RyanJ

Look at all this GREAT info <img src="gr_grin.gif" border="0"> lets keep the discussion going. this isnt just about my car guys. lets get some more ideas going.

how much is it to Offset-Grind a stock LS1 crank? can you still use stock rods? difference in LS1 and LQ4 cranks? Other shops people have used to port heads, other than the big 3...errr 5?


Ryan

Black Sunshine/ 00SS

iTrader: (1)

Someone help me with my math.. What is the max it can be safely punched out .060? How many cubes does that work out to be? Also, what would be the estimated power of this motor? Assuming that the cam idle is comparable to the T1.
I'd go with the 6.0 block, .060 over, stock rods & crank, ARE stage II heads, slightly aggresive cam, I'm guessing I could get to the 9's with that motor & a small 200 shot... Should be making around 500 without the shot. Hmmm. <img src="gr_eek2.gif" border="0">

RyanJ

Starting with a stock 4.000"-bore truck block (stock LS1 stroke is 3.622):

+.030 = 370cid
+.060 = 375cid

+.030, Offset ground crank (3.71-stroke) = 379cid
+.060, " " " = 384cid

+.030, 3.9" stroke = 398
+.030, 4" stroke = 408

+.060, 3.9" stroke = 403
+.060, 4" stroke = 414


BlackSunshine....with good pistons and rods a 370 cube motor will get you where you want provided you have a GOOD drivetrain and strong heads/cam. should easily handle 200+ hp N2O.


Ryan

Z00

Do you have to resleeve the 6.0l block to bore it out as well?

RyanJ

No, but 4.060 is about as far as you wanna go with the iron blocks. $$resleeved aluminum blocks$$ will go 4.100 or a little more.

2quick4u

[quote]Originally posted by racer7088:
<strong>""I started a thread about sticking SBC pistons in our blocks.""

I didn't see that one but the regular SBC valve reliefs aren't right for an LS1.</strong><hr></blockquote>

That's true, but they are not needed on a cheap buildup LS1 anyhow. The stock flattop LS1 piston has no valve reliefs. The fattop pistons for the SBC have valve reliefs cut for 23 degree valves, but you won't need the valve reliefs on an LS1 if you stay with a reasonable cam and flattop pistons. However the LS1 piston is a short skirt design. So the SBC piston skirts may have to be ground for clearance if the are the factory long skirt design. Also if they are factory SBC cast, they will have steel struts in the barrel and skirts to prevent piston expansion.

However, if you found a really good deal on a set of used SBC forged 4.030-4.060" flattop pistons at a swap meet with the right compression height and short skirts, they just might work in a cheapie buildup LS1. Also look for used aftermarket SBC 6.125" rods at a swapmeet.

BTW: what SBC piston did you end up going with on your 375 cid Terry B.?

RyanJ

Terry used custom forged pistons.

hopefully i will be able to find an inexpensive alternative to custom pistons in the Speed Pro catalog.


Ryan

-Joseph-

iTrader: (12)

I did find some SBC pistons that would work with the 4.030" bore, 4" stroke combination with 6.125" rods. Its a off-the-shelf pistons and all manufacturers should have something relatively close. Didn't write down the part numbers, but by application its for a SBC 383cid---4.030" Bore, 3.75" stroke, 6" connecting rods. I believe the compression height I came up with was about .112". It may stick out of the bore a little more than .010" though, which should be fine with a .055" head gasket thinkness---In fact I run my Gen 1+2 SBC engines with a .040" clearance between the top of the piston and the bottom of the cylinder head <img src="gr_images/icons/wink.gif" border="0">
I knew about the 23 deg valve angle of coarse by using these pistons, I agree with John though, as the stock LS1 pistons do not have valve reliefs. What is the limit on valve lift with stock pistons?
BTW here is a pic of Jason's 6.0L pistons that we ordered in, they are the LQ9 Escalade pistons (10-1) LQ9 on the left, LQ4 on the right <img src="gr_stretch.gif" border="0">


[ December 12, 2001: Message edited by: Joseph ]</p>

racer7088

If you don't have valve reliefs then you will start limiting the power you can make pretty fast. You will also have problems if you over rev and have the wrong reliefs. There's a few guys on this board that know this already the hard way! Why build some motor like this that has no P to V or will blow up easily if you do anything wrong? It's not much of a budget deal then is it?
<img src="images/icons/rolleyes.gif" border="0">

