MonteCarloSS.com
MonteCarloSS.com

CELEBRATING 20 YEARS!

Previous Thread
Next Thread
Print Thread
Page 87 of 90 1 2 85 86 87 88 89 90
#1065441 - 03/15/20 02:22 AM Re: SSLance's Build thread [Re: SSLance]  
Joined: Sep 2007
Posts: 3,171
1 Slow SS Offline
10+ Year
1 Slow SS  Offline
10+ Year
Member

Joined: Sep 2007
Posts: 3,171
Small town KY
I forgot to mention I will put a bone stock LS7 emissions legal engine in the car, with only a trunnion upgrade. I never seen any SBC emissions legal make those number with cats under the car and I’ll give them a cam and rocker upgrade.


Enjoy life, family first!
#1065446 - 03/15/20 04:03 AM Re: SSLance's Build thread [Re: SSLance]  
Joined: Dec 2007
Posts: 6,179
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,179
Peoria, AZ
I spent about $3,000 on this engine last time I went through it and it lasted thru 4 years of nothing but hard abuse after that. The question I have to come to grips with is do I, at this time, want to do that again....or do I want to spend 5 to 1p times that or more to put a dry sump, trunnion upgraded LSx in this car that is already had way more money thrown at it than I'll ever get out of it again?

This engine made me smile every time I hit the loud pedal and I've never had a co-driver or passenger say "this car needs more power". In fact, the usual response is "damn, this thing pulls so hard"...

Is the new stuff better, sure. But dollar for dollar, in my case...theres no way it makes sense.

I've leaned on a lot of knowledgeable people that I trust on this and in the end, almost to a person, they've all told me to put the aluminium pistons back in it and go enjoy it some more. And count your blessings that you caught it early. I'm leaning that way...


Lance
1985 Monte Carlo SS Street Car
#1065447 - 03/15/20 04:04 AM Re: SSLance's Build thread [Re: SSLance]  
Joined: May 2002
Posts: 4,105
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,105
Yuma, AZ
Hi Folks,

Well, I admit I certainly wasn't trying to rock the boat with an old-school versus new-school discussion. But I called the same engine builder Mark Stielow uses (used?) inquiring about an LS-7 to do 600hp, and he said, "Only 600hp? That's easy - put a different cam in it and be done with it." So then I talked to my GM friend who designed the LS-7 cam and valvetrain, and told him that my modeling of the motor also showed an easy 600hp on tap with a cam change: decreasing the LSA brought-up peak TQ and HP very fast, at the expense of surprisingly modest bottom end loss. He said that the big LSA was for emissions, fuel economy, and to give the transmission software coders an easy time of achieving stable extreme low-rpm operation.

But the real point for Lance is that bigger displacement doesn't have to be spun as fast to achieve the same power, and this alone aids reliability. Consider this: bearing wear tends to go in proportion to peak stress, and stress is force per unit area. The inertial force goes as rpm squared, and bearing area tends to go in proportion to displacement (painting with a hugely broad brush here, but still generally true.) That's two counts in favor of the bigger displacement. A minus for the bigger displacement, however, is higher moving mass. In the end, however, bearing stress should still go very roughly as the square of peak rpm, so a 383 and a 427 making the same power should result in very roughly 20-25% less bearing stress for the 427. Ditto peak stress developed in the piston.

The crack I see in Lance's piston looks like it originated in the transition between the piston skirt and the wrist pin boss, which is definitely a known area of weakness due to mechanical stress concentration and the high thermal gradient normally seen there. Again, other things being equal, larger displacement would have reduced the probability of this failure for equal power output.

There - and I didn't even have to invoke LS vs. SBC.

On edit: Lance, just saw your last post. This is what I'm afraid of: if this is your one and only failure, fine. There's no question that a simple restoration is the cheapest way out. But if this is going to be a recurring problem because you're pushing an old design way past its design limits, then dollars-to-donuts you're going to be having second thoughts. That's why I'm saying that a very careful determination of failure root cause is critical. Was there something unknown and unique about the #4 hole that brought about the engine's failure, or were all holes close to failure and #4 let go first because of a minor, normal variation there? The answer to that question will lead to one of two very divergent solutions. Remember the advice about a careful inspection of all pistons.

