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TR3 engine & box re-build


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On 11/6/2020 at 8:43 AM, iain said:

Morning  Bob, this might save you some work or at least give you a very good start.

http://tildentechnologies.com/Cams/TriumphCams.html
 

Iain

Thank you Iain. Have just added your Tilden link to Bonanza Collection in General Technical,

Kind regards, David

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On 5/30/2021 at 8:40 AM, Lebro said:

I was told that it would come out at some stage, but not under the technicalities section.

Bob.

Congrats.   You made it to the TR Newsletter

Peter W

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Bob, dare I ask you a question, after reading such a technically challenging report? What I personally have gained from reading your account is what to look out for. The no-nos.

 

I see you have an overflow bottle. Just wondering what pressure is the rad cap, since I suspect the one I have is wrong. Correct me if I'm wrong, but isn't 4 lb correct for sidescreen engines? (I read in the Forum recently you need a different rating for use with overflow.).

Thanks, and thanks for the dazzling engineering! :)

Congratulations on its well-deserved publication too.

David

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Why do you need an overflow? If you fill the radiator correctly the expansion tank is already there. There should be just enough water  to cover the bottom of the extension, look in through the filler. No more is necessary, as if you do fill it, on the first run the system will just spit of out of the overflow pipe.

Iain

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1 hour ago, iain said:

Why do you need an overflow? If you fill the radiator correctly the expansion tank is already there. There should be just enough water  to cover the bottom of the extension, look in through the filler. No more is necessary, as if you do fill it, on the first run the system will just spit of out of the overflow pipe.

Iain

 

1 hour ago, iain said:

Why do you need an overflow? If you fill the radiator correctly the expansion tank is already there. There should be just enough water  to cover the bottom of the extension, look in through the filler. No more is necessary, as if you do fill it, on the first run the system will just spit of out of the overflow pipe.

Iain

Thanks for asking the question, Iain.

First time around, with my 2, I never knew that and kept filling the expansion tank out of ignorance and right enough, at the end of every trip the excess water would form a puddle! Eventually, I fitted a Kenlowe fan, wrongly assuming the car was overheating. If I now know any better, it is thanks to Register members like you in this Forum, which didn't exist back then.

The fact is that my "new" TR, a 3, is fitted with an overflow bottle anyway (as well as having a Kenlowe). So, I was just asking, since I have one installed, might as well make sure I have the right rad cap, wouldn't you say?

David

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Hi David, Absolutely, I would guess it needs to be the same as if on the rad? Still don’t know why one needs the extra under bonnet clutter tho :-)

Iain

 

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2 hours ago, DavidBee said:

Bob, dare I ask you a question, after reading such a technically challenging report? What I personally have gained from reading your account is what to look out for. The no-nos.

 

I see you have an overflow bottle. Just wondering what pressure is the rad cap, since I suspect the one I have is wrong. Correct me if I'm wrong, but isn't 4 lb correct for sidescreen engines? (I read in the Forum recently you need a different rating for use with overflow.).

Thanks, and thanks for the dazzling engineering! :)

Congratulations on its well-deserved publication too.

David

To answer this 1st, I use the standard 4 lb cap, modified to seal to the top of the rad opening as well as the sprung seal to the lower "shelf"

The only advantage of fitting the overflow bottle is that it increases the capacity of the cooling system a little.

Whether that makes a lot of difference I don't know, but it is reasuring to find the level right up to the top every time I check it.

Bob.

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1 minute ago, Lebro said:

I use the standard 4 lb cap, modified to seal to the top of the rad opening as well as the sprung seal to the lower "shelf"

Thanks Bob!

Makes sense: more coolant, ergo more cooling.

The one fitted is a 7 lb cap. But I also have a new spare, which is 4lb — hence my question.

Now, when you write "modified to seal to the top of the rad opening as well as the sprung seal to the lower "shelf", how exactly have you modified it? I see that whichever cap I use has a bayonet-type fastening. I cannot see what I have to do to make the overfow work. Please forgive my consistent ignorance).

David

 

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The standard TR3 cap does not have a "seal" at the top, just a spring steel disc  to hold the bayonet fixing in place.

I cut this out & inserted a leather (rubber would work as well) disc which does seal to the top when the cap is locked on.

The TR4 cap has a seal there already, but is shorter so that the sprung lower seal does not reach the lower seat. There maybe caps out there which do the job without modification, but I do not know of any. Others may advise.

Bob.

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3 hours ago, Lebro said:

The standard TR3 cap does not have a "seal" at the top, just a spring steel disc  to hold the bayonet fixing in place.

I cut this out & inserted a leather (rubber would work as well) disc which does seal to the top when the cap is locked on.

The TR4 cap has a seal there already, but is shorter so that the sprung lower seal does not reach the lower seat. There maybe caps out there which do the job without modification, but I do not know of any. Others may advise.

Bob.

Thanks Bob, always so helpful!

Could you show a photo of the inside. I want to compare yours to the two caps I have and see if the correct one (4lb?) needs adapting or not. Might be handy for others too.

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2 minutes ago, Lebro said:

Will do later today

Bob

Thanks very much :)

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2 hours ago, Lebro said:

  20210715_200934.thumb.jpg.364e85c5ca0d0cfcc709e446807c2df1.jpg  20210715_200909.thumb.jpg.767469c21b042220c1959374be626e4e.jpg

Looks like I changed the leather seal to a rubber one.

Great! As always, Bob, you came up trumps :) thanks

So, what I've gleaned from you is that it is a good idea to clamp the overflow pipe where it attaches to the neck. And also that, given the overflow mechanism, a good idea to fill it right up. Since, when heat makes the water and antifreeze mixture expand, it can just overflow into the bottle below.