2quick4u

[quote]Originally posted by racer7088:
<strong>If you don't have valve reliefs then you will start limiting the power you can make pretty fast. You will also have problems if you over rev and have the wrong reliefs. There's a few guys on this board that know this already the hard way! Why build some motor like this that has no P to V or will blow up easily if you do anything wrong? It's not much of a budget deal then is it?
<img src="images/icons/rolleyes.gif" border="0"> </strong><hr></blockquote>

There are plenty of people on this board making good power with stock flattop pistons without valve reliefs. The LS1s that are using valve reliefs are the rare exception and are high $$$ race oriented motors for the most part. Flattops will give you all the compression you need on a street car (11.25:1 compression can easily be achieved with flattops) and if you run a cam big enough to NEED the reliefs then its probably not much of a street car anyway IMO. The whole point of this thread is to build a large displacement, medium output, street engine on the cheap. That means new custom LS1 forged pistons with valve reliefs is out. If you really need more piston to valve clearance, you can always pick a piston with a compression height that will give you a positive piston to deck clearance. This will buy you some valve clearance without going to valve reliefs, although you will loose some compression.

BTW: Plenty of companies make forged pistons for the SBC with 15 deg valve reliefs anyway.

[ December 13, 2001: Message edited by: 2quick4u ]</p>

2quick4u

[quote]Originally posted by Pro Stock John:
<strong>I am a fan of valve reliefs. <img src="gr_stretch.gif" border="0"> </strong><hr></blockquote>

That's becuase you are a fan of big *** lumpy radical cams too. <img src="gr_tounge.gif" border="0">

BTW: since when have you ever done anything on the cheap? <img src="gr_grin.gif" border="0">

Pro Stock John

iTrader: (34)

LOL.

I've been trying to get Nick from ARE to visit this thread, he said he'll try to check it out tonite.

But for example my 6.0 block is .060 over. ARE is doing .040 all the time, but they find that a few blocks can safely go to .060 due to core shift.

Black Sunshine/ 00SS

iTrader: (1)

Makes the cost of custom pistons a little more justified, doesn't it? There has to be an off the shelf that can fit the bill, with little or no reqired modifications. I'd be trying to spray as much as I "safely" can, so I'm thinking I would need custom anyway, but I dam sure want to make sure that I dont get P-V contact, <img src="graemlins/gr_cheers.gif" border="0" alt="[cheers]" />

Pro Stock John

iTrader: (34)

Regarding piston pricing, for forged, we are talking like $350-400 for OffTheShelf and $600 for LS1 Ross or JE's from a vendor like ARE. I am a fan of valve reliefs. <img src="gr_stretch.gif" border="0">

Ebbsnflows

iTrader: (15)

I'm not sure if your "Budget Buildup" only consists of NEW parts....but I chose the "used parts" route to save $$. Everything on my car (Heads/Cam/p-rods/LS6 intake/Lid/N20/injectors...blah-blah), I bought "used". My FLP's are the only thing I bought new...and I got a very "sweet" deal on those.

You can make 410+ rwhp N/A (EASILY) for less than $2100 if you shop around in the Classifieds.

racer7088

""BTW: Plenty of companies make forged pistons for the SBC with 15 deg valve reliefs anyway.""

You'll have to get a set of all left intake pistons though and the 15 degree GM head still may not be in the right place. You're right that if you keep lift low you should be alright. But you better check and use good valave springs.

Slow Z28

iTrader: (19)

ttt cause i like this discussion

Black Sunshine/ 00SS

iTrader: (1)

Do the truck heads tend to run cheaper than the LS6? What's the estimated total cost, to build this engine, forged pistons, stock rods, with ARP bolts, stock crank?

Slow Z28

iTrader: (19)

hey,
i just made a post about that "help me build a motor" cause i'm interested in doing probably the same thing you are doing. as for heads brand new, i checked www.gmpartsdirect.com or whatever it is and they sell for about $750. odn't know if that was for one or the pair of them. i just went off of Jason's part #'s.

Chris

Terry Burger

iTrader: (4)

I have a great iron block 375ci motor with light weight forged pistons, good rods, new bearings etc for sale at MMS. They are just waiting for a crank core to come in before they can put it together. The motor is 3k outright. Sell your alum shortblock for $1500 and you get another 30 cubic inches in a forged motor for only $1500. <img src="gr_images/icons/wink.gif" border="0">