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1 hour ago, RAHTR4 said:

Pete,

Please note, a 7lb radiator cap is correct item for the TR4A.

Regards, Richard

Thanks Richard, can you point me to the source of your advice,  as I see no reference to it in the TR4 & TR4A workshop manual (2nd ed.).   In that the TR4's general specification states 4psi.,  and the TR4A's general specification simply appends "Radiator  .. .. Pressurised - finned vertical flat tubes. No-loss system."   Have I missed something.? 

cheers, Pete

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Pete - DON'T give up with owning a TR - there are other cars out there - just put the word out on here and elsewhere and I'm sure something will come up Chin up  Cheers Rich

Or these people? http://www.leacyclassics.com/parts/classicmini/engine-components/2k7440.html Roger

. Carrying on from TR4 -v- Tr4A engine, and my purchasing a 'spare'  < here >  ..so that I might get on and have an engine ready by the time the Chance is actually bought and shipped,  we h

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Morning Pete, this is probably not going to help as fact but this subject has been around for quite some time what is the correct cap for tr4a. Some say 4 others say 7 all I can say is that Brenda has a 4lb cap and we don’t seem to have a problem, the original one that I had with the car is also a 4lb cap and that one is in the boot as one of the many small bits I carry round.

Mike Redrose Group 

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Just had a look in my Triumph book and it says 4lb for tr4 then shows the difference for the 4a radiator but no mention of cap size, so for me it doesn’t mention changing the cap I’ll stick with my 4lb.

Mike Redrose Group 

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Edited by BRENDA1
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8 minutes ago, BRENDA1 said:

Just had a look in my Triumph book and it says 4lb for tr4 then shows the difference for the 4a radiator but no mention of cap size, so for me it doesn’t mention changing the cap I’ll stick with my 4lb.

Mike Redrose Group 

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I’d  go with the Mike advice. They use their car Brenda A LOT when allowed,  it’s a proper touring car.  Copy his set up and you should be right. 
H

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Hi Pete

my 4a has a 4lb cap radiator is full to the top and over flow half full runs at just slight over half on the gauge . Your running on is probably something else other than running hot issues I too would recommend using a infra red thermometer to check against the gauge readings hopefully its nothing too serious 

Chris 

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Thanks Mike, that looks to be the same workshop manual I have, and likewise found no reference to 7psi for the cap.  Haynes manual say 3-1/4 to 4-1/4 psi for the 4 cylinder range from TR2 to TR4A.  However as has been said before - the manual, just sometimes, has an error, which is why I'm asking. I can't see why but I wonder if the 7psi cap was specified for other markets / climates.?

Otherwise I concur with Hamish's comment.

Pete.

 

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1 hour ago, trchris said:

Hi Pete

my 4a has a 4lb cap radiator is full to the top and over flow half full runs at just slight over half on the gauge . Your running on is probably something else other than running hot issues I too would recommend using a infra red thermometer to check against the gauge readings hopefully its nothing too serious 

Chris 

will do, thanks Chris.

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Pete just an additional thought. Is the cap spring seal long/deep enough. They come in different lengths.
 

it is seating on the bottom rather locking on the bayonet and not sealing-  if so it’s an unpressurised system.

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6 minutes ago, Hamish said:

Pete just an additional thought. Is the cap spring seal long/deep enough. They come in different lengths.
 

it is seating on the bottom rather locking on the bayonet and not sealing-  if so it’s an unpressurised system.

4a has the standard short reach cap so shouldnt be a problem like that, long reach just wouldnt fit.

FWIW I run 4lb cap in my 4a and always fit them to others with no problem.

sTUART.

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Thanks Hamish, I don't think its length is a problem, but I will check.

Thanks Stuart.  that's clearly fine then.  

I'm appreciative of Richard for raising the subject.

Pete

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2 hours ago, roy53 said:

Always good to check the top of the rad  where the cap seals for flatness 

My TR6 had the same issue of not drawing coolant back from the overflow bottle, it was caused by a dent in the top of the filler neck so the rad cap let in air, I did a temporary repair by filling the dent with solder and filling it  back to flat. The temporary repair has now lasted about 5 years.

