Hey all, To the best of my knowledge, I'm the first (so far the only?) person to do an LS-series swap while attempting to retain the VVT. From everything I'd read, the prevailing impression was that it couldn't be done, since the VVT required the use of the truck accessories, which extend forward beyond the Vette/F-body placement, & placed the alternator above the hood line. Well, I've pretty much gotten it done. With the possible exception of the P/S pump, my engine is in, & it clears the stock hood line & radiator just fine. This post (on LS1Tech) has most of the info, the complete build thread is right here. I hope that this helps to "de-mystify" the use of these engines a bit, since the technology is just WAY TOO FREAKIN' COOL to not take full advantage of...!! Quote: While installing the VVT system on a single-cam OHV engine doesn't offer up any adjustability of intake/exhaust overlap timing, it should be noted that simply advancing or retarding the overall valve timing can have significant effects on an engine's powerband, as hot-rodders have known for decades.Typically speaking, advancing the cam timing offers more low-end power, while upper-end performance benefits from retarding camshaft timing. Quote: Although (Billy) Godbold returned to this subject, it quickly became obvious that he had other ideas aching to burst out of his mind. Ideas that can be summed up in the initials VVT-that's variable valve timing to you and me. "The L92 truck motor is incredibly impressive, making 400 SAE corrected horsepower stock and 430 hp with headers," he began. "With one of our cams and the phaser limiter kit, we made 500 hp, and it did not lose power anywhere. It's a great cylinder head, then you add the variable valve timing. We start out by giving the smaller cams lots of advance, up to 10 degrees, then you can retard those about 16 degrees. With the larger cams, piston to valve is tighter on the intake so we go down to 5 degrees advance. These designs run best with a sweep curve of about 12-degree retard, which helps the engine carry at high rpm." With the cam phaser, you can advance or retard the cam centerline to the position it runs best at each rpm. That's cool, really cool. You can get a 60-plus horsepower gain, with no loss anywhere. You can have control of the cam timing by tweaking a curve in your ECU, just like typical electronic ignition timing. It's like going from points to coil-on-plug.

dude... seriously... that is REALLY fricken cool!!! I wonder why nobody else has done this yet. variable cam phasers have been in the chevy aftermarket since the sixties, but it's always been a black art. i guess now since there isn't a distributor anymore it's ALOT easier to do, especially since it's computer controlled. great build, by the way.

I can't wait to see that bird out and terrorizing people. I'd love to run a VVT engine later.

iansane, beautiful car. how'd you do the brakes? did you turn rotor off the stock hub? I love the wheels and the grand sport stripe.

Glad to see you got it in there. I've not been following the thread on Tech, but I'm glad you have it done. Keep us updated.

I've always been a fan of VVT on most any engine, I'm just to lazy to figure out how to make it work.

Props to you for getting it nearly completed. I know you've been working on it forever.

Hi there, got a question. I see your using the truck accessories in your thirdgen with the stock hood. I have a LQ4 truck motor and I wanted to know are those motors the similair in terms of accessories. Also a guy on eBay is selling alternator relocation brackets and was wondering would that solve the problem. Also if if I choose to not use a/c is there a delete bracket or how is that done

IIRC the a/c uses a separate belt, so you won't need an a/c delete bracket

IIRC the a/c uses a separate belt, so you won't need an a/c delete bracket

Well, the stock truck accessories won't work with a stock F-body hood, period. What I did was to use an alternator/power steering pump relocation kit from kwikperf.com - that let me keep the truck spacing out from the front of the block, but moves them into Corvette positioning, so that they fit under your hood. It was the best solution I'd found for that issue.

AFAIK, all of the "truck motors" are the same as far as accessories go. There could be some minor differences that I'm not aware of, but I haven't heard of any.

I'm pretty sure that the A/C is a different sub-system, I think that it's a different belt with just the A/C pulley running off of the crank - so if you don't want to run it, you just don't have those parts.

Hope this helps.

I find this very interesting. I'm doing a frame up on my 86 and I have a 2005 LM7 5.3 waiting to go in. I'm curious, I didn't even know that the LS series engines had any sort of VVT. What years and engines did it come in? And also what is the benefit to retaining the VVT in terms of horsepower? Is it basically an advantage from a tuning standpoint?

