Six pot engine rebuild tips

[JimEB]

Hello  :)

I reckon that sooner or later I'll have to give my PI's engine some fettling or maybe an upgrade or two  :)

I'm a novice engine builder but am mechanically minded, although it's the little tips and tricks I'm lacking, e.g. spotting faults or damage specific to components (to ensure the right new parts are sourced) and how to ensure things are lubricated properly on reassembly (to avoid wrecking on first start-up). Consequently, I thought I'd start this thread to share the knowledge and experience within CT  ;)

All tips and tricks gratefully received!  :)

[Sheepy]

Take pictures as you do it, then when you have any questions, or advice needed we can help!  ;)

[Richard B]

Best improvement I found for a MkII PI was a lightened flywheel.  ;D

[Tim Bancroft]

Going on from Richard's comments, I'd consider getting the crank, rods, pistons, clutch, flywheel and damper all balanced-smoother engine.

Hardened seats for the exhaust valves.

Nice clean and clear working space, Decent torque wrench, Payen gaskets, camlube or at the least STP for the camshaft, Stanpart manual for correct torque settings, get the block's waterways thoroughly cleaned out,take your time...... etc etc

[Nick Jones]

Jim,

Thought the car had only done 40K?  Should be 100k or so left in it.....  :P  Mine was at about 139k when rebuilt and the main problem was due to rusty bores from standing - otherwise a set of shells would have sorted it.

Agree with the above.  Balancing and lightened flywheel are very worthwhile.  
Some light fettling of the head is also worthwhile and will help efficiency as well as power.
Could go up to a TR5 spec cam (MU changed to match) but mine makes 145bhp and a fat torque curve on the standard cam with just some headwork and a TR6 manifold.  Yes electronic management as well but I don't think that makes any more power than well set up PI.

Nick

[JohnD]

This comprehensive engine build guide is about Triumph four cylinder engines but can be easily interpreted for sixes.
http://www.totallytriumph.net/spitfire/engine_building.shtml

One essential item for an engine with that long crankshaft is the crank damper pulley.    The outer and inner parts are joined by a thin rubber ring, bonded to each.    The rubber can perish and the two parts move in relation to each other.    As the TDC markings are on the outer you lose accurate TDC indication from the pulley.    So at some stage, such as before you install the cam shaft, check that the real TDC corresponds with the indicated position.

And to find TDC, don't rely on trying to tell from a dial gauge on the piston top.  Make up a piston stop.  See:
[Sorry, link no longer available]

John

[JimEB]

4058 wrote:

Take pictures as you do it, then when you have any questions, or advice needed we can help!  ;)

That's a damn good idea, thanks!

[JimEB]

timbancroft61 wrote:

Going on from Richard's comments, I'd consider getting the crank, rods, pistons, clutch, flywheel and damper all balanced-smoother engine.

Hardened seats for the exhaust valves.

Nice clean and clear working space, Decent torque wrench, Payen gaskets, camlube or at the least STP for the camshaft, Stanpart manual for correct torque settings, get the block's waterways thoroughly cleaned out,take your time...... etc etc

All sensible comments, thanks Tim  ;)

[JimEB]

Nick_Jones wrote:

Jim,

Thought the car had only done 40K?  Should be 100k or so left in it.....  :P  Mine was at about 139k when rebuilt and the main problem was due to rusty bores from standing - otherwise a set of shells would have sorted it.

Agree with the above.  Balancing and lightened flywheel are very worthwhile.  
Some light fettling of the head is also worthwhile and will help efficiency as well as power.
Could go up to a TR5 spec cam (MU changed to match) but mine makes 145bhp and a fat torque curve on the standard cam with just some headwork and a TR6 manifold.  Yes electronic management as well but I don't think that makes any more power than well set up PI.

Nick

Yep, now rocketed to 43k!  ;D

The engine is (thankfully) strong, doesn't burn any oil, crank end float is fine, but this thread is about capturing hints and tips for the future  :)

It's just that at some stage I'll probably want to warm up the engine a little  :)

[JimEB]

JohnD wrote:

This comprehensive engine build guide is about Triumph four cylinder engines but can be easily interpreted for sixes.
http://www.totallytriumph.net/spitfire/engine_building.shtml

One essential item for an engine with that long crankshaft is the crank damper pulley.    The outer and inner parts are joined by a thin rubber ring, bonded to each.    The rubber can perish and the two parts move in relation to each other.    As the TDC markings are on the outer you lose accurate TDC indication from the pulley.    So at some stage, such as before you install the cam shaft, check that the real TDC corresponds with the indicated position.

