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  #106 (permalink)  
Old 12-14-2007, 01:42 PM
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Quote:
Originally Posted by Joshua Lee
I have allready thought of that..But... At the moment I need to fix this damn #5 issue, lol... Would you go "all in" on the timing chain and cam springs? or what at this point? I am pulling it back apart this weekend...
Josh, I still suspect there's either a dimensional issue or something's causing this valve to hang up or to get out of control.

- go back over the freedom to the rocker to insure it isn't hitting on something.

- the valve sitting high on it's seat

- Springs out to lunch

- flexing pushrod

- a burred lifter bore or incorrect clearance

- a miss machined lobe

- incorrect stem to guide clearance, look to see if theres burrs, scratches, or burn marks on the stem.

- cam running too advanced or falling retarded.

- incorrect rocker ratio a 1.6 in an engine full of 1.5's for example.

- the piston set higher in the bore than the others. After all besides deck height, there is an add up of throw length, rod length, pin to crown height.

- I could assume that a rod bearing or pin to pin hole has excessive clearance, but one usually hears from those things, still you have to question these things.

Bogie

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  #107 (permalink)  
Old 12-14-2007, 04:14 PM
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Quote:
Originally Posted by oldbogie
Josh, I still suspect there's either a dimensional issue or something's causing this valve to hang up or to get out of control.

- go back over the freedom to the rocker to insure it isn't hitting on something.

It's moving free, I tested it when I set the valves... I have a hand trigger and I ran the engine prolly 30 cycles just to test everything out..

- the valve sitting high on it's seat

Wouldnt the machine shop see this? The valves had a valve job on the 1st valve bend mistake..

- Springs out to lunch

So my springs needing to be replaced just for good measure wouldnt hurt? What about locks and retainers?

- flexing pushrod

Unlikely they are big chromolly ones and I replaced the one in that hole after the 1st bent valve just to be safe

- a burred lifter bore or incorrect clearance

If felt smooth like a babys but man

- a miss machined lobe

All of a sudden? Remember this has to be a wear issue the engine was running over 2 years without this problem

- incorrect stem to guide clearance, look to see if theres burrs, scratches, or burn marks on the stem.

I will but wont some wear be from the bending?? I can post pics if that would help once it's out. The machine shop said to bring the head back and they will check bore to seat specs and such but he's dead set on the heads looking GREAT in his words.

- cam running too advanced or falling retarded.

Timing chain issue? I did have the cam 4* retarded when installed would this make it just that much easier to fail when the chain goes weak?

- incorrect rocker ratio a 1.6 in an engine full of 1.5's for example.

Nope... They are all 1.6rr

- the piston set higher in the bore than the others. After all besides deck height, there is an add up of throw length, rod length, pin to crown height.

If this is the case then the engine will come out.... I can use a simple measure tape to see if there is an issue here right?

- I could assume that a rod bearing or pin to pin hole has excessive clearance, but one usually hears from those things, still you have to question these things.

I honestly doubt its that serious...I know your just stating facts but I have to start with basics before I get that deep in the engine ya know??

Bogie


All my answers are UNDERLINED
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  #108 (permalink)  
Old 12-18-2007, 05:45 PM
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Bogie... I pulled the cover off and there is a little more chain movement then I would call "right" is there a way to measure chain stretch?
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  #109 (permalink)  
Old 12-18-2007, 07:04 PM
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Quote:
Originally Posted by Joshua Lee
Bogie... I pulled the cover off and there is a little more chain movement then I would call "right" is there a way to measure chain stretch?
The chain should be pretty tight. Probably the best test is to put a degree wheel on the crank. With plugs out, rotate the engine one full turn in the normal direction of crank rotation. Make up a pointer from coat hanger and aim it on the zero mark. Rotate again one turn in the normal direction till the pointer is again at zero. Now gently rotate the crank backwards and count how many degrees before the cam gear starts to turn.

A second set of eyes, or someone else turning the crank will be helpful.

Bogie
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  #110 (permalink)  
Old 12-18-2007, 07:24 PM
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Heads are off allready....
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  #111 (permalink)  
Old 12-19-2007, 04:52 PM
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BOGIE...

I got this reply from Cloyes timing chains

"If you had chain stretch you would bend all of your intake valves at the same time as the index is the same between cylinders.

Bending just one would makes me believe that you have a tight valve guide or a ratio issue in the cam timing, another area to look might be your piston valve relief index and or valve height in head

But not a timing gear or chain related problem.

Please let me know what you do find as I would like to keep files to help other customers.

Thanks

Your friends at Cloyes

Mike"


So now Im back to sq#1!!!!!!!!!!!!!
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  #112 (permalink)  
Old 12-19-2007, 05:30 PM
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Quote:
Originally Posted by Joshua Lee
BOGIE...

I got this reply from Cloyes timing chains

"If you had chain stretch you would bend all of your intake valves at the same time as the index is the same between cylinders.

