 New engine tragedy, Broken valve stem |
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| Jetsetsurfshop |
 Apr 2 2016, 06:36 PM
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#1
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Senior Member  Group: Members Posts: 814 Joined: 7-April 11 From: Marco Island Florida Member No.: 12,907 Region Association: South East States  |
On my first outing with the new engine tragedy struck. While giving it a little bit of RPM the engine made a noise I never heard before and then dropped a cylinder. Limped it home and this is what I found today.
That's the top of the valve you see still with the keeper! Damn. Anyone have any thoughts on what happened here? Everything we did was the same as the last build except we installed a more aggressive camshaft. (IMG:style_emoticons/default/headbang.gif) Attached thumbnail(s) 
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| Valy |
Apr 2 2016, 08:52 PM
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#2
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Senior Member Group: Members Posts: 1,675 Joined: 6-April 10 From: Sunnyvale, CA Member No.: 11,573 Region Association: Northern California |
That's a lot of lift for stock adjusters. The force they apply when they start to push is too much off axis so it tends to bend the valve stem. That together with high RPM will brake the stem at the upper weakest point, where the retainers hold the valve.
I bet it's not an interface issue as that will bend and brake the valve near its head. I would recommend adjusters that have a moving foot like the 911 ones or the ones that have a ball in their foot. |
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Posts in this topic
Jetsetsurfshop New engine tragedy Apr 2 2016, 06:36 PM
Jetsetsurfshop Oh yeah
Broke the rocker arm too.
:headbang: Apr 2 2016, 06:37 PM Mark Henry Ouch :(
what valves are those? Used stock? Intak... Apr 2 2016, 06:59 PM
Jetsetsurfshop
Ouch :(
what valves are those? Used stock? Inta... Apr 2 2016, 07:05 PM stugray
Ouch :(
what valves are those? Used stock? Int... Apr 2 2016, 07:31 PM Jetsetsurfshop
[quote name='Jetsetsurfshop' post='2325100' date=... Apr 2 2016, 07:36 PM stugray
Did you have valve relief pockets in the pistons... Apr 3 2016, 09:48 AM Mark Henry
Ouch :(
what valves are those? Used stock? Int... Apr 2 2016, 10:00 PM fixer34 If that is the valve spring retainer, then you did... Apr 2 2016, 08:17 PM Cracker Bummer! I hate to see that...it IS part of the... Apr 2 2016, 08:53 PM Jetsetsurfshop Didn't mean to be so vague. I've never see... Apr 3 2016, 05:08 AM The Cabinetmaker I'm confused. Bigger valves, monster cam, dual... Apr 3 2016, 05:48 AM McMark I would love to see the valve train geometry befor... Apr 3 2016, 06:32 AM Mark Henry :agree:
I'm guessing that the cam is a Scat ... Apr 3 2016, 06:40 AM Jetsetsurfshop Cabinetmaker
I meant stock rocker arms. Sorry.
Th... Apr 3 2016, 08:14 AM HAM Inc The valve breaking in that position is a classic s... Apr 3 2016, 10:18 AM |
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