Author Topic: AVL 500 Valve seats  (Read 264 times)

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allanfox

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on: May 19, 2021, 09:34:01 am
Morning, I have my 500 AVL top end off at present (long story) and found this, should the valve seats stick out so far?

Just doesn't look right and I have never seen seats that protrude so far into the combustion chamber before, not sure if bad manufacture (3000 miles) or of they have dropped (but both the same) or even if that is what an AVL head is supposed to look like, what do you think guys?


tooseevee

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Reply #1 on: May 19, 2021, 11:51:55 am
Morning, I have my 500 AVL top end off at present (long story) and found this, should the valve seats stick out so far?

Just doesn't look right and I have never seen seats that protrude so far into the combustion chamber before, not sure if bad manufacture (3000 miles) or of they have dropped (but both the same) or even if that is what an AVL head is supposed to look like, what do you think guys?

           Welcome & be patient, my friend. You will soon get comments from guys way more expert than I. All I will say right now is "That shore don't look copacetic to me".
'08 Black AVL Classic.ACEhead 9.8:1/manifold/canister. TM32/Open short bottle/hot tube removed. Pertronix Coil. Fed mandates removed. Gr.TCI. Bobber seat. Battery in right side case. Decomp&all doodads removed. '30s Lucas taillight/7" visored headlight. Much blackout & wire/electrical upgrades


ace.cafe

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Reply #2 on: May 19, 2021, 12:05:36 pm
They should not protrude out into the combustion chamber like that.

It should look like this picture.
« Last Edit: May 19, 2021, 12:11:38 pm by ace.cafe »
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Bullet Whisperer

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Reply #3 on: May 19, 2021, 01:17:49 pm
Cut them back, they are all too often like that - not good at all. They impair breathing and you will get increased scope for more valve lift and duration, should you want it, if you cut them back.
 B.W.


allanfox

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Reply #4 on: May 19, 2021, 01:22:02 pm
They should not protrude out into the combustion chamber like that.

It should look like this picture.

Thankyou, what I had expected to see when I took my head off!


allanfox

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Reply #5 on: May 19, 2021, 01:31:57 pm
Cut them back, they are all too often like that - not good at all. They impair breathing and you will get increased scope for more valve lift and duration, should you want it, if you cut them back.
 B.W.

Thankyou, does just look like sloppy manufacturing/finishing, I think I may have found Pandora's box in this engine!  :) 


allanfox

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Reply #6 on: May 19, 2021, 01:33:11 pm
           Welcome & be patient, my friend. You will soon get comments from guys way more expert than I. All I will say right now is "That shore don't look copacetic to me".

Sure I am in the right place!  ;)


Beavs1906

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Reply #7 on: May 19, 2021, 02:05:11 pm
Definitely not I would say it would create a bad hot spot  . Is there a gap behind the seat ? .


allanfox

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Reply #8 on: May 19, 2021, 03:48:17 pm
Definitely not I would say it would create a bad hot spot  . Is there a gap behind the seat ? .

Not really just not pressed in far enough and /or not cut back after fitting, sure local engine shop will be able to advise!


AzCal Retred

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Reply #9 on: May 20, 2021, 01:38:04 am
Those may be "Madras Glowplugs", designed to assure fuel vaporization as the intake charge passes over the white-hot edges and eliminate the need for expensive spark plugs after running for awhile... ;D

That is a truly harsh thing to find inside the engine! Maybe the seat recesses weren't originally cut deep enough? Looks like a trip to a good Machine Shop is in order - post pics of the "after", OK?
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Adrian II

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Reply #10 on: May 20, 2021, 10:57:21 am
Same advice as you got on the Hitchcocks' forum, Allan?  ;)  ;D

"There is safety in a multitude of counsellors", though those words of wisdom pre-date social media!

A.
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allanfox

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Reply #11 on: May 20, 2021, 02:24:51 pm
post pics of the "after", OK?

Will do!


allanfox

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Reply #12 on: May 20, 2021, 02:28:13 pm
Same advice as you got on the Hitchcocks' forum, Allan?  ;)  ;D

"There is safety in a multitude of counsellors", though those words of wisdom pre-date social media!

A.

Both points very true, we can cast a wide net now via the forums, makes you wonder what we did before!   ;)


heloego

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Reply #13 on: June 05, 2021, 06:34:15 pm
Oooh, that's a sick thing from the factory. Seats need to be removed and the head cut cut deeper. Recommend new seats fer sure! Hope the rest of the engine was done better!
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Adrian II

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Reply #14 on: June 06, 2021, 10:10:50 pm
No need for new seats, just cut those back until the outer edges are flush with the surface of the combustion chamber, there's plenty of valve seat material there.

A.
Grumpy Brit still seeking 500 AVL Bullet perfection! Will let you know if I get anywhere near...