[cmitchell17]

Also sorry I keep posting, but I just noticed the difference in wear on the cam retainer plate, the bad wear is on the phaser side not the cam side:



Given that I am almost positive this is the stock GM retainer plate and stock phaser, I wouldn't think there would be a significant hardness difference, but maybe the cam phaser bearing area is extra hardened. Either that or it's getting significant cam thrust load backwards towards the firewall. Or maybe this is just normal?

[KingLT1]

Originally Posted by cmitchell17

Attachment 1146872

So I emailed Johnson and told them I was shooting for 0.035 and they didn't correct me so I guess this is correct preload maybe not though.

So looking back on my notes you may be right, apparently I was shooting for around 0.050 because right now I am using a 7.750 pushrod, which gives me an average of 0.056, 7.725 would have been very close to nominal 0.035 Johnson recommendation though. I looked back on all my receipts and I think I tried pushrod lengths: 7.725, 7.750, and my original TSP 7.800. I sold all of them though and stuck with my 7.750s:

Attachment 1146873

I think I was trying to increase the preload to make it quieter, but got tired of changing back and forth and just settled with the 7.750s. But you may be right maybe I had some other knowledge somewhere that 0.050 worked better than 0.035, either way its been too long ago to remember.

I am still looking for my preload measurements done just by the rocker arm screw finger tight method, then counting screw turns. I think preload measurement is very subjective from person to person and seems like it would also be very subjected to the state of the lifter height. In the case above all of the lifters would have had miles on them from the TSP cam and recently ran in the engine.

I really think I have more measurements I did with screw turns somewhere I just have to find them, but I think both methods were consistent though

The .035 spec is for a hot engine. You have to factor in heat expansion when taking a cold preload measurement, so you need add .012-.015 on top for aluminum engines to account for expansion. Iron block stuff is different.

Also, you definitely want to measure both intake and exhaust on a few different cylinders because I have seen ported heads that had valve jobs done end up with slightly different valve lengths.

Nothing wrong with the screw turn method to verify, but I prefer to use an adjustable push rod with H/C custom lifter stuff. Start by finding base circle, find zero lash, then measure the adjustable push rod with a digital caliper, add the target preload to that number, and order the correct pushrods.

The only way I would rely on screw turn method is if you are installing a cam in a engine with stock heads, head gaskets, and factory spec lifters. Otherwise, you really need to go through the entire process as I mentioned above or a lot of times you end up with a noisy valvetrain that wears prematurely. This was a huge topic back in the day on LS engines. The LT stuff is no different in that regard.

Cam motion stuff is generally known for having smooth lobe profiles with quiet valvetrain. So if it was noisy I would look into this more. You seem to be knowledgeable, so I am not saying you did anything wrong. Just putting this info out there as food for thought. It may or may not add any valuable information for when you put the new combo back together.

[Joshinator99]

Originally Posted by KingLT1

The .035 spec is for a hot engine. You have to factor in heat expansion when taking a cold preload measurement, so you need add .012-.015 on top for aluminum engines to account for expansion. Iron block stuff is different.

Also, you definitely want to measure both intake and exhaust on a few different cylinders because I have seen ported heads that had valve jobs done end up with slightly different valve lengths.

Nothing wrong with the screw turn method to verify, but I prefer to use an adjustable push rod with H/C custom lifter stuff. Start by finding base circle, find zero lash, then measure the adjustable push rod with a digital caliper, add the target preload to that number, and order the correct pushrods.

The only way I would rely on screw turn method is if you are installing a cam in a engine with stock heads, head gaskets, and factory spec lifters. Otherwise, you really need to go through the entire process as I mentioned above or a lot of times you end up with a noisy valvetrain that wears prematurely. This was a huge topic back in the day on LS engines. The LT stuff is no different in that regard.

Cam motion stuff is generally known for having smooth lobe profiles with quiet valvetrain. So if it was noisy I would look into this more. You seem to be knowledgeable, so I am not saying you did anything wrong. Just putting this info out there as food for thought. It may or may not add any valuable information for when you put the new combo back together.

