33 degrees overlap in my hoopty also with the same OD gear sets…FBody magnum.

 

it was 0.005-.010" big across the board. so it was probably 247ish on the intake side as a whole. I don't think there is more than 5hp on the table, intake duration should be 250 at 0.010" lash, so 3-4 degrees duration and that small gain in lift isn't a massive change.

And Mike, it's not going to shift the peak 500 rpm lol. Kenny's car peaks before 7 with that BTR4v2.. my peak MIGHT move 100rpm to the right at best now, but an MSD car is not peaking at 7500rpm lol. I don't think i'd want it that far right anyway. My guess is that peak doesn't move and it just doesn't fall off as hard as rpm approaches 8k.

I drove it last night to the guy who is going to fix my exhaust. pulls to 8000 clean as a whistle, log looks great, but i really need to get a ram air on the car. it was flashing 95kpa at the top. Plenty of power to be had there. He's also moving the merge/x to right after the collectors and not in the middle of the car. TBD if that will make any meaningful difference!

I agree with you guys on the cruising part though, it drives completely fine in 6th lol. Compared to the previous setup though, it is absolutely more sensitive under 2k, especially during low rpm coastdown and on/off throttle situations (i really do drive like a grandpa if i am not making a pull). The AMT engine and trans mounts and solid driveshaft couplers absolutely amplify the "herky jerkiness" when it starts to kick in during those moments. I have no issues with all of this, i expected it, i am just putting it out there for those who have never gotten into the 30+degrees of overlap cam life. Happy with how it drives, its much tamer than i expected, 2k and up, it's extremely smooth.

 

quit yelling at me dad!!!!

 

You can yell back even louder if you end up being right!

 

The new build woes continue, but it's why we test. Although this is bit more frustrating since like the exhaust, I placed a bit of trust elsewhere..

First of all, car will get the new mid section made week of the sept 23rd.

2nd of all, the proper lash setting appears to have had a much larger impact than I anticipated. It puked coolant all over the side of the car during a pull I made the other day. It showed marginally leaner on the wideband in a few places (13.0 vs 12.7 target) and a very quick 0.5 degree of knock retard around 7500rpm. I messed with the intake path some so it also surprised me and held 97-98kpa much longer than before. Hindsight says i should have added fuel and pulled some timing based on the significant idle changes and intake path, but i (obviously) did not think it would affect the VE model that much! This one is on me, I can accept that. Truly thought i was playing in the margin of error zone and i was proven wrong. Based on the plugs, looks like it's the driver side that lifted (no milk in the oil or overheating). Detonation appears to have kicked in and won. But I will replace both head gaskets. Weekend job.

3rd thing is bit more frustrating. Car pulls fine through a single gear, which is all i have really done due to the exhaust situation. But i decided to make a 3rd and 4th gear pull (4th is where it pushed coolant). The car hesitated and felt a bit stuck in the mud on the shift then recovered and felt like it pulled well. But the hesitation stuck with me, didn't make sense. RPM traced looked like doodoo. Triple checked fueling, tps, spark, lash, everything. All checked out perfect but RPM trace said valve float, I found it hard to believe because things are barely used at this point. Called Cammotion and said I really think i am floating on the shift and when they asked what rockers and springs, they said oh yeah you are definitely floating those on a 6spd car at your rpm. THE SPEC'D THE DAMN SPRINGS AND CAM. I put the dang rockers in the request and even asked if they good enough for these specific rockers in a 6spd car at 8k rpm on the phone before placing the order "you'll be stable to 8500rpm!" they said. The tone completely changed this time to "high rpm and stick car shift are brutal on the springs.." well no **** lol.

So now i need to go to something like 1237/8x's. The single gear RPM pulls being smooth but overloading on the shift tells me that the 1209x's are probably close to being enough, but after settling down a bit, aren't enough. 1238x installed @ 1.8 will bump me to 250lbs on the seat from 185. 700 open vs 535. but 0.100 from coil bind. Pedestal obviously gonna pedestal on these heads so i will get a shaft system in to do this. Again, this isn't hard work or a complete tear up. Just would've liked to do this from the beginning had I known.

Rant over. I am much smarter now than when i started.. which is i what i said wanted from the beginning right??? careful what you wish for lol.

I borescoped the cylinders and doesn't look there is any PTV contact, but will confirm once heads are off.

 

I’ve been running 1237x springs with a crower stainless steel shaft system
with a Cam Motion llrs cam 255/269 @700 lift
with hollow stem valves 2.250 intake 108 grams and 78 grams exhaust with tool steel
retainers set up @1.840 (I haven’t had any issues running them at that with valve float)using.050 + locks .when I started this project , I was thinking
I better spring up with this valve train were it’s so heavy.
i think a 1237x spring would be a good spring for you
but i only turn my to 7,200
I’m thinking 1238x has a lot seat pressure for a weekend warrior.

 

Honestly, this is how it goes, lol. Always something. Sounds like you have a good game plan to move forward.

 

your install height is interesting cus at 1.840, the 1237x has less seat 1209x at 1.750 where I'm at now.. i think 8k is a difference maker. I'll likely go with 1238x's at 1.800. I don't really cruise the car.


yeah luckily this isn't my first rodeo when it comes to leaning too hard on factory ****. I was mentally prepared for the BS but praying I would somehow avoid it this go around... I'll get it there soon.

