Piston/Liner repalcement

[bullstreetboy]

Guys

 

Forgive my naivety please:-

 

Is it possible to replace liner/piston with the engine block in situ? Head off of course!

 

Best regards

 

Barry

 

 

 

 

[RogerH]

Hi Barry,

yes you can - but it could be uncomfortable.

 

For a small amount of extra work I would recommend taking the engine out.

 

Roger

[Ian Vincent]

Perfectly do-able. Raise the car a couple of feet off the ground, and slide underneath to remove the sump. Much easier than removing the front shroud and radiator to remove the engine. An afternoon's work at most to have the liners and pistons out on the bench.

 

Rgds Ian

[bullstreetboy]

Uncomfortable? - not for me! .

 

I don't have the space /lifts/fitness to do it. I'm(or someone else - professional ) is replacing the head. It seems sensible to replace the liners/pistons at the same time, - the engine is burning a lot of oil. I think this replacement engine (TR4 era) has done about 56K miles. I'm not able to confirm this but remember being told this when I bought the car. It seems that Moss do not supply just piston rings only any more. They do sell replacement piston but for a few more beer tokens .....

[Motorsport Mickey]

Beware of a "professional" who doesn't have "wet liner" experience and know how to measure and adjust any new liners and pistons used. An engine just screwed together will give only enough life to get you into arguement territory.

 

Mick Richards

[TomMull]

Beware of a "professional" who doesn't have "wet liner" experience and know how to measure and adjust any new liners and pistons used. An engine just screwed together will give only enough life to get you into arguement territory.

 

Mick Richards

Yes, Mick has a good point. And there is very little to gain by trying to fix it in the chassis. Pulling the engine to do a proper rebuild, which I am quite sure you'll need, is cheaper and better in the long run than trying to do it in the chassis. You'll also get to fix the rear main seal oil leak too. My opinion, of course.

Tom

[mjdearing]

Hi Barry i think whats been said is common sense really any short cuts in this area will come back and bite you in the backside one day,get someone with previous on these engines that knows there stuff as already advised,for me engine out and full monty or short block rebuild in your case. Follow what's posted but in the end it will come down to quite a lot of beer tokens.

[Ian Vincent]

But to return to the original question, I had a suspected blown head gasket and when I lifted the head to check I found the liner heights were all over the place. Which is why I had to remove the liners to adjust them. As I said previously, not a difficult task.

 

Rgds Ian

[Drewmotty]

When my figure of 8 gaskets gave up the ghost it was simple enough to remove the liners with the engine in place.

Don't even think about removing the liners until the crank is fully protected from all the rusty water and detritus which will fall on it when the liners come out.

[RogerH]

Hi Barry,

as I said in post #2 it is do'able but a little uncomfy.

Laying on your back with arms in the air.

When the liners are out you will be faced with a rusty mass. You can clean out the lumps.

With the engine out you can get the block acid cleaned and it will be a thing of beauty when you get it back

The Fo8 gaskets will now seat properly.

Liner protrusion is a bugger to set up and it must be done right - you don;t want any muck under the Fo8's

 

You have made the problem slightly bigger about mentioning oil leaks.

 

You say about piston rings - you should be able to get these in most places - TRShop, C&M engineering or most pf the engine build shops.

However is it just rings!! You need to inspect the loners when the head is off. If there is wear in the liners then simply fit new liner/rings (£250).

 

The rear oil seal tends to leak at the best of times. With the engine out you can see better what you are doing and fitting a decent rear oil seal is a good way to go.

I have use the Chris Marx seal and no leaks for over a year now.

The front oil seal can also leak and the hub wear a groove in. Doing this insitu is more tiresome than the liners insitu.

 

How is the clutch fork pin? after 56K miles it's due to break - this requires engine removal.

 

Whatever you do it will cost far more than you think.

Do it properly and you'll get far more for your money

 

Roger

[bullstreetboy]

Thanks Guys for all the advice.

