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LTX and LSXPutting LT1s, LS1s, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects including repairs, swap info, and performance upgrades.
I am finally bringing my RS back from the dead and working to get it back on the road (last driven in 2003). To breathe new life into her I am taking the LS plunge. Although bringing the old girl back to life will have many chapters, this one (ie this thread) will be focused on the new motor.
As I approached this project I had too many recipes in mind. I wanted a streetable combo that made big power that I could drive all day without any surging bucking or valvetrain issues. I would be running full accessories with AC and needed stock like driveabilty. I took the approach that I wouldn't skimp on anything and I would pay extra attention to all the details. Buying a used core was my first choice but I got burned on an LS1 block with a cracked liner. I decided to start fresh and truly build it the way I wanted to. I debated stroker combos and all sorts of starting points. I decided I would start with an LS3 block and utilize a stock stroke crank. These cars are traction limited with big power so the added expense of a stroker wasn't needed.
New LS3 block and fresh from the machine shop for the following:
Final hone for pistons
Line bore for studs
True up decks and remove factory tolerance
Balance rotating assembly
Clean and wash
Nice view of the final hone to remove factory taper
New LS3 crank (58x)
Chamfered oiling holes
Last edited by ShiftyCapone; 02-01-2017 at 08:39 PM.
ARP recommends .0055 of bolt stretch on their 2000 series rod bolts. Lunati says that should be achieved when torquing them between 65 and 75lb/ft.
75lb/ft set the stretch perfectly.
Weisco 4.070 slugs with -3.2cc valve reliefs installed onto rods. Rings gaped at .018 top ring and .020 second ring (I think, will have to check my notes).
Rods set at .0020 to .00230 clearance with at least .002 gap between rods.
I installed an Improved Racing windage tray and crank scraper. They have various scrapers to match most stroker and main bolt combos however they didn't have one for stock cranks with aftermarket rods and ARP studs. I had to do some modification to ensure I had .020 clearance around each rod.
Improved Racing claims this is worth 2% average power increase but more importantly it prevents excessive oil frothing at high revs. Same goes for the windage tray.
Crank scraper and windage installed.
I also installed one of their oil sump baffles to keep oil from sloshing around and possibly starving the pickup tube. I was burned by a used LS1 block but was able to reuse the F-body oil pan that came with it.
To power my goals required a great set of cylinder heads, which I will expand on later. I worked closely with Tony Mamo from Mamo Motorsports (former AFR head desinger) to dial in my heads and cam combo.
With a great set of heads and decent displacement I didn't need a giant cam to meet my goals. In went a custom COMP with soft LSL lobes at 227/232 with a 114+3 and .614"/.610" lift. This cam will give me only 1.5 degrees of overlap which will ensure a smooth idle without any surging.
Stock GM 3 bolt 4X cam sprocket with an C7R timing chain. Dampened with stock LS3 chain damper system.
Melling high volume standard pressure oil pump ported by Tony Mamo.
BPR Hotrods Oil Pickup Tube clamp. Utilizes both mounting holes on the oil pump instead of the stock single bolt. Keeps pickup tube o-ring seated flush.
New front cover with 4x cam sensor.
The gray sleeve you see on the crank hub is an alignment tool from SAC City Corvette.
Another slick oiling upgrade is an aluminum oiling barbell which replaces the stock plastic unit. Geometrically, more consistent and improves oil flow to portions of the block.
Rear engine cover with another SAC City Corvette alignment tool.
One of the most critical parts of any LS motor is proper valvetrain set-up. This motor will make power to 7k rpm which makes the valvetrain become super important. I scrapped the idea of running the stock lifter trays and OEM style lifters. Instead, I chose Johnson Short Travel tie-bar lifters with axle oiling. These are probably the most important piece to my build to ensure vavletrain stability and long life.
This is a poor picture but these lifters are incredibly made. I soaked them in clean lightweight oil heated to 200 degrees in a $9 Walmart crock pot to pre-lube them and reduce pump up time at startup.
