LQ4 Build - Machining Questions
05-10-2022, 02:08 PM
#21
TECH Fanatic
Which episode and which show was that on? A 6.0L Block ready to go for 700 bucks would be a deal and a half in today's world.
Last time I looked around, Texas Speed's site said that the gen III blocks were not available, so they only had gen IV blocks for build your own short block setups.
Here's Summit's current offering for GM LS bare blocks.
05-11-2022, 07:10 AM
#22
Thanks, I''ll definitely look into that.
Another question - I considered using just a ball hone to freshen up this block, but I'd rather take it to an actual machine shop. What is the maximum amount of material that can be honed while still being able to use the stock (or stock size) pistons? I've been researching this, but I'm not finding a clear answer. Of course, the machine shop will know how much has to be honed when they receive the block, but I'm hoping I can reuse the stock pistons
Another question - I considered using just a ball hone to freshen up this block, but I'd rather take it to an actual machine shop. What is the maximum amount of material that can be honed while still being able to use the stock (or stock size) pistons? I've been researching this, but I'm not finding a clear answer. Of course, the machine shop will know how much has to be honed when they receive the block, but I'm hoping I can reuse the stock pistons
05-11-2022, 09:32 AM
#23
I would guess most people who do this never measure before and after. And not sure that it would show a difference unless you went crazy(which would the wrong way to do it). Its a process of putting controlled scratches/surface texture on the wall so oil clings better. So there will be microscopic peaks and valleys, but its unlikely that your bore mic will sink into the valley and detect any difference.
Or is the better option going to a machine shop? Is it worth paying extra for the magnaflux on an iron block, or torque plate? Sorry for all the noob questions
05-11-2022, 10:33 AM
#24
You could just reassemble it as it was and be just fine, no need to have even taken it apart unless you just wanted to spend extra money for.... some reason?
Having a 200K mile engine that is known to go passed 400K if maintained, and putting it in a truck that will only be driven on the occasional weekend means it would literally last FOREVER.
Clean the outside, paint it up, obviously use new gaskets when assembling and no body will ever know you didnt spend $2500 rebuilding it.
Just my experience, and that's if it looked fairly well maintained when taking it apart. (No sludge or flaking burnt oil on internal parts)
Having a 200K mile engine that is known to go passed 400K if maintained, and putting it in a truck that will only be driven on the occasional weekend means it would literally last FOREVER.
Clean the outside, paint it up, obviously use new gaskets when assembling and no body will ever know you didnt spend $2500 rebuilding it.
Just my experience, and that's if it looked fairly well maintained when taking it apart. (No sludge or flaking burnt oil on internal parts)
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G Atsma (05-11-2022)
05-11-2022, 03:15 PM
#25
11 Second Club
iTrader: (3)
I seriously doubt there would be a problem running the stock pistons after a run through each bore with a FLEXHONE and why in the world would you go with a stock small bore head on the 4.00 bore block? Keep the 317's and mill them to get the compression up if that's your end goal or just invest into some 243/799's.
05-11-2022, 05:39 PM
#26
ModSquad
iTrader: (6)
You’d have to spend literally minutes in each hole, to remove enough material with a ball hone, to matter. I ball hone dry, but some use oil. Make 4-5 passes with the hone per hole, and your good. You won’t remove any material, just etching the cylinder surface, for ring seal. If you happen to have a junk block laying around, try a practice hole first.
05-11-2022, 10:37 PM
#27
Ok guys, I'm getting super confused on the correct route to take on this engine as far as honing vs boring. I plan to drop off the block at a machine shop this week and have them check it. If possible, I would just like it honed and nothing more. If it needs more than that, I'll address that. But if they are able to just do a quick hone to add crosshatch, check the cylinders for roundness, etc, can I reuse stock pistons and stock size rings? I have gotten like 10 different answers on this. Ws6 store says I need to bore to .030 over and put in oversize pistons, and others are saying to run it as is with just a quick hone.
