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Guess on safe rpm range?

  
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Guess on safe rpm range?

 
KyleG KyleG
New User | Posts: 12 | Joined: 12/12
Posted: 01/23/13
09:15 PM

Its a 355 4 bolt. 10:5 compression, flat tops, Stock rods/crank, Torker 2 Intake, 64cc Double hump heads guide plate/studs, arp rockers, arp head bolts, arp main cap/rodcap bolts(I believe they are arp, I know they are aftermarket), After market main caps, Has black jack long tube headers but dont no specs, Holley 750 vs, 1 inch carb spacer(Clearance issue), Gm hei, is gear driven, cam is 508 lift with 313 duration, timed straight up and down, Is hydralic, no roller set up, Not sure if the push rods are after market we used what we started with.

I've had the motor to right at 6500. Without a problem, really rev happy motor.And when It hit the 6500, it was do to it being there be for I realized it. I just don't know whats safe... High school budget, don't have extra money to over rev. If I missed any info, let me no. I tried covering everything...  

xFourLeaf xFourLeaf
User | Posts: 62 | Joined: 01/13
Posted: 01/23/13
09:54 PM

I wouldn't go past 6500 with the stock rods and crank. If you really want to be safe set it to 6000 and you should be fine.  
xFourLeafxFourLeaf

68scott385 68scott385
Guru | Posts: 1990 | Joined: 10/09
Posted: 01/23/13
10:01 PM

rev durability depends on quality of parts used

rev possibility depends on breathing ability, carb, intake, heads, cam, and exhaust

Is that stock crank cast or forged? What kind of stock rods? Not all stock parts are created equal. Do you have part or casting numbers?

With stock cast crank & rods, I wouldn't go any higher than 6500 and wouldn't do that regularly.  
68scott385 68scott385 68scott385

KyleG KyleG
New User | Posts: 12 | Joined: 12/12
Posted: 01/23/13
10:22 PM

It is cast, and I sadly did not get any numbers off them while they were off. The guy that did our machine work said the crank was a really good crank, and is one of the strongest for its time.. As for the rods, they have lasted on a few motors with my dad for the last 20 something years(16 of that, they sat in the block). And he use to race a lot.. So, I'd say they are fairly strong. But, I know that isnt real good information lol The main reason I came to ask is a guy said it'd be safe to run over 7k. And knew that did not sound right... He told me in one of his dirt cars, he ran with a stock bottom end, but forged pistons, at 7500 all season.


Thanks for the input guys, I probably won't go over 6k very often if any at all. If this motor goes, I am screwed lol  

KyleG KyleG
New User | Posts: 12 | Joined: 12/12
Posted: 01/23/13
10:56 PM

Th VID 20130123 143327

At about 110 degrees. Still cold. About 60-70 percent throttle. Its a really rev happy set up.  

KyleG KyleG
New User | Posts: 12 | Joined: 12/12
Posted: 01/23/13
11:13 PM

Sorry, double post..  

76Skylark 76Skylark
Guru | Posts: 853 | Joined: 12/11
Posted: 01/23/13
11:49 PM

Kyle It Isn't that the engine Won't rev to 7500 but as Stated your Stuff has been around for a good while. and if the machiniest said something Like "It is one of the better ones" It might have been a factory Forged crank,But again those parts have been used and maybe Abused and you need them to last so Stay Safe and try to limit the Rpm to 6000 when showing Off. Lol  

pepsi1 pepsi1
Guru | Posts: 1718 | Joined: 09/11
Posted: 01/24/13
02:05 AM

Kyleg

Back in the day the 265/283 with a small solid lifter factory cam was still making power at 6,800RPM.  cam specs.. Thats a factory Hi-PO setup. But when you run a stock class your hands were tied.Tight Lash Duntov .030/030  .247/.254 duration @ .050 .504/.498 lift.  2300 to 6900 RPM Range.

Even though you used ARP fasteners.

1.Did you have the connecting rod resized?

2.Did you have the mains line bored, after the new main caps.

3.Your cam will spin the engine up to 6500RPM but will it stay together? It's a stout cam. Thats the $64K question.

4.Did you use Plasti Gauge or actually Mic. all your parts for their clearances.

