Author Topic: Valve seats  (Read 325 times)

Offline A10 Tim

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Valve seats
« on: 28.05. 2017 08:57 »
Hi all.
       Can any body tell me do my valve seats need to be cut.
I've given the valves a little grind in with fine paste, and seem to be a good area of grey contact between valve and seat, but there is a bit of a ridge is this normal.
Many thanks,
                   Tim.

Online Triton Thrasher

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Re: Valve seats
« Reply #1 on: 28.05. 2017 09:26 »
They are pocketed and there is probably performance to be gained from someone making a good job of relieving the outside face.  Mine were worse than that and I eventually coughed up for seat inserts, done by SRM.

Do you need more performance?

Offline muskrat

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Re: Valve seats
« Reply #2 on: 28.05. 2017 12:31 »
G'day Tim.
It's a bit hard to see but I think the contact area is a little large (and rough). 1.75mm for inlet and 2.5mm for exhaust. Any engine re-conditioner could cut/grind them back at a reasonable price. Looks like you'll get one more cut before inserts are needed.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline coater87

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Re: Valve seats
« Reply #3 on: 28.05. 2017 14:56 »
 They are a little shaded, but I have seen much worse on engines that runs like a top.

 What happens by the valve being slightly masked by the material around it is your flow becomes a little less. You flow less air/fuel, and  less exhaust gasses through the exhaust valve because the opening is masked from the combustion chamber.

 This is a big deal to guys who push for performance, flow is performance.

 For me, my days of driving anything overly fast are over. So when I reworked my iron head, I took one look down the intake port and knew whomever designed that head gave two rips about flow. Matter of fact, peak down yours and stare at the big square wall that separates the chambers. Nothing to restrict a smooth intake flow there........ *eek* ;)

 Mine are shaded more than yours, and like Musky said the next time I tare into the head it will get seats added. You dont want them to go too deep, so I would have a valve job now and plan for seats in the future if I were you.

 Lee

 
Central Wisconsin in the U.S.

Online chaterlea25

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Re: Valve seats
« Reply #4 on: 28.05. 2017 15:43 »
Hi Tim,
I can see roughness on the inside of the exhaust guides?
That would concern me more than the pocketing of the seats?
How much play between valve and guide?
A 30 degree cutter can be used to remove some or all of the ridges around the valves
New guides means recutting the seats

John
1961 Super Rocket
1963 RGS (ongoing)

Offline A10 Tim

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Re: Valve seats
« Reply #5 on: 28.05. 2017 19:19 »
Thank you all for your advice, ok it's off to the engineering shop for maybe the last cut,
And check the guides.
Thanks again
                  Tim