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Post by real57vetteguy on Jan 1, 2012 21:38:55 GMT -5
I'm sure a lot of you have seen my build thread I purchased a engine off of the Pro Touring forum. the fellow I bought it from has been A-1 to deal with and has been overly helpful. I discovered a rocker arm issue and he even immediatly sent me a new set from summit. Here is my issue, when we took the valve covers off, we noticed an issue with intake valve 1, the valve had a nic in it and the rovker arm pin that held the roller was broken, the former owner said he was driving the car and it ran great. he said he will stand behind the engine, so far he has. we checked the bottom end, it all looks great, good work, lot of port work etc. So I get the new rockers, and start adjusting, all is fine except intake valve 1 look at the pics below?  ?/ rockers on cyl 4  rockers on cyl 6  Rockers on cyl 1 look at how far the adjustment is run down???  |
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Post by red71 on Jan 1, 2012 22:13:26 GMT -5
is the shaft that slides over the rocker stud facing
the correct way? One side has a recess so your poly lock
sits properly and other side does not.
Just a thought.
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Post by bubbasz1 on Jan 1, 2012 23:21:52 GMT -5
I'm sure a lot of you have seen my build thread I purchased a engine off of the Pro Touring forum. the fellow I bought it from has been A-1 to deal with and has been overly helpful. I discovered a rocker arm issue and he even immediatly sent me a new set from summit. Here is my issue, when we took the valve covers off, we noticed an issue with intake valve 1, the valve had a nic in it and the rovker arm pin that held the roller was broken, the former owner said he was driving the car and it ran great. he said he will stand behind the engine, so far he has. we checked the bottom end, it all looks great, good work, lot of port work etc. So I get the new rockers, and start adjusting, all is fine except intake valve 1 look at the pics below? ?/ rockers on cyl 4 rockers on cyl 6 Rockers on cyl 1 look at how far the adjustment is run down??? It's late at night, way past my bedtime but I'll take a shot at it. When you say how far the adjustment is run down you actually mean how far the lock screw is run down. This would mean that the rocker adjustment down towards the head is actually less than the rest, hence the lock screw has to travel farther into the adjusting nut to contact the stud to lock it in position. So that particular valve is sticking up farther than all the rest making the rocker sit higher, or that particular rocker stud is shorter than the rest making the lock screw travel farther down to get to it's lock position, or the pushrod is longer than the rest, making the rocker sit higher(which could cause a issue with the rocker arm staying on the stem face of the valve). Some symptoms are easy to verify, pushrod length, just make sure you check it against another like valve(intake or exhaust). Stud length>>no brainer, valve height as installed. I'm not familiar with those aluminum heads but try to measure the installed height of the valve and compare it to another like valve. If the valve installed height is higher you will have to look for the problem, how's the locks in the keepers look compared to the rest, could be that valve is just long(probably not on purpose) the valve seat could be beat into the head, or the valve face could be cut wrong or on it's way to a failure. Sorry for the long drawn out scenario's but a lot of factors could contribute to your situation, some minor, some not so. |
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Post by bubbasz1 on Jan 1, 2012 23:23:20 GMT -5
is the shaft that slides over the rocker stud facing the correct way? One side has a recess so your poly lock sits properly and other side does not. Just a thought. Good one, I didn't think of that in my responce, see, must be time to go to bed>>old minds need there sleep. |
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Post by mongoose on Jan 2, 2012 8:11:48 GMT -5
Everything the guys said is a valid check. Other than seeing that the set screw is deeper in the poly lock, the photos don't reveal any causes. As said, I'd pull off a few/all of the rocker arms on that side, and start comparing.
1) Is the poly lock seating in the rocker arm completely?
2) Do the tops of the valve stems line up pretty close? Based on how deep the lock is, the stem height would be WAY off to be the cause.
3) Do the tops of the rocker studs line up?
4) Are the push rods the same length... usually 9.90", but could be somewhat different if that detail was factored into the build.
Seems like one of the above will lead you to the root cause, some a simple fix, others not so much.
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Post by rickman on Jan 3, 2012 10:22:26 GMT -5
I'd be checking everything to do with #1 intake!
Funny - anytime I've had valve train problems, it was with #1!!
Since that rocker was originally bad, could be a bent pushrod, or [hopefully not] a bent valve!
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Post by Deleted on Jan 3, 2012 12:43:59 GMT -5
who knows, if your lucky, maybe it was just a junk rocker arm and nothing got banged up. how chipped is that valve stem?
like squatch said... check the pushrods for straightness and length. pull the rockers and run a straight edge across the top of the rocker studs, and then do the same for the top of the valves. if that number one valve is sticking up higher, it could be do to how far in the seat was cut. if that is the case, you will want to make sure that spring is shimmed to the correct installed height as you'll have a different seat and open pressure on that one if its different.
that chipped valve stem is no good. sounds like a clearance issue. you might want to check all of them. use light checker springs and two solid lifters (usually found in cam degree kits), and turn the motor over slowly by hand to check for clearance issues. repeat this process for every cylinder.
good luck and i hope all goes well.
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Post by real57vetteguy on Jan 3, 2012 14:20:16 GMT -5
Best news all week, when I put on the poly locks its normally one at a time, from the top they all looked identical, you cant see the sides once installed. Looks like comp cams had a packaging error!  |
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Post by stan65cutlass on Jan 3, 2012 14:55:21 GMT -5
great news, can you use the odd one or will you need the correct one?
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Post by mongoose on Jan 3, 2012 15:03:28 GMT -5
High five on the outcome on that one!!! Phew!!!
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Post by rickman on Jan 3, 2012 15:06:21 GMT -5
Easiest fix of all!!
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Post by real57vetteguy on Jan 3, 2012 15:41:02 GMT -5
Whew is right, I pulled the rockers and used a straight edge, valves were fine, studs were fine, pushrods straight and equal length, I was getting really worried then I noticed the poly locks, I put them side by side and It was as good if not a better feeling than gazing upon my first set of Boobs!!!!!!!!!!!!
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Post by real57vetteguy on Jan 3, 2012 15:43:38 GMT -5
great news, can you use the odd one or will you need the correct one? comp cams is overnighting a new poly lock |
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Post by Deleted on Jan 3, 2012 15:52:15 GMT -5
sweet! but how is that valve stem?
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Post by real57vetteguy on Jan 3, 2012 19:29:22 GMT -5
Its not bad, it was a very minor nick on the side we cleaned it up
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