George 

 

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Thanks I've just checked the flatness of the radiator cap filler and it's fine. Where the cap's inside seal sits is not so flat though because there is what feels like a weld or solder all around that edge. I guess that's standard though. 

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^ The cap that was fitted (left) is 4lb and was missing its rubber seal. The new cap (right) is 7lb.  And if the coolant system cannot take an extra 3psi pressure, then it would be running the gauntlet anyway ..with the system about to burst.  

I looked it up, and do see in Brooklands BL Heritage approved publishing's of the TR4 Spare Parts Catalogue, p.179 plate Z29, the filler cap's part number is 122136., and in Stanpart Spare Parts Catalogue for the TR4A, p.209 plate # AG3, the cap's part number is 137691.    

A higher cap pressure being specified (for the later / slightly more powerful engine) is logical, insomuch as the higher pressure also takes the coolant's boiling point up a little.  So as I understand it ; water at sea-level atmospheric pressure boils at 100 deg.  4psi would raise its boiling point to approximately 106 degrees, and at 7psi it would be approximately 111degrees.  In normal running - the difference would not be noticed, but in a hot climate (some American or southern European markets) and the engine is stewing in its own heat, when stopped in traffic, it might make all the difference.  Likewise for a sportscar that was being marketed as being suitable for club racing.

However, using blue antifreeze 50/50 mix takes the boiling point up to 130 degrees. So does it make much difference what the pressure is ?

Anyway, for today the plan is to test the water temperature gauge's sender and thermostat to see how well they work in a cup of near boiling water.  I also need to extend the length of the expansion bottle's pipe.

And before I add antifreeze - I want to replace all the water and heater pipes, and possibly some of their clips.  I hope to order those today, but first I need to search through this forum's archive of topics and see what's been said and advised.  I do NOT want brightly-coloured silicon hoses but aside from that - I don't know one pipe, or indeed one supplier, from another.   

Pete.

 

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Pete, have I written this before?   Get yourself a free printed copy of the Moss Europe spares catalogue.   It contains a lot of tech info that is just not visible on the sales web sites.

Get both the Triumph TR publications from them.  There is a lot of good knowledge written therein.   
https://www.moss-europe.co.uk/parts-accessories-catalogues

or just ring them and ask for copies to be posted to you.

Peter W

 

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6 hours ago, BlueTR3A-5EKT said:

Pete, have I written this before?   Get yourself a free printed copy of the Moss Europe spares catalogue.   It contains a lot of tech info that is just not visible on the sales web sites.

Get both the Triumph TR publications from them.  There is a lot of good knowledge written therein.   
https://www.moss-europe.co.uk/parts-accessories-catalogues

or just ring them and ask for copies to be posted to you.

Peter W

Ironic you should say this because I did ask for a new one with the clutch release-mechanism parts ..but one was not sent.  So just today while at my storage container I picked up my previous edition.  Literally I've just got back and signed-in here while waiting for the kettle.

You see, I do pay attention in the classroom..   :rolleyes:

Pete.     

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Yesterday afternoon  I went to the dust bowl (where my storage container is) to do a few more TR jobs - related to its running temperature. 

I'm more and more suspecting the temperature gauge sensor &/or its wiring to be an issue.  I did have one fitted into the spare 4Aengine I bought in Nov 2019 (which was intended to have been rebuilt ready to go into 'Chance') but with moving house that particular item was packed safely away ..and somewhat frustratingly remains 'out of sight.'  Anyway I removed the one from Katie  simply to clean it (in case it was encrusted with rusty crud) and to check its part number, so that I might buy a replacement. .

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^ The numbers on three faces read ; GTR / 20G5 / 104.  I'm guessing GTR is the manufacturer, 20G5 being the part number, its length & fit, and the 104 might be the temperature that transmits "too flipping hot fella" to the gauge.   

Now I have those, I hope to cross reference, check it's the correct part, and to find another.

 

I also pulled the thermostat (yet again) and to make some soup. .

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^ The silver one in the middle is the new one (82-deg), the rust stained one at the bottom is the old one out of this engine (also 82-deg), the one at the top is a nos I bought for 'chance' (it is rated at 88-deg) and that to the left was one out of the spare engine.  The first three worked fine, but the latter, an old Waxstat, doesn't. 

