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Conquest Piston Ring

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HenryC
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Posts: 402
Joined: Mon Feb 15, 2016 8:31 pm
Location: Surrey / East Hampshire

Conquest Piston Ring

Post by HenryC »

Hello,

Does anyone has a new standard size piston ring I could have, buy or borrow.

I have stripped a seized conquest century engine which I hope to rebuild. I can't detect any significant wear in the bores but the old rings have a too large a gap. Before buying a complete new set of rings, I would like to check that the gap is not excessive, using a new ring, ie the bores are not too worn.

I would like to use the block as it is, rather than going for a rebore and new set of pistons but don't want to lash out on new rings if they're not going to work.

Can anyone help?
Cheers, Henry Curwen
Registrar for Conquest & Century Saloons (DJ250/1, DJ256/7, DJ260/1)

Conquest (Drop Head) Coupe DJ252

Db n j
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Joined: Sun Mar 13, 2016 8:55 am
Location: uk shropshire

Re: Conquest Piston Ring

Post by Db n j »

Henry,

I'd give John Chatfield at Thornton's (Telford) - he is a very helpful chap, and a Daimler enthusiast to boot.

HenryC
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Posts: 402
Joined: Mon Feb 15, 2016 8:31 pm
Location: Surrey / East Hampshire

Re: Conquest Piston Ring

Post by HenryC »

Thanks David,

I've emailed them and I'll give John a ring if I don't hear anything soon. It's always good to talk!

You and Marcel both gave the same advice. Must be good!

Thanks again.
Cheers, Henry Curwen
Registrar for Conquest & Century Saloons (DJ250/1, DJ256/7, DJ260/1)

Conquest (Drop Head) Coupe DJ252

Stan Thomas
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Re: Conquest Piston Ring

Post by Stan Thomas »

Good morning HenryC,

To accurately measure the bores for wear you really need a bore guage, or failing that, one of those cheap telescopic gauges and a mike (unless you have already done that)!!

However, the cylinders of your engine have Cromard liners - which are known for their low wear-rate, although I understand where you are coming from in checking by sizing with a new ring. If Thorntons cannot help, try Cox and Turner on 01935 826816 or H.P. Rings on 01246 261299 - although they might need the actual dimensions of the ring (i.e thickness and width) other than bore size.

That said - is there any "lip" at the top of the bores - as this is the best indicator of bore wear, and just exactly what is the "too large a ring gap" you speak of?

HenryC
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Posts: 402
Joined: Mon Feb 15, 2016 8:31 pm
Location: Surrey / East Hampshire

Re: Conquest Piston Ring

Post by HenryC »

Hi Stan,

Thanks for your comments and the suppliers names.

I can't feel a lip at the top of the cylinder. It's been a while since I checked the ring gap but I think it was 35 thou. New should be 9 -14 thou.

I expect the engine would run ok with 35 thou gap but I would like to build the engine as best I can. I hope to use the car a lot and on long distances.
Cheers, Henry Curwen
Registrar for Conquest & Century Saloons (DJ250/1, DJ256/7, DJ260/1)

Conquest (Drop Head) Coupe DJ252

Stan Thomas
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Joined: Sat Feb 13, 2016 2:14 pm
Location: Penkridge. Staffs.

Re: Conquest Piston Ring

Post by Stan Thomas »

Here we go - more urban myths to destroy!!

Contrary to popular belief, piston ring gaps are irrelevant within reason, unless of course they are too small and the ends butt up upon expansion.

Test conducted by piston maker Hepworth and Grandage years ago did not show any difference in working output of an engine when piston ring gaps were set at four times the stipulated amount - which we mirrored in the actual tests we ran at Tec back in the 1970's.

So all in all, i'd say there is no problem with your cylinder bores HenryC, and all you need to do is treat youreslf to a new set of rings and run a glaze-buster down the bores to help them bed in - then run on some el-cheapo oil for the first 500/800 miles (or use "runing-in" oil if your feeling rich) - to complete the process.

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