All,

I have been wanting to do a 4th gen project build for some time, and just purchased an interesting car. It's got a ton of issues, but the price was too good to pass up. First time tearing into a motor in a serious way, and I had a couple of questions.

The car itself is a 2000 Z28, that according to the previous owner had an LS6 crate motor swapped in that was bored and stroked to 383 by a local shop which has since gone out of business (bad sign?). Only other significant mods were a cam (numbers unknown as yet), head work and long tubes/straight pipes. The car started making some bottom end noise the owner described as rod knock, which he thinks is due to a spun rod bearing. The car was then parked for 5 years, covered but not climate controlled.

My plans for the first stage are to get it moving under its own power, and I'd like to do it with a budget of $3-5K. I have a ton of questions since this is my first build, and I'm hoping some of the gurus here can help shed some light on things.

Are there any meaningful differences between the LS1 and LS6 besides the heads/intake? Am I good to order a gasket/seal kit for an LS1, or do I need to be meticulous and insure everything is LS6 compatible?

For a car that sat for 5 years, is there anything I absolutely need to do besides a full gasket/seal kit, all fluids, fuel tank/lines flush, etc? Obviously I'm expecting a ton of dry rotted vacuum lines and random odds and ends, and I already have a set of decent wheels and tires. Is there anything that is a must do that I'm missing?

Is there any way with a decent mic and dial gauge to figure out exactly how much it was bored over? I'm hoping the pistons are all good, but assuming I have to change out one or more can I figure this out myself, or am I absolutely going to have to send the block off to a machine shop? Or is a machine shop a must do anyway? Is it even sensible to change out pistons/rods in ones and twos, or should I just plan on ordering a matched set?

Same with the heads, can I get by on a visual inspection and if it looks good go with it? Or should I absolutely send them off to a shop? I'm a bit hesitant to mess around with the valve train too much, as I don't have any specs on the cam and I'm not likely to get them without sending it off to be measured. Without knowing what I have, I'm leaning towards leaving it the hell alone for now. Obviously it will need a tune at some point, but would a decent tuner absolutely need to know cam and valve numbers, or is it reasonable for them to just wing it?

I know it's impossible to tell until I tear into the bottom end (getting towed to my bro's shop this week), but does $3-5K sound remotely reasonable for "rolls out of the shop on its own"?

Thanks!!

 

You might need to rebuild the bottom end. More than seals and gaskets....

 

Really hard to say until get into specific details. It might turn out to be something else causing the noise and be fairly minor - like a broke valve spring or rocker.

Background info - LS1 or LS6 383 strokers are normally honed to a 3.903 bore or 3.905 bore depending on piston selected. The block liners are too thin to really bore the old standard 030 or .040 or .060 over.

Some 383 LS1 4 inch strokers develop a nasty piston rock noise because the wrong taper piston was used by the build. That bottom of the stroke the piston comes too far out of the hole to be stable and rocks That noise can be mistook for a rod knock in some cases. Correct piston & rings from Wiseco or Diamond. Block might need a hone, definitely would need to be checked etc. Ifcthe motor has to come apart, I'm be sure and confirm the piston part numbers and make sure they are designed for use with a 4 inch crank. Help avoid possible problems later etc

Regarding your new project
Have you removed the oil filter, cut it open and unrolled the filter element? If the oil has a metallic sheen and sparkle thats not a good sign.

Does the engine turn freely and rotate 360 degrees by hand?

Worst case a new 383 stroker short block can be purchased for roughly $4700. I think you can fix your engine for less than $5,000

 

Yep, I'm expecting to find bottom end issues, just not sure how deep it goes. I'm very much on the fence about just swapping out any bad pistons/rods, throwing a set of bearings at it and hoping for the best; or just saying screw it and doing a complete rotating assembly and sending the block off to a machine shop. I guess there's always the chance I'll get lucky with a minor valve train issue, but I'm not holding my breath on a stroker motor built by a defunct race shop

That's interesting about piston rocking, I wasn't familiar with that. Our plan for now is to get the heads and pan off and see what we're dealing with, and I'm hoping we can figure out what crank/rods/pistons were used. It's been a nightmare trying to budget this, since I'm really going in blind in terms of what's in the damn car.

