What would you do?
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Joined: Jun 2010
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What would you do?
So a few weeks ago I broke my timing chain.... I found out that I have probably bent some valves to go along with it.. but I wont know that until about wed when the mechanic has the timing chain back on and checks the valves. Now this being said.... I was wondering what I could do since the mechanic is already going to have to mill the heads, what else could be done, relativly inexpensivly to make more performance. ANY IDEAS?
Safety Car
Joined: Jan 2004
Posts: 4,974
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From: Pinellas Park Fl
St. Jude Donor '08-'09 & '12, '14
So a few weeks ago I broke my timing chain.... I found out that I have probably bent some valves to go along with it.. but I wont know that until about wed when the mechanic has the timing chain back on and checks the valves. Now this being said.... I was wondering what I could do since the mechanic is already going to have to mill the heads, what else could be done, relativly inexpensivly to make more performance. ANY IDEAS?
Sounds like your tech is double dipping the labor
What is relatively inexpensive?
Race Director
Joined: Aug 2005
Posts: 13,592
Likes: 187
From: Hudson WI
NCM Sinkhole Donor
Your statement makes no since. If he's pulling the heads, why wait to determine valve damage? This can be done prior to replacing the timing chain and should have been part of a complete diagnosis.
Sounds like your tech is double dipping the labor
What is relatively inexpensive?
Sounds like your tech is double dipping the labor
What is relatively inexpensive?
Le Mans Master
Joined: Dec 2005
Posts: 7,000
Likes: 1,685
From: Southeast TX
Even if you did bend valves, milling the heads is kind of way down on the list of things that may need to be done. Bent valves can be diagnosed without removing the heads. A simple (and cheap)compression check can give you a clue whether you need to dig deeper. Valve springs can then be removed on suspect cylinders to see if the suspect valves move freely and/or rotate. Heads may or may not need to be removed. At least that's the way I'd approach it.
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From: Lakewood Ranch, FL
So a few weeks ago I broke my timing chain.... I found out that I have probably bent some valves to go along with it.. but I wont know that until about wed when the mechanic has the timing chain back on and checks the valves. Now this being said.... I was wondering what I could do since the mechanic is already going to have to mill the heads, what else could be done, relativly inexpensivly to make more performance. ANY IDEAS?
Melting Slicks
Joined: Feb 2004
Posts: 3,307
Likes: 111
From: Tucson AZ
Depending on the RPM conditions when your chain broke will depend on how many valves are bent. Sometimes it is the cam gear bolts or dowel pin shearing and it will skip a couple of times before breaking. Either way, some of the valves are left hanging and the pistons then play tag with them. You could have from 4-16 valves bent. Worst case is a valve head breaks off and breaks up the cast piston and then the connecting rod thrashes the block.
I would do a leak down check on all 8 cylinders before tearing it down. You will have to back off the rockers to get the valves closed as the cam is no longer being turned by the crank.
While you have the heads off you may want to change the cam and add a set of headers.
I would do a leak down check on all 8 cylinders before tearing it down. You will have to back off the rockers to get the valves closed as the cam is no longer being turned by the crank.
While you have the heads off you may want to change the cam and add a set of headers.
Le Mans Master
Joined: Feb 2002
Posts: 5,394
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From: cumming ga
z51vett
Racer
Joined: Mar 2009
Posts: 447
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From: Adkins Texas
If you back off the rockers to close the valves, you can hook up an air hose with an adapter to the spark plug hole. With air pressure applied if you have a bent exhaust valve you will hear the air leak from your tail pipe, same for the intake you'll hear it from the throttle body. You can do this pretty fast on all 8 cylinders.
No need to pull the engine for a cam swap, find a different shop. My 02 centavos.
No need to pull the engine for a cam swap, find a different shop. My 02 centavos.
Last edited by Pack Leader; Jan 14, 2011 at 06:17 PM. Reason: more info added
Instructor
Joined: Jul 2008
Posts: 127
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From: Newport NC
Anyways, on the LS motor there will most likely be at least a few bent valves......unless the chain popped with the motor not running