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I asked this question if someone this question on ls1gto and they said it works because the liners have the rest of the aluminum block around them.
That doesn't really make any sense.
1) what would the aluminum behind the liners have anything to do with the liner strength?
2) given the same bore spacing (which all Gen 3/4 blocks have) a 5.3 liner bored out to 4.000 (with 0.080 thickness) is going to have the same amount of aluminum behind it as a 6.0 liner that comes stock at 4.000 bore (with 0.080 thickness).
1) what would the aluminum behind the liners have anything to do with the liner strength?
2) given the same bore spacing (which all Gen 3/4 blocks have) a 5.3 liner bored out to 4.000 (with 0.080 thickness) is going to have the same amount of aluminum behind it as a 6.0 liner that comes stock at 4.000 bore (with 0.080 thickness).
On the aluminum block, you will have say .080 liner plus probly .200 (guesstimate) surrounding the liner in the block.
Vs cast you don't have a liner, the liner and the material around it is cast the same. Regardless I'm excited to get this thing tested and see the professional results. If I can keep the thinnest thrust wall around .120 and above I'm doing it.
Cwarta, throughout this thread, everybody (including myself) have assumed you're working with an aluminum 5.3 block. Is this the case? I ask because the majority of 5.3 blocks are iron.
Having said this, an iron block 5.3 can be safely bored from 3.78 inches to 3.90 inches. An aluminum 5.3 can be safely bored from 3.78 inches to 3.79 inches.
The aluminum 5.3 blocks have some of the thinnest cast-in-place sleeves of all LS engines. You won't get very far before rendering the block useless,
If you try to go too far with boring any aluminum LS block (except the LS7 block) this is what your sleeves will look like:
Cwarta, throughout this thread, everybody (including myself) have assumed you're working with an aluminum 5.3 block. Is this the case? I ask because the majority of 5.3 blocks are iron.
Having said this, an iron block 5.3 can be safely bored from 3.78 inches to 3.90 inches. An aluminum 5.3 can be safely bored from 3.78 inches to 3.79 inches.
The aluminum 5.3 blocks have some of the thinnest cast-in-place sleeves of all LS engines. You won't get very far before rendering the block useless,
If you try to go too far with boring any aluminum LS block (except the LS7 block) this is what your sleeves will look like:
I appologise fur the confusion, I have a 99 cast iron block I'm looking to do this with.
On a build such as this, we're cylinder walls are thinner than desirable, is there any advantage to going to a 160tstat to help the walls stay a little cooler?
Ignore Paul, some of his comments are intelligent and some are based off...well I don't know where he gets his information sometimes.
First, if you're dealing with a 99 casting, would you mind telling me what numbers are cast into the block. On early castings of the iron LS, GM used a base cast for all 3 blocks. These had 4.8 and 5.3 cast side by side and 6.0 cast directly below. These blocks are rare, but I have found 2 thus far at my local pick-a-part. They can safely be bored to 4.000+ due to the fact that they were designed to be able to be used for all 3, just a final bore and hone from the factory determined it's output.
Later 5.3 with just he 4.8/5.3 casting I have found to be less forgiving with regards to overboring in relation to core shift. Some with minor core shift were able to be taken out to ~3.940 and still leave enough meat for me to consider power adder worthy (think in the .180 wall range). Others, not so much as they might afford me what you are seeing with only a stockish 3.905 bore. You are doing the right thing by sonic checking, and I wouldn't be worried with a minimum of .100 on the thrust sides for a mild DD engine though I wouldn't go lower.
As far as the aluminum blocks, I have seen these vary by generation. Machinistone is correct about the gen IV, as the liners in those are stout and I haven't seen one yet that wouldn't be fine at a modest 3.905 overbore. They were after all based on the same castings as the larger bores with the same liners, just underbored. The L33 blocks I have seen vary a bit more, perhaps due to technique or casting changes. I sold one last year that if bored to LS1 specs would have still left ~.230ish wall thickness on the thrust sides so in all reality it could have easily gone over another .030 to .040 thou and still been safe for a moderate street build. Now this is assuming there are no imperfections in the factory liners once bored to those conditions.
