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Good Morning Gentlemen,
I am just about at my wits end, and need your help. I am a reasonably good gearhead, but I cannot for the life of me get the valvetrain of my HT3.4L crate engine to stop clattering. First, some background:
1984 Chevrolet S-10, 2WD shortbed
Factory 2.8L/Rochester 2SE Varajet(federal)/TH700R-4 automatic
3.08:1 open differential, P205/70R14 tires
Approximately 205,000 miles as of right now.
In early 2007, at around 175,000miles, I finally killed the original 2.8L. In its place, I dropped in a GMPP HT3.4L crate engine. This engine is bone stock, just as it came out of the crate from GMPP. From the beginning, the valvetrain in this engine was noisy.
I lived with it until September 2008. I pulled the valve covers and adjusted the rocker arms as per the procedure in my factory 1984 S-10 Chevrolet Service Manual. This involved rotating the engine to #1 cylinder at TDC, adjusting several rocker arms, rotating the engine to #4 cylinder TDC, then adjusting the rest of the rocker arms. Adjusting meant 1 ½ turns past 0 lash. This quieted things down somewhat.
During the Christmas/New Year’s holiday 2009/2010, I installed an MSD ignition with a reman distributor, and rebuilt the carb. I also adjusted the rocker arms – twice. The first time, I adjusted each cylinder individually 1 ½ turns past 0 lash. The valves were noisier than ever. Under the advice of betterthanyou, I readjusted the rockers to only 1 full turn past 0 lash. This helped somewhat.
Over the July 4th holiday weekend of 2010, I installed a rebuilt transmission into my truck. This involved pulling the engine and transmission. With the engine on a stand, I pulled the valve covers and intake for a look-see. I removed and inspected all of the pushrods and lifters, as well as inspected all the camshaft lobes. None of the lobes were flat, none of the pushrods were bent, and all of the lifters still had the crown at the base. All the lifters and camshaft lobes showed equal wear. I couldn’t find anything wrong.
I meticulously adjusted the rocker arms, cylinder by cylinder, to exactly 1 full turn past 0 lash. However, in retrospect, I think I screwed up. I tightened each rocker far past 0 lash, then loosened it to floppy, then tightened it down 1 full turn past 0 lash. The valve train is still quite noisy, and one or two have a noticeable tick.
I am now preparing to adjust the rocker arms yet again. This time, I plan on doing it with the engine running. I have already purchased a set of rocker arm oil deflector clips, and am going to the junkyard for another set of valve covers. I will do one of three things to the extra valve covers: cut them in half and only use the outboard sections; cut a long slot in the top of each valve cover; or cut individual holes above the rocker arm nuts in each valve cover. Either way, I need some form of valve cover on the cylinder heads to catch the oil that pools on the outboard sides of the heads.
I plan on running the engine until it is up to operating temperature, then adjusting each rocker individually. I will loosen each one to clattering, then slowly tighten it down to quiet, then tighten it down only ¾ more turn. Once all the rockers are adjusted, I will rev the engine a few times and listen to the valvetrain. Any loud offenders will be readjusted.
I am at wits end because I can’t figure out why I can’t do this properly. I am pissed because it takes me an average of 8 hours to R&R the valve covers, due to the need to remove so many items to give me clearance to scrape the old sealant from the valve cover flanges on the cylinder heads.
The engine runs like a top, and warm oil pressure is 65psi at 2500rpm.
So, I welcome any and all advice on doing this procedure.
Thanks for your time,
Seth K. Pyle
I am just about at my wits end, and need your help. I am a reasonably good gearhead, but I cannot for the life of me get the valvetrain of my HT3.4L crate engine to stop clattering. First, some background:
1984 Chevrolet S-10, 2WD shortbed
Factory 2.8L/Rochester 2SE Varajet(federal)/TH700R-4 automatic
3.08:1 open differential, P205/70R14 tires
Approximately 205,000 miles as of right now.
In early 2007, at around 175,000miles, I finally killed the original 2.8L. In its place, I dropped in a GMPP HT3.4L crate engine. This engine is bone stock, just as it came out of the crate from GMPP. From the beginning, the valvetrain in this engine was noisy.
I lived with it until September 2008. I pulled the valve covers and adjusted the rocker arms as per the procedure in my factory 1984 S-10 Chevrolet Service Manual. This involved rotating the engine to #1 cylinder at TDC, adjusting several rocker arms, rotating the engine to #4 cylinder TDC, then adjusting the rest of the rocker arms. Adjusting meant 1 ½ turns past 0 lash. This quieted things down somewhat.
During the Christmas/New Year’s holiday 2009/2010, I installed an MSD ignition with a reman distributor, and rebuilt the carb. I also adjusted the rocker arms – twice. The first time, I adjusted each cylinder individually 1 ½ turns past 0 lash. The valves were noisier than ever. Under the advice of betterthanyou, I readjusted the rockers to only 1 full turn past 0 lash. This helped somewhat.
Over the July 4th holiday weekend of 2010, I installed a rebuilt transmission into my truck. This involved pulling the engine and transmission. With the engine on a stand, I pulled the valve covers and intake for a look-see. I removed and inspected all of the pushrods and lifters, as well as inspected all the camshaft lobes. None of the lobes were flat, none of the pushrods were bent, and all of the lifters still had the crown at the base. All the lifters and camshaft lobes showed equal wear. I couldn’t find anything wrong.
I meticulously adjusted the rocker arms, cylinder by cylinder, to exactly 1 full turn past 0 lash. However, in retrospect, I think I screwed up. I tightened each rocker far past 0 lash, then loosened it to floppy, then tightened it down 1 full turn past 0 lash. The valve train is still quite noisy, and one or two have a noticeable tick.
I am now preparing to adjust the rocker arms yet again. This time, I plan on doing it with the engine running. I have already purchased a set of rocker arm oil deflector clips, and am going to the junkyard for another set of valve covers. I will do one of three things to the extra valve covers: cut them in half and only use the outboard sections; cut a long slot in the top of each valve cover; or cut individual holes above the rocker arm nuts in each valve cover. Either way, I need some form of valve cover on the cylinder heads to catch the oil that pools on the outboard sides of the heads.
I plan on running the engine until it is up to operating temperature, then adjusting each rocker individually. I will loosen each one to clattering, then slowly tighten it down to quiet, then tighten it down only ¾ more turn. Once all the rockers are adjusted, I will rev the engine a few times and listen to the valvetrain. Any loud offenders will be readjusted.
I am at wits end because I can’t figure out why I can’t do this properly. I am pissed because it takes me an average of 8 hours to R&R the valve covers, due to the need to remove so many items to give me clearance to scrape the old sealant from the valve cover flanges on the cylinder heads.
The engine runs like a top, and warm oil pressure is 65psi at 2500rpm.
So, I welcome any and all advice on doing this procedure.
Thanks for your time,
Seth K. Pyle
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