how to make a 6.1 spin safely 7500 rpms?

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Buschi340

Buschi340

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advises? Since i have to built a new Motor what are the absolute necessary part to change? And what are parts i can get from our chrysler dealer like gaskets, head bolts, maybe bearings..?
rods are ok on a 6.1? Just new rod bolts ( maybe i just had bad luck with one ), ARP? or are stock bolts new good enough?
 
dont know about the newer engines, but on my LA, the valve train is the limiting factor in RPMs
that, and my cam is just not geared for it

so, my guess would be you need to adress the valve train
 
Buschi340 said:
advises? Since i have to built a new Motor what are the absolute necessary part to change? And what are parts i can get from our chrysler dealer like gaskets, head bolts, maybe bearings..?
rods are ok on a 6.1? Just new rod bolts ( maybe i just had bad luck with one ), ARP? or are stock bolts new good enough?
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Are we talking sustained RPMs or up and down? Regardless you're gonna need pretty much everything to sustain that kind of RPM for long term. I know of no dealer that sells the stuff you'll need to reach 7500 safely. That's full on NASCAR type RPM, especially if you're talking about sustained RPMs. Not only will you need valve train, but I doubt the stock rotating assembly can handle that kind of RPM for long.
 
Not sure what your "build from scratch" tally is going to be, but there are some pretty affordable 392 short blocks on the market... wink wink

Fully forged
ATK HPE-SP97 Gen III Hemi 392CI Stroker Short Block Flat Top Pistons - 32 Tooth, Pre 2009

Last i checked a forged rotating assembly alone was $3000...

upload_2017-7-27_7-58-40.png
 
Johnny Pace said:
Not sure what your "build from scratch" tally is going to be, but there are some pretty affordable 392 short blocks on the market... wink wink
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The OP in in Germany so his options might be limited
 
65 Dartman said:
The OP in in Germany so his options might be limited
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I didn't notice that, but i do ship intl. I can't imagine machine work in germany being much cheaper than ocean or air freight.
 
Johnny Pace said:
I didn't notice that, but i do ship intl. I can't imagine machine work in germany being much cheaper than ocean or air freight.
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For our overseas Mopar fanatics, that's good to know about your shipping policy. A lot of companies (and individuals) won't ship overseas!
 
nonono, i already have a Motor from a wrecked 2008 C300. 80,000mls.

I am tearing this engine down want to replace the weakest parts. Maybe i expressed myself wrong. I don't want to race 7,5K rpm for hours. Ist just the peak i want to hit on my few race days on the drag Strip a year.
Means block remains stock. Pistons too? Heads are fine, cam is a crowers, springs are already behive.

I want to use most stock parts as possible because of a chrysler dealership around the Corner. Import from the States will double to triple almost everything....
 
Why so high?
If your making peak power in the 7000's your taking 700+hp and everything is gonna be custom with that engine anyways. $$$$$$$
 
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just want to be safe. That not that high considering the red area on the Tacho starts of a donor SRT at 6200rpm and Ends at 8000. So 7 k rpm should be easy to reach. I dont want my block spitting rods again onto the track.
 
vntned said:
Trade it for that GT350R Voodoo engine 8000rpm+ stock!!!
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There's a good article in Hot Rod on spinning the 5.7 and 6.1 at high RPMs

Weak links in the 5.7 and 6.1

Hypereutectic pistons

Stock Hemi main caps break at the 800-900 hp level. Easy fix is a Arrington main cap and ARP studs

Oil pump pickup tube failure. The 6.1 has a added retention tab.

Stock powdered metal rods fail. Forged rods are the way to go

Camshaft options are limited due to variable cam timing. Stock springs are also heavy. There's a kit available from Comp Cams (Cam Phaser Limiter Kit)

Stock cast crank bends at the 600hp level on the 5.7. 6.1 has a forged steel but and aftermarket replacement is recommended.
 
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The real weak points are the cast pistons, powdered rods and the oil system.
Aftermarket pistons and rods are readily available and make sure u have a healthy oil pump, a large enough sump and use the correct weight oil for your specific oil clearances
 
Sell it and get a 340. Problem solved.
 
340 is good for boat anchor as they make 120hp less than a 6.1 as they left the factory.
How many passes would a stock 340 have lasted at 425hp?
Its 2017 now not 1973

Anyway valvetrain is fine to 7500rpm if looking at the dragpak cars is anything to go by.....8000rpm onstock rockers
 
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L4staero said:
340 is good for boat anchor as they make 120hp less than a 6.1 as they left the factory.
How many passes would a stock 340 have lasted at 425hp?
Its 2017 now not 1973

Anyway valvetrain is fine to 7500rpm if lookig at the dragpak cars is anything to go by.....8000rpm onstock rockers
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The Hemi is a great engine.
But even though it a clean sheet of paper design. It's short block at its heart (rotation assembly) is basically LA.

