removing barrells

[chankly bore]

The first time I ran the local Spares Scheme-in the eighties, I think,we had a great deal of trouble with liners supplied from the U.K. with no registering diameter into the crankcase mouth. PEI wrote to the supplier pointing out that the liner should be snug in the crankcases- but what would he know.Anyway, with the above photographs I would check conrod centrality,bend and twist;circlip type and wire diameter,(there are two wire sizes).Are your bores square to the crankcase mouths and are the muffs also square to the bores.

 

[bmetcalf]

So, the oversized crankcase openings on the die cast cases are so bad after all?

 

[Bracker1]

There is no need for a clamp fit on the liner. Even a slight pressure on the liner at base will cause distortion. I think the idea was to keep the liner from turning in the muff and losing the oil feed to the piston. If properly sized and fit the liner in the muff shouldn't move. I think engines with clamp fit are just not distorted enough to bind the piston.

 

[Howard]

View attachment 990View attachment 989View attachment 991alright the Barrell I wanted off is now off, now the next question... see if you can guess it?
freshly rebuilt motor 285 miles one of the gudgeon circlips pretty well gone and at the bottom of the stroke there's similar marks, omega piston marked VOC suspect they're E7/AS/D 7.3:1

Hi

Looks like your thread has been hijacked.

What are we looking at? 2 barrels, or one barrel scored on both sides?

Why is the barrel only marked at the top of the piston travel? (if that's what the photos show)

No answers I'm afraid, never seen anything simillar, hopefully this will kickstart your original thread.

H

 

[Bracker1]

Actually it is all related. If there is binding in the piston travel, stress can generate and relieve itself at the weakest point. Not likely a circlip falls out at 285 miles for no reason. I doubt that the builder forgot to snap the circlip into position, but you never know. It's easy to blame material failure, but would be difficult to prove. Still think the initial problem of the piston fracture/liner wear is a result of the connecting rod flywheel assembly. Liner distortion can also not be ruled out. Before you rebuild double check all the tolerances. Good Luck Dan

 

[Howard]

Hi Dan

My problem, if I'm reading the photos right, is why is the barrel marked top and bottom, but there's no damage in between, apart from relatively minor scratches.

H

 

[van drenth]

For me, the problem is clear the piston pins are to tight in the small end bearing of the conrod, i did have this problem excact the same as on the pictures. solution give it "enough" clearance not only diametercally but also horizontally and not forget to drill the lubrication oil at the top at each conrod. Also the pistons should have 4 Thou (0,1MM) clearance in the liner.
Regards, van Drenth JC

 

[Bracker1]

I can't explain the specific damage. It just looks like something seized and broke. I would still double check your tolerances and make sure everything is free when you get it back together. different problems sometimes give the same result. Ultimately, the engine will be better off if you tear it back down and start from scratch. The cylinders are off and it's not much of a job to split the cases and examine. I would imagine a lack of oil would show itself before the mileage stated. Keep us posted. Dan

 

[jellywrestler]

Always learn something fro a hijacked thread so no worries..
The piccies are of both sides at the top, the same style of marks are at the bottom what's worse is they're nearly 40thou thick in places!
I hear what is being said about rods being straight, this motor ran fine before with the rar piston failing for other reasons differnt to now. also given that the issues look the same i'd tend to think that it's not an alignment issue but welcome ALL comments and people chucking in their 2cents worth. (i'm from NZ so while we no longer have 2 Cent peices it's way longer since we had 2 P ones)

 

[jellywrestler]

Looks like circlips weren't in properly or broke up for some reason and chewed thier way out,nasty.
Chris.

I think the Circlip that was in bits came out as a result of the dmage, not first as the damge is reasonably uniform on both sides

Make sure the pistons are centered in the bore of the cylinder. If the rod isn't spaced on the flywheel properly the piston can be offset and a thrust force is placed on the circlip. Just a thought. Dan

See above answer

Hi

Looks like your thread has been hijacked.

What are we looking at? 2 barrels, or one barrel scored on both sides?

Why is the barrel only marked at the top of the piston travel? (if that's what the photos show)

I hijacked my own thread asking about barrell removal and them piston damage! I've added four piccies two from the bottom of the bore and two from the top looking all the way down some of these 'marks' are nearly 40 thou or1mm deep

Hi Dan

My problem, if I'm reading the photos right, is why is the barrel marked top and bottom, but there's no damage in between, apart from relatively minor scratches.

photos added

For me, the problem is clear the piston pins are to tight in the small end bearing of the conrod, i did have this problem excact the same as on the pictures. solution give it "enough" clearance not only diametercally but also horizontally and not forget to drill the lubrication oil at the top at each conrod. Also the pistons should have 4 Thou (0,1MM) clearance in the liner.

Intersting, can you explain how that situation would lead to this happening. (not doubting you, just looking to cause an effect etc to understand how it ended up in tears

I would imagine a lack of oil would show itself before the mileage stated. Keep us posted.

I woul dimagine that lack of oil would lead to piston seizure all around not this on the sides???