FormulaBoat

iTrader: (1)

Hi all. Finalizing part collection for my dedicated E85 LSA build, and looking for experienced opinions on the Summit Pro LS H beam rods. I think these are the general Chinese made rods that most makers seem to carry and badge as their own. Engine targets are 750hp @ flywheel and 6,000rpm or less (boat). Engine will develop more power in total, but the blower is sucking some down to run itself. Rods will be slinging heavy Summit Pro LS forged blower pistons (heavy) with thick wall tool steel pins (also heavy). Consensus is the pistons are Wiesco. They seem well made upon arrival.

Appreciate to hear your experiences with them. Yep, been great your 1000hp turbo build past 7,000rpm, or nope had one fail half way down the track, or large end out of spec and spun a bearing, etc..... If any failures on them, at what power / rpm point is this happening?

It is the only part of my build that will be an overseas part, and kind of makes my stomach upset on a larger budget blower build that it will be the rod. Ugh. But if most of you have had good luck, then I'm all in. I do like the specs that are published about them. Seems to be about 3x the cost to switch to a US made H beam rod, and I'm scared to put heavier pistons on the stock rods at that power level.

Rod is not really blower specific, so I threw this post in the general section hoping for more exposure.

All ears, thanks....

Summitracing

Hello, the cranks and rods are sourced from a company here in the USA that sources them from the number one factory in China. The rods are finished honed with genuine ARP rod bolts here in the USA. This is critical. The beams are quite a bit different than many on the market and they have no history of failure in the several years we’ve carried them other than two instances of the rod bearings welding to the crank due to installation or oil pump failure. Which isn’t the rods fault. 5000fpm is the tension load of a 4” crank at 7500 and in the 8000’s with standard stroke. So yes we feel they are the best of the commonly available h-beams and better even than some rods double or triple their price. And, being Summit we wouldn’t put our name on something that could break and cost any of us downtime or warranty expense.

Here’s a more in-depth article on the Pro LS rotating components.

hiltsy855

iTrader: (35)

I'm sure the Summit rods would work but Callies Compstar H-beam rods are only ~$150 more....

SAPPER

iTrader: (10)

I personally never used them But I've talked to quite a few guys using their bottom end parts and have zero complaints. I've even checked and mic'd them for these guys and they are spot on. I think Summit stepped up on these parts knowing quality counts.
Also, almost everything is coming from overseas as a cast part then machined in the USA. Besides, the cutting bits everyone is using are probably made in China too, so no matter.

FormulaBoat

iTrader: (1)

Thanks.

I have not seen any reported failures of them either. I'm going to be easier on them than most, given my lower RPM limit. It should be OK, looking forward to their arrival and installation.

Summit, thanks for holding a reasonable price on such popular parts such as these rods and pistons.

SLOW SEDAN

iTrader: (13)

Why are you building an engine for 750 crank hp? I'd skip all the aftermarket stuff at that level and leave it alone, almost always more reliable.

FormulaBoat

iTrader: (1)

Supercharged engine, so probably making up to 900hp within itself, then minus the power to drive the blower. Not sure stock rods would be good for double their initial hp usage, let alone swinging heavier pistons and pins. Plus the pistons I already bought require a longer rod and SBC pin size, so I was changing rods at this point anyway.

FormulaBoat

iTrader: (1)

Looks like I'll never get these rods regardless. Another reason to dislike overseas sources. Had an estimated arrival date of May 2 upon ordering. No problem. This morning Summit sends me a note saying that ETA for these has been shifted to end of August. Ummmm, that's not a reasonable change. Will be switching to Callies Compstar CSC6125DS2A2AH, which is a similar style and dimension rod, from a distributor that has them in stock (Summit does not). China source rod as well. Only 3 differences I observe is that the Callies state a lower weight than the Summit Pro LS rods (618g vs 660g), pin bore diameter of 0.928" vs 0.927", and pin end width 0.960" vs 1.01". Lots of good forum reviews of the Compstars of well over 1,000hp and up to 8,000rpm in extended use. I'm well below both of these, so should be fine. Really wanted to try the Summit ones.

SLOW SEDAN

iTrader: (13)

I'm aware of your purpose, I've done dozens of LSA blower swaps on stock engines, most well over 750 crank and have had zero issues. Stock rods and pistons have been fine to over 1000whp for a long time, 750 crank is nothing.

Summitracing

Sorry about not being able to get the Pro LS rods to you in a reasonable time. The Compstars are a good option and popular for a variety of builds.