Best,
MAP



Last edited by MAP; 03/15/20 04:29 AM.
#1065448 - 03/15/20 04:41 AM Re: SSLance's Build thread [Re: SSLance]  
Joined: Jan 2000
Posts: 4,760
mmc427ss Offline
20+ Year
mmc427ss  Offline
20+ Year
Member

Joined: Jan 2000
Posts: 4,760
Pottstown, Pa
Not going the LS verses the SBC BS route. But have to ask what makes an LS an LSX??

Lance a direct phone call to any of the piston manufacturers and custom pistons can be made for not much more than stocking piston prices. When no one made a stocking piston for my 427 build, JE built exactly what I wanted for a 100 bucks more for the set. Yes the set of 8 was pricey but once and done for the next now over 15 years, 20K.
Bob

#1065449 - 03/15/20 05:18 AM Re: SSLance's Build thread [Re: SSLance]  
Joined: Apr 2001
Posts: 2,097
345HP87SSAC Offline
Moderator
15+ Year
345HP87SSAC  Offline
Moderator
15+ Year

Member

Joined: Apr 2001
Posts: 2,097
Stanberry, MO
Lance staying SBC is wise you are neck deep. If it was 10 years ago maybe a LSX swap would make sense. You have made great power and had thousands of smiles per mile with what you have. You have a great top end now, no reason to start over. Can't wait to see what is next.


[Linked Image]
New BTR Stage 4 cam makes 449 HP and 380 TQ TQ at the wheels. 6.0 LY6 VVT and 4L85E!blackgoldaero http://www.cardomain.com/ride/671193
#1065450 - 03/15/20 06:49 AM Re: SSLance's Build thread [Re: SSLance]  
Joined: May 2007
Posts: 4,822
Buick Runner Online content
10+ Year
Buick Runner  Online Content
10+ Year
Member

Joined: May 2007
Posts: 4,822
Dharma station 1 the Hydra
All mass produced products will have some compromises in their designs for various reasons, mainly for cost reductions and profit margins, and LSXs are not immune to this. Considering the LS7 costs as much as an entire small car and triple the cost of higher end crate SBCs, it sure better be worth the higher outlay. Not to mention LS7s are higher displacement than standard SBCs or even standard LSs, 7.0L vs 5.7L for SBC or 6.2L for LS3, so comparing the two is Apples to Oranges. LS engines do have inferior oil control to SBCs, its difficult to be 100% better at everything than everybody else. there is always a trade off with any option. However, even the LS7 suffers from known valvetrain issues that has become a sore point among Vette owners.

Now the valvetrain design of the LS7 is largely ok on paper, (although it should have roller tip rockers for its price tag), it is a victim of outsourcing. Long story short, GM outsourced the LS7 heads to a outside supplier who had less than stellar QC that a $13k engine should command. The supplier inaccurately machined the heads, and nobody knows how extensive the supply of defective LS7 heads is, and GM has not really addressed the problem. Anybody who is interested in LS7s should read this article. Ruthless Pursuit of Power: The Bigger Opps. Parts suppliers can be a weak link for even the best of manufacturers and hopefully that ends the this vs that talk.

Last edited by Buick Runner; 03/15/20 07:19 AM.

SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
#1065452 - 03/15/20 01:06 PM Re: SSLance's Build thread [Re: SSLance]  
Joined: Sep 2007
Posts: 3,171
1 Slow SS Offline
10+ Year
1 Slow SS  Offline
10+ Year
Member

Joined: Sep 2007
Posts: 3,171
Small town KY
First thing, I push for more power because I like what Lance is doing and would like to see the car faster while it's in repair. But that's his choice and he has to be happy with the investment. I would never LSx swap that car as there is way too much good on the table to throw away. Hence the reason my son has a gen II SBC in his car. I wasn't going to change the transmission, complete wire harness and sub frame for an equally expensive engine build. That extra 4 grand was a deal breaker for his budget. If it was a roller and he needed a fresh build and I had no parts then I would go another direction.The money is nearly the same when starting from scratch from my experience. A new GM 427 LS7 I pay 10,500 for. The sons new 396 CID LT1 cost the same with a supplied 4 bolt block and the many requested upgrades over Chads base 550 hp 396. The controller is a wash with upgrades I have done or the F.I upgrade Lance has done also.


