Rebuild of my H&C LSx C3

Vettezuki

Well-known member
Joined
Mar 26, 2008
Messages
141
Well, after years of beating on it, she started making unpleasant sounds. Turned out to be a rod bearing on its way out. While taking it apart discovered some rings were broken and one cylinder was pretty badly scored. A HG probably lifted and there was a little fluid in another cylinder. Damn thing still ran not bad. The LS is an amazing platform. Fortunately we were able to clean up with the max hone of 10 over. But just barely.

While it was apart decided to rebuild forged and drop compression a little. The motor I had with stock flat tops, and decked 4.8L heads was coming in at around 11.2:1, which on summer gas in CA is knock-tastic. I had to run Torco (which works). But figured now was a good time to reduce a bit. Went with Mahle dished pistons -5cc, which came out to roughly 10.7:1.

But hey, "while we're at it!" Changed stock rods to RPM forged rods. The lifters and cam were worn, so replaced LS1 lifters with LS7, and essentially duplicated my 224/224 114LSA cam (on a Comp or Crane core, don't recall) with the same specs on a genuine GM core.

Had the crank polished and internals balanced. All bearings replaced with King bearings. Fasteners are ARP equivalent. (Manufactured under spec by the shop that did the reuilbd.) Heads, which were already pretty heavily ported, were touched up and cleaned. New set of springs and push rods matched to the cam. FYR the shop is Pacific Performance in Anaheim. They mostly do Ford racing engines. Work seems totally competent as far as I can tell, prices are very competitive, and Troy will talk you through all kinds of options. I can recommend them unless you are under any kind of schedule pressure.

I also had to replace my McLeodd clutch which was toast. I decided to go with the Luk Pro Gold Series as a cost savings measure. It's supposedly the LS7 stock clutch more or less. I can say that I MUCH prefer it to the McLeodd. It has solid smooth engagement and grips fine. Maybe because of the spring setup it has a much softer clutch pedal. I'm only pushing about 390 to the wheels, so well within its performance envelope. It has the ligthened iron FW. Previously I had an aluminum FW. Altogether, this is a better combo for real world street driving. The McLeodd was more finicky.

I have a huge bottle neck with the exhaust, about 3 psi back pressure at WOT. There's a guy down here in SoCal that does custom Tri-Y/Mid Length hybrid headers. Those plus a competent retune should bump me well above 400, moving the whole curve up, with more torque on the bottom if anything.


But before that I will upgrade the rear suspension further, possibly with Guldstrand 5-Link, and put some sticky rubber all around. The Nitto NT-450s at 255 have served pretty well, but on the street, if I stand on it, it pretty much spins well into third on cooler days when the engine is extra happy and the tires extra hard.


Anyway, here's some engine pic porn.

LS_Rebuild_01.jpg

LS_Rebuild_02.jpg

LS_Rebuild_10.jpg

LS_Rebuild_08.jpg
 
Last edited:
Nice build, I ASSume that strange sprocket in the rear of the block is for timing, crank sensor, just that it seems strange to me they put it inside where the oil is....easier to just put it on the fly or up front, I would think...:eek::surrender:
 
Hi Vettezuky, long time no see.
Thanks for the porn.
With that many parts changed I'm surprised you didn't upgrade for a square port 6.0L configuration.
 
mrvette, yes the reluctor wheel.

denpo, I went to the point where the price would start to hockey stick upwards to make the next step. I almost went with a stroker, which only would have been another $900 or so for internals, but, I would have wanted to revise the exhaust at the same time and a retune is dictated by those actions, so poof, it's not $900 more, it's more like $3,200 more. Parts and labor came out to $3,400, so considering it's forged now, etc., and I was able to just drop it in and turn the key, it worked out. As it sits it should be good for an extremely conservative 600WHP all day long (doubt the Dana 44 is though!). I'll probably stop with the exhaust and retune which will put me around 420WHP, very streetable, and still passing smog in CA (as long as I go to shops that aren't too nosy on the visual). I'm 3,100lbs full wet now. After the exhaust, suspension, wheels tires and breaks I should drop to around or perhpas even just under 3,000 lbs full wet. >400whp and <3,000lbs on sticky rubber is plenty fun on the street. is my reasoning. :)
 
Top