Food for thought on some bigger Stroker Combos 480 inch LS1
10-23-2002, 08:32 AM
#1
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Food for thought on some bigger Stroker Combos 480 inch LS1 Just thought I would throw this out. In looking at some of the stroker combos. I noticed that most folks are using a Lunati Crank w/2.100 journals. I assume this is the practical limit for the LS1 block without having to do clearancing.
But, of course the question always comes up. How much more can I get. Well, here is an idea. In a previous post MTI states that they can go 4.200 with their current sleeves. Now, this doesn't leave a lot of wall. So no big nitrous loads. But lets look at a 4.100, 4.125, 4.150, and a 4.200.
Now, we have all seen the limits of this with a 4.125 crank. But, here is an idea. Offset grind the 4.125 crank's 2.100 journal using a SBC chevy rod with a 1.888 rod bearing diameter. this will increase your stroke .212 . This will turn your 4.125 crank into a 4.337 stroke crank.
Imagine
4.1 x 4.337 = 458.08
4.125 x 4.337 = 463.68
4.150 x 4.337 = 469.32
4.200 x 4.337 = 480.69
Offset grinding the crank to a smaller bearing diameter simply moves the centerline outward. So, if a 4.125 crank fits with no issues, this will too. In fact it may fit a bit better, as the rod themselves are a bit small is diameter, etc...
This is the way folks build 360in. motors. In fact you could do the same thing with a 360 buildup. Most NASCAR teams are going with the smaller bearings as it reduces bearing speed, and frictional losses.
Now, before you go freaking out, keep in mind that 2.100 is the journal size that Top Fuel currently uses. A good forged crank should have no issues with a 1.888 size journal.
I know that an oversquare or undersquare combo isn't ideal, but I just thought I would bring up this possibility.
Just as antoher FYI on the same topic. If you were to take the typical 347 combo 3.905 x 3.6620 = 345.69
Ok, so then you take that and make a 360 out of it. 3.905 x 3.72 = 356.42
So, just go a bit more. Take and offset grind the crank to 1.888. So that the 3.6620 now becomes 3.874. 3.905 x 3.874 = 371.18. It is slighly undersquare, and could be done fairly easily...
Anyhow, just some food for thought...
<small>[ October 23, 2002, 12:29 PM: Message edited by: J-Rod ]</small>
But, of course the question always comes up. How much more can I get. Well, here is an idea. In a previous post MTI states that they can go 4.200 with their current sleeves. Now, this doesn't leave a lot of wall. So no big nitrous loads. But lets look at a 4.100, 4.125, 4.150, and a 4.200.
Now, we have all seen the limits of this with a 4.125 crank. But, here is an idea. Offset grind the 4.125 crank's 2.100 journal using a SBC chevy rod with a 1.888 rod bearing diameter. this will increase your stroke .212 . This will turn your 4.125 crank into a 4.337 stroke crank.
Imagine
4.1 x 4.337 = 458.08
4.125 x 4.337 = 463.68
4.150 x 4.337 = 469.32
4.200 x 4.337 = 480.69
Offset grinding the crank to a smaller bearing diameter simply moves the centerline outward. So, if a 4.125 crank fits with no issues, this will too. In fact it may fit a bit better, as the rod themselves are a bit small is diameter, etc...
This is the way folks build 360in. motors. In fact you could do the same thing with a 360 buildup. Most NASCAR teams are going with the smaller bearings as it reduces bearing speed, and frictional losses.
Now, before you go freaking out, keep in mind that 2.100 is the journal size that Top Fuel currently uses. A good forged crank should have no issues with a 1.888 size journal.
I know that an oversquare or undersquare combo isn't ideal, but I just thought I would bring up this possibility.
Just as antoher FYI on the same topic. If you were to take the typical 347 combo 3.905 x 3.6620 = 345.69
Ok, so then you take that and make a 360 out of it. 3.905 x 3.72 = 356.42
So, just go a bit more. Take and offset grind the crank to 1.888. So that the 3.6620 now becomes 3.874. 3.905 x 3.874 = 371.18. It is slighly undersquare, and could be done fairly easily...
Anyhow, just some food for thought...