Bob, Although you have had a car or two and helped a buddy with his Camaro. Your actual experience based on been there done that is short sited IMO. I could write much more to support that, but I really didn't have the intent of trying to take anything away from you or bashing you in this reply. You can say what ever you want about me as I have had much enjoyment over the years at your expense. laugh I know you're a good mechanic and know quiet a bit of stuff, but the amount of actual builds and or ownership of both options is the point. Buick you kind of fit into this scenario with the exception of I haven't seen any of your builds in a high performance application?

Map, You and me run close with over thinking, I have scrapped many projects due to that and you also.

Let's let Lance make his choice and not disagree over our opinions. He has the most proven car on the site to date so he obviously knows his direction well.







Last edited by 1 Slow SS; 03/15/20 02:05 PM.

Enjoy life, family first!
#1065453 - 03/15/20 01:10 PM Re: SSLance's Build thread [Re: SSLance]  
Joined: Sep 2007
Posts: 3,171
1 Slow SS Offline
10+ Year
1 Slow SS  Offline
10+ Year
Member

Joined: Sep 2007
Posts: 3,171
Small town KY
LSX is a GM high performance engine built much stronger starting at the block.

LSx is commonly used to describe all LS based engines.


Enjoy life, family first!
#1065454 - 03/15/20 02:52 PM Re: SSLance's Build thread [Re: mmc427ss]  
Joined: Dec 2007
Posts: 6,179
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,179
Peoria, AZ
Originally Posted by mmc427ss


Lance a direct phone call to any of the piston manufacturers and custom pistons can be made for not much more than stocking piston prices. When no one made a stocking piston for my 427 build, JE built exactly what I wanted for a 100 bucks more for the set. Yes the set of 8 was pricey but once and done for the next now over 15 years, 20K.

Bob


You know you are one of the ones I lean on the most Bob and I take your advice very seriously.

But I have to relate my experience Thursday doing just what you suggest. 3 phone calls and over an hours time was spent talking with a tech at Wiseco. I accurately described my situation and exactly what I was looking for, he asked for a couple measurements that I gathered and called him back. He then said sure, we've got a piston on the shelf that we can machine just a bit and it'll work perfectly...and gave me a price.

I was skeptical so I did some further research on the part # he gave me. This is what I found.

https://www.cnc-motorsports.com/k44...ns-4-000-bore-gm-ls-standard-stroke.html

I called him back once again and re-questioned his recommendation...after once again explaining exactly what I had and what I needed. "Oh, I heard you say 'crate engine' and automatically assumed it was an LS because we do so many of those". He looked around a bit and said "Yeah, I'm not going to have anything that will work for that without a custom design, you are looking at 6-8 weeks lead time and about $1200 for just the pistons".

Click...

BTW, this was all done after a friend that runs an engine performance shop went down the exact same road, with the exact same company...and came up with the exact same recommendation...that I was skeptical about.

I am yet further convinced as to why crate engines are so popular...


Lance
1985 Monte Carlo SS Street Car
#1065455 - 03/15/20 03:02 PM Re: SSLance's Build thread [Re: MAP]  
Joined: Dec 2007
Posts: 6,179
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,179
Peoria, AZ
Originally Posted by MAP

Lance, just saw your last post. This is what I'm afraid of: if this is your one and only failure, fine. There's no question that a simple restoration is the cheapest way out. But if this is going to be a recurring problem because you're pushing an old design way past its design limits, then dollars-to-donuts you're going to be having second thoughts. That's why I'm saying that a very careful determination of failure root cause is critical. Was there something unknown and unique about the #4 hole that brought about the engine's failure, or were all holes close to failure and #4 let go first because of a minor, normal variation there? The answer to that question will lead to one of two very divergent solutions. Remember the advice about a careful inspection of all pistons.

Best,
MAP




I appreciate that MAP, and all of your advice. Problem is, I don't think it is possible to determine exactly what happened first that caused the detonation in that cylinder. There are several potential causes though...which I will address before it sees track time once again, no matter which route I take.

Given the over pressurizing of the cooling system which started two events before the final failure, and the loose head bolt between 4 and 6, I'm leaning toward that as the cause that pushed a system right at the ragged edge...just over the edge.

Careful reassembly and backing the system back away from the ragged edge just a bit is enough to make me comfortable with this design. I've still got a couple things working that might lead me down the path of upgrading the pistons but it'll only happen if all of the moons and stars align just right. This is rocket science here with an unlimited budget, this is a hobby car that I enjoy...and I"m going to keep it that way.


