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Your Personal high RPM SBC/SBF

  • 5500

    Votes: 1 5.3%
  • 6000

    Votes: 4 21.1%
  • 6500

    Votes: 5 26.3%
  • 7000

    Votes: 1 5.3%
  • 7500

    Votes: 2 10.5%
  • 8000

    Votes: 1 5.3%
  • 8500

    Votes: 3 15.8%
  • 9000

    Votes: 2 10.5%
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wind & fire = guides to power
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Discussion Starter #1 (Edited)
What's the highest RPM you, YOU personally, have turned a SBC or SBF? At what RPM did it stop making power?

It stopped producing power about 7000 rpm.

Performer RPM cam/torker 2 ported intake / 882 casting fully ported & milled heads w 2.02/1.6 valves/ 1.6 rockers. Steel shim head gaskets/ 4.11 gears / 1 7/8" hooker headers.
 

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i turned my mild small block chevy to 6000. in my old 71 chevelle. if i could only find that car again, good times.

my current 440 goes to 6500. i stick with hydraulic lifters. that is probably whats holding me back.
 

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RPM

I have turned SBF's (289 & 302) up to 8500 RPM and 351 C & W over 8000 RPM, with stock bottom ends, and have had them survive for quite some time. Never had one break on me due to over winding them.

They will all stop making serious power at some point or another, all depending on what you have done as modifications to the engine.
All these engines with the exception of one was running hydraulic lifters.

The RPM cams basic power band is 3000-6500, so if you ran out of HP at 7000 RPM, I would say possibly your carburetion was the culprit there. What size carb you running?
 

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high rpm

My grandpa used to take his 302 up to 9500 and his dumb ***** sun would take it to 11000 and almost always broke something. and the car ran .20 faster taking it to 9500.
 

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Revving it up

I have seen them turned over 9500 RPM, but not with stock bottom ends.

Doesnt make much sence to turn an engine more than 500 RPM over peak HP, drag racing, and if youre turning more than 1000 RPM over peak in a stock car, your geared too low.
 

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Race it, Don't rice it!
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We turn our open rule roundy round car to 9600 every week for 38 weeks. I turn my mod motor 8600 every week for 30 might's a season.
 

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wind & fire = guides to power
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Discussion Starter #9
750 vac holley.

Yes, you circle track guys wind 'em up huh? I heard of a 283 bored over .125 on alky turning 9000 a couple of nights ago.

Why would 9500 or even 10,000 be so hard?

Jgrass, give us some specs for that 9600 rpm screamer please.
 

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http://teamrfc.gospelcom.net
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The highest RPM I have ever taken a motor to is around 33,000 RPM, and It was still pulling really well especially for only being .16 cubic inches. (T-MAXX nitro remote controll truck)

As far as a real car goes, it is around 8000. That is a 358 with a 3.295 stroke and a 4.155 bore with Brodix 230cc runner 11X heads. The motor dynoed at 620 hp at 7800 RPM. You can tell when it drops out of the power range (greater than 8000).

Adam
 

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Revving it up

Well for most hi rpm production V-8's (american), due to mass production balancing methods, and materials used, and the assembly methods, it seems that somewhere between 6-7000 RPM is about all the factory parts will handle with any reliability. After that, inherrent imbalances, start becoming serious and come into major play. Generally, production parts arent designed to handle those kind of RPM with reliability.
Getting over 8000 RPM, does require, mainly, serious balancing of the parts. While this isnt the complete story, imagine 5 grams variation of weight at 0 rpm. Due to rigidity of the crank and block, this isnt a big problem, but when you start turning that crank up 8000 rpm, that 5 grams of weight, start taking on centrifical weights of very large proportions, for the same reason that generally an RPM ceiling of 6-7000 rpm starts tearing stock engines apart. Rod bolts stretch, pistons start separating at the ring lands, valve trains start to float, You get the picture.
Now turning over 8000 RPM, you run into other things like the centrifical weight of the crankshaft itself. The counter weights start taking on weight proportions that are tonnace.
Main cap bolts start stretching due to the forces on them and the next thing you know, a crank ventilates the oil pan.
Hense, to get into those kind of RPM's does require balancing and stronger fasteners. Other factors are the oiling systems ability to recover lubricant, without airiation, to maintain its ability to keep the bearings and steel from coming int metal to metal contact.
As I mentioned in my previous epistle, I did turn these higher RPM's with production parts, albeit with a good balancing job, and the proper fasteners. This even included running production rods and pistons. Turning an engine into the ionosphere does put a lot of wierd stresses on it, from the foundering of the block, as well as all the moving parts. Thats why you see guys putting special alloy rods, cranks, pistons etc in their engines for reliability, as well as installing main stud girdles, windage trays, oil scrapers, etc.
It not difficult to turn an engine 9000 RPM if you have the basic parts to do it, like cam grind, valve springs, lifters, carburation, air flow etc, but if you do this with an engine running assembly line internals, you are asking for a hand grenade with the pin pulled out. The trick is to keep the engine together when you do it.