I'd love to know more about this. I was going to put a turbocharger on the motor and just want to see if it's worth it to retain the VVT or not. Great looking build you have there as well!

Hey, thanks for the kind words. I don't know off-hand which years/engines came with VVT, although I wish I did. The principle though is pretty simple -

You know how a 'static' cam can be biased toward the low-end if you install it a few degrees advanced from it's ICL (or set up for top-end power if it's installed a bit retarded)?

Well, VVT lets you do either and/or both of these things depending on the programming in the ECM. (Although the overlap will remain constant, since it's one camshaft with no way to vary the positions of the intake & exhaust from each other.) The net result is that for identical engines (apart from one having VVT & one not having it), the VVT-equipped engine will have a noticeably larger average torque throughout the powerband, as well as better fuel efficiency when you're not at WOT, since the camshaft's position in relation to the crank can be varied by approx. 50 degrees.

There are a number of different resources on the topic, but here's one fairly decent discussion that I found without looking too hard:

http://www.ls1tech.com/forums/genera...t-not-vvt.html

Also, here's one of my favorite quotes that I've been "showing around":

Thats just awesome!! Technology is ALWAYS improving, and I finally thought that I'd be back in the game with my 5.3.....and now people start swapping VVT engines into thier F bodies. Guess you can just never keep up with how fast technology moves, lol. And I guess my 5.3 does not have the VVT. Best of luck with the build and I will definately be watching your progress to see how it turns out and what kind of power it's capable of!

VVT is specially helpfull on turbo motors. My cam was installed a tooth off, retarded, one time to make an ICL of 128 degrees. At that point it made crazy power from 4000-7000rpm but could hardly do anything under that, and the turbo wouldn't spool until 4000+rpm. On the other hand, have it advanced to 108 degrees ICL and it spools INSTANTLY, but drops big power just after 6000rpm. So, I'm attempting to make vvt happen on my 1st gen SBC.

VVT on a Gen-I engine??? THAT would be interesting. I suspect that you'd want to duplicate at least a couple things from the L92, namely the DIS & the cam phaser - but that would be a LOT of R&D, & to be honest, I still don't think you'd be able to equal the results from the new engines (no offense intended, but over 15 years of Moore's Law has resulted in a LOT of improvements over the Gen-I SBC design). But if you've got the deep pockets or engineering "chops" that are necessary to make it happen, then I seriously hope that you can do it, because I'd imagine that it would sell...

Anyway, I finally found the specs for the stock L92 cam again:

Stock specs are:

Lift -- .551 intake/.525 exhaust
Duration -- 204/211 @.050
LSA -- 117.

I still have a hard time believing that these engines make that kind of power while using a cam with specs that you'd expect to see in a smog-era straight-six Nova... (OK, the lift numbers aren't too bad...)

What about the tensioner? Any luck figuring that out yet?

I haven't worked on that yet, but I've just run into one little note that has me thinking that I might just have a way to work it out. If so, I'll add a post with pictures to this thread...

Thanks for the interest & the kind comments guys.

I dug up some info over at tech and this link below is very helpful. This is how Im going to run my accessories I know your going a different route but there might be some stuff here that helps ya.

http://www.ls1tech.com/forums/conver...g-vvt-l92.html

The '10 Camaro water pump looks very interesting. If it works with truck accessories, that could solve a lot of problems for those starting with truck engines but using a passenger car intake. Buy the water pump, the rest of your truck accessories work.

I'd be looking into that route but I have two sets of f-body accessories and no truck accessories so the spacer trick is my route. Im getting mostly worried about tuning this sucker with the t56 being that there is no VVT/manual factory built combo to use as a base tune. Hoping that through tuning I can wipe out the PCM capabilities and turn it into an ECM basically.

Yep, that's exactly what I was planning on trying. From looking at it, it appears that there's a good shot at making it work. (Thanks for giving that up, ya bum!)

Actually though, you'd still have to relocate the alternator, since that would still extend well beyond the hood line...

Oops.

Can you find it in your heart to forgive me???

Well, I guess I was thinking of my particular case, where hood clearance isn't going to be an issue. . .

V8Rumble you still out there? Was searching for pics of the new style Corvette DBW fuel pedal and it looks like you disappeared. Hope all is well whats going on with your car?