Looks Like I'ma gonna be a Caddy Guy - Now What? Stroker L92 LS3 Build

[CarMotorBarge]

BTW, the 223 intake duration is why the 416 and 418 LS engines make less than 600 HSP.

 

[Slidin Gator]

You will want a 223 intake duration for the cam. This is the duration that most airboat engine manufacturers put in their 416 and 418 engines that run at 5600 at WOT. Keep the lift at or below .624 for longevity.

Thanks Barge, good info that gives me more confidence in pushing the duration down some vs. the 231TSP recommendation.

 

[Slidin Gator]

BTW, the 223 intake duration is why the 416 and 418 LS engines make less than 600 HSP.

CMB,

Makes perfect sense of course. Backing up to the previous cam comparison torque curves, the baseline cam makes 600 Hp at perhaps 5,800 RPM, while the higher duration cam makes 600 Hp at 5,500 RPM and keeps climbing.

The tradeoff is at 3,000 RPM where the hot rod cam limits torque to 430 (245 Hp) vs. my 500 (285 Hp) goal. If I thought 600 Ft-lbs at 3,000 RPM was a reasonable goal I would be aiming for 500 Hp max.

I am likely to break in and dyno tune on the TSP 600+ Hp cam initially, then switch to whatever stump puller 5,500 max cam I end up with and re-run the dyno.

Seems like that gives me a "Torque" and a "Hp" option, two gear ratios for the price of a cam :cheers:

 

[Slidin Gator]

416 Long block complete is now bolted to my shop engine stand :cheers: I will post pics to show it all when the gallery is back operational.

Complete with all the goodies:
*4" Forged Liberty crank (balanced rotating assy.)
*H Beam Eagle Rods
*Forged CP Pistons 0.005" over
*ARP studs & Headbolts (Head studs are way back ordered)
*11.3:1 compression
*SST Mauly valves/spring kits
*Smith Bros Trunnion kit
*CS1195 Rollmaster timing set
*New lifter trays, front & rear timing/block cover & seal
*Texas Speed 6 K RPM cam per above


I sold the original rotating group on Ebay for a net $200, probably could have gotten $600 lately, reused the oil pump, roller lifters and rocker assemblies (with new trunnion kits) as they were all low mileage and checked out (read back in the thread).

As one of my buddies said, I cheated. Yep, told the shop to assemble the whole thing and I went and picked up a complete long block assembly versus doing the assembly myself, I got enough going on :banghead:

Long story short I have a $9,750 Long Block assembly (vs. $2,650 runnable junkyard LS3/L92motor) just itching to light up. The "Forged Stroker" part of all this build cost $2,500 including crank/rods/pistons/block clearance and I might have saved $1,200 if I had kept the original crank and built a stock displacement 6.2L (383). Also, I could have put together the exact same thing from new parts using summit etc. for not a whole lot more (maybe $11K). I do get future savings from the truck intake, valve covers and oil pan, plus the shop threw in an old 92 mm cable-controlled throttle body. I will be replacing injectors; the coils are TBD.

Next is deciding on an EFI system. I want to run dual wideband O2 sensors with the ability to operate on one. My baseline is the Holley Dominator (Terminator X is limited to 1x O2). I read a lot about several other EFI options, several of which have better tech specs for detailed tuning and might save some money. I think support is key and most tuners seem to be familiar with the Holley systems. I could use input on alternative EFI options before the next cash dive.

The hull is sitting upside down on the hull workstation (fence posts and 2x6 in the yard). It's gonna need some heavy patch work due to corrosion, but this is now officially a project in the Gator house :thumbleft:

 

[Mossy Cypress]

Good to hear Slidin, looking forward to the pics and the maiden voyage ground burning video with the dogs on the front!

 

[FISHSTICKER]

I was hoping you would post up some info so I could learn how to use a bore gauge and micrometers. Nothing but disappointment over here .

I expect to see a lot more aluminum riveting to take the place of the missing engine assembly videos :thumbleft:

 

[Slidin Gator]

I expect to see a lot more aluminum riveting to take the place of the missing engine assembly videos :thumbleft:

I'll have the sections cut out and drilled before you show up, you wanna run the hammer or the bucking bar? The Missus will get video for posting, but it's pretty much the same as previous posts, just put it on loop. :lol: :lol: :stirpot:

 

[Andy]

Will this be a pump gas engine. I’ve always heard 10.7 ,10.8 is about it for 93

 

[SWAMPHUNTER45]

Forged internals and a conservative tune it should be ok on good 93, the LS3 is reported to be 10.7:1 out of the factory with the hyperutectic pistons used.

