I started my engine (gen2 LT1) for the first time after working on it, heard the 1-2 seconds of lifter clatter I expected and while it did quieten some the valve train stayed far too noisy. The only mechanical change I made to the engine was new valvesprings, GM LS9 PN:1942055, installed at 1.75” intake and 1.76”. I have the LT4 hotcam running 1.52:1 rockers which gives me right around .500” lift. I preloaded the lifters after 0 lash 3/8 of a turn just like it was before. When the valve train didn’t get quieter after a couple minutes of run time (using 10w30M1 oil so shouldn’t have had an oil flow issue) I shut the car off and decided to investigate further. Pulled the DS valve cover and found very little oil had made it up top, then noticed some very strange looking pushrods. On the DS head 7 of the 8 pushrods were bent. I pulled the PS valve cover, also very little oil made it up on that head and 5 of those were also bent. I pulled the #5 spark plug because it’s pushrods we’re the most drastically bent on that head and found it had no odor or discoloration present (new TR55’s) like it never got fuel or spark. I popped the valve springs off that same cylinder and found no evidence that the retainer had hit the valve guide seals (also new parts). The coil bind specs I’ve seen for the LS9 springs are from 1.16” to 1.2”. Even with my tightened install height I have on my tightest 2 clearances, .047” intake and .058” exhaust before coil bind at the 1.2” spec. The engine idled and at one point I opened the throttle to maybe get 2k RPM to try and bring the oil pressure up to quiet the lifters with a touch more oil pressure. It idles cold at 30psi. To complicate things a little more, I installed a TorqHead kit at the same time which replaces the optispark, coil and ECM with gen 3 stuff. The car was running unusually smooth so I had no reason to believe it was misfiring, very little chop from the hotcam. Probably would not have guessed the cam wasn’t stock. The idle was also rock steady, better than I ever saw it run on the stock ECM. So I’m scratching my head, why did I bend so many pushrods? To summarize, the valve springs are new but not in bind, I visually verified the retainers didn’t hit the valve guides, the pushrods and lifter preload are the same, the cam lift and timing hasn’t changed. This was not my first time to do this kind of work (mechanicals, first time TH install) so I wasn’t in unfamiliar territory. Help me figure out what happened here. I used Smeding Performace’s procedure for finding base circle outlined here: https://youtu.be/uQSvg8aylx4?si=m4giyCyBla4T4y3o. Is there some way I caused the valves to hit the pistons? The only unverified potential for physical contact is PtV but how in the world would I have done that? I had spun the crank over by hand many times without the plugs in and felt no abnormal resistance before running the engine. I’m lost right now on what happened. Help me out if you can. Otherwise I’m afraid my next step is to tear the top end apart to pull out my lifters to check for stuck ones and piston crowns for witness marks and check the heads for bent valves. Thanks for any help.

 

What all did the "working on it" involve? Only valve springs or did you get into the timing set as well?
You mention very little oil getting to the top. I suppose in that case it wasn't primed before first fire (which may or may not have been warranted given the time the engine was down not indicated).

 

I went through a list of valve spring specs I'd put together for a new engine.
Seeing as you looking at .047" clearance before coil bind it got me to thinking if that's on the tight side.

Can you verify that GM part number?

For the record, in conversation with Jones Cams, while I had previously been directed to a PAC 1219 spring, which is very similar to Comps 26918 beehive spring, Jones steered me to PAC's 1218x. The differences are subtle but one thing that stands out is the coil bind height and how it's relative to the cam that was spec'd (by Jones).
It comes in at .084" on the intake and exhaust (same lobe lift on each).

1.800" installed height.
Coil bind at 1.14".
Valve lift (.360 lobe x 1.6 ratio) = .576".
Clearance (1.800"-1.140"=.660") - .576" = .084".

 

Sounds to me like the installed height was measured incorrectly, such that either it went into coil bind, or the retainers hit the guides.

Note that your IH was 1.75": that knocks .050" of available clearance off compared to the springs' design, right off the top.

I'd suggest putting a couple of the ones with bent pushrods together without the springs in them, and seeing how much clearance you have from the retainers to the guides; and mic from the spring pockets to the bottom of the retainers. You unmistakably have parts interference at one of those two places.

Coil bind height is partly determined by the wire the spring is made from. Oval wire will give greater clearance, ceteris paribus. Often to get a higher rate, they use thicker wire; the other choice being a (usually) more expensive metallurgy.

I know the LS7 springs (can't recall the part #) but I'm not familiar w LS9. I agree with the PAC spring recommendation. 1218 would be enough spring for that situation but the 1218X & 1219 would work too. Install them at the stock LS height of 1.8" or as close to it as practical without going over.

 

Are these LS7 lifters or OEM LT1 lifters?

I just went through the valvetrain on my van, running adjustment to 1-1/4 turn.