<small>[ October 23, 2002, 12:29 PM: Message edited by: J-Rod ]</small>
10-23-2002, 03:25 PM
#2
Re: Food for thought on some bigger Stroker Combos 480 inch LS1 I think the better question is can a machine shop grind a crank like this. I think this would be an awesome solution to an expensive stroker crank. With an iron block you would net somewhere around 400 cubic inches with the stock crank.
Phillip
Phillip
10-24-2002, 07:51 AM
#3
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 Offset grinding cranks is a common process in the machine shop. It just takes someone who knows how to run a crank grinder.
As I stated ARE is doing this already to make their 360's. (2.100 to 2.000)
This is not really that hard to do. I guess nobody is intersted in this idea though...
<small>[ October 24, 2002, 08:30 AM: Message edited by: J-Rod ]</small>
As I stated ARE is doing this already to make their 360's. (2.100 to 2.000)
This is not really that hard to do. I guess nobody is intersted in this idea though...
<small>[ October 24, 2002, 08:30 AM: Message edited by: J-Rod ]</small>
10-24-2002, 08:28 AM
#4
Re: Food for thought on some bigger Stroker Combos 480 inch LS1 J-rod,
I am very interested in this. I called a local machine shop here and they said that the most you could offset grind a crank would be .100. Is there a way to get the Chevy rods/acura bearings to work in an LS1? I think that would make a kick *** 390cid+ stock crank stroker with an iron block.
phillip
I am very interested in this. I called a local machine shop here and they said that the most you could offset grind a crank would be .100. Is there a way to get the Chevy rods/acura bearings to work in an LS1? I think that would make a kick *** 390cid+ stock crank stroker with an iron block.
phillip
10-24-2002, 08:39 AM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 When you offset grind, the actual amount of stroke increase is 1/2 of the amount of offset grind, so for this case, stroke is increased by 0.106.
10-24-2002, 08:49 AM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 They are probably only used to doing it for big journal to small journal. Which is .100. Acura Rod bearings haven't made it exactly to the masses yet. But they are out there. Most rod MFGs. make rods to use either the Accura or the Quad4 bearings.
10-24-2002, 08:57 AM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 I think a bore thickness of 4.155 or greater is reaching the limits of reliability especially considering the strokes you are talking about.
(I personally wouldnt go above 4.125 bore)
cheers,
Chris
(I personally wouldnt go above 4.125 bore)
cheers,
Chris
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10-24-2002, 09:02 AM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 From Hot Rod magazine:
Bearing Sizes
The more friction you cut out of the engine, the more power you’ll make. Modern thinking includes using the smallest bearing surfaces that are practical, a feat achieved only through the use of custom crank machining and custom connecting rods. It can be applied to any other engine, though the example is of a small-block Chevy: today’s racers abandon the stock, 2.100-inch rod journals for 1.888-inch versions and use a tiny rod bearing originally intended for an Acura application. The smaller the bearing diameter, the less the friction loss through bearing speed.
I don't think this picture is the two side by side, but it went with this story.
<img src="http://64.14.193.106/p160811_image_large.jpg" alt=" - " />
As for the stroke only increasing by half. I think you have it backwards. If you offset grind the crank from 2.100 to 1.888 you would be decreasing the journal size overall by .212 which moves the centerline of the rod further out, but doesn't increase where the outside of the crank and the rod actually sit. It simply moves the centerline. Remeber, the crank swings all the way around in a circle, so you don't reduce the ammount by half.
Actually Hot-Rod magazine has a letter from someone asking this same question. This is the edition with the ZL-1 on the cover. It shows the math used to come up with this number. I will post their answer to the same question when I get home tonight.
<small>[ October 24, 2002, 09:04 AM: Message edited by: J-Rod ]</small>
Bearing Sizes
The more friction you cut out of the engine, the more power you’ll make. Modern thinking includes using the smallest bearing surfaces that are practical, a feat achieved only through the use of custom crank machining and custom connecting rods. It can be applied to any other engine, though the example is of a small-block Chevy: today’s racers abandon the stock, 2.100-inch rod journals for 1.888-inch versions and use a tiny rod bearing originally intended for an Acura application. The smaller the bearing diameter, the less the friction loss through bearing speed.
I don't think this picture is the two side by side, but it went with this story.