Then a splash of 110 Sunoco on the hot days would be excellent insurance for a long life. We found stroked engines handle duration well and like a octane boost but my data is off a 4.5 and 4.6 inch so not an apple to an apple.

 

[Slidin Gator]

Will this be a pump gas engine. I’ve always heard 10.7 ,10.8 is ain’t for 93

Andy,

This is a pump gas (93) build and Swamp is correct, the stock crate LS3 is 10.7:1 static compression with weaker components and a need to tolerate poor quality fuel (87 or even less). I will always be buying premium and have the option of dosing the fuel with Octane booster if needed (E85 mixing is an option). As it stands, the 11.3:1 is reasonably conservative.

9-9.5 compression and 35-38 degrees total advance is/was the basic recipie for N/A power on 93 with the older GM (etc.) engines, up through Vortec. These days folks are building boosted pump gas LS motors with 9-9.5 static compression. The difference with the LS (and pretty much anything put out in the last 20+ years) is the head design, they burn quicker, allowing (requiring) less timing advance, which allows for higher compression. The LS3 heads run less timing than even the earlier LS cathedral port engines, with typical WOT advance in the low 20's.

Remember that the factory has to go conservative, Joe blow decides to put 87 (+/-) in the car, it needs to run without blowing up, which it does by reducing timing. The factory ECU uses knock sensors to reduce timing in the event of lower octane fuel, all is good, just less power. Plus, being constrained by emissions, the factory settings can't respond to hard pulls and higher timing and a rich mixture, my 1986 boat does not require emissions compliance :cheers:

I honestly expect that I am not going to have enough prop to hold this engine back, in which case I will make peak torque down low when I hammer it but will have to cut back timing near max RPM and can always go a bit rich (don't want that whole rev limiter stuff going on). The area where I will focus tuning is for response and economy in the 2.5-4K, making sure it does not knock under acceleration, otherwise it's smooth idle and reduced performance at WOT/Max RPM as needed.

Finally, this is not the first time this combo has been built, it's been put into several airboats previously, which is one of the key reasons I decided to stick with the recommended cam vs. experimenting (yet).

 

[kwanjangnihm]

 

[Slidin Gator]

Excellent meme Kwan

But I think you are really premature, I'm still a long way from the dark side, I can just barely see it right now.

Oh, wait, that's just the sun going down :cheers:

 

[pipedog]

Excellent meme Kwan

But I think you are really premature, I'm still a long way from the dark side, I can just barely see it right now.

Oh, wait, that's just the sun going down :cheers:

:lol: :lol: :lol: :lol: :lol: :lol: :lol:

 

[Slidin Gator]

Ok, starting to get the hang of the new forum setup, here is a bunch of Pics of the new stroker. Anyone got a line of a HIGH IRON paint??? I sure would like this block to pass the magnet test, if you know what I mean !

 

[Slidin Gator]

I bought an LS3 oil pan to replace the truck pan from Smuggler (www.airboatparts.com). It's the same volume, just shallower, less prop blockage.

 

[FISHSTICKER]

Can't wait to see you throw that 540 in the dumpster

 

[GB III]

Now you've done it FISHSTICKER!

 

[kwanjangnihm]

Can't wait to see you throw that 540 in the dumpster

 

[Slidin Gator]

Can't wait to see you throw that 540 in the dumpster

I'm not sure that is gonna happen, I'm not building this to replace the 540, it's a whole other boat. With premium pushing towards $5.00 a gallon versus my stash of $3.50 100LL ($4.50 now), my 540 boat looks like the economy froggin rig right now.

 

[Slidin Gator]

so look up the references to Dave’s build he did for Airboting Magazine I have all the articles but for the life of me can’t locate them to reference the months and year of the 4 articles. He builds a carbed 418 from ground up gives tq specs and clearances for his builds a lot of great information.

FYI, Airboating Magazine is reprinting Dave / Waterthunder's article on building LS motors. Part 1 is in the latest issue (May/June 2022). Part 2 will be in the Jully/August issue.

www.airboatingmagazine.com

A key paragraph in part 1 stands out for me:

On most all carbureted motors less than 430 cubic inches go with a cathedral port head to keep port velocity up. I wouldn't use a L92/LS3 head on a motor unless it was fuel injected or a larger displacement motor turning higher RPMs. As for the LS7 head, well unless you're running a solid roller on a 427 or bigger turning 7,000 plus RPMs, it's going to hurt you more than help you.

I'm going to assume this is for non-boosted applications.