 

My main problem is lack of space to do any sort of engine rebuild. At over 70 now, I know I would struggle to do it myself, and don't know of any local assistance who has worked on this type of engine before.

 

It's looking like I'll just have to go with the head change and hope it cures the oil burning.

 

Barry

[RogerH]

Hi Barry,

small garage and age are a bad combination

Do the head rebuild and see how it goes. If you find anything on the way report back.

 

Roger

[bullstreetboy]

Roger

 

As always - thanks for advice and support

 

I'll go with the head change first. Have a look at the liners, maybe just change the rings.

[RogerH]

Hi Barry,

when you take the head off DO NOT rotate the crank.

 

Otherwise you will be doing a Fo8 gasket change.

 

Roger

[bullstreetboy]

Roger

 

"when you take the head off DO NOT rotate the crank."

 

Thanks for that vital piece of info.

 

It seems to me:-

 

That any inspection of the piston/rings will therefore disturb the liner seals.

I can't even get each piston to TDC and scape the carbon off without disturbing the liner seals.

I can just replace the head IF I can get it off. Local garage man says he had a Jaguar hanging on the head before it finally let go.

I don't have the room/gear to pull the engine.

 

Looks like I'm up the proverbial creek without a paddle.

Edited May 9, 2017 by bullstreetboy

[RogerH]

Panic ye not.

 

Sometimes the heads do stick.

if yours appears stuck then remove the front and rear exhaust manifold stud. My front stud went in too far and was gripping the head stud.

 

If you need to rotate the crank - then you simply need to hold the liners down. I have tubes (over the studs) with big washers/plates at the bottom that sit on the liner.

You can then rotate the crank. You could do the same with wood etc.

 

Roger

[bullstreetboy]

Good Idea Roger

 

watch this space!

[Motorsport Mickey]

Barry,

 

Just to enlarge upon the excellent advice you've been receiving a favourite way to help break the cylinder head seal upon the studs and block to remove is by turning the engine over with rope stuffed through the cylinder plug holes, the valves then being protected but helping lever the head off the block and break the seal.

This may depress you but cylinder head removal by doing it this way also stands an excellent chance of disturbing the cylinder liner seals and giving future leaks into the sump.

Forgive my basic explanation of the TR wet liner engine (not trying to teach you how to suck eggs) but this is how the core is set up. The cylinder liners fit into low bored "spigot" holes about 3" deep in the lower part of the block, quite loosely when new or freshly rebuilt but after a couple of years (and certainly after 57 thousand miles which may be 10 or more years accumulation) they will have formed the opinion that they are now part of the block and will resist attempts to move them.

They are sat upon what are called Figure of 8 gaskets shaped thus OO which connect together at the centre of each pair and there are 2 pairs which connect the liners together in siamesed pairs making up the 4 cylinders. Midway down each liner (at about 4") is a machined shouldered edge (about 1/4" or 6mm wide) which sits upon the machined spigot hole mentioned previously which is what locates the liners within the lower 3" deep in the lower part of the block.

Contrarily for a fixture such as this which will resist attempts mightily to disturb the head when corroded and sludged into position you do risk disturbing the Figure of 8 seals midway up the liners if you try "the rope trick" as described above, or even if the head is removed by more normal methods and then crank is turned over without the liners being restrained against the feeble drag of the piston rings.

Using large washers over the cylinder studs in the centre of each siamesed pair so that they spread over the top of each liner and the using a tube (old piston gudgeon pins are good for this) over the washers and secured by the cylinder head stud nuts and tightened to about 40 lb ft,( not critical) prevents this. Then and only then can you start to define what exactly is required to remedy your heavy oil use.

The TR engine doesn't use valve stem oil seals as standard and so it may be valve wear in the guides or quite a few other items. The pistons can be removed by knocking up from underneath once the sump is removed and then measured against the diameter of the liners (remember pistons are made oval and need checking in hot cross bun fashion X ), if the difference is less than 5 thou then replacement piston rings can be fitted (even at this wear limit the engine will give good results).

