Forged short block

Author
Discussion

Gelf VXR

Original Poster:

713 posts

206 months

Friday 27th May 2016
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For those going forged bottom end or short block, what is your route and source for parts?

Ive spoke to Roger about engine out and a 416 stroker rebuild, cost is very prohibitive, much more than below, ill consider to do the grunt work myself. Build rest of the engine first, pull swap out the LS2 and sell that to help finance the project.

My goals are NA daily driver with a lot of grunt, Ive got Mast 240cc heads with 2.165 valves (not 2.08), max rpm 6400, I don't want a dry sump, Ill get custom cam from FTI.

I'm thinking about importing a short block, either a LS7 or a dry sleeved 427ci LS3 (overkill?) The ERL is solid and leaves room on the table

Mast mahle/compstar LS7 427 = 7500 USD

Texas speed mahle/compstar LS7 427 = 7350 USD

cnc motorsports mahle/eagle LS7 427 = 6100 USD

ERL dry sleeve weisco/compstar LS3 416/427 = 7900 USD

Any thoughts?

gsd2000

11,515 posts

182 months

Friday 27th May 2016
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in hindsight i should have purchased an lsx B15 376 shortblock and used my trickflow top

but another option is thompson motorsports for a shortblock

http://www.thompsonmotorsports.net/product_info.ph...

gsd2000

11,515 posts

182 months

Friday 27th May 2016
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or speak to dynotorque, because i know craig has built a lot of na strokers

ArnieVXR

2,449 posts

182 months

Friday 27th May 2016
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Can't think who might have a fully build 418cu stroker (which will probably never get used) sitting on a pallet scratchchin

wormus

14,496 posts

202 months

Friday 27th May 2016
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For NA I'd go with an LSX 454 crate engine. Not worth buggering about with stroked, sleeved blocks and most after market parts in my opinion aren't as good as OE. Having had an iron block in the front of mine I can honestly say, I couldn't tell the difference between that and the alloy block. About the same weight as adding a supercharger to an alloy engine.

ArnieVXR

2,449 posts

182 months

Friday 27th May 2016
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Big, long crank on that LSX454. My LSX427 is similar and suffers piston wear. The aftermarket blocks have longer liners IIRC. The LSX454 also has the LSA bolt configuration and a 58x reluctor to deal with.

Weight penalty is 65KG BTW

Must admit, though, they do look nice idea


wormus

14,496 posts

202 months

Friday 27th May 2016
quotequote all
ArnieVXR said:
Big, long crank on that LSX454. My LSX427 is similar and suffers piston wear. The aftermarket blocks have longer liners IIRC. The LSX454 also has the LSA bolt configuration and a 58x reluctor to deal with.

Weight penalty is 65KG BTW

Must admit, though, they do look nice idea
I thought the 454 had same stroke as the LS7 with same, longer liners than something like the LS2 ? Ligenfelter do a box that will convert the 58x signal to 24x. This might help

"So with a better understanding of the different LS engines produced by the factory, let’s take a look at stroking them for more performance. We contacted Horace Mast of Mast Motorsports for some advice as his company is dedicated solely to engineering and supplying complete LS engines to the aftermarket. His best advice is limiting the stroke to 101.6mm (4.00?) in any standard deck height LS block. (Horace says that most of his engines end up with a 9.230? deck height after surfacing.) This will provide up to 416 cid for an LS3 and 427 cid in an LS7. He has built LS3 and LS7s with 4.100? stroke cranks, but says that the have poor long-term durability, and he doesn’t recommend them, especially for daily driven street cars.

The problem with strokes in excess of 4.00? in a LS motor is that the piston skirt is not properly supported at the bottom of its travel, causing a lot of rocking and premature wear. In fact, Mast’s 4.00? stroke engines use specially designed Mahle pistons to minimize this problem and to provide a more stable ring package. Horace maintains that the same holds true when using the taller deck LSX block – Mast limits displacement to 454 cid even though 511 cid is possible. Even then Mast warns its customers about using these engines as daily drivers because there are too many compromises in the area of piston stability.

Other companies like Flatlander Racing who sell K1 stroker kits for LS engines agree with Mast on the 4.00? stroke for normal deck height motors, but are more aggressive on the LS7 putting the limit at 4.120? stroke and 4.250? for the LSX blocks."

http://www.enginebuildermag.com/2011/03/2011-strok...


I do agree though, adding a stroker kit to a standard block is not a good idea, it's what killed my last engine.