When choosing heads I was bombarded with options. All of which have their pluses and minuses. Although there are many solid options on the market I needed a large bore chamber at 62.5cc that didn't get there through excessive milling. Had I had flat top pistons without valve reliefs I could have increased my available options. I also wanted the following which is not available on many heads "out of the box".
Criteria:
Lightweight hollow stem valves sized with 2.165 intake
Heavy Duty PAC dual springs
Ti Retainers
62.5 CC chamber (wanted .035 to .040 quench) with a .040 cometic head gasket
The best choice for me, was Mamo Motorsports 235cc heads. These heads are based on an AFR casting that Tony applies his own CNC program to. On top of that he hand tweaks each head to address the areas the CNC tooling can't reach. That work is primarily focused on the chamber. Also, Tony offers a 10mm rocker bolt upgrade to be used with his proprietary Yella Terra Pro Series 10mm rocker arms.
Chris! Hey! Haven't talked with you in a long time. Glad to see you kept your RS. Did you ever get the body straightened out?
Nice engine! What are doing for a transmission? Rear?
I have a set of AFR 245's going on my 408. I'd love to send them out to Tony to work them over. He spec'd my cam as well.
Pretty nice build. Should make a ton of power. Why did you feel it needed 2.165" valves? They work good in the factory square port heads because of how the port is shaped but generally considered to larger for the bore size. Curious how they would act in a cathedral port style head.
Pretty nice build. Should make a ton of power. Why did you feel it needed 2.165" valves? They work good in the factory square port heads because of how the port is shaped but generally considered to larger for the bore size. Curious how they would act in a cathedral port style head.
I actually mistyped that and the valves are 2.100 intake and 1.6 exhaust for the exact reasons you mentioned. The slightly smaller valve is not only lighter but also unshrouds the chamber a bit more. You don't lose any performance since the heads are so efficient. Tony says these heads are good to 550rwhp on an N/A motor. My combo should come in around 500 at the wheels.
Chris! Hey! Haven't talked with you in a long time. Glad to see you kept your RS. Did you ever get the body straightened out?
Nice engine! What are doing for a transmission? Rear?
I have a set of AFR 245's going on my 408. I'd love to send them out to Tony to work them over. He spec'd my cam as well.
My build thread is down a little in this section.
Long time no speak man! I have been reading your thread for months now. In fact, what I have posted so far has spanned 1.5 years. I am moving slow as free time is my weakness. I plan on running a magnum TR6060 with a relocated torque arm. Clutch will be monster dual. Rear is TBD but will likely be a 12 bolt, or 8.8 inch of some sort. I'll post more on that stuff as I get to it. Took me long enough to get this much done on the motor.
I can definitely see 500 whp. Or close to it. I've seen bigger cammed stock ls3 headed deals make near that. Good luck with the build it should be a blast on the street
Long time no speak man! I have been reading your thread for months now. In fact, what I have posted so far has spanned 1.5 years. I am moving slow as free time is my weakness. I plan on running a magnum TR6060 with a relocated torque arm. Clutch will be monster dual. Rear is TBD but will likely be a 12 bolt, or 8.8 inch of some sort. I'll post more on that stuff as I get to it. Took me long enough to get this much done on the motor.
I hear ya on free time!! Week nights after my kids go to bed is when I hit my projects.
Keep the progress coming!
Wipe pattern was established, and ironically didn't need any shims underneath the rocker pedestals. Likely due to the machine work to true-up deck height. Pushrods were also measured, ordered and received today from Manton. 11 different lengths with .038" preload.
.060" is a little wide isn't it? For a .600" lift cam, the pattern should be closer to .030".
There's an excellent tech paper on valve train geometry by Jim Miller if you're interested (but seeing as you've already ordered pushrods....probably not).
.060" is a little wide isn't it? For a .600" lift cam, the pattern should be closer to .030".
There's an excellent tech paper on valve train geometry by Jim Miller if you're interested (but seeing as you've already ordered pushrods....probably not).
The range that Yella Terra and Tony Mamo recommend for these valves and rockers is around .045 to .065. I too thought it was a bit wide but they assured me being centered is far more important than width. Just a little off center will side load the valves and cause premature guide wear.
