wallaby Posted May 16, 2002 Share Posted May 16, 2002 A beautiful drive today ended with what I thought was a fouled plug. I drove it home on what seemed like LESS than 7 cyls. and started checking things out. I pulled the plugs and found No.s 6 and 7 to be darker than the rest, put in new plugs....same result. Then substitute cap & wires: no change. I thought crap, I have a cam that's gone flat...but I don't hear any loose lifter noise or anything, but I pull the valve cover and there it is clear as day: a broken valve spring. Number 6, exhaust. My engine is New. Rebuilt 10,000mi ago. The heads were off for valve seals about 4,000mi. ago, but the springs are just 10,000mi. old. OK: what causes a valve spring to break? Is there anything I can do to prevent it? I have a Comp Cams XE268H cam, and the matching lifters and springs. Spring #911-16. (Now THERE is an ironic part number!) So maybe it is a fluke thing, and the other springs are fine; can I replace the spring without pulling the head? ( dang thing is pretty close to that A/C box....) Link to comment Share on other sites More sharing options...
Guest Posted May 16, 2002 Share Posted May 16, 2002 Rice Racing told me the 911 springs are the minimum spring, and the 924's are the premium. He cautioned me against using the 911. Still if they sell the things, I'd think they'd last more than 10,000 miles.... Link to comment Share on other sites More sharing options...
wallaby Posted May 16, 2002 Author Share Posted May 16, 2002 Yea, and you'd think that they'd be better than stock. I have all my old stock stuff, I wonder if I could use one of those? oh well.. Next I'll have to find out if I can order up just ONE spring. Link to comment Share on other sites More sharing options...
Guest Posted May 16, 2002 Share Posted May 16, 2002 The springs can be replaced without removing heads. You need an air fitting to fit in the spark plug hole, and a spring compressor that fits on your rocker stud. These items can be bought at your parts store. Also needed is an air compressor to keep the cylinder under hi-pressure which holds the valve closed. Done it many times. Forgot 1 thing. While the cyl. is under pressure, take a brass punch and tap the valve retainer to release it from the keepers before trying to use the spring compressor. If you don't need to do the valves or any other type of machine work, then this is still deffinately easier than removing the heads. ------------------ George Lines [This message has been edited by George Lines (edited 05-18-2002).] [This message has been edited by George Lines (edited 05-18-2002).] Link to comment Share on other sites More sharing options...
Guest Posted May 17, 2002 Share Posted May 17, 2002 Wallaby, do yourself a favor and replace the whole set, comp's single springs break quite often. It seems that they can't withstand any harmonic viration for any length of time, big blocks due to design have a low magnatude harmonic event at 4900 to 5000 rpm's. Just on the off chance that this is what caused the problem I wouldn't take the risk, next time you drop a valve! To be honest I have seen a lot of problems with comp's springs, a customer bought a set of the $300 pacalloy race springs they looked and checked good but after only 12 passes down the 1/4 mile shifting at 7600 rpms the valves began to float! When I pulled them off and checked them they had lost 45#'s of seat pressure and 110#'s of open pressure. I much prefer K motion or Isky springs, I have some K motion springs that have been on the same small block dart heads now for 4 yrs, .725 lift roller shifted at 8400 rpm's that have only lost about 2 percent of pressure. The 924 comp springs are a dual spring and much less likley to break since the two springs share the load. Don Link to comment Share on other sites More sharing options...
wallaby Posted May 17, 2002 Author Share Posted May 17, 2002 Don, I have been following your discussions with the others here, and have come to respect your advice. However, what you are telling me is bad news. I figure that you are probably right, and I don't want to give you the chance later on to say "I told you so". But that means the darn heads will have to come off again and go in to be set up. Not to mention the cost. I was really hoping for an easy fix. It seems like I am changing head gaskets as often as my oil. (actually, I am). Sheesh. ....my wife is going to freak out. But thank you for the advice. Link to comment Share on other sites More sharing options...
wallaby Posted May 17, 2002 Author Share Posted May 17, 2002 ok, It's been 20 minutes. My mind is racing. How insane would it be to install one of my old stock springs? Is that like a cardinal sin? ,Or does my cam have too much lift to even consider it? Link to comment Share on other sites More sharing options...
Guest Posted May 17, 2002 Share Posted May 17, 2002 Wallaby, I did some checking and found a Isky spring that would work without cutting the heads! The part # is 935-DR it is capable of .550 lift will give you slightly more pressure than the 924 comp's but not enough to hurt you. Don't even think about the stock springs they won't handle over .490 lift most of the time without binding and wiping out the cam! Don [This message has been edited by Rice Racing1 (edited 05-17-2002).] [This message has been edited by Rice Racing1 (edited 05-17-2002).] Link to comment Share on other sites More sharing options...
wallaby Posted May 17, 2002 Author Share Posted May 17, 2002 Thank you Link to comment Share on other sites More sharing options...
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