Problems with preload on 1 lifter, what to do?
 

OK, I have AFR pedestal mount heads, and an FTI custom cam. Last year I lived with a noisy lifters. I was using the stock pushrods but I had to cut down the pedestals on the exhaust rockers to get enough preload to quiet them up. Anyway, I replaced the lifters with new ones from FTI, and I got 6.300 pushrods for the exhaust. Well, with the stock intake pushrods, I was getting 1/8th turn preload, and with the 6.3 and a .015" shim on the exhaust I got 1/4 turn. Well, I started it and it was NOISY. So I got 6.300 pushrods for the intake now. Here's what I have now, on the intake I'm running 6.300 pushrods with the .015" shim, with this I'm gettimg 5/8th turn of preload. On the exhaust, I'm just running the 6.300 pushrods without a shim, and I'm getting just about the same preload as the intake. BUT, on the #5 cylinder, on the exhaust I only have a little over 1/4 with the 6.300 rod and no shim. I had this too when I ras running the 6.300's and shims on the exhaust, but at that time I didn't use the shim because of the fact that it was only at 1/4 turn without it. I noticed the helicoil was a little messed up on the bottom, so I cut the bolt down just a hair, but it didn't help, so the coil isn't the problem. I also put a washer under the head of the rocker bolt, and it didn't make a difference. Now, do I live with it since its within spec, or do I mill down this one pedestal to gain some preload? I don't know what to do... I'm at wits end. Thanks,
Paul

hey, did you know that they make different size shims. this is what tuning is about. each rocker may require a different shim. get a shim kit with a few sizes and do it the right way. dont mess up the heads or try to invent things. and 5/8 preload is a bit high. you should set it for 1/4 and no more than 1/2 turn. as for noisy, typically valve train mods do give some noise so if its a light tapping sound you hear its normal.

Killercanary What kind of bolt-downs do you have? Maybe its the rockers that are a little different and causing your probelms. You might try swapping them around to see if things change. Otherwise, with all the good parts that you have on that thing, I would suggest a good set of adjustable bolt-downs. The YellaTerras are real nice, and competitively priced too.

It is so nice not having to mess around with shims! The adjustables are so much easier.

andy

Andy..I think he has Scorpion rockers that he bought at FTI, where the heads and cam came from, Ed likes these.

Paul, if you haven't tried different shims do that first, I not to keen about milling that one pedstal down. Are you sure it is not the lifter? The lifter could be bad and this would cause you issues with your preload. I ended up at 1/4" turn on my Holleys and they are pretty quite even under my fabbed alum valve covers.

How's your dad's car coming? The cage looked nice from the pic's you sent. My car is all buffed out and ready to start re assembly, the thing is blinding out in the sun, I am very happy. The motor is just about all done just need to put the oil pan and front cover back on, I glass beaded and cleaned everything and repainted and cleared it all, can't put a dirty motor back in my engine bay.

Take Care