The facts people are finding are that depending on the casting/core shift, many are safely able to go over what as been repeated religiously about the orginal 98-99 LS1 castings that were literally only able to go .007-.010 over which just isn't the case anymore. Good luck, I hope to see your build come to fruition.
My participation and advise on this and several other automotive enthusiasts forums are based on several decades of personal experience, automotive industry publications and maintenance guides, regular contact with high performance engine and transmission shops and occasional off-forum interactions with other forum members.
My advise not go past a 3.79 inch bore on a aluminum 5.3 block is in line with accepted industry practices of experienced machine shops, the GM specification as well as several non-GM publications. Nothing I’ve posted in this (or any other thread) is anything that can’t be researched and discovered by pretty much anybody. The very small overbore limit GM puts on this block is because they do use a thinner sleeve. Of course, variations from venders and component availability dictates that some blocks will be more forgiving of bigger overboreing.
No competent machine shop will tell you that the aluminum 5.3 can be bored beyond 3.79 inches. If they agree to attempt it, they’ll want full payment first and offer no guarantee that it’ll work.
Machinishop, you may have had good luck doing so (and I greatly respect your experience and participation here) but I know a shop that’s attempted it twice only to hit the sleeves outer ribbing. The better advise to somebody spending his hard earned money is to steer them away from boring a 5.3 this far.
Mr. Sausage, it would be more appropriate for you to say “so-and-so may be off a bit here, here’s my experience...” rather than saying “ignore him”. Nobody here knows where you (or anybody else for that matter) gets your information either. Please, do share your experiences but don't tell others to outright ignore other people's experiences and advise. While it is true that some folks around here give advise when they shouldn't, you should be aware that my advise is researched, educated and adult.
Advising anybody that it’s OK to bore this block well beyond it’s specified limit is bad advise-and could be costly to the guys reading this advise.
When giving advise on a public forum, it behooves us all to be as accurate as possible. Incorrect advise may be costly to less experienced folks just coming into the world of motorsports and will leave a bad taste in their mouths.
My advise not go past a 3.79 inch bore on a aluminum 5.3 block is in line with accepted industry practices of experienced machine shops, the GM specification as well as several non-GM publications. Nothing I’ve posted in this (or any other thread) is anything that can’t be researched and discovered by pretty much anybody. The very small overbore limit GM puts on this block is because they do use a thinner sleeve. Of course, variations from venders and component availability dictates that some blocks will be more forgiving of bigger overboreing.
No competent machine shop will tell you that the aluminum 5.3 can be bored beyond 3.79 inches. If they agree to attempt it, they’ll want full payment first and offer no guarantee that it’ll work.
First, if you've had such "extensive" experience with this line, you wouldn't have posted that misinformation to begin with. Second, please tell me the names of the aforementioned shops. Thirdly, you must be disregarding pretty much every "competent" vendor on this forum. I've yet to see any of them say that an aluminum 5.3 block can at most be taken to only .010 over. The most I have seen regarding the issue is to have the block checked.
You're either confusing the information widely circulated about the 5.7, that really had a very thin liner, with the 5.3 blocks or you really don't have a clue for what you speak. The LM4/L33 variants are known to have the same thickness liners as an LS6 when bored the same. As far as the "no competent machine shop" comment, I'll relate that next time I have ProLine do machine work for me. Not once was that comment stated, nor was an eyelash batted, in regards to the (2) L33s I've done in the past. Better yet, they didn't request a dime from me until machine work was complete and I arrived for pickup.
I've sonic checked several 6.0L blocks, most have .100 - .120 between cylinders, about the same as you now have on thrust and nonthrust, several even thicker. I wouldn't push it, you'll be well under .150 on thrust surfaces which is the absolute minimum most competent builders will use.
My participation and advise on this and several other automotive enthusiasts forums are based on several decades of personal experience, automotive industry publications and maintenance guides, regular contact with high performance engine and transmission shops and occasional off-forum interactions with other forum members.
My advise not go past a 3.79 inch bore on a aluminum 5.3 block is in line with accepted industry practices of experienced machine shops, the GM specification as well as several non-GM publications. Nothing I’ve posted in this (or any other thread) is anything that can’t be researched and discovered by pretty much anybody. The very small overbore limit GM puts on this block is because they do use a thinner sleeve. Of course, variations from venders and component availability dictates that some blocks will be more forgiving of bigger overboreing.
