TR2/3/3A Thinking of upgrading to 86 or 87 mm liners and pistons....

[karls59tr]

My car has a mild street cam and it runs fine. Would there be much adjustment to do in terms of timing and distributor adjustment? What else is involved in the upgrade other than to remove and replace the liners?

 

[Jerry]

buy a head gasket like this. Not much else will change.

Head Gasket Big Bore 87mm to 90mm LUCAS

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bpnorthwest.com

 

[karls59tr]

buy a head gasket like this. Not much else will change.

Head Gasket Big Bore 87mm to 90mm LUCAS

Your One Stop Shop For All Your British Automotive Parts. Order Online Today! We Have The British Auto Parts That You Are Searching For. Order Today! No Sales Tax. Fast, Courteous Service. Rich Selections. Order Hard To Find Parts. Family Owned & Operated. Fast Shipping.

bpnorthwest.com

Looks like a good head gasket. Do you mean not much else will change in terms of horsepower and performance?

 

[CJD]

You will feel a bit more torque. If you don't change anything else, the upgrade will not be night and day...but very noticeable.

 

[TFB]

Unless your motor has some other issues that need attention,like smoking,low compression,valve job needed,head gasket leak etc, I would not take apart a good running motor for this slight displacement increase.
Now if you are in need of rebuild I think the 86mm are cheaper than 83mm and of course most would upgrade.
Tom

 

[Jerry]

I put 87mm in my engine. I also had the luck to find an aluminum head with bigger valves already set for a real good price. The combo is a lot more HP. ( I don't know how much, but I can feel it and my friend says it is a lot more HP than his). I did not change the cam. I have HD6 SU carbs. Great little car.

 

[mctriumph]

You will have to upgrade the fuel due to better compression.(The 86 was always a factory option for the Tr3.)
I have always liked 87mm myself.When you do it, freshen up the low end and use the good bearings.
Also you can forget about using the hand crank only a gorilla can crank the larger pistols.
Mad dog

 

[karls59tr]

You will have to upgrade the fuel due to better compression.(The 86 was always a factory option for the Tr3.)
I have always liked 87mm myself.When you do it, freshen up the low end and use the good bearings.
Also you can forget about using the hand crank only a gorilla can crank the larger pistols.
Mad dog

OK i will go with 87mm. Upgrade the fuel in what way? Karl

 

[mctriumph]

Lets just say" Ethel" to drag and old saying out of the dust bin. As always the timing needs to be set
for the fuel getting consumed. The old school way is to warm up the engine, drive up a modest hill, and listen for
any detonation as you accelerate in 3rd. Advance the timing until there is just a little tiny bit, Now drop it back 2 deg, and lock it down.
You don't want any detonation,as it does real damage at speeds where it goes unnoticed.
One more trick on breakin, never lube the rings on install. They will seat in the first 60 seconds of running, otherwise
the can take months to stop using oil.
Mad dog

 

[Sarastro]

I absolutely agree with Tom (TFB). We have a saying in the aerospace industry: "better" is the enemy of "good enough."

 

[KVH]

I’ve had good luck with 87s for years and years. Only one issue, and that was when I ordered rings separately. I was sent the wrong rings. I get a bit frustrated by the lack of suppliers, but just be alert.

 

[mctriumph]

Venolia pistons are the beast
MD

 

[karls59tr]

I absolutely agree with Tom (TFB). We have a saying in the aerospace industry: "better" is the enemy of "good enough."

I see your point of not having to upgrade if it's not really necessary. I just had cylinder head work done and replaced the head gasket. That was the time to upgrade to the 87's but unfortunately I do not have a proper shop to do the work and I'm getting too old to crawl underneath and tap out the old liners. Anyway the car is running fine for the cool Fall weather we are having here so I'm just going to enjoy the ride for now. One thing I need to do next year is to replace the timing chain. Pretty sure it's worn and making noise. A fellow club member gave me a set of new gears from a project car he never used so I just need the chain. I'm fairly confident I can tackle this job but I'm a little intimidated about getting the chain set properly and not have it one tooth out? Any thoughts?

 

[Sarastro]

It's not just one tooth. The camshaft is timed to within 1/4 tooth. The procedure isn't simple and I would hate to have to do it with the engine in the car. As a minimum, I think it would be necessary to remove the radiator and grille. (I'm thinking TR4A here; not sure about the TR3).\

FWIW, here is my experience; > Engine Rebuild <

 

[Jerry]

As mentioned above, the one problem I had with my last set of liners was the piston rings. The oil ring was the set of two thin springs, and a wavy piece in the middle. I have not had luck with that type of oil ring. I also think the liner sets have too much ring gap as sent from whatever factory they come from.

 

[karls59tr]

It's not just one tooth. The camshaft is timed to within 1/4 tooth. The procedure isn't simple and I would hate to have to do it with the engine in the car. As a minimum, I think it would be necessary to remove the radiator and grille. (I'm thinking TR4A here; not sure about the TR3).\

FWIW, here is my experience; > Engine Rebuild <

Thanks for he info.

 

[TFB]

As mentioned above, the one problem I had with my last set of liners was the piston rings. The oil ring was the set of two thin springs, and a wavy piece in the middle. I have not had luck with that type of oil ring. I also think the liner sets have too much ring gap as sent from whatever factory they come from.

I suggest anyone getting new liner and piston set measure carefully before install,not taking for granted that the manufacturer has got the fit right.
My replacement 86mm set from Moss last year had piston to liner clearances varying from .0035 top to .0015 bottom .So not only tight,but tapered.
I had my speed shop hone straight and round .0045.I tried to size myself with my lisle ridgid hone which works fine on my cast iron motorcycle cylinders but the liners were very hard and would have taken way to long so I sent them out.
I bought a very nice dial indicator bore gauge for around $70 ,but you will also need a 3-4" mic to go with it.My
Starrett snap gauges will be retired.
Tom

 

[bobhustead]

I simply copied the marks from my old gears. Easy if you make sure the old and new gears are facing the same way up, exactly line up the bolt holes on the cam gear (just put bolts thru the holes thru both gears), and make sure the teeth are exactly aligned. Crank gear is easy, only a few teeth so it is hard to screw up.
Bob

 

[karls59tr]

I simply copied the marks from my old gears. Easy if you make sure the old and new gears are facing the same way up, exactly line up the bolt holes on the cam gear (just put bolts thru the holes thru both gears), and make sure the teeth are exactly aligned. Crank gear is easy, only a few teeth so it is hard to screw up.
Bob

So it's not as complicated as I've been led to believe? That's good to know. Not clear on what you mean by "having the old and new gears facing up" but i guess if I had them in front of me I'd see what you mean. Where did you buy your chain the last time you replaced one? Is it better to get a chain where there is one link that separates? Karl

 

[mctriumph]

The gears wear,but not as much as the chain. Get a speedy sleeve for the snout so the new
seal has a chance to NOT Leak. Watch out for cheap tensioners. Hardest part of the job is the
R&I of the front apron panel. Up date the fan to Tr7 blades too.
MD