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^ I've now refitted the new replacement.  The one that was fitted has been cleaned of its rusty deposits and with the 88-deg one have been labeled and kept as spares.  The old Waxstat (right) which didn't work has been binned. 

 

Next up was the expansion bottle. . .

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^ after cleaning as best I could while it was in situ., I pulled it out to clean it up and check that it wasn't cracked or otherwise damaged. The rusty colour staining was a hard encrustation. Whatever the root cause Katie has had this overflowing issue for a long time.   In any case it then took a flipping age to clean it off, with a coarse industrial scouring pad and a scraper.  Fortunately the bottle itself is in good shape and has been refitted. Its overflow pipe only reached a third of the way into the bottle. That's now been replaced with a new length of pipe which reaches to the bottom (cut at 45-deg so it can't go flat to the bottom).

 

I also pulled the bypass hose off ..

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^ The bottom jubilee clip, on the water pump was loose enough to turn and pull up without undoing first) and there was again a fair degree of encrustation to be seen.  I've been told that the small hole size in this casting is correct for the TR4A, whereas the TR4 had a noticeably larger drilling. Again things were only cleaned up before the pipe was refitted.  There was also hard rust deposits within the first 1-1/2" of the rubber pipe ends. I used a small rotary wire brush to get rid of those and then wiped the inside of the pipe with a smear of silicon grease before refitting.

Can anyone explain why the difference in this pipe's hole ?

 

The next and final job of the day was to get up-close-and-personal with Katie's  fan . .

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^ The four blade fan is pretty useless at best and ..if possible, even more so when fitted back-to-front and with one blade slightly bent.  The fan's rotation is anti-clockwise when looking forward from the engine and so the ribs in the aluminium blade ought to face forward ..to offer a mediocre of leading-edge shape to the otherwise lacking aerofoil.  As fitted, reversed / rotated 180-deg. - the overall blade angle of attack is the same but the leading edge is facing backwards and so would induce stall.

Hey ho, it is an easy mistake to make but a pain-in-the-access to correct. Getting a spanner onto and undoing the four bolts has one's knuckles scraping over the radiator core, which feels similar to a cheese grater.  They did however come out and the fan was removed with the radiator in situ. .

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^ The existing, surprisingly heavy fan with aluminium blades but a hub of two layers of steel. And its replacement ..a very lightweight plastic contoured-blade fan from the TR6 (also GT6 &/or Triumph 2000 perhaps) which has the same pcd / hole spacings.  So it's a straight swap, except that the TR6 fan's hub is level with the back edge of the blades (not the middle of their roots) - and when fitted this pushes the fan 1/2" further forward than the TR4 type. Awkwardly too, its fastening bolts (those from the TR4 are fine to reuse) sit into the bottom of the cup (hub) ..and that makes it very much more difficult to fit them, not least because a flat or ring spanner cannot be used. 

The cardboard shroud between the radiator and the grille prevents the radiator from simply being unbolted and pushed forward.  But I was able to lift the radiator and rest it on a block of wood, without having to drain or totally lift it out.   In retrospect that might have been easier though. 

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^ It looks a reasonably clean working environment (outside) but this is after sweeping up the sand and dust that blows literally everywhere.

..so laying on one's back with hair (or bald patch) in the wet I achieved this access  . .

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^ although I couldn't get a hand through that gap,  I could see what i was doing when reaching under the chassis, to get my fingers in to loosely fit the bolts and the plate. And then, with a 1/2" socket on a 1/4" drive ratchet I could get between the radiator and those bolts to tighten them up. Finally tightened with an 3/8" drive ratchet. 

P1380290s.jpg.9d7ab4a22bb7c77d577135f1ee9ad7f5.jpg

^ The original lock plate as removed off the TR4 fan. The central hole is hexagonal and it is supposed to fit / lock around the head of big bolt through the crankshaft's fan-extension. The four fan-securing bolts then lock it from unwinding.  I flattening and refitted the plate correctly, albeit inside the TR6's fan.  And after fitting and final tightening I even painted it (using a toothbrush to get in there). 

