Advanced Engineering Tech - 247/255 624/624 114lsa LSR cam

Building a new setup for my light weight GTO(3100 -3300 pounds race weight) and i have a few questions on LSR cams in general but mainly this one in particular. I will be building a 415ci motor with tfs 235 heads, 12.2 to 1 compression, fast 90,90 or victor jr and of course all your necessary bolt ons such as 1 7/8s headers to cut outs, UD pulley, no power steering and electric water pump. Running a built 4l60e with 3500 billit convertor (1.77str) so it doesnt slip too much on the top end. One of my questions is im keeping this setup hydro roller. How would the aggressive LSR lobes have an effect on a valvetrain consisting of LS-7 lifters, chromoly push rods, harland sharp or scorpian rockers, and prc 660 lift springs? Another question is basically how well this cam would work with my setup? This is the first stroker motor i have built (only built 347s and 370s in the past) and i notice this stroker motors tend to be a little more sensitive towards cam lobe design then some of the shorter stroke motors. Basically im looking for a flat power band that is going to twist 7k + rpm and i believe this cam spec paired with the more aggressive lobes would get me a killer power curve with some very high numbers. Final question is any idea what my numbers would look and please specify dyno type? I run a stock 3.46 gear (will determine gear based on how car runs once motor is done) aluminium DS, and the converter looses barely any hp due to the low str (gained 9whp locking converter). Thanks for any tips/advice/facts given.

Evan

You will have issues with those rockers and anything more aggressive than XE lobes. I'd stay with stock + a trunion upgrade. Also, I'd probably tighten up the LSA if you go single plane...

Shane

how would stock rockers be better for aggressive lobes then a roller tip?

how would stock rockers be better for aggressive lobes then a roller tip?

nothing about roller tip.... just those rockers. lol get a good reliable rocker.

ive always considered a harland sharp to be a reliable rocker.

Its not at all about reliability. Harland Sharp makes great rockers. Its not at all about quality. Its all about weight over the valve tip. You won't have any issues with the stock rockers and trunion upgrade. Most commonly available roller tip rockers for the LSx engine family are just much too heavy to be compatable with the RPM capability of these engines... I have 3 TFS headed engines in my shop right now using Manton 7.625" pushrods and upgraded stock rockers shimmed .090". 1 has an LSK lobed cam and the two others have LSL/XFI cams. ALL turn in excess of 7K with no valve float issues.

Shane

so your recommending a stock rocker for that cam?

Absolutely.

Would you consider ls-7 lifters approved for the LSR grinds?

Its not at all about reliability. Harland Sharp makes great rockers. Its not at all about quality. Its all about weight over the valve tip. You won't have any issues with the stock rockers and trunion upgrade. Most commonly available roller tip rockers for the LSx engine family are just much too heavy to be compatable with the RPM capability of these engines... I have 3 TFS headed engines in my shop right now using Manton 7.625" pushrods and upgraded stock rockers shimmed .090". 1 has an LSK lobed cam and the two others have LSL/XFI cams. ALL turn in excess of 7K with no valve float issues.

ShaneInteresting.

Would you consider ls-7 lifters approved for the LSR grinds?

I've used them on many LSL cams with great results. IMHO, the GM lifters are woefully underrated. Failures are mostly due to lifter tray breakage, improper or worn springs, or incorrect preload.

Shane

Ultra lite yella terra rockers are also a good option if you want to go with a roller rocker. IMO, that much lift with a stock rocker is going to cause excessive guide wear after a while, the tip is going to be walking across a good area of the valve and is at some point, going to be pushing on the valve at some angle.

A roller, will be easier on the valve bushings/guides, which if you want to run in excess of 600 lift, I would do.

If you're going to keep the lift at or under 600 then yes you can get away with a stock rocker with pretty much any application, at least anything that's running in the rpm range that a hydraulic roller will run in.


Also... if you're going for n/a performance, I can tell you that a 3xxx anything converter isn't gonna get it done. You're gonna need something in the 5000+ rpm range if you want the track #'s that it will be capable of. The 4l.anything tranny is gonna be a major issue at the power level you're looking at runing. Best start looking/planning on a Th400 setup now, no way is a 4ljunkie gonna take the abuse that a motor like you're building is going to dish out.

Ultra lite yella terra rockers are also a good option if you want to go with a roller rocker. IMO, that much lift with a stock rocker is going to cause excessive guide wear after a while, the tip is going to be walking across a good area of the valve and is at some point, going to be pushing on the valve at some angle.

A roller, will be easier on the valve bushings/guides, which if you want to run in excess of 600 lift, I would do.