I checked the two rad caps I have. The one fitted was 7lb and no double rubber. The new one, supplied as a spare, has two rubber seals and is rated 4lb. So of course I've swopped them. Next, will fill to the brim. Between one DIY task and the other, I took KST 277 for trial runs up to 75mph and fast acceleration, overdrive fine engagement, acceleration solid, all good. Only problem: some overheating. I switched on Kenlowe, but — maybe the warm weather? — some overheating over to the next mark after 185F.

Thanks again, always learning

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Thanks, Bob!

Yes, you mentioned different lengths. I read that, then promptly forgot.

Will have a look tomorrow between DIY often put off, now urgencies :)

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On 7/16/2021 at 7:30 AM, Lebro said:

Just check that the 4lb cap has the same depth as the 7lb one.

Your car is just a bit older than mine TS 9551  O

 

Bob.

Between breakdowns, I checked. The new one from cap lid to sprung base is longer than the 7lb one. The overflow bottle looked like it had pink stuff in it. So I thought HELP OATS!!!

But I was wrong. It was rusty, sludgy brownish water. So I extracted it and washed it out. Got bluecol and put in 50/50. My guess is that it hasn't been flushed, so that's a small task even I should be capable of doing. But you never know. Don't count your chickens, the saying goes.

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  • 2 months later...

Having now clocked up 2000 miles on the engine, I gave the head studs another check - slackening, then re-torquing to 105 ft lb.

I had purchased some "unfinished" pushrods from Cambridge Motorsport - they come with the lower end fitted, but the top end is separate,

the rods are hollow (& made from "Moly steel)

https://cambridgemotorsport.com/classic-historic/12718-triumph-tr2-4a-chrome-moly-pushrod-set.html

They are approx ½" longer than standard, & have to be cut down to the desired length. I got these because having lost 60 thou from the head, & approx 40 from the block face the standard rods were too long. Up to now I have had some spacers under the rocker shaft pedestals, but that is not ideal as it moves the geometry of the rocker away from the ideal. After much very careful measurement, I removed 12.7mm from the top end of the rod (hacksaw, then lathe) which gave me rods which were 140 thou shorter than standard.  The top ends then need to be pressed into the hollow rod. These are now fitted, & all setup.

While at it I changed the oil & filter again, am now using Westway 20W50 semi-synthetic, which has 1500 ppm zinc.

Will take it for a run when I can find some fuel !

Bob.

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Thanks for the engine oil tip, Bob.

Your expertise in action always a fascinating read,

Ciao,

  David

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I have a 3A which was always overheating in traffic. This was a very long time ago. Some years back I had the radiator overhauled and fitted with extra fins and offset tubes. The cap is a plain sealer with no lbs and allows the hot water to expand into the overflow. The  small original pipe has been renewed and the lid on the overflow is the correct depth and rated at 4lbs. I do have an extra fan , a Kenlowe, but the new rad works so well that it hardly ever comes on.

. The upgraded radiator is the best answer to start with. I will look for the old receipt and post it on here tomorrow.

good luck Richard & B

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On 10/5/2021 at 5:36 PM, Lebro said:

While at it I changed the oil & filter again, am now using Westway 20W50 semi-synthetic, which has 1500 ppm zinc.

 Bob

Any reason for using Westway 20W50 semi-synthetic over their mineral grade equivalent? 

Chris

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He’s showing off, the Newley rebuilt engine with Marx seal is able to hold the thinner semi synthetic in.:P

Mick Richards

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But it's not thinner, it's 20W50 !  Having read about oils on here at some length the consensus was that there is nothing wrong with using synthetic oil in a classic car as long as it has enough ZDDP, which this stuff has in abundance !

(& I was showing off) (& it was cheap)

Bob

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41 minutes ago, Lebro said:

But it's not thinner, it's 20W50 !  Having read about oils on here at some length the consensus was that there is nothing wrong with using synthetic oil in a classic car as long as it has enough ZDDP, which this stuff has in abundance !

(& I was showing off) (& it was cheap)

Bob

As usual Bob… you’ve covered all the bases ;)

Mick Richards

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On 10/6/2021 at 3:36 AM, Lebro said:

Having now clocked up 2000 miles on the engine, I gave the head studs another check - slackening, then re-torquing to 105 ft lb.

I had purchased some "unfinished" pushrods from Cambridge Motorsport - they come with the lower end fitted, but the top end is separate,

the rods are hollow (& made from "Moly steel)

https://cambridgemotorsport.com/classic-historic/12718-triumph-tr2-4a-chrome-moly-pushrod-set.html

They are approx ½" longer than standard, & have to be cut down to the desired length. I got these because having lost 60 thou from the head, & approx 40 from the block face the standard rods were too long. Up to now I have had some spacers under the rocker shaft pedestals, but that is not ideal as it moves the geometry of the rocker away from the ideal. After much very careful measurement, I removed 12.7mm from the top end of the rod (hacksaw, then lathe) which gave me rods which were 140 thou shorter than standard.  The top ends then need to be pressed into the hollow rod. These are now fitted, & all setup.

While at it I changed the oil & filter again, am now using Westway 20W50 semi-synthetic, which has 1500 ppm zinc.

Will take it for a run when I can find some fuel !

Bob.

Hi Bob, Can I ask a question - when you redo the head stud torque, do you back them all off and retorque from 1 - 10 again? Reason I ask is that I need to remove the rear exhaust side stud to replace the heater valve and I'm not sure if I need to loosen and re-torque all the studs (new ARP studs just installed on rebuilt engine), or if I can just remove the one stud, change out the broken heater control and retorque the one stud without any warping of the head... (hope this doesn't constitute a post hijack..)

 

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