JoeRJr

I joined a few days ago, and did my best due-diligence in searching for an answer before posting. My flame suit is on in case I missed an obvious post on it though.

I am building a 6.0 out of a 2003 Savana Van. It's going in a 1986 C10. I purchased what was supposed to be a low mileage engine and 4L80E trans. It was not low mileage. I put the engine on a stand and ran a compression test on it. Compression test ranged from 150 psi to 185 psi. I decided to pull it apart.
It has a newer head on one side, and all associated hardware too. It also had stuck oil rings on every piston, and obvious carbon in the cylinders as a result.
Rod/Main bearings looked brand new. Cam bearings are smoked, with plenty of exposed copper on every one. Cylinder bores are in nice shape. Pistons have skirt wear and need to be replaced.

As a result, I'm rebuilding my not-so-low-mileage LQ4. Block is at the machine shop now getting cam bearings. Heads are cleaned and ready to reassemble.
I'd love to put flat top pistons in it, but can't find ones that work with pressed in wrist pins. They're only available for floating pins. I've seen plenty of threads recommending new rods, but they were from a few years ago. I'm not ready to buy new rods for a .4 compression gain(9.6 to 10.0), so my question is: Is there STILL nobody making a flat top piston for the LQ4? If not, I'll run an original set and be done with it. Thankfully there are plenty of other ways to gain a few HP.
Thanks for any help.
Joe

G Atsma

Buy LQ9 pistons. The LQ9 was basically a high compression LQ4. Call WS6store and they will help you out. The are vendor/sponsors of this site and are very fair and knowledgeable.

Ls7colorado

iTrader: (3)

What he said,
EVERY LS engine Ive torn down the cam bearings looked like they had 500,000 miles on them with plenty of cooper showing from 70,000 mile ls1's to 315,00 mile 6.0's

But lack of oil changes is what caused the carbon buildup and stuck rings, and its probably been sitting too, I bet if you would have ran it for a little while with new oil the compression would have been much closer.

tech@WS6store

iTrader: (2)

The pressed pin lq9 only happened one year or actually less than that. Then came the gen4 rods and floating lq9/ls2 style pistons. We have only floating pin pistons available for that. They are very inexpensive vs forged etc.
Depending on how they fit into your rod, you may have to have the rod machined for a floating style small end with an oil hole in it OR you can find a nice set of gen4 rods nearly anywhere esp fb etc for like $100-$150. They are much better than the gen3 and we recommend them alot. That is your best option.
Our rpmspeed flat top 6.0 pistons are available in std/.020/.030/.040. They have a hard anodized top also.
Pistons and rings runs $320 for the kit on those.
Or we have complete rebuild kits with bearings and all gaskets timing set and oil pump for $699 shipped.

Let me know if you have more questions!

Thanks
Ws6store
Rpmspeed

brandon6.0

iTrader: (32)

Nest to find a used set of gen4 lq9 piston and rods. Would be a better and stronger combo + the flat tops and more compression. This is the Only way to get flat tops without going custom.

Ls7colorado

iTrader: (3)

Dont know if you wanna add any machine work but some people have also bored over .065 to 4.065 and use stock LS3 pistons/rods

JoeRJr

Thanks for the reply. The world seems evenly divided on these cam bearings. Some say don't mess with them or you run the risk of them spinning, and others say they have no trouble with them. My machinist swears he has no trouble changing them, so I'm trusting him and getting them changed. I bet you are right on all of the carbon stuff. Some synthetic oil and a beating might have fixed it!

JoeRJr

Thanks for the suggestion. It's overkill for my project though!

This is what I was hoping to avoid. The price of rods would pay for a different intake, or headers...all for the sake of a few compression points. This pushes me towards stock pistons. I'm not against spending money on it, but if my dollars go further being spent elsewhere, I'll do it.

Great website! I will be exploring tuners as soon as I get my engine stuff sorted. Do you have an engine kit that utilized the stock press fit pistons for my 6.0? I'd be interested in that, for sure.

Thanks. The LQ9 pistons use floating pins. They aren't the same size as the pressed in pins on my 2003 engine. I appreciate the tip on the WS6 Store. They've got lots of goodies there.

