LQ4 to LQ9 upgrade

**Woodchuck** · 01-03-2018, 04:27 PM

Hey,
Just joined the LS1 crowd. I'm an old Motorhead that used to run 'A' body Pontiacs (that's Tempest, LeMans, GTO for you kids) back in the day. Anyway I am building my first LS1. It's a 6.0 LQ4. Interesting motor design, I like it! The project started as a 2005 LQ4 out of a GMC 2500 plow truck with the intension of making over 400 street-able horsepower. This is my son's project and his intension is to shoehorn it into a Porsche 944.
So the engine is completely disassembled now and is in excellent condition internally I have purchased stock bore LQ9 flattop pistons and pins to improve compression. So my first dilemma is:
Do I need new rods? The LQ9 have floating wristpins and the LQ4 are pressed in. I'm lacking a press to separate the original pistons and rods (any alternatives to the press method out there?) and I haven't found any specs on wrist pin tolerances and it not a place I want to have a problem at.
We are running on a tight budget and the intent at the end of the day is to make 425+/- HP at around 5500 rpm. and about the same amount of torque. That being said I feel the stock rods will be strong enough if they are interchangeable as I'd rather spend my money elsewhere.
Just as a point of interest (and I'd like to here opinions on this matter) is we want to go with a carburetor and a MSD ignition control.

**tug686spd** · 01-03-2018, 07:12 PM

You can use gen 4 floating pistons on gen 3 pressed piston/Rod but you can't go the other way. It will end up just like the gen 3 pressed rod/piston. Here's a diy video or just have a machine shop do it for you. A better option would be to get a set of gen 4 rods to go with the pistons. Stronger and the floating pin is a better design.

**tug686spd** · 01-03-2018, 09:55 PM

Also if you have a trip to Pa planned anytime soon I've got a Vic jr and msd6010 on the local Craigslist.

**Woodchuck** · 01-04-2018, 12:30 PM

I'll look it up on CL. The VIC Jr. is a dual plane isn't it?
Thanks

**Woodchuck** · 01-04-2018, 12:32 PM

Good info on the rods, Gen IV it is.

**tug686spd** · 01-04-2018, 12:59 PM

It's a single plane. https://williamsport.craigslist.org/...414326738.html

***SMWS6TA*** · 01-04-2018, 01:54 PM

When I made my 6Liter into a 403 I went with floating rods. So much easier to deal with.

**Woodchuck** · 01-04-2018, 02:49 PM

Sorry,
I feel a dual plane would be a better choice for a street motor. I'm kind of a fan of low end torque, you know like Pontiacs used to have....
But thanks

**tug686spd** · 01-04-2018, 04:54 PM

Originally Posted by Woodchuck

Sorry,
I feel a dual plane would be a better choice for a street motor. I'm kind of a fan of low end torque, you know like Pontiacs used to have....
But thanks

You are in for a real surprise once you get this motor fired and running. These factory heads in stock form flow better than about any fully ported casting of yester year. Plenty of info to be found on the Ls if you spend the time and dig around. Here a good intake comparison for you. Make your own decision but if trading 10 ftlb for 10hp is the only difference I'm going with what looks way better. 20 LS1 Intake Manifolds: Tested! - Hot Rod Network
And after all this info you still want more here's another long read. With the right factory parts you can build something to run circles around that old Pontiac. Numbers are as I remember 326, POS BOP 350, 389, 400 and 421? LS Cam Test Comparison - Hot Rod Network

I'm a little older myself and my first car was a 68 camaro with 64 vette 327, powerglide and 308 gears. Wish I knew then what I know now. My buddy had a 65 gto, 389 6 pack, 4spd car. Man when them carbs were working she would run.

**tug686spd** · 01-04-2018, 04:59 PM

What the heck, how about the head test to. These links should keep you busy for a while. The Ultimate Chevrolet LS Cylinder Head Test - Stock LS1 Dyno - Hot Rod Network

**Woodchuck** · 01-05-2018, 04:13 AM

Your buddy should have kept the Goat, that combo is worth big bucks today. The 327 is my favorite smallblock. My first car was a 69 LeMans with a 350 HO. I've been studying the LS pros and cons. I was going to leave the heads stock except better valve springs. My HO valves would float at 6 grand (Duhh).
So depending on who you talk to the double row cam chain ( I was surprised to see a single chain) is the only way to go with beefed up valve springs. Whazzup with the clearance problem? My timing chain cover is cracked, probably from the battle to remove the harmonic balancer. Is there and LS cover that will cover the double chain properly since I have to buy one anyway?
I'll do some more research on your Vic Jr. I may be interested afterall. This motor is going into a Porsche 944 remember(says my son), I doubt it will weigh 2500 pounds assembled. So I don't want to go crazy with over tuning it.

***SMWS6TA*** · 01-05-2018, 06:29 AM

Also in addition to above. Throw on LS3 rectangular style heads and intake and have way more airflow and power over the LS1 cathedral style heads.