05-11-2022, 11:31 PM
#28
TECH Fanatic
Let the machine shop tell you what size the bores end up with, odds are (hopefully) they've done this a few times and can advise you. It's easy to get caught up in the guessing game of piston and bore sizes, but realistically the machine shop is where the magic happens.
05-11-2022, 11:44 PM
#29
Let the machine shop tell you what size the bores end up with, odds are (hopefully) they've done this a few times and can advise you. It's easy to get caught up in the guessing game of piston and bore sizes, but realistically the machine shop is where the magic happens.
05-11-2022, 11:51 PM
#30
TECH Fanatic
The machine shop is the place that controls the finish dimensions, ask them to size the bores to a safe dimension that allows for a good choice of pistons.
I would never buy any part of the rotating assembly before I had a finished block. just my .02.
I would never buy any part of the rotating assembly before I had a finished block. just my .02.
05-12-2022, 06:24 AM
#31
As @theunderlord said, I'd find out what the block needs before ordering pistons.
1) I have an LS2 block that seemed good to go with standard diameter pistons. When checked it needed to go .010 over to clean up a nick in one cylinder. Best to know what you have to work with before getting parts in my opinion and experience.
2) NA heads are critical, so I pick heads then intake once knowing block is good. Everything thing else determined with that in mind.
3) Seen way too many slow sucky "425hp" 350 Small Block Chevy engines dyno 220 whp with awesome forged internals and junk cylinder heads slapped on top because owner blew the budget on an incredible forged rotating assembly, built a motor that's done for at 5,000 rpm 😀 😄 😉 It's even sadder with the 250whp forged 454 big blocks.
1) I have an LS2 block that seemed good to go with standard diameter pistons. When checked it needed to go .010 over to clean up a nick in one cylinder. Best to know what you have to work with before getting parts in my opinion and experience.
2) NA heads are critical, so I pick heads then intake once knowing block is good. Everything thing else determined with that in mind.
3) Seen way too many slow sucky "425hp" 350 Small Block Chevy engines dyno 220 whp with awesome forged internals and junk cylinder heads slapped on top because owner blew the budget on an incredible forged rotating assembly, built a motor that's done for at 5,000 rpm 😀 😄 😉 It's even sadder with the 250whp forged 454 big blocks.
Last edited by 99 Black Bird T/A; 05-12-2022 at 06:29 AM.
05-12-2022, 09:54 AM
#32
ModSquad
iTrader: (6)
As @theunderlord said, I'd find out what the block needs before ordering pistons.
1) I have an LS2 block that seemed good to go with standard diameter pistons. When checked it needed to go .010 over to clean up a nick in one cylinder. Best to know what you have to work with before getting parts in my opinion and experience.
2) NA heads are critical, so I pick heads then intake once knowing block is good. Everything thing else determined with that in mind.
3) Seen way too many slow sucky "425hp" 350 Small Block Chevy engines dyno 220 whp with awesome forged internals and junk cylinder heads slapped on top because owner blew the budget on an incredible forged rotating assembly, built a motor that's done for at 5,000 rpm 😀 😄 😉 It's even sadder with the 250whp forged 454 big blocks.
1) I have an LS2 block that seemed good to go with standard diameter pistons. When checked it needed to go .010 over to clean up a nick in one cylinder. Best to know what you have to work with before getting parts in my opinion and experience.
2) NA heads are critical, so I pick heads then intake once knowing block is good. Everything thing else determined with that in mind.
3) Seen way too many slow sucky "425hp" 350 Small Block Chevy engines dyno 220 whp with awesome forged internals and junk cylinder heads slapped on top because owner blew the budget on an incredible forged rotating assembly, built a motor that's done for at 5,000 rpm 😀 😄 😉 It's even sadder with the 250whp forged 454 big blocks.