Lance
1985 Monte Carlo SS Street Car
#1065457 - 03/15/20 04:07 PM Re: SSLance's Build thread [Re: SSLance]  
Joined: May 2007
Posts: 4,822
Buick Runner Online content
10+ Year
Buick Runner  Online Content
10+ Year
Member

Joined: May 2007
Posts: 4,822
Dharma station 1 the Hydra
So you think there might have been a failure in the head gasket that leaked combustion gasses into your cooling system and overpressuried it?


SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
#1065459 - 03/15/20 05:16 PM Re: SSLance's Build thread [Re: SSLance]  
Joined: May 2000
Posts: 1,678
BadSS Offline
20+ Year
BadSS  Offline
20+ Year
Member

Joined: May 2000
Posts: 1,678
Pearl, MS, 39208
After doing a little digging on the internet and GM’s Performance website it does appear that the pistons in the HT383 and ZZ383 are +0.005”, 4.005” bore, pistons with a 1.400” compression height. The part number for the replacement block also states it has a 4.004” bore (for final honing of the 4.005” pistons). This means a standard replacement 4.000” bore piston will not work – there would be too much piston to cylinder wall clearance.

So that means to me that there are two choices (one with possible options).
1) Replace just one piston and let her rip. If it’s the same weight as the rest it would not require another rotating assembly balancing or if it was a little heavier you could just weight match that piston and it would still be “balanced”. This wouldn’t require any machine work if the cylinders are not worn and a quick hand-hone with pressure stones would do. You might want to take detailed pictures of the cylinder walls once all the way down - one looked like it might have a shinny spot (could have been camera angle). I would only go this route if you check the current ring gap and find that it was 0.026” or less. Recommended hyperucrackedit gap for a street engine is 0.0065” per bore – that’s 0.026” for a 4” bore. The circle track recommendation of 0.0070” per inch or 0.028” and the drag racing recommendation is 0.0075” per, or 0.030”. Depending on what the gap was would determine if you might be able to go back with just one piston.

2) Go with a new set of forged pistons (with what you do, I’d go with the 2618 alloy). All the possible options in this scenario will require a rebalance of the rotating assembly and boring and honing the block.

2a1) New pistons and run your 5.7” PM rods. You might be able to skip the boring if you can get a place willing to cut you 4.005” bore pistons (common LS piston) with the SBC valve pocket reliefs. DSS Inc makes a SBC 1.400” compression height piston in 2618 alloy (22320-4030) – this is the only place that I could find that had a published part number for an old SBC (w/23-degree valve pockets). I know NOTHING about them but it seems that they are doing better now than when they first came out although from what I could find they still fall a little short of the better known brands. The problem with this is making sure the top ring is set lower than any possible ridge at the top of the bore.

2a2) New pistons and go with a better set of 5.7” rods. All applies above regarding the only piston I could find for this combo. However, you would replacing the next most weakest link. Scat makes a nice set of “stroker” I-beam rods for $330 or less.

2b) New pistons with longer rods. The options increase a little more here, but your deck height of what appears to be 9.015-ish now means you’ll have only a few choices that will put the piston under the deck or no more than 0.005” over. There are a ton of options that will put it 0.010” (give or take depending actual deck height) out the top of the block. I’ve never run one peaking out more than 0.005”, but this is typical for a number of engines and 0.010” give or take a little shouldn’t be an issue – you can just adjust quench/squish with the head gasket. This option is a little more expensive than 2a2, but you can go with a better known company. The only down side to this is that not all of the “stroker rods are created equally. Maybe Slow can say which he’s had good luck with – I’ve been using Compstar rods lately and been very happy with the clearances on them, but they run over $600.

HTH

#1065465 - 03/15/20 06:20 PM Re: SSLance's Build thread [Re: SSLance]  
Joined: Sep 2007
Posts: 3,171
1 Slow SS Offline
10+ Year
1 Slow SS  Offline
10+ Year
Member

Joined: Sep 2007
Posts: 3,171
Small town KY
I have been very fortunate with after market rods and never had any failures. Chevy 6.0 inch rods I have used are, Eagle H- beam being the cheapest. The Camaro has Scat 6.0 H beams, forged pistons and a forged scat crank good for 1000 HP, good bang for the buck IMO. I have good confidence in those Scat parts. In older builds I was running Manley 6 rods in several engines pre 2005. I have used Callies Compstar rods also with Callies dragon slayer crank, cost has me hunting in other areas and for me that's way over kill. Those are top self for high power and religious beatings.