 

I didn't spin it over 8000 but I have 1237X springs on my ls7 casting 427 and it did great on the engine dyno with T&D adjustable rockers. .775" lift on the intake and they were at a nice spot from coil bind.

On a more serious note, I don't think the lash change is what caused you an issue. Also I forget GM ecu's have open loop fueling. An ECU with closed loop fueling really is nice.

To me, it really sounds like when it bogged down a bit on the 4th gear shift it started detonating, and got worse as you pulled through it. Pulling the engine down that hard can definitely cause knock if you're on edge with fuel or maybe a cylinder has an issue causing it to run lean or hot. It also could've been pinging a little top of 3rd and shifting into 4th set it off bad.

What in the RPM trace looked like valve float, and was it in 3rd gear or 4th gear you noticed it?

I don't trust knock sensors to do anything useful on a heavily modified engine, especially not with headers and a big solid roller.

If it knocked that hard you need to make sure you don't have any cracked ringlands or cylinder walls. This is a SBE?

Hoping for the best for you man that its an easy fix!

 

I definitely feel it might be a cracked sleeve over a headgasket. Hoping its the gasket tho.

 

Factory computer is open loop at WOT. Closed loop during cruising.

The rpm trace got wavy, meaning it would gain and lose rpm. Right after the shift from 3rd to 4th it dropped to 6k and there was a brief spot where it lost 200rpm to 5800 and then it appeared to gather itself and pull, that was the hesitation. But if you play it back slow enough, it fights itself to gain rpm the entire way, even at the top of 3rd before the shift, up donw up down up down... i played back some pulls from the old setup to see if it was data collection. It definitely is not a collection issue. I'm sure it was detonating to do something like this though lol

the cracked liner hlis definitely something in the back of my head. But it was not bubbling an ounce at idle about 4 min after the pull, oil was clean, compression and leakdown are good. Nothing obvious on the pistons when I borescoped. I'll give it a good look when the heads are off, but I agree, hoping the liners are good.

thoughts and prayers are needed

 

Ryans99ls1 your right about spring pressure with 1209x @ 1.750 spring pressure @185lbs and 1237x being 175lbs @ 1.840 seat pressure
but by the time you get to 1.650 the 1209x is @ 235lbs and 1237x @283lbs seat pressure.
in my way of thinking setting them up like that.it would be easier on the cam when it was first starting to open the valve. But have more spring pressure @ the same lift after opening. 1209x @1.100/510lbs and 1237x 1.100/585lbs
were my valve train was so heavy I didn’t think a 1209x would take care of it.
but unlike you I will never turn my motor 8,000 rpm
that was reasoning behind setting the springs like that.
It’s been working for me with no valve float so I guess i will stick with it
talk to Bobby from Cam Motion at LSX fest today .going to have them do a regrind on my old cam. incoming cam from Mike Jones .I’m going to have to decided which one I’m going to run

 

Good point on the spring rate. I am thinking 1238x's at 1.800" are the move for 8k rpm. Just curious about the life of that spring, only one way to find out though!

Bobby is who I was bouncing ideas off of during this most recent call with them. Good guy.

 

I hope the 1238x work for you,so you can give us some feedback on them.
but I would think that with that much spring pressure it would be hard on your valve train.
as far as wear.
as far as the life of a valve spring in the words of Ron White pum to the crash site

 

That makes two of us that hope they work. If they don't, i must have something else going on because that is more than enough spring. But i will no doubt give them a torture test.

My thought is that an out of control or borderline valvetrain is MUCH harder on parts than one with stiff springs. And if the valve bounces off the seat less, is that really "harder" on parts? The rocker arms will be fine, 3/8 series 5 rods are very good, and the lifters are high quality. 8620 core shouldn't care. I did grab some ARP rocker studs too. (the fastener is the weakest part of this whole equation anyway).

The big thing is that i discovered that the Comp BSR shaft fits these T&D rockers.. i was able to convince T&D to send me some replacement rocker bushings by telling some white lies, since they insist on doing the rebuilds in house. They couldn't/wouldn't answer whether or not the bushing OD was the same as a stock rocker. Well it is, because i pressed their replacement bushing into a factory rocker arm perfectly. So i ordered the Comp BSR shaft with factory rockers, i will pull those rockers off, press on the T&D's and move on. That, along with the studs should make things much happier with higher rate springs.

 

Sounds like you got a plan,I’m hoping to get to your power level @680rwhp this round.
Bobby Akers call today my monster triple is in with the aluminum flywheel (40 lbs)from mantic twin (30lbs)
were on the same page as far as were we want to go,,looking forward to the feedback on 1238x springs

 

Did you get the ones for the LT? Part number - 234-7208
I believe the LS ones don't work with the LS7 rockers.

 

Thanks for confirming on the T&D rockers. Is there a way to order just the shaft from Comp or is it the full kit only which includes rockers?

 

Idk why I keep calling them ARP's. I meant the Comp ones. I thought about the LT ones from ARP but it seems like they you want you to use their weird perma locks? No experience with those.. so figured I'd just wait for the comps to come in.

Nope, I tried ordering their bushings and they said I have to send the shafts in if I want bushings.. so you gotta bite the bullet and buy the whole thing. I asked if I could buy the shaft and they said no to that too.

I'm willing to bet CHE would make the bushings if you gave him the dimensions though. He was all ears when I called him. He does custom stuff too.

 

Maybe we are talking about different things? The ARPs are just a stud and a nut