Edited by wormus on Friday 27th May 17:50

jameshsv

5,844 posts

159 months

Friday 27th May 2016
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gsd2000 said:
in hindsight i should have purchased an lsx B15 376 shortblock and used my trickflow top

but another option is thompson motorsports for a shortblock

http://www.thompsonmotorsports.net/product_info.ph...
Ive been looking at the 383 stroker forged shor block and the ls1 shorg blocks

wormus

14,496 posts

202 months

Friday 27th May 2016
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jameshsv said:
Ive been looking at the 383 stroker forged shor block and the ls1 shorg blocks
I ran a 383 LS1 for a while and there was no doubt it scuffed the piston skirts in no time and used oil. Stick with the stock 3.622 crank unless it's had liners.

ArnieVXR

2,449 posts

182 months

Friday 27th May 2016
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Great picture illustrating differences in sleeve lengths:


stevieturbo

17,229 posts

246 months

Friday 27th May 2016
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I'd always be cautious about re-linered blocks...mainly from bad experiences in the past ( non LS though )

But the ERL stuff does look like a lot of work goes into them

http://www.enginelabs.com/engine-tech/engine-block...

If one of them does meet your needs and budget, go for it.

That said, some of the LS3 based 416's etc would be very good value too, and no weight penalty. For a n/a build I cant see strength being a problem for either

Thompson Motorsport do seem to get very good reviews, Vengeance Racing also build some very cool stuff too, and Ron is very helpful to deal with so would be other options.

Gelf VXR

Original Poster:

713 posts

206 months

Saturday 28th May 2016
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Thank you for your input, I'm steering away from a stroked LS2/3 without sleeves, choice is sleeved LS3 or LS7 block, with 4" crank. ERL can be bored from 4 to 4.185.

I've no plans for power adders, but who knows, I tending towards ERL, choosing an ls3 core, the ls3 came after the LS7 and is said to be 20~30% srtronger and has improved breathing bay to bay.

The lsa / ls9 again stronger than the ls3, also has oil squirters for additional 825USD, how beneficial are those oil squirters on a street NA application?

stevieturbo

17,229 posts

246 months

Saturday 28th May 2016
quotequote all
For n/a I can see no benefit at all with oil squirters unless it was a balls out high compression race engine.

Even with boost...they're nice to have, but by no means essential. But they do help with piston cooling so can be a good idea for a boosted engine that will get a hard life.

AND....there isnt any room for the GM style squirters and long stroke setups.

Even my 3.825" crank is touch and go for clearance ( I do reckon some of mine have probably broke off...but I aint opening it up to find out lol )

The crank counterweights can foul the squirters, and the piston skirt at BDC....so a long stroke engine, I simply cant see how that type of squirter will fit.
Some where they drill through the main bearing webs and create an oil jet from there would fit any build though....except again crank webs might affect the oil jet during rotation.

Boosted LS1

21,165 posts

259 months

Saturday 28th May 2016
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The ls7 block had doweled main bearing caps which really do locate the caps firmly. The ls9 block is probably the strongest factory block being made from a better grade of alloy specifically for high torque/blown applications. You could build that up using an lsa crank, eagle rods and a set of forged pistons.

I agree with Stevie about the squirts, they get in the way unless your pistons are designed to suit. That said you could ask about this aspect when speccing the build.

stevieturbo

17,229 posts

246 months

Saturday 28th May 2016
quotequote all
Boosted LS1 said:
The ls7 block had doweled main bearing caps which really do locate the caps firmly. The ls9 block is probably the strongest factory block being made from a better grade of alloy specifically for high torque/blown applications. You could build that up using an lsa crank, eagle rods and a set of forged pistons.

I agree with Stevie about the squirts, they get in the way unless your pistons are designed to suit. That said you could ask about this aspect when speccing the build.
It isnt just the pistons, they hit f**king everything...or more correctly, everything wants to hit them lol and the OEM squirter design will not work with strokers.

But total waste of time/money for a n/a build anyway.

Given all the prices quoted above and seeing what goes into the ERL, I'd probably go for that.

Gelf VXR

Original Poster:

713 posts

206 months

Saturday 28th May 2016
quotequote all
That's my conclusion for the way to go forward also

jameshsv

5,844 posts

159 months

Saturday 28th May 2016
quotequote all
wormus said:
I ran a 383 LS1 for a while and there was no doubt it scuffed the piston skirts in no time and used oil. Stick with the stock 3.622 crank unless it's had liners.
Cheers for the sound advice wormus

stevieturbo

17,229 posts

246 months

Saturday 28th May 2016
quotequote all
I ran a 383 stroker on LS6 block for a long time. Yes the pistons did get scuffed a little, but it never presented any problems.

But...unless you need the extra capacity I wouldnt bother with the 4" stroke.

If it's n/a though, yes that extra capacity would be desirable though, so blocks with longer liners would make sense. Not absolutely essential, but if you can, do it.