Truck Norris cam

[Aaronwelling1]

Where do I start for tuning? Any major things I should know before I fire up for the first time or items I should be very aware of ?

The truck is an 01 Tahoe. Mechanically stock other than a cold air intake with a K&N filter. I already tuned VE tables and MAF tables last year. I do not have wide band sensor. Never figured I?d get that far or crazy with rebuilds. Added in spark all over on the spark tables. I have no knock retard when towing currently. I don?t remember exactly all the settings. I can log into my laptop later and post the current tune file if that helps. I?m not sure how to do that but it can?t be hard I imagine. Anyway I?m doing the truck Norris cam kit with the pushrods and springs. My goal is daily driver with a fair bit of towing. I just swapped in 4.10 gears from the factory 3.73 and that helped a lot more than I thought it would with such a small jump. Not crazy revving down the highway when empty either. So I?m happy with that. A few more ponies and a bit more torque for the mountains where I live at would make this a much more enjoyable driver. I figure the cam will be a great start. Possibly long tubes and an exhaust if necessary however I?m old and don?t appreciate the loud exhaust as much a I use to. Any suggestions on a free flowing but quiet muffler would also be appreciated. Thank you in advance !

[Aaronwelling1]

Where do I start for tuning? Any major things I should know before I fire up for the first time or items I should be very aware of ?

The truck is an 01 Tahoe. Mechanically stock other than a cold air intake with a K&N filter. I already tuned VE tables and MAF tables last year. I do not have wide band sensor. Never figured I?d get that far or crazy with rebuilds. Added in spark all over on the spark tables. I have no knock retard when towing currently. I don?t remember exactly all the settings. I can log into my laptop later and post the current tune file if that helps. I?m not sure how to do that but it can?t be hard I imagine. Anyway I?m doing the truck Norris cam kit with the pushrods and springs. My goal is daily driver with a fair bit of towing. I just swapped in 4.10 gears from the factory 3.73 and that helped a lot more than I thought it would with such a small jump. Not crazy revving down the highway when empty either. So I?m happy with that. A few more ponies and a bit more torque for the mountains where I live at would make this a much more enjoyable driver. I figure the cam will be a great start. Possibly long tubes and an exhaust if necessary however I?m old and don?t appreciate the loud exhaust as much a I use to. Any suggestions on a free flowing but quiet muffler would also be appreciated. Thank you in advance !

Uploaded the current tune. truck runs very well on this tune but im always open to suggestions.

[bk2life]

Uploaded the current tune. truck runs very well on this tune but im always open to suggestions.

posting the tune is only a part of the prcoess.
You need to post a log as well.
This way we can compare the tune, with the log, to otgher tunes we might have and see what you can or need to adjust.

Just the tune does nothing.
-its like posting a car doing awheelie. It's cool to look at, but without the scan, or more info, the pic is uesless.

[Aaronwelling1]

posting the tune is only a part of the prcoess.
You need to post a log as well.
This way we can compare the tune, with the log, to otgher tunes we might have and see what you can or need to adjust.

Just the tune does nothing.
-its like posting a car doing awheelie. It's cool to look at, but without the scan, or more info, the pic is uesless.

Fair enough. I?m doing the swap this weekend when time and the weather is cooperative. After that I?ll get a log posted. Any specific pids I should log other than the obvious ones used for ve and maf tuning ?

[Aaronwelling1]

The cam I ordered is from Amazon. BTR truck Norris kit. It list the cam specs as follows. 212/22x .552/.552 107lsa

It comes with the valve stem seals, springs, and pushrods 7.4in.

Will I need to change rocker arms for clearance ? Like I said the motor is pretty stock. Also any tuning to adjust before initial start up and logging ?

[danmw2003]

You should degree in the cam and make sure its on the correct installed centerline. You should also measure pushrods, just popping in whatever the kit comes with, can be hit or miss, and potentially cause you issues if you dont check. Especially if you change anything like milled cylinder heads, thinner head gaskets or a decked block. Cams also vary in base circle from stock. Dont mess with the rocker arms aside from replacing the trunions.

[edcmat-l1]

Unless you're experienced in degreeing camshafts, and have checker springs, degree wheel and dial indicator, it's a waste of time. Chances are you won't do it correctly if it's your first time anyway. Make sure the dots are lined up and let 'er eat.

Unless you've milled the heads, installed thinner head gaskets, or the engine has been modified previously, the 7.4 pushrods should be a "drop in" deal.

You're free to check everything and anything you want to check, but a basic kit like this in an otherwise stock engine is a no brainer.

[TheMechanic]

I check all my cam installs. Just what I've done over the past 40+ years. They were always off. Some by as much as 4 degrees. However I have not had ANY quality LS cam/kits that were not a straight up no need to fix. Seems that the indexing has improved a TON since I started in this industry. While I still check I wouldn't have any problem or be scared of installing without degree'ing.

[edcmat-l1]

I don't check anything that's not a higher HP engine that I feel REQUIRES added attention. And even those I'll rarely move. It's more about making sure the valvetrain is perfect.

Changing a cams ICL only moves the power band one direction or the other ever so slightly. There are no magical HP increases by making a cam that checks at 110 and should be at 108, 108.

Not to mention to added difficulty in trying to degree one in the vehicle. That's not even worth it to me.

[Alvin]

I recommend checking pushrod length on every build. It's pretty easy to do and we think saves camshaft life + reduces that sewing machine noise. The same setup on two cars will often come out different. One of the old thunderracing guys has a nice write up on LS1tech I refer people to asking about this.. No special tools needed.