The following 2 users liked this post by Che70velle:
01CamaroSSTx (05-12-2022), theunderlord (05-12-2022)
05-12-2022, 10:57 AM
#33
11 Second Club
iTrader: (3)
Either you mic the pistons and measure the cylinder bores yourself to determine if you have the proper P-W or send them and the block to a reputable machine shop to be checked out. Typically when you order new pistons they'll call for the bore size needed to achieve proper P-W clearance and depending on the piston material and the engine's intended use those numbers are subjective. It is true that parts made today are more precisely made than those of the olden days but I'd still send them and the block to the machine shop if I'm having to bore and hone a block.
05-12-2022, 03:52 PM
#34
Normally a shop will want to bore and hone at the same time, even if it takes 2 separate machines as sometimes they set them up or a day aside to do those jobs at once or like an assembly line. Having them bore now and hone to spec later, they usually charge more and you wait quite a while longer. Most machine shops will be able to let you know how much material itll take to "clean up" bur ive never wanted just a clean up. I go to the shop with a plan and they do what i ask. 4.030 is the first standard minimum bore. Max is really in the 4.070 range but varies year by year and block by block. So you have plenty of material to work with.
900 seems very high for what they are wanting to do.
A dingle ball hone will only prepare a surface. It may "fix" a few imperfections but will not fix cylinder taper or bore outof round. I would never recommend it as there are always more reliable and better ways to get it done that really are not that much more expensive.
I realize in all builds, you get the itch to get it done. Its best to calm that impulse down and make a plan, have the parts in hand, and go to the shop with all of it.
If you need an undersize bearing for the crank being turned or an oversize piston vs what you have, we can get them swapped out very easily also, no hassle there AS LONG AS THE OTHER PARTS ARE AVAILABLE. I dont like to have a disclaimer like that but its very necessary now sadly.
900 seems very high for what they are wanting to do.
A dingle ball hone will only prepare a surface. It may "fix" a few imperfections but will not fix cylinder taper or bore outof round. I would never recommend it as there are always more reliable and better ways to get it done that really are not that much more expensive.
I realize in all builds, you get the itch to get it done. Its best to calm that impulse down and make a plan, have the parts in hand, and go to the shop with all of it.
If you need an undersize bearing for the crank being turned or an oversize piston vs what you have, we can get them swapped out very easily also, no hassle there AS LONG AS THE OTHER PARTS ARE AVAILABLE. I dont like to have a disclaimer like that but its very necessary now sadly.
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G Atsma (05-12-2022)
06-11-2022, 10:26 AM
#35
Ok, I picked up my block from the machine shop yesterday. Ended up doing cam bearings, hot tank, deck, and hone. The shop checked for taper and out of round, and said there was really no reason to bore for what I am wanting to do, which I agreed with. So now, I'm ready to order the rpmspeed rebuild kit.
My question is this - is it worth putting in a factory size flat top piston that comes with the kit? Or reuse factory? It seems like a minimal cost to add, will bump up the compression a little, and will save time from cleaning up the old pistons, etc. Lmk what you think I should do.
My question is this - is it worth putting in a factory size flat top piston that comes with the kit? Or reuse factory? It seems like a minimal cost to add, will bump up the compression a little, and will save time from cleaning up the old pistons, etc. Lmk what you think I should do.
06-11-2022, 06:07 PM
#37
06-13-2022, 11:09 AM
#38
For me, getting compression up is always a priority. Even with flat tops, 317s would just get you to 10:1.
I would strongly consider flat tops (something aftermarket with valve reliefs, if you can budget it) and then mill the heads, or get better heads.
Most people want more compression, especially more than the stock 9.5 that a LQ4 makes. In your truck, most people are going to want to be between 10 and 11 to 1. And most people like the ability to run whatever cam they want without concern with valve to piston clearance.
But, if you know your goals and don't think they will change, then you don't necessarily need to go to those steps. Flat tops and milled 317 heads would get up to around 10.3-10.5:1, and would support a reasonable cam.
I would strongly consider flat tops (something aftermarket with valve reliefs, if you can budget it) and then mill the heads, or get better heads.
Most people want more compression, especially more than the stock 9.5 that a LQ4 makes. In your truck, most people are going to want to be between 10 and 11 to 1. And most people like the ability to run whatever cam they want without concern with valve to piston clearance.
