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If the duration is at 0.050", I'd say that's a pretty stiff cam, especially with lift at over half an inch. One would hope the builder matched the valve springs to the cam. Makes me wonder why it has dampers instead of a second, inner, spring on each valve. But I'm not an expert, just throwing out some thoughts.
Pete
You're probably more of an expert than the previous owner. All he was expert at was scamming people. Thanks for the input.
Alas the list doesn't provide information about the valve springs.
I will provide some tongith
That is a serious build with that cam and those pistons. High 10+ compression.
Rockers are 1.5x ratio but only 3/8" stud diameter. 7/16" would be more stable with that lift.
The springs are probably the "stock" ones with the heads and not matched to the cam.
I'd go to Comp Cams site and see what they match up the springs at for that cam.
You can change the springs without pulling the heads. Just need air compressor and adapter to screw into spark plug hole. Rotate to each cylinder where the valves are fully closed. Use a valve spring clamp. They make several types that attach and compress spring. Push retainer down and using a magnet take out the locks. Release the spring slowly and inspect. You can also take the spring to a decent machine shop and have them compress it to get the ft lb rating and the fully compressed height. A little computation of the installed height, compressed height (binding height) and the lobe lift and you will know if the springs are not a good match. (installed height - binding height = the maximum clearance for cam lobe lift). You should NOT go to the max clearance but allow some leeway.
Once you get to the bottom you can change the springs to the correct ones (if that is the solution) by reversing the process.
Good luck with the fix......
Last edited by bmans vette; 08-24-2017 at 05:04 PM.
Look at the top of the matching valve. That's not dancing, it's a convulsion.
I will.
Originally Posted by bmans vette
That is a serious build with that cam and those pistons. High 10+ compression.
Last time I calculated the CR it was 10.5.
Yes it's a serious build, kinda ridiculous actually if you don't plan in drag racing it. That's why I had the L33/LS6 hybrid in backup, probably a little less HP but with a nice fat torque curve.
I have a friend who had a 600+ hp twin turbo Audi setup built, and he finds it more scary than fun. A tad over 300hp is all I'm asking for.
Originally Posted by bmans vette
Rockers are 1.5x ratio but only 3/8" stud diameter. 7/16" would be more stable with that lift.
The springs are probably the "stock" ones with the heads and not matched to the cam.
I'd go to Comp Cams site and see what they match up the springs at for that cam.
You can change the springs without pulling the heads. Just need air compressor and adapter to screw into spark plug hole. Rotate to each cylinder where the valves are fully closed. Use a valve spring clamp. They make several types that attach and compress spring. Push retainer down and using a magnet take out the locks. Release the spring slowly and inspect. You can also take the spring to a decent machine shop and have them compress it to get the ft lb rating and the fully compressed height. A little computation of the installed height, compressed height (binding height) and the lobe lift and you will know if the springs are not a good match. (installed height - binding height = the maximum clearance for cam lobe lift). You should NOT go to the max clearance but allow some leeway.
Once you get to the bottom you can change the springs to the correct ones (if that is the solution) by reversing the process.
Good luck with the fix......
Thanks for all the tips.
I have a spring compressor, but only time I used them was for the reassembly of the LS engine, I used LS6 spring, and it's a single spring setup. I didn't know about spring dampers before this but thanks to you guys I'm now a little less ignorant.
Thanks for all the tips. I didn't know about spring dampers before this but thanks to you guys I'm now a little less ignorant.
My suggestion would be this....you said that you have aluminum heads, so I'd get my hands on a STRONG magnet, which won't stick to the heads, but should snag all of the metallic particulate. Then I'd shoot a couple of cans of WD-40 down through the oil passages at the ends of the heads, to "wash down" any residual crud. (maybe pull the intake, and flush the lifter valley down, too)
Then I'd pull the pan, and clean it thoroughly, as well as check the oil pump screen for debris. swap the valve springs for something more suitable, replace the bad rocker arm, and give it a go.....
BTW, how was the oil pressure before you shut it down?
Looking at the valve spring pad (where the spring rests on the head)....To me, it seems like the valve spring is much smaller than the pad. Just a thought, maybe you have the wrong valve springs installed and this is why the spring dampener is eating itself. Also the valve spring wire looks thick (diameter) like its a very heavy spring. Maybe a set of Beehive springs is in order?
Looking at the valve spring pad (where the spring rests on the head)....To me, it seems like the valve spring is much smaller than the pad. Just a thought, maybe you have the wrong valve springs installed and this is why the spring dampener is eating itself. Also the valve spring wire looks thick (diameter) like its a very heavy spring. Maybe a set of Beehive springs is in order?
For sure the springs are going. Best bet so far is that they used the springs that came with the Chinese heads regardless of the cam. I wouldn't mind being schooled on which spring to shop for given my setup. If you guys have suggestions, I'm listening.
Denis, you have the part number for the cam. Go to Comp Cam's website, look up that cam and see what springs they recommend. I'm betting the PO went cheap and used the springs that came with the heads- and that will be the root of your problem.
Denis, you have the part number for the cam. Go to Comp Cam's website, look up that cam and see what springs they recommend. I'm betting the PO went cheap and used the springs that came with the heads- and that will be the root of your problem.
Exactly.
I suggested that in an earlier post.
Good luck fixing the problem.
All right guys, I probably didn't explain myself right, I didn't mean asking you to do the job for me, it's just that as 1Hotrodz was suggesting beehive I felt there was a lot more to understand than just picking comp cam proposed springs.
However I went and check on Comp cam website and the springs installed look awfully like the 987 recommended springs.
As soon as I get back from vacation I'll check this out.
Thanks again everyone for all the information.
My advice if you do decide to salvage this engine is to remove all the vavle springa on the bad side, the reason is because when metal pieces were flying around in that valve cover, some got extremely hot and act like little pieces of molten steel, and they can stick to places that they hit, just like when your welding, pieces could be stuck inside of the valve springs and you cant see them right now, and you sure wouldnt want any flying off at 5000 rpm only to mess up another part of the head....
My advice if you do decide to salvage this engine is to remove all the vavle springa on the bad side, the reason is because when metal pieces were flying around in that valve cover, some got extremely hot and act like little pieces of molten steel, and they can stick to places that they hit, just like when your welding, pieces could be stuck inside of the valve springs and you cant see them right now, and you sure wouldnt want any flying off at 5000 rpm only to mess up another part of the head....
That's the plan, I ordered all the replacement parts and tool from Summit yesterday.
Crazy how it's impossible to find a valve holder hose in any auto part store in Montreal.
As soon as springs are out I'll post pictures.
08-24-2017, 04:13 PM