5.7 is basically a 318 bore with 360 crank. And 6.1 340 with 360 crank. And hydraulic roller cams.

The big change for power and the main reason for redesigning the short block is the head package. But really a roller cam 318 with 3.58 crank and edlebrock rpm is equal to 5.7 hemi and roller cam 340 with 3.58 crank and edlebrock Victor heads is equal to 6.1/6.4 hemi. Except no MDS or VVT.

Plus a 425 hp 340 can last a long time and really is only a cam headers and intake away. My cousin runs one in his late model 3 season on last build hitting 7000 rpm plus
Stock rods and crank.
 
A std 340 with cam, intake and headers aint ever gonna see 425 hp without thorogh rebuild and quality components.

Apply the same theory to the G3

A std 6.1 with cam and headers will make 450hp and a 6.4 over 500hp.

The.engines are different era's and the quality factory machining and casting is far superior to the old LA engines.

Yep a large range of G3 factory engines are let down by pistons and rods but factory cranks are well up to handling 1000hp and blocks up to 1500hp. Try that with factory 340/360 stuff.

The G3 offers the average hot rodder the ability to bolt together an engine from factory parts and make lots of power without any out of the ordinary machining or custom parts.

Get a 6.4 engjne, slide in a 274 comp cam and fit a dragpak manifold and nice carb and you will see high 10's in a 3000lb dart with the ability and reliability to drive across county thats not something you can do with a 340
 
My point wasn't to dismiss the new hemi or even LS etc.. yes there great got a lot of good components OOTB. But doesn't mean older engines are necessarily inferior. If you build a 360 and a 5.7 hemi too similar specs your gonna come out with similar results.
And that really goes for any brand of engine that size.

And I disagree 340 has enough CR and cylinder head airflow to make 425 hp
If a 360 magnum can so can a 340.

And that's my main point it all comes down to heads and that's what make a stock hemi great but a 318-360 is just an upgrade away.
So really it just preference and budget.
 
Yes i understand, i come from a LA background and was about to put a 418 cube combo together but after wanting a more powerful combo (over 600hp) it became aparent the G3 is a better option.

Example best 340 head flows 200cfm
Well ported W2s 320fm
Indy heads 340cfm

Std G3 6.4 heads 340 cfm and can be had used for under $500 at times.
 
So I can see both sides of both arguments.

Arguably the old 340 is a great choice with a forged crank factory in the early days. Looking at later model LA's they were sort of crap. Cast crank wasn't fantastic but not terrible, low compression and not the greatest rods either. Head flow was fine for 1980 standards but even performance heads leave something to be desired compared to some of the newer stock heads from Chrysler and GM.

On the G3 Hemi side, there is plenty of good and bad. The cranks are decent but not phenominal. Both 5.7 and 6.1's have powdered rods that really aren't worth much. Any build should consider a rod swap and even a rebuild on a stock engine for unlimited reliability. Pistons are a huge weak link and were never meant to hold higher than stock hp levels. The bean counters rule the world these days and unless its necessary no manufacturer really overbuilds on purpose. But the same tricks used back in the day take this engine from good to wild in a hurry...but parts are more expensive.

So in my mind they are a horse a piece...you want more power out of a small block build the G3. you want easy and cheap parts but are ok with a lower power output then go LA. Either way you will be spending money machining, stroking, and replacing parts. I just think you get further along for the investment in the new platform. (not counting the hassle installing it compared to an LA that bolts in)
 
273 said:
My point wasn't to dismiss the new hemi or even LS etc.. yes there great got a lot of good components OOTB. But doesn't mean older engines are necessarily inferior. If you build a 360 and a 5.7 hemi too similar specs your gonna come out with similar results.
And that really goes for any brand of engine that size.

And I disagree 340 has enough CR and cylinder head airflow to make 425 hp
If a 360 magnum can so can a 340.

And that's my main point it all comes down to heads and that's what make a stock hemi great but a 318-360 is just an upgrade away.
So really it just preference and budget.
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The new Hemi isn't saddled with the troublesome 59 degree lifter angle... And the G3 heads are much superior to any SBM head and the design of the oiling system allows 7500 revs with mostly stock components...
 
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