But, if you know your goals and don't think they will change, then you don't necessarily need to go to those steps. Flat tops and milled 317 heads would get up to around 10.3-10.5:1, and would support a reasonable cam.
06-21-2022, 09:13 PM
#39
Hey, if your doing a tear down, fyi.. Ls2 pistons are what the lq9 have. So if you find someone who swapped their factory LS2 pistons for forged ones, I've snagged ls2 pistons for $100-150 shipped in past. Worth a good 10hp.
Hi,
I bought an lq4 a couple weeks ago pulled from an '02 2500hd. I have it torn down completely to the block and have some machining questions I'm hoping to find the answers to. This is my first full engine rebuild, so I apologize if these questions seem super basic. Here's what I'm trying to figure out:
1. I will be reusing the stock pistons, new rings and rod bearings of course. The cylinder walls appear to be in great shape and should be fine with a light hone I believe. How do I ensure that the machine shop stays within spec and does not hone too far? How would I go about selecting a ring size to fit this, or would you use factory rings?
2. On an iron block ls, what else must be checked when at the machine shop? Does the block need to be decked no matter what, or can I just use the straight edge method? I plan on having them do cam bearings, hone, and hot tank the block. Is there anything else that's absolutely necessary for a basic rebuild?
3. Help me pick which heads to go with - has stock 317s and I am looking for cheap, readily available heads to find at the junkyard. I'm thinking 5.3 706 heads, but are there any reasons this would not be a good choice? Would any porting/machining be recommended for 706 heads, or are they ok in factory form?
3.1. I have pretty much decided on a cam - SUMMIT 8713R - however, this was chosen based on 317 heads and is what summit recommended for my application. However, would this still perform well with 5.3 heads?
4. Injectors & Throttle body - This may be difficult to answer, due to differences in tuning and other things, but based on other info given, what size injectors would you predict I would need for that cam? I assume stock lq4 injectors would be close to maxed out, but would they still be ok possibly? Throttle Body - going to be running the stock truck intake (shaved). Is there a throttle body that will fit it that's actually worth upgrading to?
I apologize in advance if these have been answered. I researched like crazy, and these are the last couple questions I'm looking for some help on. Thanks
I bought an lq4 a couple weeks ago pulled from an '02 2500hd. I have it torn down completely to the block and have some machining questions I'm hoping to find the answers to. This is my first full engine rebuild, so I apologize if these questions seem super basic. Here's what I'm trying to figure out:
1. I will be reusing the stock pistons, new rings and rod bearings of course. The cylinder walls appear to be in great shape and should be fine with a light hone I believe. How do I ensure that the machine shop stays within spec and does not hone too far? How would I go about selecting a ring size to fit this, or would you use factory rings?
2. On an iron block ls, what else must be checked when at the machine shop? Does the block need to be decked no matter what, or can I just use the straight edge method? I plan on having them do cam bearings, hone, and hot tank the block. Is there anything else that's absolutely necessary for a basic rebuild?
3. Help me pick which heads to go with - has stock 317s and I am looking for cheap, readily available heads to find at the junkyard. I'm thinking 5.3 706 heads, but are there any reasons this would not be a good choice? Would any porting/machining be recommended for 706 heads, or are they ok in factory form?
3.1. I have pretty much decided on a cam - SUMMIT 8713R - however, this was chosen based on 317 heads and is what summit recommended for my application. However, would this still perform well with 5.3 heads?
4. Injectors & Throttle body - This may be difficult to answer, due to differences in tuning and other things, but based on other info given, what size injectors would you predict I would need for that cam? I assume stock lq4 injectors would be close to maxed out, but would they still be ok possibly? Throttle Body - going to be running the stock truck intake (shaved). Is there a throttle body that will fit it that's actually worth upgrading to?
I apologize in advance if these have been answered. I researched like crazy, and these are the last couple questions I'm looking for some help on. Thanks