My vote today is Scat 6.0 rods with a forged assembly. And any of the above are a solid upgrade over 5.7 PM rods.

I have taken one new GM engine apart and tossed the PM rods. Because they just come apart without notice. I don't care what anyone says or what they're rated for. I will not use them in any performance engine. Lance I don't want to curse you with bad luck. I have seen a few let a couple guys down at 6K.


Last edited by 1 Slow SS; 03/15/20 10:16 PM.

Enjoy life, family first!
#1065466 - 03/15/20 07:52 PM Re: SSLance's Build thread [Re: 1 Slow SS]  
Joined: May 2000
Posts: 1,678
BadSS Offline
20+ Year
BadSS  Offline
20+ Year
Member

Joined: May 2000
Posts: 1,678
Pearl, MS, 39208
Yep the Callie’s are over kill for most folk’s builds. The last few of mine have been in the 550-700 range and planning on spraying.

The HT383 comes with a good 4340 crank so if he goes with a better set of rods he’ll have a good bottom end. I did have a chance to ask who I think is the best engine builder in the area about PM rods and like you and others on some technical forums will not use PM rods in anything other than a low rpm stock or near stock application.


Original owner of 1985 SS black hardtop w/gray interior. Frame-on restoration - 406 sleeper w/ heavily ported FIRST TPI. However the 1.875" headers, 3.5" duals, TH400, Ford 9", notched frame, and 10-point cage w/swing-out bars might tip you off it's not a lil' ole 305 TPI. Other mods: 2" drop, 18" wheels, f/r disk brakes, and custom stereo system.
#1065467 - 03/15/20 09:07 PM Re: SSLance's Build thread [Re: SSLance]  
Joined: Jan 2000
Posts: 4,760
mmc427ss Offline
20+ Year
mmc427ss  Offline
20+ Year
Member

Joined: Jan 2000
Posts: 4,760
Pottstown, Pa
Doing the forged pistons no matter how you cut it puts the price well over a grand for a refresh. Doing just a replacement piston if all others are good is still some money but is the easy route and if you behave should last several more years. Even though the 383HD and 383ZZ are the same shortblocks neither was a race engine, they had limits. "A man's gotta know his limitations", wasn't that Clint?


I always thought an LSX engine had one of these as it's foundation. Didn't know putting a .700" lift cam in an LS1 makes it an LSX.
https://www.summitracing.com/parts/nal-19417351
Bob

#1065470 - 03/15/20 09:37 PM Re: SSLance's Build thread [Re: SSLance]  
Joined: Dec 2007
Posts: 6,179
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,179
Peoria, AZ
Thanks guys... Really appreciate the input.

Pulled the rest of the pistons today and found these.

#1 Just a slight bit of pitting from detonation

[Linked Image]

and #8 Cracked ring lands

[Linked Image]

Top of piston and all rings look good, no sign of any other damage except marks down the side like compression was getting by a bit.

Check out the inside of #4

[Linked Image]

The crack goes halfway around the top of the piston with burn marks inside the piston.

So, it's really hard to tell what happened first in #4, broken ring lands or foreign substance raising compression or lowering octane causing detonation. I know this though, almost half of the piston are showing some sort of damage. This is a good sign that this will not be a quick fix scenario.

There is a bit more rod bearing wear in #5 than the rest, just like last time. Not anything critical once again but notable and something to watch. I'd been paying attention to hot idle oil pressure and it had started to slip some about a year ago...this is probably why.


Lance
1985 Monte Carlo SS Street Car
#1065471 - 03/15/20 10:03 PM Re: SSLance's Build thread [Re: SSLance]  
Joined: Jan 2000
Posts: 4,760
mmc427ss Offline
20+ Year
mmc427ss  Offline
20+ Year
Member

Joined: Jan 2000
Posts: 4,760
Pottstown, Pa
Although hard to detect these days because of the ethanol coloration of the plug's center porcelain, detonation may be seen as tiny specs of black alum stuck to the plugs center porcelain. Anything showing on that #4 plug.

