LQ4 with 706's and a cam - pushrod length?
12-05-2020, 09:40 AM
#21
Ok. Got it. I think. Ha. Gonna dig into it today finally. I have 7.325 and 7.350. It’s in the car so don’t really have a good way to stick an indicator on there. I’m using new factory GM lifters. Of course, can’t confirm since it’s eBay and the guy buys them in bulk. I have a measuring tool but it’s not made for full spring pressure. I’ll let ya know.
02-05-2021, 08:02 PM
#26
Teching In
Thread Starter
Finally got my swap done. But headaches were had. Still one headache left...
TLDR: I'm a dumbass and have no business under the hood of my own truck. Lol
When I got the call that the machine shop was finished resurfacing my 862's, the tech mentioned he had to take off "a lot" to get it to true. I was at work at the time and was in the middle of something and forgot to ask how much is a lot. Dang it!! Anyway, I slid in the cam, put on the melling 295 oil pump, installed the morel 5315 lifters after tearing them down, hosing em out with brakleen, and soaking in oil for almost a week, installed the heads, then stock pushrods and trunnion upgraded rockers. Fired it up after a few 10 second cycles of no fuel/spark to prime the oil, sounded like Armageddon, threw random misfire code, but tapered down to a mild sewing machine. I drove it around the block and back and all seemed uncatastrophic. I took it to work the next day, about 60 miles round trip, and data logged the drive. SOLID 8 degrees knock retard any time I give it pedal. Tore the valve covers off, rechecked lash, and found that I could push the #2 cylinder intake valve down by hand easily. Thought, hey maybe I got something lodged in the oil passage upon reassembly, so it's not pumping up. Looked up morel preload and found it's something in the neighborhood of .040. Ordered up some BTR 7.0350 pr's, installed, and it was much quieter, except that one intake valve still. Put the stock rod back over it and it was quieter. Fast forward a week, after about 4 stages of maf tuning, I got it to where I got zeroes across my knock retard board. But it still sounds like a sewing machine, and now it's louder on the driver's side. I have been running octane booster on top of the 92 octane I already run, which seems to make the truck peppier. I think... Yesterday, I data logged STFT's just for giggles, suuuuper lean on bank 1, nearly perfect on bank 2. Think I have a collapsed lifter or a few... Ordered another set of head gaskets and a set comp lifters. I'll report back when I get a chance to do the swap.
Do you think it's possible I may have pumped up the morels with air upon teardown/reassembly? I only did it because I read it's a good habit, just in case there's debri inside from the plant... Is it possible I have too SHORT of a pushrod, not too long? Like maybe I should bump up to 7.450 or so?
TLDR: I'm a dumbass and have no business under the hood of my own truck. Lol
When I got the call that the machine shop was finished resurfacing my 862's, the tech mentioned he had to take off "a lot" to get it to true. I was at work at the time and was in the middle of something and forgot to ask how much is a lot. Dang it!! Anyway, I slid in the cam, put on the melling 295 oil pump, installed the morel 5315 lifters after tearing them down, hosing em out with brakleen, and soaking in oil for almost a week, installed the heads, then stock pushrods and trunnion upgraded rockers. Fired it up after a few 10 second cycles of no fuel/spark to prime the oil, sounded like Armageddon, threw random misfire code, but tapered down to a mild sewing machine. I drove it around the block and back and all seemed uncatastrophic. I took it to work the next day, about 60 miles round trip, and data logged the drive. SOLID 8 degrees knock retard any time I give it pedal. Tore the valve covers off, rechecked lash, and found that I could push the #2 cylinder intake valve down by hand easily. Thought, hey maybe I got something lodged in the oil passage upon reassembly, so it's not pumping up. Looked up morel preload and found it's something in the neighborhood of .040. Ordered up some BTR 7.0350 pr's, installed, and it was much quieter, except that one intake valve still. Put the stock rod back over it and it was quieter. Fast forward a week, after about 4 stages of maf tuning, I got it to where I got zeroes across my knock retard board. But it still sounds like a sewing machine, and now it's louder on the driver's side. I have been running octane booster on top of the 92 octane I already run, which seems to make the truck peppier. I think... Yesterday, I data logged STFT's just for giggles, suuuuper lean on bank 1, nearly perfect on bank 2. Think I have a collapsed lifter or a few... Ordered another set of head gaskets and a set comp lifters. I'll report back when I get a chance to do the swap.
Do you think it's possible I may have pumped up the morels with air upon teardown/reassembly? I only did it because I read it's a good habit, just in case there's debri inside from the plant... Is it possible I have too SHORT of a pushrod, not too long? Like maybe I should bump up to 7.450 or so?
02-06-2021, 01:07 AM
#27
100% Redneck
You're see sawing back and forth... with milled heads I can't see needing 7.450 pushrods. Did you measure for pushrod length on assembly or just drop in the pushrods and torque them down? Measure (with a pushrod checking tool) then do a sanity check with the rocker bolt turn method. The Morel lifters don't need nearly the preload (.030 - .035") as LS7 or Comp 850 lifters. One full turn of the rocker bolt from zero lash is around .079 preload
Last edited by 1FastBrick; 02-07-2021 at 12:32 AM. Reason: corrected the preload equation
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