The good news is this engine is a pearl and a design classic, and recounting the times myself and many other TR owners have rebuilt what you may think of as major components (replacement crank anybody ? ) literally at the side of the road highlights what some of the other posters have described. The components can be accessed and replaced individually and although as pointed out again in some other different posts an engine removal and strip gives an excellent result a home rebuild replacing liners (even individual liners) can be done in a home garage successfully. Don't prejudge what should be bought or replaced until the engine is stripped and measured, it can take you down the wrong and expensive route when a simple component replacement or process will sort it for you.

Initial advice would be to contact the local group and see if there are some bravos with good wet liner experience who will help a fellow TR owner get to grips with the engine problem, or failing that some local referrals to a good engine specialist who knows how to apply old school engineering for a successful result.

 

Mick Richards

[Charlie D]

Barry,

I found these ideal for holding down the liners:
M12 Square Plate Washers 50mm x 50mm 50 Pack
Screwfix part number 28801
B and Q sell them in smaller quantities.

 

Charlie

[bullstreetboy]

Guys

 

The head is off without too much of a struggle!

 

A little surprise awaited me though. The engine was fitted with TWO head gaskets and a shim gasket. Measurements show the head had been skimmed by a huge 2.5mm. A scrapper for me I think.Can anyone make use of it?

 

The good news is that there is no detectable lip on the liners. Judging by the top of the pistons it looks like my assumption of oil seeping down the guides may be right - 2 & 3 were really oily. The final engine start before the head removal had the "hydraulicing" symptom again. The engine smoked immediately on starting.

.

So for now I'm just going with a head change. Unfortunately, a risk I have to take due to lack of space, fitness etc.

 

Once again thanks for all the valuable advice.

[BlueTR3A-5EKT]

Do not junk the head just yet.....

 

What is the chamber size of the head you have removed? Is the shroud over the valve still there?

If you go up on piston diameter that may rescue the head from being too high compression.Sorry chaps 'Brain Fade'

 

This thread covers combustion chamber volumes

http://www.tr-register.co.uk/forums/index.php?/topic/61982-ported-head-combustion-chamber-volume/

Edited August 21, 2017 by BlueTR3A-5EKT

[Motorsport Mickey]

Err... don't want to depress you Barry but skimming a TR head by OVER 4.5 mm has been done previously and if done correctly is fine.

 

The two headgaskets is a bit strange but possibly done to reduce the compression ratio, you didn't mention if the copper gaskets are solid or copper asbestos sandwich. If solid the fitment of a steel shim with pressed compression rings in between would be correct. The arrangement of these gaskets would need lining up carefully and because of the oil feed hole through the block to head the gaskets would need retorquing at intervals to ensure the head 105 lb ft is maintained. If this is not done loosening off of the torque could allow oil " seepage" from the oil feed hole along the block and into cylinders.

Check for oil staining along the block and cylinder head surface.

Also whilst it's apart check the liner heights above the engine block, get 4 measurements around each liner, you are looking for a consistent measurement between 3 and 5 thou ie 3.3.3.3. Or a set of 5.5.5.5. or in between.

 

Mick Richards

[RogerH]

Hi Barry,

as above - don't junk it yet.

If you were going to have it overhauled then get the workshop to check it out to see what has been done.

 

Roger

[Lebro]

 

If you go up on piston diameter that may rescue the head from being too high compression.

 

?

 

Bob

[Ian Vincent]

?

 

Bob

I agree with Bob. Increasing the piston diameter will increase the compression.

 

An easier way to reduce the compression (if it is too high) would be to open out the combustion chambers a little, e.g. modifying it from a TR3a head to a TR4a head by introducing a chamfer. All you need for this is a set of grinding wheels, a burette and some paraffin. The latter two are to make sure you get all the combustion chambers the same size. Mine are all between 63.25 and 63.5 ml and work fine with 87mm pistons.

 

Rgds Ian

 

PS some photos of the combustion chamber / head would help.

Edited May 24, 2017 by Ian Vincent