the way down from the top. The remains of the liner will then drop/pull out.
Clean up the block, especially the groove at the top for the lip on the liner.
Chill the new liner in freezer for a few hours, add Loctite or similar and push gently home with a piece of flat wood.
Space up the rings and drop in the pistons with lots and lots of new engine oil. Fit new Big End bearings to correct size. Size is marked on bearings.
Usually the oilpump does not need replacing. Cut valve seats in the cyl head and fit new valves.......

 

[Tengtooltom]

http://vapormatic.co.uk/engine-part...seriesid=&s=&modelid=F3.152#part_list/VPB9611


Use this liner kit. Note that it is FINISHED. The others listed are SEMI finished which means that they have to be bored to size after fitting

 

[Welderpaul]

Its a Fordson Dexta, 1960 ish. Lots of common parts it seems between Dextas and Masseys

Thats a clever tool, i like it a lot....but, why do you need to take the ridge off? If the piston rings make contact with the bore up to the bottom of the ridge, whats the point in doing anything above it? Obviously there is a reason or that tool wouldnt be about, just i can't see why it would be needed?

Why do the bores wear as an oval?

Cheers fellas.

 

[madkayaker]

The bores wear olive due to the piston rotation in one direction on the con rod

 

[Welderpaul]

Ah, TTT, i could see a faint edge around the top of the bores - that will be the liner then

I've just read that if you use a liner, when it is pushed in, it distorts and will need machining. Is this likely, or will the 'finished' kits be ok do you think?