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Did you ever get around to checking pushrod length? Your valvetrain was unusually noisy the last time I seen you at the track. There's a good chance with your head/cam setup that you could use different pushrods.
Make sure the valve is closed, loosen a rocker, tighten it back down. You should get 1/2 - 1 full turn of preload on the lifter before the rocker bolt is tight. Any more or less, and you're giving up some power.
Did you ever get around to checking pushrod length? Your valvetrain was unusually noisy the last time I seen you at the track. There's a good chance with your head/cam setup that you could use different pushrods.
Make sure the valve is closed, loosen a rocker, tighten it back down. You should get 1/2 - 1 full turn of preload on the lifter before the rocker bolt is tight. Any more or less, and you're giving up some power.
I did not. That’s one of the reasons I let someone else do the engine rebuild for me. I figured they would’ve done that.
That's a good rule of thumb Joe! A good starting point for determining if different pushrods are needed.
The rocker arm bolt is 1.25mm per turn, so .050". The 1.7 rocker arm ratio means that the pushrod will move down like 1.58x as much as the bolt. So 1 full turn is .079". Depending on whether you have older style or newer style lifters, you'll want somewhere in that range of preload. I had to get .075" shorter pushrods because I got 2 full turns of preload. .075" shorter pushrods took my preload from 0.158" down to .083", which is still acceptable.
I did not. That’s one of the reasons I let someone else do the engine rebuild for me. I figured they would’ve done that.
I believe they did, but the problem is that using a pushrod length checker with fresh lifters and freshly torqued headgaskets won't be nearly as accurate as checking once the engine has been ran. Same issue I had. They measured out fine with a comp pushrod length tool, a month later they were too long. When thousandths of an inch can make a difference between a good engine and valve float, its better to recheck them later.
I believe they did, but the problem is that using a pushrod length checker with fresh lifters and freshly torqued headgaskets won't be nearly as accurate as checking once the engine has been ran. Same issue I had. They measured out fine with a comp pushrod length tool, a month later they were too long. When thousandths of an inch can make a difference between a good engine and valve float, its better to recheck them later.
Is this because head gaskets continue to crush AFTER they've been torqued? This would also explain the need for retorquing after a bit...
Most headgaskets have a sealant that melts and takes up less space. Some graphite center layer gaskets won't fully compact until a while after they are torqued. Small diameter bolt heads or stud washers will settle onto the aluminum at the top of the head deck after a few hours. These only amount to thousandths of an inch usually, but it all adds up. Engines with stud mounted rockers might need the valvetrain readjusted after full break in is completed for similar reasons. Its not completely absurd to think that the preload would be changed on fixed mounted rockers like the LS.
I believe they did, but the problem is that using a pushrod length checker with fresh lifters and freshly torqued headgaskets won't be nearly as accurate as checking once the engine has been ran. Same issue I had. They measured out fine with a comp pushrod length tool, a month later they were too long. When thousandths of an inch can make a difference between a good engine and valve float, its better to recheck them later.
Ill have to get in there. When it comes to checking tolerences and clearances I lose patience. I like fabbing stuff on a hillbilly Chevette. I’m too ADD for precision measuring to be building engines.
Did you ever try the F-body oil pan? I was doing some measuring tonight and it looks close if I was to move the firewall back about 3” around the engine. I was going to get the Holley 302-1 pan if it won’t clear. I think that’s the number of it anyways.
Did you ever try the F-body oil pan? I was doing some measuring tonight and it looks close if I was to move the firewall back about 3” around the engine. I was going to get the Holley 302-1 pan if it won’t clear. I think that’s the number of it anyways.
Steve
Hey cool another chevette getting swapped. Hope these pics help. I originally went with a muscle car pan because the fbody ones were outrageously priced. Luckily china stepped up their game so I bought a pan on rockauto for like 95. I started fitting the engine with the fbody pan quickly found out the firewall needed to go. Not exactly sure how much furthur back it is now. Since the factory firewall is an odd shape it isn't just moving the firewall back and it seems easier to make one. The pan is nearly flush with the crossmember. The trans isn't all the way up so the engine is a little more leaned than it will be when finished. Th400 won't fit in factory tunnel apparently lol
I never tried in my car besides the initial drop in. I’m sure it’s do-able but like the post above me you might run into the tunnel just as much as the firewall to get past the mid hump in the pan.
Did you ever get around to checking pushrod length? Your valvetrain was unusually noisy the last time I seen you at the track. There's a good chance with your head/cam setup that you could use different pushrods.
Make sure the valve is closed, loosen a rocker, tighten it back down. You should get 1/2 - 1 full turn of preload on the lifter before the rocker bolt is tight. Any more or less, and you're giving up some power.
im not entirely sure how tight to go before starting to count my preload tightness. But im coming up with between 1.125-1.25 turns before the bolt is tight. That’s with me snugging the bolt by hand with a .25” extension.
Wondering if you had any issues with that Aeromotive fuel pump setup? I was looking at just installing one of those vs trying to get a F-Body fuel assembly to fit the tank. Looks like its got foam around it to eliminate starvation issues.
I’ve had no issues with it. It has the foam with a rubber bottom to act as a sump. Just a little re-shaping of the hatch floor with a hammer to clear the fittings was all that was needed. You can hear the pump but it’s not really noticeable once the car is running.
I’ve had no issues with it. It has the foam with a rubber bottom to act as a sump. Just a little re-shaping of the hatch floor with a hammer to clear the fittings was all that was needed. You can hear the pump but it’s not really noticeable once the car is running.
Well no big updates to the car. I switched over to some 225/50/15 DR to compete at a small event on Friday. For not being out all winter the car drove great to and from the track. I set some new personal best which really surprised me because I was also foot braking the car. So as of now my new best ET is a 10.29 @ 129mph. I made it to the final and did my best to tree the other guy as he was consistently faster than me all night. I gambled and lost by .003 on the light. I’m sure he would have still won after seeing his ET but it was my only shot. Besides that it makes me excited to get back into this car and start working on it again. The slips are in order and I’m car 730
02-20-2019, 11:44 AM
