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Original Message
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| Valve train noise |
| By Gregory Westphall - 08/11/2003 9:25:18 AM; IP 12.158.13.35 |
Hello all,
This is my first posting. I have reviewed the forum and have been impressed with the number of responses and insight that its participants have. I have a question regarding valve train noise that I have been experiencing since the engine was rebuilt. Here are the specs. 1969 Mercury Cyclone CJ. 428 + .040, 10.5:1 pistons, A/T, FPA tri-y, Unilite, Performer RPM Heads, RPM Intake and waterpump, Crower Solid Lifter #16356 level 3 camshaft, std shaft rockers, ball cup push rods, mechanical holley fuel pump, 800 dp.
As stated my engine has been making valve train noise and giving me problems since day one of the rebuild. When the engine starts up cold the noise is barely legible. As the engine warms up the noise becomes more and more pronounced. Just the opposite as one would expect for rocker arm noise. I have always looked to places other than the rocker arms like a header leak, fuel pump or timing chains because of this. This weekend I decided to pull the valve covers with the engine cold and measure the clearance. To my surprise the clearance was around .015 for the intakes and around .017 for the exhausts. This is less than what I set them 2-weeks prior (.020 I, .022 E) not to mention the engine was stone cold. How could this be? I put the valve covers back on and started the car up and let it warm up as it warmed up the noise returned. Then I pulled one of the valve covers again and remeasured the clearance. To my surprise the clearance had grown and in some cases beyond the spec thus producing the tappet noise. It seemed as though the valves I set last had the most clearance. I normally set them from front to back with the engine hot. This time I set them from back to front. As I got towards the frond of the engine the clearances were spot on. I installed the valve cover on the passenger side, started the engine and let it get hot again and then removed the valve cover on the drivers side only to find the same thing. I reset those valves and installed the valve cover and sure enough the valve train noise disppeared and has remained that way since Saturday. I have driven the car pretty hard with several 5800 rpm shifts and it seems to still sound great. Can anyone explain to me why the valve lash would increase as the engine gets hotter? This has me baffled.
Some additonal information. I threw a rod in it in 1984. The broken rod split the camshaft in two and sent parts flying all over the engine. The car sat for 10 years before I was able to get back to it and give it the proper restoration it deserved. My dad is the original owner. I had the same noise with hydraulic lifters when the engine was first started up after the rebuild. That is why I went to solid lifters. I thought that maybe the machinist had removed the restricter at the back of the block that helps keep up oil presuure for the lifters. It also made the same noise with the stock CJ cast iron heads.
I know it probably sounds like I am an idiot and can't adjust a valve train properly but that really isn't the case. I have never run into this problem on any other engine I have worked on. Is it possible that the camshaft is walking or the rocker shafts or arms are flexing as the engine gets hot. Could I have damaged something in the structure of the block that would cause things to move around. During assembly we found that we had to slightly scrape 2 of the cam bearings in order to get the camshaft to spin properly. I have read that this can be required in older engines and is not uncommon. The rocker shaft assemblies are over the counter standard adjustable units with aluminum pedestals. The rocker arms are Ford Power Parts.
Any help would be appreciated. For now I am going to enjoy the peace and quiet and hope the noise only returns after 3000 miles. |
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