timing chain maintenance

[jvandyke]

My 1098 has always had some "rattliness" about it. May well be prefectly normal (properly adjusted valves helped) but I find myself wondering about timing chain stretch and rattliness. I have no evidence that the lower end of this motor has ever been touched. I have some receipts from a PO's PO for some head work 20 years ago, but I don't see anything in the pile of papers for any internal engine parts. No idea about overall mileage either as odometer was set back to zero in '86. Maybe I'll try to record it sometime, although it could be one of those "I'd rather not know" things. Revs high and seems to pull hard so I'm not looking for trouble. It'll find me eventually anyway, always does. :smirk:

 

[Billm]

May be time to change the chain tensioners (at least) and the rod bearings (or maybe rod & mains).
Sounds like you have a good engine that could do very well with just a little bit of help.
BillM

 

[Guest]

May be time to change the chain tensioners (at least) and the rod bearings (or maybe rod & mains).
Sounds like you have a good engine that could do very well with just a little bit of help.
BillM

+1

 

[DrEntropy]

Only "maintenance" wot works is replacement, along with the tensioner.

 

[Colin8]

I've never heard of a tensioner on a 1098 engine, so I looked at Vizard's book. The early A engines had a single row chain that is tensioned by two neoprene rings inserted into the camshaft sprocket. The neoprene tensioners work efficiently for only 5K-10K miles. This was news to me as I didn't think there was any tensioner in the single row timing chain setup.

The dual row chain was added at the introduction of the 1275 but with no tensioner. These lasted much longer but eventually loosened up and started to rattle, but always less so than the single row chain. Later, Leyland introduced a single row chain with a 'strip' tensioner.

Vizard says to convert to the 'strip' tensioner, you need the backplate, tensioner and timing chain cover from an A+ engine. I'm not sure when the A+ was introduced, but it's late in the 1275 engine production.

So, when you guys recommend changing the tensioner on the 1098, are you referring to the two "O" rings in the cam gear?

 

[jvandyke]

As in item 48 (from Moss)? I started this thread because I hadn't heard much about timing chain issues and wondered if it was common to replace components (chain and sprockets) or just renew tensioner rings.

 

[Colin8]

Very interesting, I learned something new here. My timing cover is off my 1098, but I haven't removed the chain and gears yet and didn't know the rings existed. I was planning to 'upgrade' to a dual row chain as I've heard it's better and a bolt-on replacement. Vizard also says the 'strip' tensioner from the A+ engines can be adapted to a dual row chain. I wonder how difficult it might be to find the components from an A+ engine?

 

[DrEntropy]

As in item 48 (from Moss)? I started this thread because I hadn't heard much about timing chain issues and wondered if it was common to replace components (chain and sprockets) or just renew tensioner rings.

Chain and "rings" (yep: #48) replacement. If the sprockets show wear, they need replacing too... but beware th' dreaded "Might-as-Wells"! :smirk:

 

[dklawson]

Mini Mania should be able to supply any of the A+ parts you need if you want to fit a later style tensioner to the 1098. The A+ was used from roughly 1980 on in the Mini and Metro. The 1275 engines are routinely fitted as "upgrades" to earlier small bore cars so there are plenty of parts available for them.

 

[Hap Waldrop]

Very interesting, I learned something new here. My timing cover is off my 1098, but I haven't removed the chain and gears yet and didn't know the rings existed. I was planning to 'upgrade' to a dual row chain as I've heard it's better and a bolt-on replacement. Vizard also says the 'strip' tensioner from the A+ engines can be adapted to a dual row chain. I wonder how difficult it might be to find the components from an A+ engine?

To use the A+ chain tensioner, it's same Rolon unit as the MGB, you have to do some drilling and tapping and have the A+ timing cover. The better/easier route if you have the 1098 timing cover with the rubber seal (instead of the earlier felt seal covers) then just install a dual 1275 timiong gear set and get you a 1275 oil slinger, the single row oil thrower/slinger will not work with the dual chain set up.

 

[jlaird]

The new timeing gears for 948s are not built for tensioners and this goes way way back.

We just do without and change the chain every 20 years or 200 thousand miles. LOL

 

[Billm]

Do be advised that you MUST countersink the two screw holes below the crankgear and use flathead screws, otherwise the dualrow chain won't fit.
For street use I would have a hard time justifying anything more than the 1275 dualrow chain, the A+ is a bit of overkill.
Bill

 

[nomad]

Try rocking your engine back and forth while watching your distributor rotor to get and idea of what you need. I had an unknown mileage 10CC 1098 that I could turn the crank a quarter turn before there was any detectable movement in the rotor. Figured THAT was why I could'nt get it to run smoothly!! There was a reason they went to dual chain.
KA.

 

[Pythias]

Something else to check-----

My 1098 rattles but its the crank pulley, not the timing gears. The riveted type used on the the 948 and 1098 is not all that strong, and the rivets sometimes work loose. I've even had one shear apart during normal driving, almost leaving me stranded, as the water pump and genny no longer operate without a lower pulley to turn them.

--Grab your fan and wiggle it back and forth. See if you can create the clanking sound while watching the pulley---

I sure wish someone made a one piece at a reasonable price......

 

[Hap Waldrop]

Something else to check-----

My 1098 rattles but its the crank pulley, not the timing gears. The riveted type used on the the 948 and 1098 is not all that strong, and the rivets sometimes work loose. I've even had one shear apart during normal driving, almost leaving me stranded, as the water pump and genny no longer operate without a lower pulley to turn them.

--Grab your fan and wiggle it back and forth. See if you can create the clanking sound while watching the pulley---

I sure wish someone made a one piece at a reasonable price......

You can use the 1275 harmonic balnacer on the 948. We used to carry the Romac balancers, but as of late we had a ahrd time importing them. Moss makes a repalcment harmonic balancer, and you can send a 1275 unit to be rebuilt to dapner Dude, and he will rebuild it for about $100.

 

[jvandyke]

Interesting stuff. I don't quite understand how those rubber rings are supposed to provide tension for the chain. I noticed when I did the valve clearance that movement of the crank seemed to move the cam/valve train pretty efficiently but it could easily be there is slop in there that a neophyte wouldn't notice. I'm not even sure my rattles involve the chain, just guessing. It does seem worse when the motor is warm. I don't have a fan to pull on anymore, since I pulled the mechanical fan after putting in an electric. Probably just leave it all well enough alone until I need to do something major. I assume the suggestion of introducing a harmonic balancer is to reduce vibrations and not so much to effect the chain tension. Bottom line, rattles or not, it runs well and I'm enjoying it so I should probably not introduce problems I don't have.

 

[Colin8]

For my 1098, I purchased a used 1275 damper from ebay and sent it to DamperDude for rebuild. The results look very good but it hasn't been installed or tested yet.

Rolon? Don't know what that is. Did you mean Rulon? We used Rulon material for plunger seals in semiconductor transfer mold equipment. It's a very tough, hi-temp, slippery thermoplastic material that would be great for a tensioner application. https://www.sdplastics.com/rulon.html

Thanks for the tip on the dual row oil slinger. My 1098 cover has the rubber oil seal, so now I'll need to find another slinger.

So, it sounds like using the dual row chain without worrying about a tensioner is the hot set-up for a 1098 - Yes?