Agreed 100%. My shop used the adjustable length pushrod to measure for my Johnson 2110R lifters and CamMotion cam. I ended up with different length pushrods between intake and exhaust due to my Mast heads! I’m really glad they took the time to carefully check. I don’t think you can just “try 3 different lengths” and hope it works out…probably won’t lol.

[cmitchell17]

Originally Posted by KingLT1

The .035 spec is for a hot engine. You have to factor in heat expansion when taking a cold preload measurement, so you need add .012-.015 on top for aluminum engines to account for expansion. Iron block stuff is different.

Also, you definitely want to measure both intake and exhaust on a few different cylinders because I have seen ported heads that had valve jobs done end up with slightly different valve lengths.

Nothing wrong with the screw turn method to verify, but I prefer to use an adjustable push rod with H/C custom lifter stuff. Start by finding base circle, find zero lash, then measure the adjustable push rod with a digital caliper, add the target preload to that number, and order the correct pushrods.

The only way I would rely on screw turn method is if you are installing a cam in a engine with stock heads, head gaskets, and factory spec lifters. Otherwise, you really need to go through the entire process as I mentioned above or a lot of times you end up with a noisy valvetrain that wears prematurely. This was a huge topic back in the day on LS engines. The LT stuff is no different in that regard.

Cam motion stuff is generally known for having smooth lobe profiles with quiet valvetrain. So if it was noisy I would look into this more. You seem to be knowledgeable, so I am not saying you did anything wrong. Just putting this info out there as food for thought. It may or may not add any valuable information for when you put the new combo back together.

Thanks, and agreed preload needs to be checked and double checked. I looked back on my spreadsheets and I did in fact check all of the cylinders and it averaged out the same as I showed in the screenshot. So technically running the 7.750's I have now would have on average gotten me 0.055 of preload.

I think trying to do this with a hot engine would be very difficult unless it's the middle of the summer, by the time you get everything off and set up you would have had a lot of cool down.

I think my main concern is why I have so much variance in my measurement, over 0.040, so right away I am trying to hit a preload value within +/-0.010 and my zero lash measurement is +/-0.041.

So I got a BTR 230 cam with a 4 degree limiter block, some Delphi lifters, and a GEN V conical spring set. Problem is I now can't find my stock retainers.

So at this point I think I am just going to drop the new BTR cam and Delphi lifters in, fly cut the pistons, and then just keep my existing PAC TSP 0.660 springs. I did order a set of reatiners for the conicals but techincally I guess I could change the springs to the conicals without pulling the engine in the future, but it will be a pain. I would think 175 psi from the compressor would hold the spring well enough to get the retainers off not sure though.

I was wanting to try the conicals, hoping they might have an impact on noise. I'm just going to put it together and measure, then hope all of the advertising BTR puts out about valve bounce and stability is true and is not just marketing BS haha.

I also bought a cam bearing tool, but then wasn't thinking and realized I don't have the crank out of the engine, so I am just going to roll with it. I still feel like something is pushing that cam backwards, I guess I can check end play but not sure if there are machining differences that would affect that with an aftermarket cam as opposed to the stock GM spec. I think I will take my chances on it since I am running 0.028 Cometics at almost $250 a pair, so I don't want to have to then buy a new set of bearings and rod bolts, just to be able to take the crank out to replace one cam bearing.

[Tim M]

I've got the same part type combo, but with only 1500 miles on it. I used only the turn method to set the pushrods. Quiet now, but time will tell.

I have also changed valve springs on the car using no air compressor. Just put the piston on TDC and the valve only drops slightly. One can pull it up the .25 inch as you prepare to install the locks, etc.

Good luck!

[cmitchell17]

Originally Posted by Tim M

I've got the same part type combo, but with only 1500 miles on it. I used only the turn method to set the pushrods. Quiet now, but time will tell.