We'll have it in the shop later this week, I'll be sure to capture the oil and cut the filter open. As far as the block being seized, I'm not sure. A bunch of accessories were removed a couple of years ago in prep for pulling the motor, but that was never completed. I have the parts, but the crank bolt was removed and I wasn't able to try and spin it over when I looked at it. Honestly if I had to do a short block I'm not sure I would bother with a stroker. I'm going for a fun streetable build to beat up on stock 5th gens and Mustangs, so I'd be perfectly happy with an SBE LS1 with heads/cam and LTs. Going down the 383 rabbit hole just doesn't seem necessary at that point. I mean if I can get the one I have working for a reasonable price, hell yeah; but it's not like I'm dead set on a 383

Probably sound like an idiot tackling a project of this scale with such limited knowledge, but I have a standing offer to buy the car off me for what I paid if it all goes pear shaped, so I figured what the hell

 

Provided the 4 inch stroker crank isn't damaged it will cost basically the same to rebuild as a 346 or 383.

The extra 40 to 50 rear wheel foot pounds of torque the stroker makes definitely makes for a more fun car to drive.

FWIW - Having had a heads & cam LS1 346 & currently having a 383 LS1, I will take the 383 LS1. The extra bottom end torque is more fun in normal driving.

BTW - you can estimate a budget but it's really a guess at this point. Usually, if you think it will cost $5,000 have $7,500 on hand. You may want to upgrade to a different cam and you may want to dump the old LS1 lifters for new LS7's or More. A Fast 90/92 intake, 92 mm TB and 36# injectors would like be a nice upgrade if the car still has an LS6 intake...and so on

Look forward to your updates & best wishes.

 

if it didn't get built right the first time thats not good,for 5-7,500$ i would get a gm ls3 crate, cant go wrong there

 

Whats wrong with just dropping a 6.0 in? Of course thats if you need to build the engine. You can pick up a lq4 for under $1500 all day long. Or even step it up to a ly6 for $2000 or less, you can even pick up a L92 (aluminum 6.2) for under $2500. That will surely get you rolling for $5000 or less, possibly way less.

If it were me and I had $5000 Id grab a l92, Ls3 intake/injectors/rail, cable throttle body, cam/valve train and let it eat you can have a EASY 450+rwhp

but like others have said, you need to see whats going on with it first

 

how much for the bad 383 ls6?

 

Wow, I had no idea the LQ4's were so cheap. If the block turns out to be scrap, that's *really* tempting. My DD is a 5th gen SS, and I'd love to drop an LS3 in, but from what I've seen that's a bit more than I want to spend at the moment. A 6.0 iron block would be great though. I've been kicking around the idea of FI in the next couple of years anyway and that would be a perfect starting point if I ever go that route. Honestly I've been very torn between getting it running ASAP and doing forged internals just in case, and an iron block seems like a good compromise.

Unfortunately I still don't have it in the shop, it's getting hauled up by a buddy of ours who runs a tow truck, and he's been waiting until he gets a run headed that way to try and save us some $$ (the car is about 30mi away at the moment). Poked him again today, I'm really hoping we can start tearing it apart this weekend, but still not sure if that's actually going to happen.

As far as selling off the LS6 I honestly have no idea. Have to crack it open and see what it looks like first. If the block is in good shape I may still want to try and rebuild it, but if not it would depend on how bad the condition is. Still, I guess at a minimum it's worth a couple hundred bucks in scrap aluminum, which just adds to the budget.

 

Welp, it took forever but I finally managed to get it in the shop and tear into it. Some interesting discoveries. Apparently now we're seeing just how deep the rabbit hole goes.

First off, it does not appear to be an LS6 as far as I can tell. The heads are 853's, which would be stockers for a 2000 LS1, though they do show signs of hand-porting. The valley cover also seems to be an LS1 spec as opposed to LS6, which had a PCV fitting IIRC.

The shop that originally built the motor was MTI in Houston many years ago, and I did notice they put MTI branded pushrods in (but nothing else was branded). The valvetrain looks damn near perfect, dual springs, obviously upgraded pushrods. The lifters looked absolutely mint, and the cam had only the faintest witness line in the center where the lifters ride.