<img src="http://64.14.193.106/p160811_image_large.jpg" alt=" - " />
As for the stroke only increasing by half. I think you have it backwards. If you offset grind the crank from 2.100 to 1.888 you would be decreasing the journal size overall by .212 which moves the centerline of the rod further out, but doesn't increase where the outside of the crank and the rod actually sit. It simply moves the centerline. Remeber, the crank swings all the way around in a circle, so you don't reduce the ammount by half.
Actually Hot-Rod magazine has a letter from someone asking this same question. This is the edition with the ZL-1 on the cover. It shows the math used to come up with this number. I will post their answer to the same question when I get home tonight.
<small>[ October 24, 2002, 09:04 AM: Message edited by: J-Rod ]</small>
10-24-2002, 10:26 AM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 I stand corrected. You get 1/2 of the offset ground amount, but you get it on BOTH ends..... I guess I forgot that the rod goes up AND down. <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" />
10-24-2002, 04:38 PM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 Phil,
Did you get a quote on how much it would be to offset the stock crank? I'm VERY interested in this, as I'm trying to do a budget buildup (6.0L block, heads, big cam, lots of nitrous).
Did you get a quote on how much it would be to offset the stock crank? I'm VERY interested in this, as I'm trying to do a budget buildup (6.0L block, heads, big cam, lots of nitrous).
10-24-2002, 06:50 PM
#12
Re: Food for thought on some bigger Stroker Combos 480 inch LS1 wouldn't there be a point when you would have to watch out for the piston skirt hiting the crank at the botom of the stroke? this would only apply the 4.125+.212 stroke.
i am very interested in the idea on a stock crank, get an extra .212 stroke plus bore it .040, that seems like it would be prety cheep, lets say it cost $400 to do the crank(complete guess) pistons are $800? how much are rods? i have no idea on that one, do this on a 6.0 iron block and you would have a 393
4.040 x 3.832= 393
lets say the rods are $800, so for 2k you would have a 393 with forged pistons, how strong are these rods? what about the crank? will it be ok turned down that much and then throw some boost or N2O on it?
i am very interested in the idea on a stock crank, get an extra .212 stroke plus bore it .040, that seems like it would be prety cheep, lets say it cost $400 to do the crank(complete guess) pistons are $800? how much are rods? i have no idea on that one, do this on a 6.0 iron block and you would have a 393
4.040 x 3.832= 393
lets say the rods are $800, so for 2k you would have a 393 with forged pistons, how strong are these rods? what about the crank? will it be ok turned down that much and then throw some boost or N2O on it?
10-24-2002, 07:18 PM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 Food for thought guys,
I'll throw this one out to get the grey matter thinking.....
MTI (or?) 4.200" sleeved LS1 block
Lunati 4.250" stroker crank (they sell them)
Offset grind the crank to Honda (Acura)rod bearings,
that gives you 4.462" stroke....
Now it gets interesting,
4.200" bore, 4.462" stroke,
495 cubic inches!!! <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />
Can't wait to see the replies to this one...
Cheers
<small>[ October 24, 2002, 07:19 PM: Message edited by: Will Race 4 Food ]</small>
I'll throw this one out to get the grey matter thinking.....
MTI (or?) 4.200" sleeved LS1 block
Lunati 4.250" stroker crank (they sell them)
Offset grind the crank to Honda (Acura)rod bearings,
that gives you 4.462" stroke....
Now it gets interesting,
4.200" bore, 4.462" stroke,
495 cubic inches!!! <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />
Can't wait to see the replies to this one...
Cheers
<small>[ October 24, 2002, 07:19 PM: Message edited by: Will Race 4 Food ]</small>
10-24-2002, 07:34 PM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 the cost of a decent set of rods for your 1.88 rod jurnal would run yuou in the amount of 1200 bucks..
steve frank
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10-24-2002, 11:46 PM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 i have a 3.800 crank that had a 2.100 pin,i offset ground it to a 2.000 pin to gain more stroke , my stroke is now 3.850, the machining process does not work like you think it would, they cant leave one side of the journal as is and machine around it the cutter chatters and screwes it up so they have to cut metal all the way around the journal losing approx .050 of the stroke you think would be maximum. so if you were to use a honda bearing , you would be .050 smaller in stroke then what on paper would be max stroke, its a great way to add stroke for $s spent
10-25-2002, 12:06 AM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 No problem Scotty.
