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-   -   '70 Nova LSX swap LY6/TH400 (http://www.offroadfabnet.com/forums/showthread.php?t=8160)

entropy 05-29-2012 12:31 AM

Quote:

Originally Posted by TheBandit (Post 120623)
The LS uses a non adjustable valvetrain. Lifters preload can be altered with different length pushrods.

Well there you go... I guess that GM had a better idea:laughing1:

entropy 05-29-2012 12:25 PM

Decided to do some reading on these GM V8's that I haven't (obviously) paid much attention to...


:laughing1:Hilarious:laughing1: like reading about all of the iterations of the Ford engines!
So to review...:sleep:

TheBandit 05-29-2012 01:11 PM

What are you trying to say? GM is behind Ford on V8 engine development? I'd say that's obvious in terms of technology implemented and HP/cube, but in terms of reliability/HP and $/hp, I'd say GM still has Ford beat by a good margin.

Ah crap, are you baiting me into another Ford vs. Chevy debate?

entropy 05-29-2012 07:52 PM

Quote:

Originally Posted by TheBandit (Post 120642)
What are you trying to say? GM is behind Ford on V8 engine development? I'd say that's obvious in terms of technology implemented and HP/cube, but in terms of reliability/HP and $/hp, I'd say GM still has Ford beat by a good margin.

Ah crap, are you baiting me into another Ford vs. Chevy debate?

First your question:
The single thing that created the cult of the SBC the BBC, the Mouse and the Rat, was that ANYONE could throw one togeather and I mean anyone. The keys WERE Simplicity and interchangeability hell you could put a Rat oil pump in a mouse! Have you looked at all the permutations of the gen III and IV, it is like trying to read a Ford list:laughing1:
That is all I was saying. Hell I get bored with the blue religion fanatics too:smokin:

As to your statement and I quote:
"Ah crap, are you baiting me into another Ford vs. Chevy debate?"

CarterKraft 05-30-2012 10:44 AM

Quote:

Originally Posted by entropy (Post 120647)
First your question:
The single thing that created the cult of the SBC the BBC, the Mouse and the Rat, was that ANYONE could throw one togeather and I mean anyone. The keys WERE Simplicity and interchangeability hell you could put a Rat oil pump in a mouse! Have you looked at all the permutations of the gen III and IV, it is like trying to read a Ford list:laughing1:
That is all I was saying. Hell I get bored with the blue religion fanatics too:smokin:

As to your statement and I quote:
"Ah crap, are you baiting me into another Ford vs. Chevy debate?"

E you nailed it on that one. :beer: That's the reason I love the SBC.
At work we have quite a few engine designs that have come out over the years they vary from large to tiny but one thing remains the same...
If I give them the SBC stamp, meaning "this is a good engine" no crazy assembly procedures, no finicky setup, easy parts fitup and common engine layout anyone can build it, in a desert or in a coal pit. They run forever and take allot of abuse.

Sure it's apples and oranges but the intention is the same, one is easy one is not, and my key to being a good technician is laziness, makes you fast and accurate case you only want to do as much as you have too.

Sorry for the hi-jack. :devil:

entropy 05-31-2012 11:52 AM

Had a chance to measure stuff yet?

TheBandit 05-31-2012 02:47 PM

No not yet. I pulled the pistons from the Simple Green and looked for pitting. On both uncleaned pistons and pistons that were exposed to Simple Green, I found one area of pitting that looks like a casting flaw on an as-cast surface above the pin bore at the transition to under the rings. It's hard to explain, so I will try snapping photos later. Other than being clean, the pistons look good. I don't expect to see a shift in dimensions, but I will measure with the tools I have available when I get a chance.

The last week has been busy with other things. We just had 800 sq ft of concrete patio and walkway poured around our house so I've been prepping for that - running buried sprinkler lines, moving gas and electrical lines, etc. Looking forward to spending my summer barbequeing out there.

entropy 05-31-2012 04:02 PM

ah, priority's.

TheBandit 06-04-2012 01:18 PM

Well crap. I looked at the pistons again over the weekend and things went sour. They are leopard-spotted now with oxidation, primarily around the skirt. Water rinsing, compressed air drying, WD40 and bagging apparently wasn't enough after soaking these in Simple Green. I am so frustrated I can hardly type without clenching my jaw.

Thankfully engines, car projects and money are not the most important things in life.

Now to research replacement parts again...