The cylinder bores look great at least visually. There was some minor surface garbage from sitting for so long, but we got the motor turning over easily pretty quickly and with minimal effort.

Here's the rub: there are signs of pretty significant damage in the rod/crank area. The rods and crank themselves look ok as far as I can see, but the block was clearly taking a beating at some point. One of the guys helping us with the teardown suggested it might have been from a previous broken rod. The working theory at the moment is that the motor suffered some form of catastrophic bottom end damage in the past, and this was the event that led to the motor being rebuilt by MTI. It would explain the damage to the block, with no other indications of major meltdown.

I have read that for SBC stroker builds it is necessary to clearance the block to accomodate the "swing out" (for lack of a better term) of a stroker crank, essentially the horizontal stroke. Is this still an issue for LS series engines? Some of the block damage to me looked more like a gradual shaving down of the block, possibly due to insufficient clearance between the block and the rods?

Further mystifying, was the oil. The oil looked like hot garbage that hadn't been changed in 30K mi. but was *completely* devoid of any glitter, sparklies or other sign of motor death. Poured it out over a shop rag to be sure, and it's completely clean. Cut open the filter, and found nothing but more dirty *** oil. Then we pulled the pickup tube. Holy jeebus, chunks of metal shavings lodged into the screen, bigtime. Initially I figured ok, it spun a bearing, we expected that. But looking later at the photos, I'm wondering if these aren't shavings from the block as a result of insufficient rod-block clearance. Has anyone ever seen anything like this?

Is it possible that all of the carnage I'm seeing on the block was a result of bearing pieces getting thrown around inside the pan? I wouldn't have expected them to be heavy enough to do what I see, but I'm nowhere near an expert. Is it even feasible that a bearing was damaged to the point of throwing chunks into the pan, but leaving *no* outward indication of failure on the caps?

I'm totally confused as to how I have metal shavings on the pickup screen, but *zero* sparklies in the oil. Possible that this is just the screen doing it's job? I would have expected any loose bits of bearing or block shavings to eventually be ground down to the point of passing through the screen.

The shop closes early on Sat. and we were rushing to get the motor on the stand, so I haven't gotten the bearing caps off yet to look, but hope to have that this week. At this point, we're going to get this thing to a machine shop to be cleaned and measured and go from there. I would still love to hear any input though about whether we have a scrap block, or something that can maybe be saved. Apologies for crappy cellphone pics, but it anyone has anything to add, I would love to hear it.

 

"I have read that for SBC stroker builds it is necessary to clearance the block to accomodate the "swing out" (for lack of a better term) of a stroker crank, essentially the horizontal stroke. Is this still an issue for LS series engines? Some of the block damage to me looked more like a gradual shaving down of the block, possibly due to insufficient clearance between the block and the rods?"



Not hard a fast rule with an LS stroker. Depending on which crank, rod, piston combo was used it may be an issue and require clearance work. If the parts were carefully selected and checked, it might not require much/any clearance work.

I think you will have to tear it down the rest of the way to see what you have.

 

That looks like a stock crank to me. Are you sure that's a 4 inch crank?

 

I'm also curios to know what the bores measure out to be as those look to be stock pistons too.

 

That is definitely an LS1 block, not an LS6 block. The valley is the dead giveaway.

Definitely not a stroker either. Crank and rods are stock, pistons look stock but might even be a stock replacement set.

 

agreed with above ,looks like a stock ls1 short block .look for part numbers on the pistons .lots of carbon on the pistons .get a cheap caliper and measure the bore and stroke .

 

Yep, that was my first thought too as soon as the heads came off that they were stock pistons. Haven't measured the stroke yet, but I plan on it. To be honest, I'm almost relieved by that. I was concerned that if the block had already been bored over there wouldn't be enough sleeve left to clean it up.

If it turns out to be stock stroke/bore, I suspect I'll have the machine shop bore it out for a 383 build. I was expecting to have to rebuild the bottom end anyway, so no real loss there.

 

Save your money and buy my LS3 short block. Lol
Zero miles...

 

If it's an LS1 block you CAN'T bore it more than .005. The liners are thin on LS1's.

 

Yep, I'd just be looking at the standard 3.903-3.905 for stoker pistons

 

Save yourself some cash and just do a 6.0 swap