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Time To Change Valves?


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#1 happydude2012

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Posted 10 August 2018 - 08:35 AM

The tips of some of my valves are very slightly suffering with that flattening thing where the end looks abit like a chisel thats been hammered.

 

is this a thing? or should i just calm down and carry on? the valves need reseating whcih im doing as part of the refurb.



#2 harrythehat

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Posted 10 August 2018 - 08:52 AM

Hi

if you don't do anything it will stop you getting a true valve clearance reading and noisy tappets to boot

 

have them machined down or feeling confident fine grindstone



#3 nicklouse

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Posted 10 August 2018 - 08:55 AM

The tips of some of my valves are very slightly suffering with that flattening thing where the end looks abit like a chisel thats been hammered.
 
is this a thing? or should i just calm down and carry on? the valves need reseating whcih im doing as part of the refurb.

Pictures.

#4 happydude2012

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Posted 10 August 2018 - 09:32 AM

can upload photos, too big.

 

But check this out

 

https://youtu.be/7K0V19PH6s8

 

 

this is the latsest video of tapping;



#5 GraemeC

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Posted 10 August 2018 - 10:05 AM

Make the photos smaller!
That vid does not show us what you're asking about.



#6 nicklouse

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Posted 10 August 2018 - 10:07 AM

can upload photos, too big.

 

But check this out

 

https://youtu.be/7K0V19PH6s8

 

 

this is the latsest video of tapping;

then host them on Imgur.



#7 happydude2012

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Posted 10 August 2018 - 10:23 AM

https://imgur.com/a/DH5CTF7

 

 

Hope this works



#8 Retroman

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Posted 10 August 2018 - 10:28 AM

It certainly a thing that needs doing but as you are tearing it down soon anyway I would leave it till then

 

Otherwise you are doing 1/2 a job

 

Unless you can do a head swap



#9 happydude2012

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Posted 10 August 2018 - 10:29 AM

thanks guys

 

so why have the stems been hammered like that? 

Is it that the 1:5:1 rockers are slapping too hard on the valve stems? too much clearance and return at 15 thou?

Or could the double valve springs be too much?


Edited by happydude2012, 10 August 2018 - 10:30 AM.


#10 nicklouse

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Posted 10 August 2018 - 10:48 AM

looks like a very poor or misguided build to have that happen so soon.



#11 ACDodd

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Posted 10 August 2018 - 10:55 AM

You all must under stand that a performance based build wears out much faster than a stock engine.
I have found d over the years that optimum or highest average torque is achieved between 2&5krpm is found with 1.3 to 1.35:1 rocker ratio. Certainly higher ratios give more top end hp but usually at the cost of shorter service life in road applications. Use the minimum spring weight you can get away with and only enough rocker ratio to give you the biggest area under the curve for the cam chosen.
There is nothing stopping you using 1.5 rockers with cams for the street, but you must perform regular lobe lift checks. As soon as wear is found change the cam. The cam and followers in my experience when usesed like this become a regular service item. You need to budget for this when you spec your builds. Swiftune makes some of the best components available and there camshafts are very good. Just consider the mechanical stresses involved with the whole system including what you actually want in terms of service life from your engine.


Ac

Edited by ACDodd, 10 August 2018 - 11:13 AM.


#12 happydude2012

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Posted 10 August 2018 - 10:59 AM

looks like a very poor or misguided build to have that happen so soon.

 

With the greatest respect Nick, im not sure thats a helpful statement at all really. But typical of your style  ;D 



#13 ACDodd

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Posted 10 August 2018 - 11:08 AM

Valve tips also take a hammering using high lift rockers. Some of this can be offset by performing proper alignment checks and geometry correction during your dry build.

Ac

#14 happydude2012

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Posted 10 August 2018 - 11:15 AM

You all must under stand that a performance based build wears out much faster than a stock engine.
I have found d over the years that optimum or highest average torque is achieved between 2&5krpm is found with 1.3 to 1.35:1 rocker ratio. Certainly higher ratios give more top end hp but usually at the cost of shorter service life in road applications. Use the minimum spring weight you can get away with and only enough rocker ratio to give you the biggest area under the curve for the cam chosen.
There is nothing stopping you using 1.5 rockers with cams for the street, but you must perform regular lobe lift checks. As soon as wear is found change the cam. The cam and followers in my experience when usesed like this become a regular service item. You need to budget for this when you spec your builds. Swiftune makes some of the best components available and there camshafts are very good. Just consider the mechanical stresses involved with the whole system including what you actually want in terms of service life from your engine.


Ac

 

now thats advice! 

Luckily i do have a little pot of emergency mini cash for this type of thing.

And i will put a bit more away from now on taking this advice into consideration.

thanks AC. once again.



#15 happydude2012

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Posted 10 August 2018 - 11:16 AM

Valve tips also take a hammering using high lift rockers. Some of this can be offset by performing proper alignment checks and geometry correction during your dry build.

Ac

do yoi think whilst the engines out i would be just as well to replace the valves or just have the existing reseated?






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