I have also changed valve springs on the car using no air compressor. Just put the piston on TDC and the valve only drops slightly. One can pull it up the .25 inch as you prepare to install the locks, etc.

Good luck!

Thanks, are you running the conical springs or dual springs? From the wear I see, especially on the #4 intake, I see too much load/pressure or maybe combination of speed and pressure. I am going to pull the PAC dual springs on that lobe and any of the others with excessive wear and test them. I actually have 2 sets of PAC springs when I got my TSP, which I ran the first set of springs with the TSP cam and the second set with my Cam Motion cam. So I can replace it with one from the first TSP cam set. I just need to get everything put back together and going and need the room in my garage. I guess if I have to pull the motor again, I'll just have to pull it again.

I know it seems I always have a lot of trouble with the locks/keepers getting stuck and without a c-clamp style compressor with the heads off it becomes difficult trying to get them off without beating everything up.

[cmitchell17]

I put the new BTR cam and LS7 lifters in and measured preload and it was extremely consistent. Within a few thousands on each cylinder, when I measured with the Johnson's I was getting in the +/-0.040 variation. Not sure the differences, if any, in the spring plunger, but either something else was going on I didn't notice or I really screwed up something.

So I am getting on average 0.060 of preload using my old 7.800 in pushrods. This is of course cold and no head gasket. If I go up to 7.850 pushrods that should put me around 0.067 accounting for cold engine (~0.015) and Cometic thinner head gasket (=0.028). So thankfully that is close to where it looks like I should be with LS7/Delphi/Stock lifters, I know there are some sources that say more like 0.100, or at least up to 0.100.

It's kind of hard to achieve a +/-0.010 tolerance, when the only commercially available pushrods are at the least 0.025 increments with most at 0.050 increments.

[KingLT1]

You can get custom length pushrods from Manton if need be.

[Tim M]

I'm using PSI 1516 beehive springs. Seems pretty burly, but a rep at Katech mentioned it is a spring commonly used for LT1 applications. I went a step further and employed LT4 Ti intake valves as well.

[cmitchell17]

Originally Posted by KingLT1

You can get custom length pushrods from Manton if need be.

I probably wouldn't want to know how much that would cost haha, but my biggest issue, and the reason why my measurements are all over the place, is just I think because of the lifter plunger springs. I have light springs installed in the intake and exhaust valves on #1 right now. Everytime I measure with the dial gauge it seems like its different and I am getting inconsistent lift values, some are 0.100 under the BTR230 cam spec of 0.644, then sometimes its close, then sometimes its over. They I think are actually purpose built that came with the comp cams degree wheel I have so I feel like they would have made them significantly weaker than any spring plunger in the lifters but I guess not.

I wish they made a solid lifter for measuring that you could adjust the height with, but luckly I was able to find my original factory lifters and the non-AFM ones were 100% solid and no matter how hard I pushed I couldn't get them to move, so they ended up working great and now I am getting measurements that make sense, at least somewhat make sense.

[cmitchell17]

Originally Posted by Tim M

I'm using PSI 1516 conical springs. Seems pretty burly, but a rep at Katech mentioned it is a spring commonly used for LT1 applications. I went a step further and employed LT4 Ti intake valves as well.

I looked on their website and the specs look similar, but they do advertise them as "beehive" but I guess thats just terminology differences since the conicals do look pretty similar to a beehive and the beehives really don't seem like that have much of a taper at the bottom compared to the top anyway so they are more similar to conicals I guess.

[GreenZLE]

Would it be worth it to go with an adjustable rocker with Johnson Lifters? Is there a readily available one for LT engines?

[Joshinator99]

Originally Posted by KingLT1

You can get custom length pushrods from Manton if need be.

Believe you can also get them from BTR if memory serves. Only way to fly when dealing with short travel lifters IMO.

[Tim M]

cmitchell17: I mistype...PSI's are beehives, not conical. Similar to the OEM part, but different specs, of course.