TheBandit 07-13-2012 12:24 AM

Let me introduce you to my daily driver, a 2007 Chevy Cobalt LTZ.This econobox is pure luxury. Leather. Heated seats. Around 30mpg average on the way to work. And guess what? This little baby is packin' LSx power! That's right, the word's first Cobalt with a transverse mount mid engine V8.

http://cjnn.xtremefabricator.com/ima...ly6swap386.JPG

See? There it is!

http://cjnn.xtremefabricator.com/ima...ly6swap387.JPG

For all of you wondering if an LSx block will fit in the trunk of a Cobalt, well folks, there it is!The bare block was heavy, but moveable with a buddy's help. We turned it upside down on the stand and picked it up by the end cylinders. I put a piece of plywood in the trunk to support it and pushed it against the rear seats to keep it from shifting under hard braking. Next stop is QMP Racing in Chatsworth for cleaning and inspection. From there I'll figure out what machine work is needed and decide what internals to stuff it with. I'm also dropping off the crank to be polished and the bare heads for cleaning.

Been doing my rain dance so hopefully some money will start falling from the sky soon!

JaysinSpaceman 07-13-2012 01:44 AM

Sweet!

CarterKraft 07-13-2012 09:39 AM

I was reading this post in my email update and I have to tell you I got a little excited, then let down but excited again the engines getting built.

I have to get mine sent off, mostly cause I am tired of taking it off the lift to use that bay.

TheBandit 07-13-2012 03:49 PM

Did the idea of an LSx powered Cobalt get you excited? If so you might appreciate this little gem I came across: http://www.yourcobalt.com/forums/can...ct-canada.html

I'm very happy to have the block at the shop. It gives me some motivation to get the heads assembled and organize the garage a bit so I can get back to work on this thing. I've been traveling a lot lately; spent two weeks out of state and another week out of the country last month. Prior to that it was weeks of prep for concreting our sideyard and back patio. I'm ready to get some car stuff done now!

CarterKraft 07-13-2012 04:19 PM

Clint, did I suppose you have read that thread, does he really have 200k in that thus far... I kinda hop skipped through there to get to the completed pix and there aren't any and it just arrived at his house 4 years later. Kind of made me feel good about the unfinished Bronco in my shop that's been there 2 years, I don't think I've billed out 4k yet though.

TheBandit 07-24-2012 01:37 PM

I honestly haven't read the Cobalt thread, but I did look at a lot of the pictures. The guy still exists, but hasn't really updated on the project for a few years so I'm not sure where it's at. I would think if he got it finished he would have posted it someplace.

Update

I talked to the machine shop. They finished cleaning the block and checked the crank. The crank is straight and in spec - a light polish is all it needs. On the block, the deck heights are mismatched at 9.2375 and 9.2395 (0.002in difference). They are flat (no problems front to rear). Their opinion was that I could get away with the difference, but recommended I deck it to match the two sides. Assuming a 0.051 gasket, 6.125 rod, 1.304 compression height and 3.622 stroke, the current dimensions give 0.0485 and 0.0505 quench, so I should be able to safely shave the deck some and improve quench while matching the two sides. But by my calculations the difference in height is only about 0.05:1 difference in compression ratio; I'm not sure if this is necessary - what do you think?

They are also recommending line honing the mains, but didn't have any measurements to say why - just that in their experience they tend not to be straight on these blocks from the factory. I asked if they could measure, but they said by the time they set it up and measure they may as well hone it. I am not too keen on machining for the sake of machining. Any thoughts on this? In my reading I haven't heard of this being a problem.

As for the bores, they recommend going 0.030 to ensure they clean up. They said they will likely clean at 0.005 but there's no guarantee. Since I need to order pistons first, I prefer to get 0.030 over so I don't have to hassle with returning pistons if it wont clean at 0.005.

I found a few good sales on forged pistons and rods, so my plan is Wiseco 2618 flattops and Callies Compstar rods w/ ARP2000 bolts. This will bump the compression ratio to about 10.25:1. In my research I came across two challenges with flat top pistons for this engine. First, there are only a few piston manufacturers that have L92 head specific valve reliefs. Second, none are available for the factory rod pin size (0.945) in this bore size (4-4.030) - most of the aftermarket pistons have 0.927 pins to match 99% of the aftermarket rods. This meant I couldn't really combine a forged piston with my factory rods. The nearest thing is a 4.065 forged piston from Mahle, but I don't want to bore that much. There are true flat-top pistons without valve reliefs that would work (LS2 pistons come to mind since they have the same 4" bore), but with my high lift VVT cam I don't want to run any risk of valve-piston clearance issues.