If you're going to keep the lift at or under 600 then yes you can get away with a stock rocker with pretty much any application, at least anything that's running in the rpm range that a hydraulic roller will run in.


Also... if you're going for n/a performance, I can tell you that a 3xxx anything converter isn't gonna get it done. You're gonna need something in the 5000+ rpm range if you want the track #'s that it will be capable of. The 4l.anything tranny is gonna be a major issue at the power level you're looking at runing. Best start looking/planning on a Th400 setup now, no way is a 4ljunkie gonna take the abuse that a motor like you're building is going to dish out.

when you say 4lanything/4ljunkie do you mean 4l80/85e?.

You'd be fine with a 4l80, but honestly the weight of the tranny and the power they take up, unless you absolutely must have the overdrive I wouldn't put one in a car. The tranny is a TON heavier then a Th400, and are pretty expensive, to the point that you could put a 30 inch tire on the car to drive on and make the lack of overdrive more tolerable, and just go back to a 28 or whatever for the track.

4L80's are a good tranny, just a big heavy mofo, that Imo anyone that is concerned enough about performance to build a motor like is in the first post probably could benefit big time from the weight savings.

4l60, 4l65, any 4L6x anything is a POS. Junk, will not hold up to any serious track abuse. I've thrown it out there before, if one of the sponsor's on this board, or anyone for that matter really thinks one of those can take the abuse put up and send me one to put in my car.... guess what, I said that almost 4 years ago, and to this day, I've still never seen anyone even offer to send anything. Otherwise, even the people building them know that they won't take a season of racing with anything making more then 425 rwhp at the tires without having to be worked on for something.

You'd be fine with a 4l80, but honestly the weight of the tranny and the power they take up, unless you absolutely must have the overdrive I wouldn't put one in a car. The tranny is a TON heavier then a Th400, and are pretty expensive, to the point that you could put a 30 inch tire on the car to drive on and make the lack of overdrive more tolerable, and just go back to a 28 or whatever for the track.

4L80's are a good tranny, just a big heavy mofo, that Imo anyone that is concerned enough about performance to build a motor like is in the first post probably could benefit big time from the weight savings.

4l60, 4l65, any 4L6x anything is a POS. Junk, will not hold up to any serious track abuse. I've thrown it out there before, if one of the sponsor's on this board, or anyone for that matter really thinks one of those can take the abuse put up and send me one to put in my car.... guess what, I said that almost 4 years ago, and to this day, I've still never seen anyone even offer to send anything. Otherwise, even the people building them know that they won't take a season of racing with anything making more then 425 rwhp at the tires without having to be worked on for something.

i feel same way 4l60e,s are junk for racing no matter who builds them.the only reason i have 4l85e is i street drive alot but made 650hp on superflo so i just wanted a strong 0d trans.car has been in 9,s off the foot brake.:rock:

Ultra lite yella terra rockers are also a good option if you want to go with a roller rocker. IMO, that much lift with a stock rocker is going to cause excessive guide wear after a while, the tip is going to be walking across a good area of the valve and is at some point, going to be pushing on the valve at some angle.

A roller, will be easier on the valve bushings/guides, which if you want to run in excess of 600 lift, I would do.

If you're going to keep the lift at or under 600 then yes you can get away with a stock rocker with pretty much any application, at least anything that's running in the rpm range that a hydraulic roller will run in.


What are you basing this information on? There are plenty of setups out there running stock rockers over .600 lift. Yes some of the aftermarket heads have softer guides but if setup properly guide wear won't be an issue with any rocker. FWIW the only failures I've seen with stock rockers have been the stock needle bearings falling out but I've seen that on as many stock motors as modified ones and the trunion upgrade is a simple way to eliminate that. I've never seen the body of a stock rocker arm break, but we've seen that on aftermarket rockers. You don't have to take my word for it but cajun said it above and emphasized setting up the stockers properly.


4l60, 4l65, any 4L6x anything is a POS. Junk, will not hold up to any serious track abuse. I've thrown it out there before, if one of the sponsor's on this board, or anyone for that matter really thinks one of those can take the abuse put up and send me one to put in my car.... guess what, I said that almost 4 years ago, and to this day, I've still never seen anyone even offer to send anything. Otherwise, even the people building them know that they won't take a season of racing with anything making more then 425 rwhp at the tires without having to be worked on for something.