Bending just one would makes me believe that you have a tight valve guide or a ratio issue in the cam timing, another area to look might be your piston valve relief index and or valve height in head

But not a timing gear or chain related problem.

Please let me know what you do find as I would like to keep files to help other customers.

Thanks

Your friends at Cloyes

Mike"


So now Im back to sq#1!!!!!!!!!!!!!
Well first I've said a few times that you really need to look closely and measure that valve stem and the guide in a bunch of places for clearance. You need to look at the stem for length wise scratches or discolorations that could indicate the stem and guide are binding. The whole external parts of the guide needs to be looked at carefully for physical damage that could show up as cracks in the guide or where it blends with the port roof, on the spring side you want to look for similar cracking in the guide or where the guide and spring pad actually everywhere around all inside and outside edges of the spring pad looking for cracks. A dye penetrant inspection would be worth the money just to rule out any problems arising from cracking that allows the guide move around. The seat needs to be inspected to make sure the insert is in tight with no cracking of the seat ot the head's casting around it. I'd also ger some 1/2 inch grade 8 bolts, hardened washers and nuts sufficient foe every head bolt hole, and torque 'em up when doing inspections to be sure that there isn't a crack that only shows up when there's a load on the bolt bosses.

As far as Coyles comments go, I've seen timing errors caused by the timing set stretching or failing that have been anywhere from one, to a few, to many, to all. So I would be quick to reject the idea of the timing set slip sliding away on you just yet.

Bogie
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  #113 (permalink)  
Old 12-19-2007, 05:38 PM
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Bogie...

I know its a long shot but if I make a short video ofme moving the chain can you visually just nod yes or no to being too loose?
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  #114 (permalink)  
Old 01-02-2008, 08:43 PM
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Bogie...

I finally took the passenger head off and the #6 exhaust valve tapped the piston just enough to see the carbon was gone.... Does that help us in any way? lol....

I'm also taking the heads in tomorrow hopefully to get a second opinion....

I noticed that the lifter on #5 where the valve bent seems a little sticky, can I hone the lifter bores??

Thanks x 10000000000000000000000000
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  #115 (permalink)  
Old 01-03-2008, 10:28 AM
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Quote:
Originally Posted by Joshua Lee
Bogie...

I finally took the passenger head off and the #6 exhaust valve tapped the piston just enough to see the carbon was gone.... Does that help us in any way? lol....

I'm also taking the heads in tomorrow hopefully to get a second opinion....

I noticed that the lifter on #5 where the valve bent seems a little sticky, can I hone the lifter bores??

Thanks x 10000000000000000000000000
Yes you can hone the lifter bores. Check the clearances, they should be about .001 to .0015. If your shop is capable of this, checking the lifter bores for being truly at 90 degrees to the cam centerline is a good thing to look at. The same can be said for lifter alignment with the valve and rocker centerlines; what I'm hunting for here is that miss-alignments can result in parts inclusive of the tappet, rocker, or valve binding because of introduced side loads. I'm also trying to rule out that miss-alignments between the tappet and rocker could lead to a bending of the push rod. Also while we're here, you want to look for any potential binding of the push rod in its guide or contact where it passes thru the head. High cam lifts in general or high lift ratio rockers i.e. 1.6:1 or greater can change the geometry to where the push rod gets to rubbing or binding somewhere along its length.

I'm intrigued by the fact that your problem seems to be at opposing cylinders 6 left and 5 right and they follow each other in the firing order 1-8-4-3-6-5-7-2.

Bogie
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  #116 (permalink)  
Old 01-03-2008, 04:42 PM
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What throws up a red flag when them two valves are the only ones hitting??
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  #117 (permalink)  
Old 01-04-2008, 11:58 AM
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Quote:
Originally Posted by Joshua Lee
What throws up a red flag when them two valves are the only ones hitting??
Nothing in particular, but 5 and 6 share a common crank throw between the 3rd and 4th main bearings, the lobes for both are located between 3rd and 4th cam bearings.

Maybe it's just coincidence or maybe something else is going on. I'm not pin pointing anything, just pondering.

Which valves are doing the impacting and which one was the worst, too lazy to go thru 8 pages to find the answer.

Bogie
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  #118 (permalink)  
Old 01-04-2008, 02:23 PM
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#5 Intake bends (twice now)
#6 Exhaust touches but no damage (both times)
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  #119 (permalink)  
Old 01-07-2008, 10:55 AM
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Quote:
Originally Posted by Joshua Lee
#5 Intake bends (twice now)
#6 Exhaust touches but no damage (both times)
Number 5's intake lobe and number 6's exhaust lobe are located next to each other on the cam with their lifters opposite each other and only a small space apart. I'm wondering if the cam can move enough to where the incorrect lobe is clipping the lifters, or if something else related to this area is happening. I think it bears some careful inspection and testing.

Bogie
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  #120 (permalink)  
Old 01-07-2008, 04:05 PM
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hmmmmm..... chain stretch still isnt a option?
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