Degreeing a cam in is a lot harder to pull off. I've never seen a cam that didn't have far more advance or retard in it than it supposed to.. Like it's not unusual to see one 6 degrees off. BUT.. unless you are picking at flyshit for every last little bit of power.. it just isn't worth it. A long time ago I used a two piece timing cover on my personal z06. I don't know if anyone still makes these things but the timing cover was literally cut in half so the bottom half with the crank pulley could stay on. This cam required me to put like 5 degrees of retard in it. I really was trying to set some records with it so I got and adjustable set and did it all proper. Well.. about 2 months later I got the itch to take that out and put the cam straight up.. Easy just pull waterpump and upper timing cover off to fix. I didn't even unstrap it from the dyno.

The graphs overlaid each other.. I mean zero difference. It felt better down low.. but 0 difference at wide open.

[Alvin]

Here is a copy of the post I was talking about on checking pushrod length. I very much think it's worth it.. Almost every cammed car we pull apart all have 7.400's and quite a few have chewed lobes.. We aren't immune to that and see cam/lifter damage occasionally too.. but we also think it is less common than with stock/other shop built things.

https://ls1tech.com/forums/generatio...l#post13166359

[danmw2003]

I always check pushrods for various, and legitiment reasons, but its not always the pushroods fault for wiping out a cam lobe. Incorrectly set up springs are just as likely to take out cams as an incorrect length pushrod. Most people check none of this stuff, and try to tune around mechanical issues. Or they just flat out have failed parts or whole engines. All becasue they didnt bother to check a few things, and just threw it together because someone told them send it, and that it should be fine. Everyone's doing it! Expensive gamble if you ask me, just to not take the time and do a few simple checks. I dont like to do things twice if I can help it. I do agree though, that degreeing in a cam is not as important, but it can have an effect on how it runs.

[edcmat-l1]

I recommend checking pushrod length on every build.

I think that goes without saying. I was referring to degreeing the cam. Checking PR length is a quick no brainer as you're installing them.

[Aaronwelling1]

Thanks for all the advice. I did the swap today. Other than a few crack porcelain on the spark plugs I had to track down the swap went well. There is definitely the ?sowing machine? issue. Maybe a 3/4 turn to tight on the bolt once lash is removed. I?ll read that post before about measuring rods too. The kit came with 7.4 rods. Once I swap the plugs and wires in the morning I?ll start getting the tune at least ball parked. How dangerous to the motor is running with the push rods the slightest to small ?

Thanks again in advance. I?ll definitely post a log file after I get the VE and the MAF tables closer. I?d love to have you all pick over the tune and log for advice incase I miss something or could do something better.

[LS ROB]

I recommend checking pushrod length on every build. It's pretty easy to do and we think saves camshaft life + reduces that sewing machine noise. The same setup on two cars will often come out different. One of the old thunderracing guys has a nice write up on LS1tech I refer people to asking about this.. No special tools needed.

Degreeing a cam in is a lot harder to pull off. I've never seen a cam that didn't have far more advance or retard in it than it supposed to.. Like it's not unusual to see one 6 degrees off. BUT.. unless you are picking at flyshit for every last little bit of power.. it just isn't worth it. A long time ago I used a two piece timing cover on my personal z06. I don't know if anyone still makes these things but the timing cover was literally cut in half so the bottom half with the crank pulley could stay on. This cam required me to put like 5 degrees of retard in it. I really was trying to set some records with it so I got and adjustable set and did it all proper. Well.. about 2 months later I got the itch to take that out and put the cam straight up.. Easy just pull waterpump and upper timing cover off to fix. I didn't even unstrap it from the dyno.

The graphs overlaid each other.. I mean zero difference. It felt better down low.. but 0 difference at wide open.

Have you found the sewing machine noise to be from too long or too short of pushrod?

[gametech]

Have you found the sewing machine noise to be from too long or too short of pushrod?

Typically it is from pushrods being too short. It seems tons of aftermarket cam "kits" just come with factory length 7.4" pushrods, even though the higher lift cams are necessarily ground on a smaller than stock base circle. The enormous amount of plunger travel the factory lifters have allows this to work, but is why you hear so much about the sewing machine noise with cam installs. The real problems occur when different thickness head gaskets, milled heads, or aftermarket heads are involved. It is just too easy not to go ahead and check for proper length.

[Aaronwelling1]

Typically it is from pushrods being too short. It seems tons of aftermarket cam "kits" just come with factory length 7.4" pushrods, even though the higher lift cams are necessarily ground on a smaller than stock base circle. The enormous amount of plunger travel the factory lifters have allows this to work, but is why you hear so much about the sewing machine noise with cam installs. The real problems occur when different thickness head gaskets, milled heads, or aftermarket heads are involved. It is just too easy not to go ahead and check for proper length.

What?s the dangers of running them slightly to short ?

[2xLS1]

https://www.youtube.com/watch?v=4XFVGCYUHco

[gametech]

What?s the dangers of running them slightly to short ?

Slightly too short just makes a little noise, as you still have preload. Way too short is like beating your components with a hammer.

[Aaronwelling1]

Got it. That?s what thought but there no replacement for experience. Better to ask i think.

I just today tuned the VE and MAF. I find it interesting the truck seams to like a lot more timing now. Also it want MUCH less fuel below 3000rpm. Not what I expected but this is my first cam swap like this. Opinions ?

I?ll post a log file tonight with a longer drive. And the current tune. I want everyone to pick them over to make sure im not missing anything. I use this truck for service calls so reasonable dependability is important.