I had to use a .025" shim under my Yellas to get a similar wipe pattern. Did you use check springs or a solid lifter?
What intake do you have sitting on there?
No shims needed and I triple checked. I use a solid roller to degree the cam but I used the Johnson Lifters since the heads had to be bolted on. I followed a method that ensures you are at zero lash on the base circle without applying any preload. Once I got the hang of it, it was pretty easy to do by feel. Just time consuming.
... they assured me being centered is far more important than width....
Funny. That statement runs contrary to the science behind the idea. But then again, for every way, there's another I suppose. And who am I to argue with Tony Mamo.
To me, the wide sweep demonstrates a couple of things: The first is that extra movement being applied across the guide. Left unchecked, it'll beat the crap out of them in short time. I lost a set new heads (new guides needed which meant a valve job) with a sweep that concentrated more on centre than width.
The second is the wasted cam motion. When the geometry isn't correct, not all of the information is being transferred to the valve. The area under the lift curve is lost.
The sad part of all this checking is that you never know if you nailed it until a few thousand miles have passed by and symptoms haven't developed.
I've worked the VGT on my latest using the mid-lift method. It cost me a set of rockers to get it as close to 100% as I could but that guaranteed the narrowest sweep and centered.
Was able to see this hoss in person last night. The Tony Mamo heads are the truth. Based on the newest member of your family, I'm excited to help you put the motor in the car in 2048.
Funny. That statement runs contrary to the science behind the idea. But then again, for every way, there's another I suppose. And who am I to argue with Tony Mamo.
To me, the wide sweep demonstrates a couple of things: The first is that extra movement being applied across the guide. Left unchecked, it'll beat the crap out of them in short time. I lost a set new heads (new guides needed which meant a valve job) with a sweep that concentrated more on centre than width.
The second is the wasted cam motion. When the geometry isn't correct, not all of the information is being transferred to the valve. The area under the lift curve is lost.
The sad part of all this checking is that you never know if you nailed it until a few thousand miles have passed by and symptoms haven't developed.
I've worked the VGT on my latest using the mid-lift method. It cost me a set of rockers to get it as close to 100% as I could but that guaranteed the narrowest sweep and centered.
Skinny Z. I am glad you made this post. After I read it I went back and did some more research. There are definitely multiple opinions on this but a few are adamant that narrow wipe is better than centered, which validates your thoughts as well. I went back back over and second guessed what I had been doing. I came to the conclusion that although my procedure was spot on, my technique was poor. I found out that when I was checking for wipe, I was inadvertently allowing the roller tip of the rocker to ever so slightly make contact with the valve tip. In addition, I found that using sharpie marker doesn't always mean the artifact it produces is pure. I started over, used a true dry erase marker and changed my technique to ensure the only contact between the roller tip and the valve was when I would turn over the engine. Thank goodness I did because I found that I DO need shims (.110 worth). My wipe patter was dead centered and much more narrow (now at .040"). My previous technique made a wipe too large (although acceptable at .060) and was actually not centered, but the "smudge" of the sharpie made it appear as so.
So, needless to say I had to reorder new pushrods. Money better spent now than burnt guides in 2k miles.
The idea behind shaft rockers is to generally get perfect geometry. The stand offset and height can be changed to center the pattern but also get a narrow sweep. Glad you figured it out
I'd hate to see those nice cylinder heads ruined and am happy to hear you've sorted it out.
Yeah, shaft rockers are the way to go. Despite the best efforts of anyone who's adjusting the geometry on a pedestal style rocker, there are always compromises. Get the valve side correct and the pushrod side may suffer. And that's something we really can't address. I dropped 600 bucks on offset trunnion rockers to get mine dialed in.
Unfortunately, poor valve train geometry is something that doesn't manifest itself until the damage has been done (unless you have an engine dyno and can demonstrate the effects of the lost cam motion when things aren't right). Otherwise you don't have any indication until you see bits of valve stem seal floating around under the valve covers. Ask me how I know.....
It's been a long time since my last update and things are coming to the end with the engine build and will soon be time to move onto the drivetrain.