I'm not saying the 4L6x's are great trannies but they can take a fair amount of racing. Alot of it is in the maintenance and tune though. We have many cars running more than 425rwhp on 4l6x trannies and they're working fine, hell we have a gto that races a hell of a lot more than most on this board still on the stock trans. Have them tuned properly and do your maintenance and these trannies can last for a long time going 1-2-3 behind a good amount of power. Alot of people don't maintain them properly or have them tuned for performance (instead of comfort as they are from the factory) and try to do highway racing with them. Locked in 4th down to 2nd will kill these quickly. However the OP here should probably look at something other than a 4l6x unless that's his only option for some reason.

as far as the rockers go... i like all the advice from different people. As far as the 4l60e goes, its possibly my absolute favorite thing i have ever invested in. The trans is down right amazing. Real close friend of mine is running a built 4l60e in his 700hp N/A camaro. Has never given him an issue in 3 years of him running it. People have no faith in the transmission and should cut them some slack because they are great transmissions. Performabuilt did a fantastic job with mine and i couldnt ask for more. If this transmission does eventually fail i will just have it rebuilt. As far as converter goes, in no way am i looking to break any records at the drag strip. This is more of a big cube street car. I could careless about street manners (no a/c, no p/s, no heat, etc etc etc) if i cant cut better then a mid 1.6 or even as high as a 1.7 thats fine.

you took the heat out too? damn dude and you all called me crazy!

What are you basing this information on? There are plenty of setups out there running stock rockers over .600 lift. Yes some of the aftermarket heads have softer guides but if setup properly guide wear won't be an issue with any rocker. FWIW the only failures I've seen with stock rockers have been the stock needle bearings falling out but I've seen that on as many stock motors as modified ones and the trunion upgrade is a simple way to eliminate that. I've never seen the body of a stock rocker arm break, but we've seen that on aftermarket rockers. You don't have to take my word for it but cajun said it above and emphasized setting up the stockers properly.



I'm not saying the 4L6x's are great trannies but they can take a fair amount of racing. Alot of it is in the maintenance and tune though. We have many cars running more than 425rwhp on 4l6x trannies and they're working fine, hell we have a gto that races a hell of a lot more than most on this board still on the stock trans. Have them tuned properly and do your maintenance and these trannies can last for a long time going 1-2-3 behind a good amount of power. Alot of people don't maintain them properly or have them tuned for performance (instead of comfort as they are from the factory) and try to do highway racing with them. Locked in 4th down to 2nd will kill these quickly. However the OP here should probably look at something other than a 4l6x unless that's his only option for some reason.

Well said... I won't get into any internet arguments but I can tell you from hundreds of cam swaps worth of experience in the LS series of engines, .650" lift is no problem for stock rockers IF they are set up properly. I have analyzed wipe patterns, checked geometry and preload with dial indicators on the engine stand time and time again with different heads at 11, 12, 13.5, and 15 degree valve angles. Believe me, properly set up, the wipe patterns between a cam with .575" lift and .650" lift are almost indestinguishable from each other. It is true, a full roller rocker WILL reduce friction in the valvetrain, but internet myth has blown the whole guide wear issue way out of proportion.

IMHO, a stock, trunion upgraded rocker with a good set of Manton pushrods, Comp 921 springs, and a quality retainer are HARD to beat when it comes to stability, lack of maintenance, and longevity.

I'm running an LSK .649" lift 227 lobed cam in my CTS-V daily driver now with 20K on the cam and springs. NO smoke on startup, NO issues whatsoever. I pull and spot check springs about every 6 months just for R and D. This is the third car these particular springs are on and still going strong after 4+ years.

Shane

great thread.

How are you guys shimming the stock rocker setup? I was not able to find any shims when I was setting up my heads so I moved on to YT's. The wipe pattern from the stockers was wide and in some cases skewed to the front/back of the valve stem. I would have thought by now a vendor would have developed a shim set for the stock rockers. Seems to be a neat little hole in the market that hasn't been filled.

We sell a kit for $15.99. Its a T&D part number. You do have to grind the tabs off the bottom of the stock rocker stands. I am looking into having custom billet rocker stands made but they will be much more expensive. I actually have the shims and custom Manton pushrods in stock.

Shane

"Failures are mostly due to lifter tray breakage, improper or worn springs, or incorrect preload. "

Shane, what do you consider the correct preload for a LS-7 lifter? Thanks.

Usually 1 1/4 turns from zero lash which is just over .050"

Shane

Thanks Shane.

who do we get the stock rocker upgraded with? harland sharpe you guys????

anyone interested in a set of 4.100 cometic head gaskets. Have 200 miles on them and ill sell them for 100 shipped. Cost me 210.

I use the Comp trunion upgrade kit. We have them here:

http://www.thunderracing.com/catalog/?action=vshop&vid=3&pcid=108

Thanks,
Shane