Chris ARE 360. This is the same procedure they used to get your 360. I gues I am simply proposing it as another budget stroker option.
Also, on big motors it would help get those extra inches everyone is always looking for.
Chris ARE 360. This is the same procedure they used to get your 360. I gues I am simply proposing it as another budget stroker option.
Also, on big motors it would help get those extra inches everyone is always looking for.
10-25-2002, 12:16 AM
#17
Re: Food for thought on some bigger Stroker Combos 480 inch LS1 I just got off the phone with Jackson auto machine here in Maryland and they can do this. You just need custom pistons setup for LS1 wrist pins and 1.888 acura rod bearings. Anyone know the cost on the rods?
Phillip
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10-25-2002, 07:15 AM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 Shirl Dickey sent me this msg over on the Corvetteforum about the big inch LS1. I thought it was important to this thread to post his comments here.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"> The combination you suggested (4.125 crank, offset ground to 4.337") is not practical... This is because the reluctor wheel and the counter weights limit rod length to 6.125" (and longer with the combination you suggest). The 4.337" stroke and 6.125" rod results in a piston compression height of only .947", and with a SBC wrist pin diameter of .927", leaves only .483" (to zero deck) for the ring pack and top ring spacing etc... There may be an engine builder out there that would specify such a piston, but I am not one of them... There is no custom piston manufacturer that would make such a piston either... I know that Ross will not build a piston with less that about 1.035" compression height and that requires a support ring under the oil ring... So until someone comes up with a tall deck LS1 case, I think your 480 cid LS1 engine is just a pipe dream... No flames intended, Your comments please...
Shirl
SD Racing Enterprises </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">So, going out all the way to 4.337 does not appear to be practical. So, I need to sit down and figure out how much stoke you can get without getting into problems with the pistons...
As for the offset grinding and crank chattering. I will have an exact answer on that a little later this morning.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"> The combination you suggested (4.125 crank, offset ground to 4.337") is not practical... This is because the reluctor wheel and the counter weights limit rod length to 6.125" (and longer with the combination you suggest). The 4.337" stroke and 6.125" rod results in a piston compression height of only .947", and with a SBC wrist pin diameter of .927", leaves only .483" (to zero deck) for the ring pack and top ring spacing etc... There may be an engine builder out there that would specify such a piston, but I am not one of them... There is no custom piston manufacturer that would make such a piston either... I know that Ross will not build a piston with less that about 1.035" compression height and that requires a support ring under the oil ring... So until someone comes up with a tall deck LS1 case, I think your 480 cid LS1 engine is just a pipe dream... No flames intended, Your comments please...
Shirl
SD Racing Enterprises </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">So, going out all the way to 4.337 does not appear to be practical. So, I need to sit down and figure out how much stoke you can get without getting into problems with the pistons...
As for the offset grinding and crank chattering. I will have an exact answer on that a little later this morning.
10-25-2002, 09:42 AM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 You can pick up Honda 1.888" rod journal Carillo or Crower rods that were used for 1 Nascar race for $500 or LESS.
http://cgi.ebay.com/ebaymotors/ws/eB...tem=1869918416
Its probably not a good idea to grind a stock cast crank down to a 1.888 rod journal size. It would probably be OK on a Forged crank.
http://cgi.ebay.com/ebaymotors/ws/eB...tem=1869918416
Its probably not a good idea to grind a stock cast crank down to a 1.888 rod journal size. It would probably be OK on a Forged crank.
10-25-2002, 01:19 PM
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Re: Food for thought on some bigger Stroker Combos 480 inch LS1 </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"> ... I know that Ross will not build a piston with less that about 1.035" compression height and that requires a support ring under the oil ring...
Shirl
SD Racing Enterprises </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">You can relay to Shirl that is B/S, I have a set of custom Ross pistons in my hands that have a comp height of .975"
Shirl
SD Racing Enterprises </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">You can relay to Shirl that is B/S, I have a set of custom Ross pistons in my hands that have a comp height of .975"