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Unleaded Conversion


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They showed the TR6 makeover on Wheeler Dealers yesterday again, and I wondered if others here had had it done for the 300 quid they paid?

 

Also if Lead provided a 'soft' seat for the Valves, how come they insert 'hard' seats for unleaded ?

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Hi Denis

I had the head done a few months ago, mainly because the gasket blew big time. So while the head was off I checked the valve seats and they all leaked so I decided to have the head unleaded, the company I used was very local and they skimmed it slightly, new valve’s, seats and guides. Cost me £550. Probably would have been cheaper to send it to Pete Burgess up north but hey ho.

 

Re Hard seats, I nicked this off Wikipedia: - Tetraethyl lead works as a buffer against microwelds forming between the hot exhaust valves and their seats. Once these valves reopen, the microwelds pull apart and leave the valves with a rough surface that would abrade the seats, leading to valve recession. When lead began to be phased out of motor fuel, the automotive industry began specifying hardened valve seats and upgraded exhaust valve materials to prevent valve recession without lead.

 

Sorry if this is not what you ment. :unsure:

Edited by Kevo_6
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HI, I called www.knightengineservices.co.uk/ just outside Northampton a few weeks ago looking to see what was involved and what the costs were to convert a TR4 head, not 6, but don't imagine the costs would be more than 50% more (for the extra 2 cylinders).

Had quite a long conversation and he told me depends on what you need doing (guides,etc ...) but he said for the basic 4 exhaust values and seats and including a skim, £200.

He said the inlets were normally ok. But he could do anything needed up to including replacing all the values and guides if I wanted.

I rang 2 or 3 in my local area and this guy came across as knowing what he was talking about.

 

Plan to send the head over to him later in the year once she's laid up for the winter. He did say that I'd have to strip the head as this would be an extra costs if he had to strip and rebuilt.

 

Also thinking of using him to put in 89mm pistons and liners along with any other machining that might need doing as part of on going rebuilding process.

 

Mark

Edited by MRG1965
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  • 2 years later...

HI, I called www.knightengineservices.co.uk/ just outside Northampton a few weeks ago looking to see what was involved and what the costs were to convert a TR4 head, not 6, but don't imagine the costs would be more than 50% more (for the extra 2 cylinders).

Had quite a long conversation and he told me depends on what you need doing (guides,etc ...) but he said for the basic 4 exhaust values and seats and including a skim, £200.

He said the inlets were normally ok. But he could do anything needed up to including replacing all the values and guides if I wanted.

I rang 2 or 3 in my local area and this guy came across as knowing what he was talking about.

 

Plan to send the head over to him later in the year once she's laid up for the winter. He did say that I'd have to strip the head as this would be an extra costs if he had to strip and rebuilt.

 

Also thinking of using him to put in 89mm pistons and liners along with any other machining that might need doing as part of on going rebuilding process.

 

Mark

Hi Mark,

I'm looking into getting the head done...did you ever use the company you mentioned as I am not far from Northampton.If so did they do a good job

 

Regards

Richrd Young

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If you are looking to have the cyl. head overhauled for unleaded always have the following checks/ work done

 

1) Flatness of head face, TR6 heads warp? Often the reason for blown head gaskets, especially early heads! Later recessed block heads are very much less prone.

2) Valve seats warp and for cracking between valves seats, again early heads are more prone. Later heads were modified to combat 1 & 2?

3) When re-cutting valve seats only go for the 3 angle cut seats, not the single cut, less pressure required to seal and no heavier valve springs than TR5, as cam lobes/followers will suffer.

4) Valve guides can be bronze lined, this saves some money. This now seems to be common practice.

5) Exhaust valves s/b high grade s/steel.

 

Bruce.

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