My tuner has been tuning and designing LS builds since the beginning. He used to own Thunder Racing, After my last tune session he told me I have way too much untapped pwr left in my 403 by using my 243 heads and cam setup. He knew it was a budget build at the time but said when I'm ready to "invest" again on heads let him know which way & how much pwr I wanted. Stay LS1 I'll be mid to high 500's, convert over to LS3 heads be solid in the mid 600's with a custom grind cam for either head as a NA built motor or if I go boosted a few more items and it would be a scary beast. Not sure I want that much on a street car that see's the track on occasions. but it would be fun as hell. I have a friend that has a 383 also tuned by my tuner and it's putting out 505 to the rear wheels thru a stg3 T56 and 9" rear. He's got PRC heads and a bigger cam profile then I do. So that's why he's about 50-60 hp more then me.

Since I had to change my plans last summer I should have had the car painted but my transmission decided it wanted more attention so all the paint $$$ went to the transmission. $3200 later I have a STG3 T56 rated for 750ftlbs of tq.

***SMWS6TA*** · 01-05-2018, 06:36 AM

Comp Cams LSX One-piece Aluminum Timing Cover $230 from WS6 Store. Says it will fit double roller timing chains.

The LS2 chain is pretty stout chain. They are not the same quality of the old 350 days. I've read that the LS2 chain can safely handle upper 500's into the high 600's. It's when you get into high boost or nitrous that the need for a double roller is needed.

**tug686spd** · 01-05-2018, 09:10 AM

I've run single chain on all my motors but one. I like big cams and big stall so by no means am I easy on the valve train and haven't had any trouble. Valve springs and timing chains are wear items so if your going to drive like me (an ass) maintenance is needed. 20k miles is the most I'll go on springs.

On the harmonic balancer I've always used a small three jaw puller on the inside of hub. You'll see the tabs I'm talking about when you look at it. And for installing them I use a propane torch. Stand it up on the belt surface on garage floor, crank the torch up good and point it in the back of the balancer at a 45 angle. Mainly hitting just inside the hub, roll balancer back and forth to heat hub evenly to about 275f. Then push it right on by hand.

I won't get into a cathedral vs rectangle you can decide on that. But I run cathedrals. Stock casting against stock casting a rectangle will make more on a bigger motor not a 6.0 in my opinion the rectangle will work better simply due to twice the valve size and port volume.

And if the motor is truly going to end up in the Porsche how much torque is really wanted. You've got a extremely light car, a weak rear and can't fit a real good tire in there. So I see it as either build the motor to fit car (sacrifice tq for more hp) or tune some tq out by killing timing down low. I put 4 stock 4l60's, 3 built 4l60's and 3 rear ends in my trans am before I started tuning power out. Remember I drive like a ass, back when we thought we were bad asses with our maybe 400 crank horse power we could give all it had with little worry. Now they've made it way easier to make real good power and made the rest of the drive train weaker.

The GTO I believe is still in his parents garage. Haven't talked to him in a few years because he moved out of state but he ain't the type to get rid of it. The last time I saw it the 1/4's were getting rough but he's got another set boxed and waiting. We were pretty young then and life got in the way for both of us I guess you could say. But my 68 is just sitting waiting for the day to come back out.

***SMWS6TA*** · 01-05-2018, 09:38 AM

^^agree on building the engine for the car and purpose. There was a guy on here that lives in MS that did a LS1 in a Porsche. Mean little car. I think he came up with some fixes for the transmission and half shafts to put some strength in handling the power.

I build my 8.8 about 4 yrs ago. I knew I was going to kill my shitty 10 bolt and did mine mostly out of seeing if I could for the challenge. Been abusing it since. Planning on getting a WaveTrac for the 8.8 now that they make one for 31 spine axles 8.8's . It's on the list, a very long list at times it seems.

***SMWS6TA*** · 01-05-2018, 09:39 AM

Here's that thread about the Porsche Build

http://www.ls1.com/forums/f124/ls1-p...-build-164274/

**tug686spd** · 01-05-2018, 02:55 PM

And by no means am I saying you have to do anything to the motor. In stock form you and your son would be more than happy with the performance. Well at least for a little bit anyways.

**Woodchuck** · 01-07-2018, 04:37 AM

Morning,
-20 in northern Vermont. All the woodchucks are hibernating except me. Anyway I separated the original rods and pistons and to my surprise the pins that came with my Sealed Power flattops float perfectly on the original rods. Problem solved. Waiting for my rebuild kit from Summit, then I'll be making forward progress.
Today I am researching cams. I think I am leaning toward a GTO- CTS-V type grind. Once again I am looking for midrange power, the heads are stock LQ4 save for heavier springs. Any ideas?

**Woodchuck** · 01-07-2018, 04:44 AM

Glad to hear you guys hung on to your old muscle cars. I wish I kept mine, they only made a few hundred 350HOs in a LeMans frame.
I had to rent a large puller for the balancer and would not hook up to said tabs. Brute strength and ignorance is not always the answer.

**tug686spd** · 01-07-2018, 05:20 AM

-8 in Pa where I'm at when I got up. Not sure your floating pin is going to work. Or it to work the small end needs bushed/bearing whatever to want to call it so it don't wear the pin or rod.

Hanging on to my old ride is about all I've don to it though. Hasn't been on the road since 98. I have accumulated pretty much a complete new car over the years, just need to get on it one day. Here's my old mans 55 I swapped this past summer.