 

The engine isn’t a fresh build, it was down about a month as I did the work needed. I didn’t touch the cam or lifters. The only unsealing of the engine involved removing valve covers. The work performed involved replacing the valve springs, guide seals, spark plugs, and installing the TorqHead. The mic was absolutely read correctly while measuring install height and the accuracy of the mic was verified with dial calipers to .001”. That coil bind clearance of .047” was based off the 1.2” coil bind height but if you go by the 1.16” coil bind height I have .087” before bind. Different places are quoting different coil bind heights. I just stated the most conservative figure. Also, as I said above but there’s a lot I said, I pulled the valve springs off the cylinder with the most dramatically bent pushrods and saw absolutely no indication of retainer to valve guide contact. I’m using Comp 787 retainers and standard length valves. I don’t know what I have for lifters because the engine was rebuilt before I purchased the car. I’m actually working on my ‘96 SS, not my ‘86, but these bits of the engine are the same and what it’s in doesn’t change anything. The LS9 valve springs are the replacement spring for the discontinued LS6 springs and have identical specs. I thought to go with the PAC1218’s but in the reading I was doing to find a better replacement for the LT4 springs that were in there i saw quite a few people using the LS6 spring with up to .525” lift. I have less than that and the Hotcam isn’t all that wild of a cam. The part number for the spring set is a copy/paste from Summit where I bought them from but here it is again… 19420455. I think I addressed everything important that y’all have asked about. I’ll update as needed

 

I've read all of your procedures and changes. You've got everything covered as to what isn't giving you the problem and it looks to me that it comes down to the spring itself.
I think you owe it to yourself to physically measure the clearance in the spring at max lift.
As you're well aware, the lifter is going to give up some of that lift when it's compressed during rotation without oil pressure. Getting a dial indicator on the tip of the rocker will show how much lift you're actually seeing.
What I'm doing (right now actually) to work through this exact procedure, is to use my valve spring compressor to get a full lift value. I use my stud mount compressor and it's "adjustability" to good effect.



Following your progress as you get there.

 

Alright but be patient as I’ve got a normal guy’s life and don’t get to spend all my time playing in the shop now that the long weekend is over. I’ve actually put the Camaro aside and moved over to the Bird. I wanted both at Goodguy’s but with this it’s looking like it may just be the Bird and there were things it needed addressed before the show too. It may be a couple days before I get over there to do what you’re asking. One thing that just occurred to me, how tightly can the spring seat fit the ID of the spring? By the numbers the Comp 4705 spring seats should have fit but they were a very tight fit, one I couldn’t achieve by hand which I thought very strange. I haven’t done this job very often, never on an installed head, but never had a fit so tight the spring couldn’t be installed or removed by hand. Once I would start compressing the springs to install the keepers they would pop down over the seat. That thought only now occurred to me and I’m wondering if that has “adjusted” my coil bind figure while running even though checking by hand didn’t show an issue. I’ll smash those springs down tight and get a measurement, probably be the end of this week though and I won’t have this coming weekend to do any work on the car.

 

Interesting observation on the seat fitment. I can't say I've encountered that before. I know Comp gives dimensions for their locators but I'm not sure GM does regarding that spring.
I could be a source of interference I suppose although I'm more inclined to think it's the installed height vs coil bind. Which, by the way, prompts me to ask how you measured your installed height. Do you use a height micrometer by any chance?
​​​​​​As for patience for your progress, I always try to keep the hobby aspect of this in focus so I'm seldom in a rush. My shortblock has been in my shop since June. Of 2022! I'm just now finishing up the top end and hope to have it back in the car before the snow flies in these parts. Might have a 6-8 week window in that regard. If not, it'll wait till the spring as I'm garageless these days.

 

Issue resolved, coil bind got me and sofakingdom was right while over on ST skinnyZ got me to double check my tool. Engineers are the one group of jerks that deserve to be whipped at a post more than anyone else. Who designs a tool like a height mic that will read drastically different depending on what part you’re using like standard retainer vs beehive retainer? The last time I used the tool I checked that and marked the tool .135 so I’d know what to add to my reading. This time I forgot to use my own advice so I set up my valve spring .135” lower than I thought I did. So that leaves me with a question. Is it good practice to replace my head gaskets since the little 1/2” holes the pushrods go through were all buggered up when my PR’s buckled? It’s not that I think they’ll leak but I wonder if those pieces where it peels up are going to be falling into my oil pan.

 

The recess built into the top of the height micrometer has caught more than one person out.
Prior to this engine, I had used someone else's and the offset was different from the one I currently have.
.190" vs .135".
It got me to looking back over my build notes from 5 or 6 years ago as the stack up of shims, locators and keepers didn't match up with what I had done previously. Still not sure if I had messed up the spring height although if I did, it was to the too long end of the scale rather than too short.
Live, learn, spend more money then move on.