P1380283s.thumb.jpg.314569cbc623a0f10e4020ff8805ae97.jpg

^ While the fan was off I took a couple of photos of the fan-extension on this car, which  is interesting ..insomuch as it appears to have been modified to clear the steering rack . .   So I have to ask - is the engine sitting low or is the rack sitting high ? 

Some of you might wonder why I take so many pictures ?  Well that's because very often I can see more from a photo, taken with a camera in a position I'd never get my fat head in.  For example, the eagle eyed among you might have spotted the U-clamp which is securing the steering rack. !  I hadn't spotted that from above.  

I wonder how long Bob's been driving it around like that ? 

An equally interesting question might be what else has rusted away because an overflowing radiator has been ignored for years ?

P1380296s.thumb.jpg.1fdb928a1b037e249677c432ecba5c55.jpg

^ TR6 cooling fan in place. Admittedly it's not very 1960's but I prefer it to fitting an electric fan.  And very oddly ..with the engine running on fast tick-over.. the blast of air coming back and down the side of the engine (where it is safer for fingers) is in stark contrast to what was not at all happening with the original fan (as that was fitted).  

Although it's only 2-1/2 miles from the dust bowl to home.. already the temperature gauge suggests things are noticeably better than they were.

These are just single steps at a time ..but they do seem to be in roughly the right direction.  

But I'll not use the car until the steering rack fastening is corrected.

So that's all for right now,  I bid you a good weekend. 

Pete.

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The fan extension has probably been worn away by rubbing on the rack. On my car that was because the extension was loose on the crankshaft, and the Woodruff key was worn to less than half its thickness.

Pete

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Thanks Pete,

I didn't notice any slack in the fan extension as I removed the old fan and fitted the TR6 one, but then I wasn't looking for that.  Next time I have the bonnet open I'll grab it and see if I might discern any movement. 

Mind you this fan belt make a row.  I did slacken it a tad yesterday to see it it might help but I suspect its polished and perhaps the rubber burnt from it having been too tight for too long.

P1380287s.jpg.d0024b59062ea566d1cfab894d2b61f3.jpg

 

Cheers, Pete.   

 

Edited by Bfg
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Afternoon Pete, looking like your getting your water problem sorted, as you have no antifreeze in yet looking at all that crud from your pipe work I would take out the radiator not much of a job, and give it a good clean out by shaking it around with water and radiator cleaner you get more crude out doing it this way than just flushing with a hose pipe. I would also disconnect the heater hoses and flush that out both way but with not to much pressure.

Mike Redrose Group 

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Thanks Mike, I plan to replace all the hose very soon, so I'll be flushing the heater out at that time.  I wonder if it's worth my while taking the radiator to a professional to be properly cleaned out and pressure tested ..just to be certain.?  I have no idea of the cost but I believe Rich C-R uses an establishment in Colchester which isn't too far away for me. 

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If you do take the rad out Pete, give the crankshaft dog bolt a tweak to make sure it's tight. Your fan belt looks to me as if it's been running too loose for too long, so it's bottoming in the pulley.

That extension does look rather low though, how are your engine mounts?

Pete

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 "give the crankshaft dog bolt a tweak to make sure it's tight. "

Good point, it's likely got a crankshaft dog bolt holding the front pulley on (with rounded corners as a hangover for when a cranking handle would be used on it) which is a Grade 5 bolt of 5/8th UNF and a capacity of 150 lb ft.

The workshop manual for TR3s says give it 140 lb ft, but it's 50 years old now and as a deference to age I tighten them to 120 lb ft and have never had one come loose. Which is just as well because I've found 6 engines amongst those I've stripped which had come loose and when being rebuilt only had 40 or 50 lbs on them (typical ring spanner limits), and had nasty additional machining carried out into the side of the woodruff slot in the pulley by the crankshaft woodruff key, giving an additional 6mm side clearance on the key in the worst case, and a nasty "clacking" sound. Use a 1 1/8th AF single hex socket which drives on the flats on the bolt, put the car into 1st gear and blocks in front of the rear wheels which should get you there.

Mick Richards   

Edited by Motorsport Mickey
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