So that's pretty much where I stand. Any thoughts?

entropy 07-24-2012 02:08 PM

Please re-specifically, clearly define, exactly what you plan on, and what you expect that, this engine will do “in your chassis” and if the factory as produced engine would achieve that result.:biggrin:

TheBandit 07-24-2012 02:29 PM

From earlier in the thread: be at least as powerful as the old 350 before it gave up the ghost. Start and run predictably strong. Have crisp throttle response. Not leak. Sound just a little choppy. Low 12s in the quarter. Drive to cruise nights and be proud to open the hood. Tear up an autocross course and perform admirably on track day. It will get semi-beat on. I can limit the RPM which will go a long way toward keeping things together, but it will see WOT pulls on a regular basis.

The factory engine with a cam swap would have achieved the results I am looking for. I have thought about getting another used shortblock, but it's the devil you know vs. the devil you don't. The reason for going to the upgrade components is peace of mind. I would be pissed if I spent all the money on machine work, balancing, and my time assembling and putting this into the car if I had a failure. I would hate to miss the opportunity to get things right. I know I (and even my wife) will forget about the money spent in a few months, but it will instantly be remembered if something breaks. I don't think I will ever know what the 0.002 difference means in deck height, but I'm asking to confirm. The line hone seems like a waste of money to me, but again I'm asking to confirm. The crank spun easily by hand in the block before, so it seems they couldn't be too far off.

MeanMike 07-24-2012 03:24 PM

If your like me you have to justify in your mind why and how something needs to be done. For the line hone, here is the reasoning. First, lets assume the main jounrals on the crank are dead straight or around .0001" max runout. The mains in the block must be aligned to within the tolerance of the bearings (ie: .002" bearing clearance, the mains must be closer than that). Lets say that at best you have the mains bore concentricity is .001". That means the main journal that is the farthest out of tolerance (.001") is going to have a spot where the bearing clearance is only .001". .001 should feel great when assembling the engine on the stand.

That's fine and good until you realize that the crankshaft bends under load. It will obviously bend more with a high hp engine than a stocker. If it bends even .001" on the main journal that was already tight, you're going to have contact. Without buying a stronger crank that flexes less, you have two possiblities to fix the problem. You either make sure there is zero misalignment with the mains, or you open up the bearing clearance on the mains. Opening bearing clearance probably means a bit less oil feeding to the rod journals. So, which is the best fix at this point? Making sure there is zero misalignment in the mains.

The deck height difference would not concern me one bit. The only reason I would cut them would be to ensure they are flat and have the correct finish for your head gaskets. Even if they cut them, I doubt they would get it any better than .001" and more than likely they will be no better than they are now. I would also question the accuracty of a meaurement to .0005". Did they measure both ends, is the main journal parallel to the deck surface?

entropy 07-24-2012 03:31 PM

Then IF the OE GM Engine would deliver the results, you do not need anything but OE replacement level parts. And a 0.002 difference in Deck height is irrelevant, as is the main bore, as are Forged Pistons as are forged rods etc.

That said you are changing the Cam and so…
To make some piece of mind additions/changes to the engine is "I feel good" insurance.
The deck height distance is not large enough to worry about on this level of build, that said with a forged rod and piston you would like to get the quench down into the 0.040 range on the street the minor gain in CR is just that minor but the increase in efficiency and fuel tolerance would be worth it over the next 100K miles.

The main line… I am going to say that I agree with your assessment leave it; and then say I’ve been learning about these engines form friends in the race side of builds and the blocks have earned a certain reputation… still the crank spins leave it on a hot street engine.

In this engine aftermarket forged pistons are a waste of time on Factory powder rods.
This solves the problem of wrist pin diameter, change them both.

The above written to fast, so, I’ll re read it later gotta go!
E

TheBandit 07-24-2012 04:08 PM

MeanMike thanks for the reply. I follow and understand your logic, but I'm curious to know how much better alignment the shop would do over what was done at the factory already. Don't they hone the mains in the factory process anyway? Is there something inferior about how they do it or does the block just shift a lot after the first running heat cycles? Also just by doing a line hone job, isn't the machine shop disturbing things that I might not want them to? For example, opening the main bearing bores up slightly? Don't they normally cut down the caps to do a main hone or do they just run the hone through? I would much prefer a measurement to guide me on this than going in blindly running a hone through here, but I guess I'm out of luck on that front.

If I look at my old main bearings (picture here), except for the second bearing with rust issues, I didn't see any abnormal wear, for example one side worn more than another to indicate a misalignment or out of round situation. I found this photo of someone's mains which seem to indicate that kind of problem. My bearings don't show this kind of wear.


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