Ls7colorado

iTrader: (3)

JoeRJr

I was going to see where a mid-level camshaft and a set of headers got me. I'm not going racing or anything. I picked up an old truck. The body is really solid, but the 4.3L is worn out and leaking from all corners. I was going to drop a small block in it when I came across this engine and trans. I figured I've give it a go.
Once I saw the compression problem I tore it down, and figured as long as I was changing pistons I'd grab some flat tops. It's not necessary for anything I'm building though.
Joe

A.R. Shale Targa

iTrader: (2)

KCS

iTrader: (20)

I would consider buying the floating pin pistons from WS6store and resuse the press fit pins. You might have to have the piston pin bores honed to fit, but that should already be done in most performance builds IMO.

tech@WS6store

iTrader: (2)

We have press fit dished pistons available but no press fit flat tops.

Ls7colorado

iTrader: (3)

Just put it all back together with the high lift asa cam and spring kit from WS6 store and let it rip! http://www.ws6project.com/user_stor/...oducts_id=8670

lq4s are cheap, if it messes up just grab another one it will be cheaper than a rebuild anyways

00pooterSS

iTrader: (40)

If you want the most for the money then just mill the heads and do a drop in truck cam, drop in truck cam you can use LS6 valve springs that are $70 from ws6 store, drop in truck cams will keep your dynamic compression up pretty high too and they are made to retain low end power. It would be a hell of a fun driver with lots of low end grunt with that setup.

Cam motion and brian tooley have some great drop in truck cams. You can retain stock push rods too, and with almost all LS cams the stock lifters are fine.

That with premium fuel, a good tune, electric fans and headers and you'll have a really fun truck.

KCS

iTrader: (20)

JoeRJr

Thanks everyone for taking the time to reply. Lots of great ideas here.
Shale Targa, I didn't think you could gain that much compression from that small a head shave! I'll keep that in mind.

ls7Colarado, that looks like an interesting cam. There are SO many of them out there for these engines.

Pooter, you've got me thinking again. I used to drive a Dodge Cummins. I really miss the torque of that truck. I'll have to do some reading on that to see what others have built. Good thing I'm not in a hurry to get this thing finished!

KCS, The piston pins are different sizes depending on whether they are press fit or floaters. In order to use them, you'd have to do as you suggested; make the piston holes bigger or get new rods. I don't think either of these options is worth the few points of compression gain. I'm pretty sure this engine is going to go back together with the stock style pistons and a new cam.

tech, thanks for the help. You've got lots of great stuff at your store. As soon as I figure out what I'm doing, I will get my rebuild kit from you.

Joe

gagliano7

You can also use a thinner head gasket for a little more compression. I have 62cc heads and .045 head gaskets for my LQ4 build. The stock head gaskets are .051. I should be around 10.65 : 1.

tech@WS6store

iTrader: (2)

Sometimes the pins dont fit like they should so i dont want to recommend it then they not work and 86 an engine. Some do. I have put our floating 6.0 pins in a gen3 rod and they do in fact "float" BUT they dont have the clearance necessary for a steel on steel fitment. That is why I had 2 sets of gen3 rods honed out on the small end and had an oil hole drilled/chamfered in to make sure they had adequate clearance and oil. Now, could they have worked, drop in, with no issue? Yes. But I do not want to have an issue with them so I spent the ~$80 extra to do it. They cleaned up the big end too of course for that. Not bad really. $10 a rod.
Like you said they COULD reuse their stock press pin (or we have new ones) and then use that floating pin piston there and not increase the price as well, but in my opinion the floating rod is the better setup whether you get gen4s, buy aftermarket, or modify your gen3s.

00pooterSS

iTrader: (40)

My idea wasn't really any different than what you were already aiming for, so it shouldn't necessarily have you "thinking again". You said you wanted to do a mild cam and headers and see where it got you, and you mentioned bringing up compression. You also mentioned not spending money on certain pistons for a small gain and would rather put the money elsewhere. I recommended doing it the way I did to get the most bang for buck utilizing the right cam for your goals. You can do a larger cam or something like a take out LS6 cam, but everyone that does a larger cam or LS6 cam in a truck comes back and says it's horrible when done in a truck and actually feels slower.

The best mild cam for a truck is a drop in truck cam, makes more power than stock down low and carries to around 6000-6500 rpm. Should be perfect for what you're wanting to do. And milling the heads... as stated that could get you around 10.2 or so. Or you could source some cheap 5.3 take off heads with 61 cc chambers and get 10.65, or some 799/243 heads and get 10.3

If you ran a .040 gasket instead of a .052 those numbers go up about .4 points

The cam LS7 colorado isn't bad but you'd need a decent size stall and more serious valve springs etc.. That cam would be a little better in a stalled car than a stock stalled 4L80 pick up. However I agree with him about boring it out to 4.065 and putting $300 LS3 pistons in it, but then you're back to the rod dilemma.