Harmonics is another equation. When you start turning things hi RPM, ( take a stick and tie it to a string and spin it around your head sometime at variing speeds, you hear different tones), these can tend to cause crystalization of the metals in your engine, causing failure. If youve ever wound a 4 or 5 main inline 6 up anykind of RPM, you will know what I mean, as you can start to feel them, at relatively low speeds. The reason that you will feel them in a 4 or 5 main inline before you will in a 4 main V-6 or a 7 main inline is because due to the lesser crankshaft support of the fewer mains, you will have more crankshaft flexing and at lower RPM. The reason this isnt such a serious problem with V-6's, is due to the shortness of the crank, and having as a rule 4 mains to support it. More rigidity.
 

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Race it, Don't rice it!
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7,806 Posts
Dart Block 364 ci
Cola Crank 1.88 rod journals, 2.0 mains, 3.34
JE custom pistons 4.185 bore, 375g
Dyers Rods 375 g, 6.2, 6.75 wide
Brodix -12 heads, 320cc flow
Titanium valves 2.10/1.75, Ceramic lifters, 750+ lift, 1.8 rockers, 3/8 solid pushrod,
5 stage drysump
Methonol fuel

Power: [email protected]
Torque: 650 range

I turned it 9600 with a 6.30 gear. The car was so crap that one night we had to turn it over peak to keep from blowing the tires off so I could get into the corner.
Ran this engine for 15 night's before a rebuild was in order. The rebuild was $7800. Cost is 27,000 new. We never could get that power to the ground so we changed to a 388 making 650-675.
 

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wind & fire = guides to power
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Discussion Starter #13
I bet that had a nice smooth idle about 950 rpm:p
320cc runners and a 780 cam...curious, if you did let it idle...where was it?

Maybe Griffen could look at that engine... if he is truly set on 10000 it looks like a GREAT starting point!
 

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wind & fire = guides to power
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Discussion Starter #15
No tach? I bet Johnsons heads have intake runners TWICE if not more than twice the size of your heads! I wasn't even aware SBCs could have heads that big!
 

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NXS said:
No tach? I bet Johnsons heads have intake runners TWICE if not more than twice the size of your heads! I wasn't even aware SBCs could have heads that big!
Yeah.. Thats it.. No tachometer.
 

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Come Home Safe Soldier
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I have not ever needed to run my SBC over 6500.Just did it once to say I did.I just drive mine,and put gas in it.I would like to run it one day this summer to see what it will do.I just have to remove a ton of stuff from the trunk.I managed to shed about 7 lbs.My daughter outgrew her car seat.LOL.
I used to work for a moving company and one of our vans had a real bad knock in it.We purchased a reman 351 to put in and started the bad engine up,reved it as high as it would,just to see it grenade.When the rod broke we put a window in the oil pan,plus had one heck of a mess to clean up!
 

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wind & fire = guides to power
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Discussion Starter #19
Ok, what gives?

Two people, here, over 10% claimed to have turned 9000 rpm with a SBC/SBF.

So why didn't anybody try to help that griffen kid any more than you did?

if you turned 9000 then 10,000 is very very close.
 

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Big Block Z28
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When my 70 Z28 was new with a factory diaphragm pressure plate, the pressure plate had a tendency to "oil can" at high RPms. I saw my tach hit 8000 during a full throttle shift from first to second when the pressure plate "oil canned" and failed to release. I switched to the 3-fingered Borg and Beck type pressure plates after that and have beeen using them ever since. (That was in the days before rev limiters.)
 
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