[65madgoat]

Budget FORGED crank for you:

https://www.ebay.com/itm/155049151562

[65madgoat]

Budget FORGED crank:

https://www.ebay.com/itm/155049151562?

[RocktimusPryme]

Originally Posted by PDC

Not wanting to argue - but genuinely curious about how many documented failures there are of the Eagle cast 4.25 crank in a build that did not see boost or spray. Particularly a street oriented build in the +/- 550 hp/tq range…

I completely agree, Im not saying there has never been an issue with a SCAT/Eagle crank, but when compared to how many of these things sell and have to be living perfectly normal lives in their engines Im just willing to roll the dice with the statistics.

It might have been David Freighburger, I cant remember, but some big name with cars I was watching experienced a broken crank, and was like, "In 40 years of hot rodding this is the first actual broken crank Ive ever experienced".

You have to be working pretty hard for the crankshaft to be your failure point.

[Skippy597]

Originally Posted by 65madgoat

Budget FORGED crank for you:

https://www.ebay.com/itm/155049151562

Ive never heard of SGI. Anyone on here using them?

[tom s]

Did I miss where it said forged?

[Tim Corcoran]

I ran a 4.25 Eagle cast crank in a 455 and raced it for many years in a 3550 race weight 65 Lemans making around 650 HP and going low 10's. It finally went and took out the block crank rod and pistons. The cam and the heads were not hurt.

[Skippy597]

Huh, well Tim I'm not sure if that helps or hurts my decision lol.

[Tim Corcoran]

If you ever plan to race it with slicks often or plan to upgrade for more power then get a forged crank

[Jay S]

Originally Posted by Skippy597

Ok so I've decided the cast stroker crank is the way to go so I'll get that on order and start piecing together the parts. But I also decided to use my hydraulic HLJ lifters instead of my solids and use the comp 51-116-3 (pretty much a RAIV cam but more lift). I think with the 1.65 rockers and everything else it should have a good bottom end and pair decently with the 336 gears.

The 51-116-3 has .313 lobe lift just like a RAIV. Same cam CMC grind as all the other RA4 copies, Melling SPC-8, summit’s, Edelbrock grind. ect…

I suggest spending a coupe hundred more dollars and get that SGI crankshaft. It is a lot better crank than the cheap cast cranks. It is also known as Star Galaxy…

[Dragncar]

Its going to cost 4-5 hundred more dollars for a forged crank.
And its well worth it IMO.

[Skippy597]

Originally Posted by Jay S

The 51-116-3 has .313 lobe lift just like a RAIV. Same cam CMC grind as all the other RA4 copies, Melling SPC-8, summit’s, Edelbrock grind. ect…

I suggest spending a coupe hundred more dollars and get that SGI crankshaft. It is a lot better crank than the cheap cast cranks. It is also known as Star Galaxy…

Jay do you have any experience with sgi cranks? I'm sure most cranks are from the same place just never heard of them.

[65madgoat]

SGI has been around a while. I understand tolerances may not be like a Molnar forged crank for $1000, but you get what you pay for.

Old thread on SGI:

https://forums.maxperformanceinc.com...d.php?t=759853

[Skippy597]

OK I'm convinced I will go with a forged crank. Do you guys like the SCAT cranks? I love molnar stuff but its another $100 premium.

[Jay S]

Originally Posted by Skippy597

Jay do you have any experience with sgi cranks? I'm sure most cranks are from the same place just never heard of them.

They have been around for quite a while. I have not had SGI or Star Galaxy stuff for a long time. Not sure how quality is these days, but I wouldn’t be afraid of one on a budget build, it is much stronger crank than any of the cast cranks. The Speedmaster E head copies are pretty capable heads, I would not be excited about running shore cast cranks on anything but stock D ports.

The SGI are a pretty comparable crank to Eagle, both are ground in China. I think they may both are forged at the same foundry, and machined in different places (both in China). Eagle or SGI (cast or forged) need to be checked out before you run it to make sure it is with in spec.

