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Old 05-13-2011, 06:45 PM
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cam lobe down

Ok, I will probably get a bunch of negative answers, but I want to know what all you experienced guys think anyway. I have what I believe is a bad cam lobe on my #2 cyl. on my 283, the push rod only actuates the valve about half or 3/4 of what I think it should. I have about 105 compression on that cyl, but that is about the same on all cyls. I do not see a collapsed lifter, and have adjusted all valves about 4 times to get them as perfect as can be. Ok, here is the maybe dumb question, I don`t have the money to overhaul yet, and wonder about putting in a longer push rod temporarily for about a couple months worth of saving days and still drive to work? 100 thousands or so longer and alot of Lucas additive maybe. Is this an option or will that make the lobe go down even faster. Give me some thoughts. I hope there is a temp. fix. Thanks

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Old 05-13-2011, 06:51 PM
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Might check your valve springs close. I do not see any options. Running it will only create more metal in the pan an bearings where you do not need it. Also would cause valve problems eventually.
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Old 05-13-2011, 07:20 PM
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A longer push rod will not open the valve any further than it is opening now. Yes, rocker arm to valve tip geometry might be better, but gross valve opening is determined by the cam lobe and rocker arm ratio.

Keep good oil in it, and drive it as long as you can, an overhaul is imminent.
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Old 05-13-2011, 07:46 PM
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Don't mess around trying to find a quick get you through fix, might as well face it and fix it when the funds permit. No additive or longer push-rod is going to really do you any good. JMO


Cole
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Old 05-13-2011, 08:02 PM
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If it is a failed cam, you will just cause more damage if you keep running it.If the cam did fail there is a lot of metal particles in the oil and they will eventually destroy everything
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Old 05-13-2011, 08:40 PM
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If you absolutely HAVE to drive it w/o replacing the cam and lifters, remove the pushrod and lifter and plug the lifter bore both bottom and top w/Dorman p/n 550-009 concave expansion plugs, leaving the oil journal open to pass oil through that lifter bore. If it's the intake valve cam lobe that's bad you can leave the exhaust working. If it's the exhaust valve, do both valves of the bad cylinder the same way.

You will have frictional and pumping losses that make the loss of power more than just 1/8 of the engines output, but at least it won't be grinding even more metal into the oil. You still should change the oil and filter, and hope that more lobes aren't on their way out.

OR- change the cam and lifters.
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Old 05-14-2011, 02:11 AM
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Don't take a chance doing more damage,check this out www.summitracing.com put this in search: SUM-K1103, new cam & lifters $102.95 these are a good bang for the buck and won't hurt your wallet.
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Old 05-14-2011, 08:06 AM
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can the summit kit be put in by me pulling the front parts such as water pump, sprocket and chain, intake manifold and push rods? am i gambling by not changing cam bearings?
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Old 05-14-2011, 09:04 AM
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It is a very typical small block chevy problem. I have seen those old engines wheeze along for quite a while will bad lobes on the cam. I wouldn't worry too much about the metal in the oil, it is probably wearing off pretty microscopic particles. Plus you will rebuild/replace the engine most likely anyway.
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Old 05-14-2011, 09:12 AM
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Quote:
Originally Posted by db flyer
can the summit kit be put in by me pulling the front parts such as water pump, sprocket and chain, intake manifold and push rods? am i gambling by not changing cam bearings?
Basically, yes. The grill might need to be removed, cooling system drained and the radiator removed and AC compressor (if you have one) will need to be moved out of the way as well. The 'gamble' will be in whatever metallic debris is left behind in the engine that cannot be cleaned out w/o disassembling the whole engine, not in reusing the cam bearings.

If the main bearings aren't shot, which isn't that likely to have happened, replacing the cam and lifters will be the best choice next to rebuilding the engine.

Competition Products sells a Chevy cam (stock specs) for $14.00. Add a set of lifters and the gaskets to that, add coolant and an oil/filter change and break in additives and cam break in lube for the lobes and lifter bottoms and you have a better than even chance of success.
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Old 05-14-2011, 09:47 AM
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I believe I do not have to remove heads right? I just did a valve job last month. What did you mean about a cam price? I did not understand the $14. Thanks
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Old 05-14-2011, 09:49 AM
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X however many times i agree do the cam kit swap save yourself all the trouble trying to save it like it is. Easy to do in the vehicle as Cobalt stated you may have to remove the grill depending on what the engine is in, By the way what is the engine in ? just so we know what exactly you are working on. Bearing should be fine they are in most cases anyway pending on how long you have been running it this way.JMO


Cole
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Old 05-14-2011, 09:51 AM
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Quote:
Originally Posted by db flyer
I believe I do not have to remove heads right? I just did a valve job last month. What did you mean about a cam price? I did not understand the $14. Thanks
Heads stay on, valve covers removed to loosen and readjust the rockers is all that's needed on the heads.

The $14 is the cost of the stock spec cam from them. Plus shipping, etc.
http://www.competitionproducts.com/b...superbroom.pdf
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Old 05-14-2011, 10:04 AM
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the 283 is in a 56 chev. 210. I bought this car in 2002 and have only put about 2000 on it since then. Now that I`m semi retired, I just want a good driver. I did a rebuilt head exchange from a reputable shop, about 45 days ago, and thats when I noticed the valve movement about 1/2 of what it should be during valve adjustment. Thanks
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Old 05-14-2011, 10:59 AM
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Drain coolant remove valve-covers /distributor/intake and carb/ timing cover and chain and gears loosen and remove some of the bolt to the oil pan so it can drop down enough to get the timing cover off and back on. JMO Loosen the rockers and pull and note where the push-rods where at pull the push-rods and old lifters and after you have the chain and gears off then pull the cam out.
And repeat the process in reverse going back in.



Cole
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