Bob

#1065472 - 03/15/20 10:23 PM Re: SSLance's Build thread [Re: SSLance]  
Joined: Dec 2007
Posts: 6,179
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,179
Peoria, AZ
#4

[Linked Image]

[Linked Image]

#1 with slight detonation pitting on piston

[Linked Image]

[Linked Image]

[Linked Image]

#8 with cracked ring land

[Linked Image]

[Linked Image]


Lance
1985 Monte Carlo SS Street Car
#1065474 - 03/15/20 11:58 PM Re: SSLance's Build thread [Re: SSLance]  
Joined: May 2002
Posts: 4,105
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,105
Yuma, AZ
Engine autopsies require patience, patience, and then some more patience.

After having done hundreds of loudspeaker death autopsies, it's exactly the same thing. Sweat the small stuff, and sweat bullets for the really tiny stuff. My experience in this was why the other engineers called me when everyone else was stumped. Not trying to brag, but I usually got to the bottom of things. But you've already got this engine apart, so it's probably too late for that.

Doing a good autopsy from a distance and without the parts in front of you is nearly impossible. In real life, one clue leads to another leads to another...

Anyway! Just a few thoughts:

1. The first photo of #4 piston made me think that over-reving the motor might have caused a crack that started at the bottom face of the wrist-pin-bore/skirt transition. But if so, the crack would have ended short of the ring land area. That's not the case, so we can strike that cause.
2. You mentioned detonation a few times. Detonation does align better with the crack pattern in #4. But why did you think of detonation?
3. You mentioned a loose head bolt near #4. But was that a cause, or an effect? Detonation can cause the head to "hammer" the head gasket in such a way as to compress it unevenly, and uneven compression can cause a head bolt or two to be low on break-away torque.
4. Just curious if your ignition system includes a knock sensor? Are you running street 91 octane btw? Any methanol content yet, or too early in the driving season?

Be all that as it may, higher displacement means better reliability for the same HP target. Moving up from 6.28 l (383) to 7.00 l (427) would be a very nice stepwise jump. But 427 is either going to come in aluminum or iron, and if iron, you will NOT like the handling results. The LS-7 hits all the sweet spots, I think.

Lance, look at all the money you have in this motor, from the EFI conversion and back. Then add the value you place on your time just in tearing-down this motor and all the EFI work. In this larger context, I'm sure an LS-7 isn't so expensive after all. I'm not trying to sell you on anything, but just look at this from a cold value proposition standpoint. And, remember the risk that I mentioned about whether this is a one-time fluke or something that will be a regular part of your future because of the stress you're putting into a dated design. And on top of all that, take 100lb off the front axle with the LS-7! (Or about conserved weight if you decide to go with an all-aluminum BBC - another option. 500HP is downright lazy when you're at 500 CID.)

May I suggest you do a simple restoration, sell this motor, and then upgrade? Again, not trying to insist on anything - just submitting this for your careful consideration.

Best,
MAP

PS: In a 383, I definitely like 6" rods, as I used in my 383 build. Manley rods and forged pistons. ARP everywhere. The longer rod decreases peak piston acceleration and allows more piston dwell time near TDC. It also reduces side-load on the piston skirts. All are good benefits for piston longevity.


Last edited by MAP; 03/16/20 12:05 AM.
#1065475 - 03/16/20 12:23 AM Re: SSLance's Build thread [Re: SSLance]  
Joined: May 2007
Posts: 4,822
Buick Runner Online content
10+ Year
Buick Runner  Online Content
10+ Year
Member

Joined: May 2007
Posts: 4,822
Dharma station 1 the Hydra
You are lucky that piston didn't shatter and blow the block.


SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.

2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.

Never argue with an idiot.
They will just drag you down to their level and beat you with experience.
#1065478 - 03/16/20 01:22 AM Re: SSLance's Build thread [Re: Buick Runner]  
Joined: Dec 2007
Posts: 6,179
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,179
Peoria, AZ
Originally Posted by Buick Runner
You are lucky that piston didn't shatter and blow the block.



I'm not sure how it stayed together. That crack wasnt really fresh...


Lance
1985 Monte Carlo SS Street Car
#1065479 - 03/16/20 02:35 AM Re: SSLance's Build thread [Re: SSLance]  
Joined: May 2002
Posts: 4,105
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,105
Yuma, AZ
Still waiting with bated breath whether other pistons had cracks...