No competent machine shop will tell you that the aluminum 5.3 can be bored beyond 3.79 inches. If they agree to attempt it, they’ll want full payment first and offer no guarantee that it’ll work.
Machinishop, you may have had good luck doing so (and I greatly respect your experience and participation here) but I know a shop that’s attempted it twice only to hit the sleeves outer ribbing. The better advise to somebody spending his hard earned money is to steer them away from boring a 5.3 this far.
Mr. Sausage, it would be more appropriate for you to say “so-and-so may be off a bit here, here’s my experience...” rather than saying “ignore him”. Nobody here knows where you (or anybody else for that matter) gets your information either. Please, do share your experiences but don't tell others to outright ignore other people's experiences and advise. While it is true that some folks around here give advise when they shouldn't, you should be aware that my advise is researched, educated and adult.
Advising anybody that it’s OK to bore this block well beyond it’s specified limit is bad advise-and could be costly to the guys reading this advise.
When giving advise on a public forum, it behooves us all to be as accurate as possible. Incorrect advise may be costly to less experienced folks just coming into the world of motorsports and will leave a bad taste in their mouths.
I'll put it very simply, you're ignorant on this subject, and on top of that I don't appreciate the insinuation that I don't have a competent machine shop because I state that in fact there are 5.3L blocks with incredibly thick liners which can be bored to LS1 bore size and beyond.
My personal experience in relation to this subject involves measuring liner thickness with a caliper, sonic checking these blocks personally, boring them oversize to the point where the liners break apart, and re-sleeving these blocks as well. It is a fact based upon these measurements done by myself and plenty of other machinists that the L33 & LM4 aluminum 5.3L blocks have the same liner as the LS1/LS6 for the simple reason of GM choosing to have less castings to make similar motors. The LH6 aluminum 5.3L blocks have even thicker liners.
Do you own a machine shop? Are you a professionally trained machinist or engine builder? Have you personally had an LH6 block in front of you to inspect liner thickness?
Irregardless, you are completely ignoring the fact that this guy has posted the sonic test data from his block, if he did that properly and roughly backed it up with a measurement by a set of veniers that his cast liner thickness is in the .250"-.300" range then you don't have a leg to stand on with your proclamations of knowing more than those of us who have actually "been there and done that."
Originally Posted by Cwarta
Machinestone, you always have great, intelligent posts I can count on to be true. What would you say the bare minim wall thickness should be ?
If it was a production cast iron block for an NA application, then I would say .150" on the thrusts would make me feel good for a daily driven performance motor. For race only applications I've had cheater motors with no aftermarket source with a half fill and only .090" on the thrusts...they worked ok.
For an aluminum block you have a significant amount of aluminum backing up the sleeve and giving it rigidity, so you don't need quite as thick a liner, there's even blocks being used right now that don't even have a cast sleeve so the piston rides right on the specially processed aluminum, I have honed a couple of those blocks. That being said I still would not want to go less than .125" minimum due to the issues of core shift with the GM manufactured blocks, keeping liner thickness also makes honing them perfectly to size and shape easier.
Just thought I would update this. Just left the machine shop awhile ago, and I stayed there while he sonic tested the block. The results were almost perfect with mine. I was at most .003 off on 1 the rest were within .002 or .001 of my readings. My builder and I are confident that this block will meet my needs just fine NA. I also started a build thread if anyone is interested.
I'm in the middle of the new build for the Gto, and were building a completely new engine. I originally was planing a 5.3 turbo build, but have since decided on a max effort N/A setup 6.0.
I work at a well drilling company and we have precision instruments to measure well casings thickness. I used the cast calibration, and tested all 8 cylinders, ran the instrument over every inch of that cylinder and recorded the thinnest # for each "side"
In a week I will be having the block professionally sonic tested to compare with my results. As a test method I checked a few places on the block with both the calipers and this wall thickness tester. The calipers showed .010 THICKER than the tester did, so take that for what it's worth.
These are my results, please excuse my poorly drawn paper. Ill be attempting a bore from 3.780 to 4.00.
Here is a chart I go by for the max "Recommended" overbore. The only exception is the rare block that says 4.8/5.3/6.0 on it. It can be bored a tad over 4.000"
06-30-2013, 12:57 PM
