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Re Sleeving


Paul H
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2 litre Mk2/3 engines for the UK market all have domed pistons, whether fitted to Vitesse, GT6 or saloon. Triumph used the same basic cylinder head casting for 2 and 2.5 litre engines from the late sixties. To achieve a reasonable compression ratio, 2 litres have domed pistons and 2.5 litres have flat top.

Sleeving is both possible and accepted practice.

My question would be: why is the seller really wanting to dispose of this engine? Buying another engine to rebuild instead of repairing this one doesn't make sense... Unless perhaps this one is worse than described.

Nigel

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28 minutes ago, Nigel Clark said:

2 litre Mk2/3 engines for the UK market all have domed pistons, whether fitted to Vitesse, GT6 or saloon. Triumph used the same basic cylinder head casting for 2 and 2.5 litre engines from the late sixties. To achieve a reasonable compression ratio, 2 litres have domed pistons and 2.5 litres have flat top.

Sleeving is both possible and accepted practice.

My question would be: why is the seller really wanting to dispose of this engine? Buying another engine to rebuild instead of repairing this one doesn't make sense... Unless perhaps this one is worse than described.

Nigel

Thanks Nigel , so my mk2 vitesse HC xxxx has domed pistons ? 

Paul 

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26 minutes ago, Nigel Clark said:

2 litre Mk2/3 engines for the UK market all have domed pistons

Are you sure? I thought mk2 GT6 and very early mk3 (up to KE10000) had flat-top pistons, as do all Vitesse Mk2 and early mk2 saloon. The change to dome-top was, as you say, for a common head casting, but it wasn't done at the introduction of the Mk2 engine.

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1 minute ago, NonMember said:

Are you sure? I thought mk2 GT6 and very early mk3 (up to KE10000) had flat-top pistons, as do all Vitesse Mk2 and early mk2 saloon. The change to dome-top was, as you say, for a common head casting, but it wasn't done at the introduction of the Mk2 engine.

I didn't realise that, and thought the change to domed pistons came when the Mk2 engines adopted the TR5/6 type cylinder head, that is with the first Mk2 engines. Anyone know for sure? I'm happy to be corrected.

For what it's worth, my GT6 Mk3 engine KE14xxx has domed pistons.

Nigel

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I thought my mk2 vitesse HC xxxxx had flat piston heads as when testing for TDC with the plugs out and a screwdriver in I couldn’t detect a dome section . If it is domed would there be a telltale tab in the gasket rear 

Paul 

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I don't know about gasket tabs - the context I know them from is the recessed bore change on the 1300 engine. It's possible the same change happened on the 2L at some point and possibly simultaneous with the pistons / head casting / camshaft but it's decades since I've had the head off the GT6 so I don't remember that detail.

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3 hours ago, dougbgt6 said:

GT6 domed pistons came in in 1972 on  KE10001 

http://triumphspitfire.com/historyG3.html

Doug

Thank you Doug. Every day is a school day.

Back to the main question... Why does the eBay vendor really want to sell the engine he bought to rebuild that turns out to have two dodgy cylinders? It would be interesting to ask the vendor for close up photos of the cylinders in question. Surely it needs a rebore and six new pistons.

Nigel

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13 hours ago, dougbgt6 said:

Yeh, I wouldn’t touch it. There’s something he’s not telling.

Doug

I just read it that he is trying to do a very cheap job and so won't pay for a rebore or regrind, intending to get away with just fitting new rings and bearings as he has a STD set of both.

he mentioned resleeving as a way of using STD pistons as they tend to be much cheaper if picked up NOS as no-one wants them usually.

 

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14 hours ago, Nigel Clark said:

Back to the main question... Why does the eBay vendor really want to sell the engine he bought to rebuild that turns out to have two dodgy cylinders? It would be interesting to ask the vendor for close up photos of the cylinders in question. Surely it needs a rebore and six new pistons.

Nigel

In all probability he's bought another engine as a complete unit for far less than it will take to have this one rebored and then to source oversized pistons and rings. Depending on the cost of the rebore - say £50 per cylinder, that's £300 for the rebore, another £200 for pistons, add £40 for rings... over £500 if he wants to do them all properly, and on top of what he's already spent... so it could be the case that the costs are spiralling. He'll need to be very sure of the condition of the replacement engine, though, otherwise he could be back to square one again.

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1 hour ago, Colin Lindsay said:

In all probability he's bought another engine as a complete unit for far less than it will take to have this one rebored and then to source oversized pistons and rings. Depending on the cost of the rebore - say £50 per cylinder, that's £300 for the rebore, another £200 for pistons, add £40 for rings... over £500 if he wants to do them all properly, and on top of what he's already spent... so it could be the case that the costs are spiralling. He'll need to be very sure of the condition of the replacement engine, though, otherwise he could be back to square one again.

Hi Colin,

You're not as suspicious as me!

I was in a similar position to this eBay vendor when rebuilding a 2500S engine for my GT6 a couple of years ago. The original pistons were good enough to reuse with new rings  and four of the cylinders would have cleaned up with a light honing. The other two cylinders had scoring and corrosion pitting, necessitating a rebore. I had the engine bored +20.

I never regretted spending the extra money to do the job properly. The total cost of the rebore and new County pistons including rings was about £450 including VAT. If i had the block hones and pitted new rings on the old pistons, the cost would have been around £100, so in effect I paid about £350 extra for a 'proper job'.

One message here is that when buying an engine, whatever the buyer may say, you never really know its condition until you strip it down.

Nigel

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2 hours ago, Nigel Clark said:

One message here is that when buying an engine, whatever the buyer may say, you never really know its condition until you strip it down.

Nigel

True; I've had the Herald block rebored to +30 and bought new pistons and rings - I could have run as is but it was smoky and needed the work. At least this way I'll know it's been done, and properly. A total cost of about £400.

It all depends on what the vendor in this case wants as an engine for his own car, and how much he's prepared to spend in the end; maybe he's just scared himself off, when faced with the final cost? 

I'm not suspicious as it won't be me buying it! If I was, it might be a different matter... but then I'd be buying one with the expectation of having to complete the work from scratch, no matter what claims are made about previous work.

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