#1065480 - 03/16/20 05:10 AM Re: SSLance's Build thread [Re: SSLance]  
Joined: May 2002
Posts: 4,105
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,105
Yuma, AZ
Two more thoughts for now:

1. Lance - how do you know how fresh a crack is? Soot accumulation around its edges can form within seconds in a sub-optimal combustion scheme. The rate of soot accumulation in the rest of the chamber doesn't necessarily correlate. Cracks, once started, can grow very quickly.
2. Note to self: all this is a powerful reminder for me that gas-burning motors are the past. And since a while ago, for GM too - they're committed to a 100% electric future. A couple of decades from now, we'll all be thinking - "cracked pistons: how quaint."

Best,
MAP

#1065482 - 03/16/20 05:54 AM Re: SSLance's Build thread [Re: SSLance]  
Joined: Jan 2000
Posts: 4,760
mmc427ss Offline
20+ Year
mmc427ss  Offline
20+ Year
Member

Joined: Jan 2000
Posts: 4,760
Pottstown, Pa
Couple decades from now, if I'm still here, we'll be trying to figure out why we had to buy electric cars back then. What are we going to do with all them batteries in the junk yards?
And why did we allow them to dig up a national park for the lithium?
https://www.latimes.com/local/calif...lifornia-environment-20190507-story.html
Back to the future.
Bob

#1065483 - 03/16/20 01:13 PM Re: SSLance's Build thread [Re: SSLance]  
Joined: Jun 2006
Posts: 1,740
Travis Jones Offline
10+ Year
Travis Jones  Offline
10+ Year
Member

Joined: Jun 2006
Posts: 1,740
Ferndale, MI
ah man, I didn't mean to make the LS vs SBC debate come front and center, I was just giving Lance a gentle ribbing.

Two quick points of order - First trunion upgrades on LS motors with less than .630 lift are a waste of money (and there's tradeoffs in valvetrain stability above .600 lift). The C5r/C6r/C7r all used factory rockers and ran around Cirque De Sarthe for 24 hours straight. The NA COPO Camaro used stock rockers with Johnson short travel lifters to hit 8500 RPM (and pass GM validation testing - which is harder than we would EVER push one of these motors). The only reason that factory rockers fail are valvetrain geometry issues, usually caused by incorrectly sized pushrods or lifter issues after a big cam gets installed. Second comparing the wet sump LS oiling system and the wet sump SBC oiling system for the use case of any of us is non issue, we aren't spinning it high enough, or making enough power for it to be an issue, assuming we run an Melling high volume pump in either application and can keep oil in the sump (there's good road race pans for both engine platforms).


I think #4 went lean and caused your issues. Fuel distribution between cylinders can still be an issue with Throttle Body Injection, it's just a fancy electric carburetor and reversion is possible at higher RPM. MPFI ensures each cylinder gets adequate fuel.

Lance, if you call up Diamond, JE, or any other piston maker, they can make you the exact piston you need in whichever alloy you choose. That's the simplest, cheapest solution. Get Pistons, slap it back together and let it eat.


86 SS 6.0L LQ4, TBSS GEN IV intake, 92mm TB, 30lb injectors, Summit Stage 3 NA Cam, Stainless long tube headers, Stainless 3in exhaust, Microsquirt ECU, FABbot AR5 5-speed, Torsen LSD, QA1 Lvl 3 Suspension Kit, UMI Front & Rear Braces. Check out my build blog on Summit Racing's OnAll Cylinders https://www.onallcylinders.com/author/travis-jones/
Page 87 of 90 1 2 85 86 87 88 89 90

Random Images
500/thumbs/DSC00199.JPG
by nighttech
500/thumbs/IMG_13351.jpg
by jvssmail
500/thumbs/L69_Spark_Table.jpg
by Duts87SS
989/thumbs/my_monte_34.jpg
by 85montanezcarloss
1164/thumbs/IMG_00281.JPG
by Witman69
Help MonteCarloSS.com


Recent Contributors
finallySS
Authorized Vendors
Tell them you saw it
on MonteCarloSS.com!


CustomMonteSSParts.com
Dixie Monte Carlo Depot
GSI Interiors
HRpartsNstuff
Mikes Montes
Savitske Classic & Custom
Powered by UBB.threads™ PHP Forum Software 7.6.0