And to find TDC, don't rely on trying to tell from a dial gauge on the piston top.  Make up a piston stop.  See:
[Sorry, link no longer available]

John

Brilliant info John, thank you!  ;) I've already seen the finding TDC thread - interesting, understandable reading.

[JimEB]

Richard_B wrote:

Best improvement I found for a MkII PI was a lightened flywheel.  ;D

Have you got a spare one Richard?  :P

[rotoflex]

Stake the thrust washers.

[69vitesse]

rotoflex wrote:

Stake the thrust washers.

Why? They only drop out after huge milages and years of neglect.

[69vitesse]

4247 wrote:

Hello  :)

I reckon that sooner or later I'll have to give my PI's engine some fettling or maybe an upgrade or two  :)

I'm a novice engine builder but am mechanically minded, although it's the little tips and tricks I'm lacking, e.g. spotting faults or damage specific to components (to ensure the right new parts are sourced) and how to ensure things are lubricated properly on reassembly (to avoid wrecking on first start-up). Consequently, I thought I'd start this thread to share the knowledge and experience within CT  ;)

All tips and tricks gratefully received!  :)

Practical Classics have been running a Triumph 6 rebuild series.

[Slimboyfat]

2729 wrote:

Why? They only drop out after huge milages and years of neglect.

Thirty odd years ago we bought several hundred warranty engines from BL that had sat out on the car park at Canley for a few years.

Bearing in mind these were all less than 12 months old when exchaged a surprising number of them had dropped a thrust, or chucked a rod.

[JimEB]

2729 wrote:

Practical Classics have been running a Triumph 6 rebuild series.

Yep, I've heard of this. I've also received via a CT forum user the scan of a fantastic article from Classics Monthly, October 2009  :)

[rotoflex]

2729 wrote:

Why? They only drop out after huge milages and years of neglect.

Still, would you want to find that years after a very good rebuild you must rebuild again, only because the thrust washers dropped?  And worse still, discover expensive damage to the crankshaft & block due to the thrust washers having dropped?

[Nick Jones]

Get some solid phosphor bronze thrust washers from here
http://www.customthrustwashers.com/

Lovely work

Nick

[piman]

Hello Nick,

reading his story, his description of the original thrust washers doesn't seem right. Admittedly it is many years since I have rebuilt an engine but my memory is of white metal style bearings, rather than a thin copper plate? Certainly his replacements lasted no time at all, so possibly some sub standard replacement?

Alec

[Hughbert]

I managed to get some Triumph BL OEM thrust washers last year still in the BL boxes still wrapped and they were  a white metal alloy type so did they do two types as the supplier above states his are superior which is a big claim and that the Triumph ones were only plated steel.

So how did I buy OEM Triumph white metal alloy ones :-/ and have seen others for sale too stating white metal alloy?

[Nick Jones]

Looking through the selection I have, some are clearly white metal and the used ones mostly show some signs of distress.  I also have some with coppery/bronze coloured faces, though still on a steel backing, which seem to fare better and I know there are some who rate these alot more highly than the white metal ones.  I have also seen comment that if you only have one of the coppery/bronze coloured ones, fit that on the more highly loaded flywheel side, so I guess the same goes for the solid PB ones.

Nick

[Hughbert]

Like most things that are old classic car related stories get around embellished etc someone has a bad part which was more down to the crap quality control of the time than the actual engineering and before you know it its gospel. As most of us have a car that was never thought at the time by the designers or engineers who originally built them would still be running around in 2013 they did the best they could with what technology, materials and the budget available to them and they did a good job .

Now today we have greater access to better materials and to a certain extent no budgets imposed on us the owner of our cherished car so we fit the best of modern parts/materials available to us. But we forget that what the chaps back then had was nothing like we have today. So many of us criticise parts that fail that were never designed to do the job they have done for so long. Then some part is made in a new material and the old part is crap so an other myth starts about poor quality parts designed and made in the days of BL.

[esxefi]

I made some solid PB washers to fit to my bro in laws' car(now sold) a few years ago and the old ones I removed were steel backed with a copper? bearing material.they looked like OE parts and had a stamping on the rear.

[Nick Jones]

Hugh,

Completely agree.  I've never had a TW problem myself in 25 years />>100k miles or even seen one in the flesh.  Have seen a good few battered looking washers though - mostly removed from one or other of the 1500 engines that lived in my Herald (they looked better than the other bearings though  :'()

The copper faced ones I have are stamped "AE" on the back.

Nick

[99176]

Equalize piston heights regardless of whether you want them recessed, level or proud.