I have pretty much went to Molnar for my cranks lately.

[Dragncar]

Originally Posted by Skippy597

OK I'm convinced I will go with a forged crank. Do you guys like the SCAT cranks? I love molnar stuff but its another $100 premium.

I have 2 of them and both were spot on.
Kinsler put 1500 HP though one. Guys have had them to 900 HP NA but around 1000 HP the non fully counter weighted have issues I hear.
They are certainly stronger than any PMD block.
All Pontiac uses them quite a bit and sells them for use in IA2s. Frank runs 7s with one NA.

[Cliff R]

The failure rate for cast cranks at or above the 700hp mark is 100 percent!

I tried to use them here WAY back when they first came out. At that time I was using one of the best crank grinders in that industry. He checked a couple out for me and told me that by the time he fixed all the problems with them I could have bought a Moldex forging instead!

Over the next decade or so they got better with the machining, balance, indexing and fit/finish so I tried one..........and.......it ATE the thrust bearing right on the dyno during "run-in". Dumb ass me didn't polish the thrust bearing surface even though it looked fine at a glance. Turns out that it had very light machining marks in it that were just "high" enough to take out the bearing. So off the dyno it comes, all back apart, complete cleaning, polished the thrust bearing surface to a "mirror" finish and back on the dyno it goes.

I avoided those cranks here for another 15 years or so until I was hired to assemble and dyno an engine where the owner had a "falling out" with his engine builder/machinist. So I took on the job and was remarkably surprised how much better the fit and finish was on the crank, rods, and everything else. It was all "no-name" Chinese crap, but made the grade and survived a pretty good thrashing on the dyno. The entire "package" was supplied by Butler Performance. I still remember the gray "flaky" cardboard used to box the parts, especially the unmarked "H" beam rods. It was ALL Chinese but as mentioned light years better than the crap I worked with over a decade earlier. Literally is was all spot-on except for having to run a ball-hone thru the small ends of the rods for about 25 strokes to get the pins to fit without freezing them.

So they have stepped up there game, but it makes me wonder how many engines were built with the chit they were selling originally.

So............even with ALL that said I would still INSIST on using a forged crank here. It's not that much more money and as B-man mentioned if nothing else you will sleep better at night!.........FWIW......

[Skippy597]

Thank you guys! This is why I love this forum, if I wasnt ready to be wrong I wouldn't have posed the question. Forged crank it is. I imagine I'd be fine with scat crank and I beam rods or is it worth it to upgrade to molnar and H beams.

[Mr Twister]

Originally Posted by Skippy597

Ive never heard of SGI. Anyone on here using them?

I said ohh outloud when I saw that. Like in a bad way...

[b-man]

Scat makes good cranks and rods for many different engines. Chinese forgings like most everything else but machining and finishing is done in-house.

I noticed every Ford flathead I’ve seen on the internet lately built by high end builders use a Scat crank and probably their rods as well. The forged 82mm VW stroker crank and 5.7” H-beam rods I’m using for my 1957 oval window bug hot rod 175 hp 2276cc build are from Scat, according to my engine guy they have the closest tolerances of any of the aftermarket VW cranks and rods.

Also having a more torque-oriented 140 hp 2276 built for my 1966 VW single cab pickup and it will be using 5.4” Scat I-beam rods and maybe a Scat crank as well, depending on which brand my builder chooses but Scat is one of his 2 go-to suppliers.

Scat got their start making VW parts but smartly branched out into multiple brands and have been very successful at it.

So I would not hesitate to use Scat cranks and rods, others might not agree but that’s what I’m spending my money on.

[Dragncar]

Originally Posted by Skippy597

Thank you guys! This is why I love this forum, if I wasnt ready to be wrong I wouldn't have posed the question. Forged crank it is. I imagine I'd be fine with scat crank and I beam rods or is it worth it to upgrade to molnar and H beams.

Molnars all day long. Or Scat H beams.