1981 T3 Chrome Bore or not??

[henwilv]

Howzit  - I have a T3 1981 ex Policia. It has a broken oil ring. The bores are reputedly chrome, but, to be honest, I wouldn't know by looking at them, but there certainly isn't any iron liner.
The broken oil ring has a mark near the gap that looks like 00E . It's made up of dots.
The bike has done 100,000km.
The piston has four rings.

How do I identify if the barrel is chrome or if it is a replacement with a nigusil coating?
The reason for the question is because I need a set of rings and I have to get the right ones for the coating. Rings for the chrome are like hen's teeth!

Any pointers/advice much appreciated

[TOMB]

Take a magnet iron bore magnet will stick doesn't stick Chrome unless the cylinders have been replaced with newer cylinders it might be the nagisil  but the bike originally came with chrome.

If it has a slight pull with a magnet it probably will be Nagisil but you'll also be able to see I believe hash marks and then you can tell if it's she has marks in the magnets sticks really strong then you have iron boar

TOMB

[Dave Swanson]

As suggested;  iron liners the magnet will stick well,  chrome - not at all.  If Nigusil the magnet will hang on slightly. 

[jwinwi]

Rings for chrome and Nigusil are the same - made from Iron like these: https://www.mgcycle.com/index.php?main_page=product_info&cPath=68_129&products_id=4368
MG Cycle buys many items from Stein Dinse...

[henwilv]

Rings for chrome and Nigusil are the same - made from Iron like these: https://www.mgcycle.com/index.php?main_page=product_info&cPath=68_129&products_id=4368
MG Cycle buys many items from Stein Dinse...

That's interesting - TLM in the Netherlands have told me this is not the case, but others have said it is and I wonder who is right. It leaves me in a bit of a dilemma.

[Jens_L]

A summary of what my conclusion would be:

If the piston has 4 rings, it would have been a plated bore once for sure ( Strange for an '81 bike, I would suspect Iron lined).

   - Chrome lined bores used iron top rings, Iron lined cylinders used Chromed top rings
      The Iron rings can be used in a iron lined cylinder, the chrome ones can't be used in a plated cylinder.
      Then again the LM used Iron rings in an iron lined cylinder.
All literature I own says Nigusil cylinders have different rings but anyway, 4 rings would mean iron rings and since they were there I would replace them by the same  ones?

[Antietam Classic Cycle]

Guzzi made the T3 in 1981?

For police use, yes.

[TOMB]

The OP location is Germany so for the model year 1981 conceivable and possible he's proving it, that there wasn't 850 T3 made in 1981 probably for the just the European market and A
as another person indicated it was made for the local police and government agencies etcetera and the bike was probably never sold in the United States

TOMB

[Antietam Classic Cycle]

Quote: I have a T3 1981 ex Policia.

[Kiwi_Roy]

Since you have the engine apart you can see the bore, chrome is shiny eh!

[Frenchfrog]

If it's got 4 rings I would be almost certain the bores are chrome.Having said that , my T3 from 78 had chrome with 3 rings ( and the bores failed around 50,000 miles) . I don't think any of the Nicsils had 4 ring pistons though and were introduced on the next model which was the T 4.

[henwilv]

Guzzi made the T3 in 1981?

That's what the little plastic ring on the brake lines says, 7/81. Maybe there was a special last run for the Polizia. It is a police model from the tank.

[henwilv]

As suggested;  iron liners the magnet will stick well,  chrome - not at all.  If Nigusil the magnet will hang on slightly.

Is the chrome not plated on to an iron liner? That is what TLM in Holland suggest because they say a magnet will be attracted to it.

[jwinwi]

Is the chrome not plated on to an iron liner? That is what TLM in Holland suggest because they say a magnet will be attracted to it.

Chrome was applied directly to the aluminum cylinder wall.

[henwilv]

Chrome was applied directly to the aluminum cylinder wall.

Right, thanks, I probably misunderstood TLM - all will be revealed tomorrow when the magnet gets to work

[henwilv]

For police use, yes.

It is an ex Police bike, has cast wheels. Was bought in three boxes and a plastic drum and reassembled here in Germany about 20 years ago.

[henwilv]

So it's Nigusil, which is probably why they look so good. Now I need to find a ring set of four rings since they didn't change the pistons to the 3 ringers.

This is beginning to look like an opportunity to bite the bullet and buy a 1000 kit because there would be less faffing around and the job would be finished and done

[Frenchfrog]

Try and get the piston weights to match the originals if you do upgrade...or rebalance the crank.I did not do that to mine and regret it .It might still happen.

[jwinwi]

So it's Nigusil, which is probably why they look so good. Now I need to find a ring set of four rings since they didn't change the pistons to the 3 ringers.

This is beginning to look like an opportunity to bite the bullet and buy a 1000 kit because there would be less faffing around and the job would be finished and done

This is a set of 4 rings: https://www.mgcycle.com/index.php?main_page=product_info&cPath=68_129&products_id=4368
Maybe you can buy direct from Stein Dinse?

[henwilv]

This is a set of 4 rings: https://www.mgcycle.com/index.php?main_page=product_info&cPath=68_129&products_id=4368
Maybe you can buy direct from Stein Dinse?

Stein-Diese have been very helpful indeed, but they don't have.

[John A]

Chrome was applied directly to the aluminum cylinder wall.

The difference between the expansion rates between chrome and aluminum is one of the main reasons it fails. Porsche and GM tried it as well, they had problems and discontinued the practice. It works well on iron.

[DesertPilot]

The difference between the expansion rates between chrome and aluminum is one of the main reasons it fails. Porsche and GM tried it as well, they had problems and discontinued the practice. It works well on iron.

I'd been wondered about that off and on for close to half a century.  Thanks for clearing up a very long-standing mystery!

[Moparnut72]

I never thought of that. Duh. Should have been obvious. Kind of like the two diesel pickups I have owned. My 12 valve Cummins would start on the first compression stroke. My 2013 always has to turn a few revolutions before it starts. Always wondered why until a couple of years ago. The 12V has purely mechanical fuel injection,  the '13 is common rail. The ECU has to talk to the cam and crank sensors before it can tell the injectors when to fire. Duh again.
kk