After sorting out my push rod length screw up I now have the correct length push rods giving me the correct lifter preload.
Now that the bottom end was buttoned up I focused on making the engine pretty. I started by painting the front accessories as well as shaving smooth the FAST intake. I sanded forever and it only looks decent. Next time I will pay someone and use sandable primer instead of adhesion promoter primer.
After everything was painted and buttoned up I think it turned out pretty nice. The valve covers are the Holley units that I shaved down the coil bosses. They will be replaced with the tall version of the Holley covers. The standard ones interfered with the rocker arms. Likewise, I didn't like my faux carbon fiber paint job so they are currently getting hydro-dipped which will make them look a lot better.
Added in this pic that I didn't elaborate on are the ATI balancer and a black Nick Williams 102 DBW throttle body.
Last but not least the fuel rails. I bought 4 different sets trying to use the short LS3/LS7 injectors on an cathedral port intake. The only one who makes a rail for this is Nasty Performance. They are expensive but not overkill but I love the quality of these Ebay units I bought. Really well made for the price. Since I loved the way these looked I will try out the FAST injector spacers for the time being. I was afraid they would look too tall but they aren't so bad given the raised height of the FAST intake. Not the best lighting for these pics, will snap a few in natural light later.
I almost did, and they do look amazing. However, they don't have the OEM oil baffles nor do they have PVC ports, not to mention the $800 entry fee.
You have to plumb them which looks awful and most guys experience oil leaks. The Holley units are the only aftermarket cover that maintains OEM design.
I almost did, and they do look amazing. However, they don't have the OEM oil baffles nor do they have PVC ports, not to mention the $800 entry fee.
You have to plumb them which looks awful and most guys experience oil leaks. The Holley units are the only aftermarket cover that maintains OEM design.
I knew about the baffles and port, I used to be able to get them for around $500. Looks like the guy I bought mine from no longer sells them. I have them on BBC and they don't leak, so maybe it varies by manufacturer
Those indeed are pretty cool. However, PVC venting is going to be important to me not to mention oil control at 7500 rpm. Instead of having my cake and eating it to I'll have to settle for a taste. Wait till you see the hydro dipped. Asthetically, It is as close as you can get to the real thing.
Were will the ac set on it and how. I bought a L92 last week and I am starting my build for my Iroc. Lots of parts to purchase.
The AC compressor is bolted in the pictures above. It sits right below the water pump outlet. It's on the left side of the photos which translates to the front right passenger side.
Been awhile since my last update. I went with the MMS RPS BC2 Twin Disk Carbon Clutch. This clutch is super light but still utilizes a steel flywheel. Most of the mass is removed from the outside of this clutch. The carbon disks have an incredible life span and are so light I can use a stock GM master cylinder and slave. Ton'y claims 15 to 20rwhp increase with this clutch which can help offset the losses of an aftermarket rear end.
Flywheel with integrated carbon disk.
Multi Layer but total around 30Lbs
Bellhousing on. The dowels were a pain to get into the block and I had to hone out the holes to get them to hammer in.
The LS3 starter also does not work with the F-body bellhousing. A little grinding should make it clear.
Here is a good shot of the Hooker Swap headers ceramic coated in black. They should look really good once installed. I also ditched the FAST fuel injector spacers which go under the injector for ones that ride on top. Much better product and comes with the OEM style retaining clips.
I’m curious, are you using the Improved Racing oil cooler adapter? If so, does it clear your headers? Your engine build is very similar to mine and I had to use a non-thermostat unit. Great attention to details when you assembled it. Have you installed it since January?
I’m curious, are you using the Improved Racing oil cooler adapter? If so, does it clear your headers? Your engine build is very similar to mine and I had to use a non-thermostat unit. Great attention to details when you assembled it. Have you installed it since January?
The engine is indeed in the car and you can see the rest of the project come together here.
I will likely run a remote oil thermostat and just run the lines right from the oil pan with the earl's adapter. I should have room but I won't know until I get it mapped out.
02-01-2017 | 08:14 PM
I have them on BBC and they don't leak, so maybe it varies by manufacturer 
