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No.3 pot has been low on compression since car was re-commissioned in 2013, but lately it's got a lot worse, now around half the value of the other 3.

Car still running ok, so I was going to leave it till I stripped the whole engine. With the current restrictions, I decided to whip it off now to see what was happening.

Following a suggestion from Hamish, today I made an adapter out of an old spark plug to allow me to inject compressed air into the pot.

So rocker box off, turned engine till No. 2 rockers were rocking, so that I knew both valves on No. 3 will be closed. (yes there was clearance between valves & rockers)

inject air at approx 50 PSI, & lo & behold lots of air exiting from the exhaust (none form carbs). Result, so now I know what to expect to see when head comes off.

This could be interesting, as it was last put on by the Triumph factory circa 1965 (factory recon engine)

Bob.

1666382418_Headleaktester.jpg.4036f089a8389f126f83e2d384c4a6c7.jpg

Edited by Lebro

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That's a good idea. Be interesting to know what you find when the head is off the engine.

Nigel

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I reckon that's a cast iron warranty claim !

Mick Richards

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That is a really canny idea from Hamish! 
 

i once made a TDC tool out of a spark plug, as pic.post-9473-0-54928800-1514739882_thumb.jpeg

wonder what other uses they have ......

steve

Edited by Steves_TR6

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27 minutes ago, Motorsport Mickey said:

I reckon that's a cast iron warranty claim !

Mick Richards

Just can’t get the workmanship that lasts nowadays :rolleyes:

 

steve I can’t claim anything. Saw the pressure test idea on tv  that it could show either inlet or exhaust valve bypass or rings or head gasket depending on where you could hear the air escape and bob made up his own adapter. 

Edited by Hamish
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What a great idea

:D

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It is a good idea and this has actually been a standard practice on piston aero engine for many years. Google Lycoming pressure test for some good info. 

( It is also standard practice to cut up the old oil filter on each change to see if the bits are getting any bigger etc)

I hope you sort it Bob

Rog

 

 

 

 

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AKA leakdown test.  As Bob, found listening for air movement can tell you a lot.  I got a cheap leak down tester from eBay some time ago, very useful and indeed it can tell you more than a compression test.

Edited by peejay4A

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5 hours ago, peejay4A said:

AKA leakdown test.  As Bob, found listening for air movement can tell you a lot.  I got a cheap letdown tester from eBay some time ago, very useful and indeed it can tell you more than a compression test.

Ditto, I think my leakdown tester cost £15 onEbay.

Rgds Ian

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Itching to start the job, but Gaskets not yet arrived, so waiting till they do.

Bob.

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Thanks Bob / Hamish .. I'd not seen that adapter before. Good idea.

Pete.

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Update - gaskets here, so here we go :o

Bob.

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On 4/5/2020 at 5:27 PM, Steves_TR6 said:

That is a really canny idea from Hamish! 
 

i once made a TDC tool out of a spark plug, as pic.post-9473-0-54928800-1514739882_thumb.jpeg

wonder what other uses they have ......

steve

Damn good fishing weights

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Hi Bob,

let us know what you find...i guess if its factory engine then its gonna have soft valve seats and potentially a recession/burnt valve issue?

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OK, so everything is disconnected, head is free to lift off, except it wont ! (not really surprised !)

I have got a couple of mm lift at the front, but the back won't budge. I am using an engine crane, which started off attached mid way along the head, I have now got it almost at the back, and left it hanging while I have lunch & think about the next step.

Any ideas ???

Bob.

IMG-20200408-WA0009.thumb.jpeg.82b7285c025188735e55e5f2bbed7736.jpeg  IMG-20200408-WA0011.thumb.jpeg.d502b5bc3811ae9aa2a55c0af9e01ea0.jpeg

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Have you taken out the rear exhaust stud? it is sometimes screwed in tight to the head stud.

Stuart.

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I did try, & also the front, but both resisted turning using the two nuts locked together method.

Will try again. not enough room to get my stud extractor on it without removing the exhaust manifold, which I was hoping not to have to do !

Thanks for the tip - back to it.

Bob.

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Bob - Have you tried undoing the head stud which the exhaust manifold stud may go into?

Don't want to worry you, but it took me 3 days to get the head off and that was with an engine out of the car and the whole thing suspended off the head! No luck - in the end I used a rotary stop hammer drill with a blunt chisel on top of the studs ( located by a head nut, half on,  to stop it from jumping off. Very very slowly I was able to get it to move - the engine was seized so I couldn't user the old rope trick ( feed rope into a cylinder at TDC via the spark plug hole and then turn engine over on the starter and it should push head off on the compression stroke!)

Be patient and you will get there without damaging too much!

Good luck cheers Rich

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I'd try any and all studs for a double nut removal Bob, as stated above a blunt chisel in a hammer drill giving it a couple of Brrrrppps on the ends often breaks inside corrosion and you may get lucky and remove a couple. If you are resigned to lifting the liners the rope trick may just lift the stubborn end, and then sort out later.

Mick Richards 

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Lebro,

Six cylinder (and Spitfire) experience is that the head doesn't stick to the block, but to the studs.    Remove the studs, and, with luck, the head will come off.

  • Stud removal can be by double nutting - rarely works and stresses the threads.
  • A stud removal tool - preferentially a roller type, not cam type, but there may not be enough stud projecting for that
  • Welding a nut on the stud!   The heat helps, and all the above makes new studs necessary, so why not?

 

Doesn't always work - a friend with a Rolls and an alloy head had great difficulty unsticking all the studs and even then it took ages to shake the block off the head.

Good luck!

John

Edited by john.r.davies

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Rear manifold stud removed by welding nut onto it. 

20200408_160637.jpg.6975d9671f7c8f14894fbccd6f83acf8.jpgMuch use of engine hoist, & various thicknesses of bolster chisels have got it to here:     20200408_160614.jpg.76a166b6abd12e8ce8bbfc19b01dc672.jpg Hope not too much damage done :o

Only one stud causing the problem - this one:  20200408_160619.jpg.cbbbc3fe7d59854c3304ec2b86f83acd.jpg  Left it with plus gas sitting in the hole while a cup of tea was consumed.

Onwards & upwards

Bob.

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Hi Bob,

Drink some more tea and treat the head to a cuppa WD40 or your plus gas for a night soak.

Maybe lower it and lift it to clear deposits will help.

Cheers,

Waldi

 

 

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IMG-20200408-WA0022.thumb.jpeg.2a1af3d0edd6f1c05ec2499c7a2f5b72.jpeg 'tis off, much energy exerted, & much vandalism with crowbars etc. but seem to have got away with it.

20200408_170926.thumb.jpg.f0775645d55af632ed299550e5cbc251.jpg  20200408_170948.thumb.jpg.b68d3e682268cef2b4621e4e4d23f48b.jpg  20200408_170958.thumb.jpg.0f9527cf92c88ff3b3c772f53fe2af21.jpg  20200408_171004.thumb.jpg.6a3731ae1e4fa9652c0ecc097d062da8.jpg

Think I can probably re-use the gasket ?  no sign of bad erosion on No. 3 Exhaust valve, but will see properly tomorrow when they are all out.

Interesting there does not seem to be the usual crack in the centre.

Bob (knackered)

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Hi Bob ~

I found this stud extractor very good when I renewed my 3A engine. You would be very welcome to borrow it but I'm afraid that

getting it in the Post is a big problem at the moment.

I think I bought it from Frost's??

Tom.

 

Edited by Fireman049

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