  Kyle: Just for a little FYI. When you send in your parts list, let us know if they are forged or cast. Your cam is really stout. I'm guessing your cam is somewhere around .240* to .248* at .050. Did you change the valve springs with the cam. If not you will kill the stock valve springs.

  Is you trans a manual or automatic?

I would not Rev your engine over 6200 RPM. But thats my 2 cents. (I know it will Rev. higher) but Frankly not knowing what the rest of your engine has in it. Be safe not sorry. You don't want to have everything to come apart.

Bob  

pepsi1 pepsi1
Guru | Posts: 1718 | Joined: 09/11
Posted: 01/24/13
02:57 AM

Kyle
Although the connecting rods as you say are good, be carefull. Steel rods have a fatigue rate too. Where that is a guessing game. If you have a good Lunati Sledgehammer set-up it still has a lifetime limit too.
  Aluminum Rods I got rid of after 300 Runs. Those where documented runs. I never went over 400 runs on a stock rod ratio. You could never tell when they will give up.
  I remember back in the day. When an engine felt stronger or it seemed like it was making more power. It was going to blow up. There's that thin line between Okay and disaster....

  The next time you build an engine, get a log book and document everything.

Bob  

pepsi1 pepsi1
Guru | Posts: 1718 | Joined: 09/11
Posted: 01/24/13
02:59 AM

Kyle
The next time you build an engine. Pick up a Log book. Document all everything....

Bob  

redneckjoe69 redneckjoe69
Addict | Posts: 2337 | Joined: 03/10
Posted: 01/24/13
04:53 AM

if your using factory pushrods, id get a set of hardened ones for the guideplates.      its kinda over-cammed if your only gonna rev it to 6,000rpm, IMO.    id rev it to 7,000rpm with the correct valve springs, and no power adder.  my thinking is,...its either gonna blow-up or not?      sounds like a decent combo and your not claiming any problems at 6,500.  

Pontiacman2 Pontiacman2
Moderator | Posts: 8956 | Joined: 09/08
Posted: 01/24/13
08:32 AM

Icon QuoteKyleG:
It is cast, and I sadly did not get any numbers off them while they were off. The guy that did our machine work said the crank was a really good crank, and is one of the strongest for its time.. As for the rods, they have lasted on a few motors with my dad for the last 20 something years(16 of that, they sat in the block). And he use to race a lot.. So, I'd say they are fairly strong. But, I know that isnt real good information lol The main reason I came to ask is a guy said it'd be safe to run over 7k. And knew that did not sound right... He told me in one of his dirt cars, he ran with a stock bottom end, but forged pistons, at 7500 all season.


Thanks for the input guys, I probably won't go over 6k very often if any at all. If this motor goes, I am screwed lol


Most look for the 442 cast cranks as I heard they are better,But I doubt that.

6000Rpm would be the max. I would ever turn it with stock rods and 6500 with the GM X-rods and ARP bolts.  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

KyleG KyleG
New User | Posts: 12 | Joined: 12/12
Posted: 01/24/13
11:18 AM

The connecting rods were not resized, Main lines were bored, its a turbo 400 with 4.11 rear gear.

Dad built the motor 16-18 years ago. The motor didn't get 500 miles on it do to it being parked. We just put in a new cam, bearings, lifters, and all that and got everything machined. As for the heads, dad can not remember if he used after market valve springs and valves. He said he probably did, but thats probably LOL As for push rods, he told me he had never had an issue with the brand, or what they are, so idk on that either lol The pistons are supposed to be aluminum and the rest is supposed to be cast. We did have a log book, but never thought to put anything in it lol

IMG 20120902 133836
IMG 20120902 143814
IMG 20120902 161147
Pics from the rebuild.  

pepsi1 pepsi1
Guru | Posts: 1718 | Joined: 09/11
Posted: 01/24/13
04:25 PM

Kyle
  If the parting line on the first throw of the crank is wide. It's probably a Forged Crank. It's hard to tell by your pictures. If you can get those Numbers.

The early forged cranks had only (4) numbers for a casting. I'll give you some.

1182, 2690, then 3941182, 3941188, 3892690. As you can se how they added numbers to the forgings. Those numbers are only a partial list. They are the 2 piece rear main seals.
  The stock HiPo connecting rod, that you will probably not see, unless somebody has an old set is the Chevy Pink rod. They are a strong stock connecting rod. We used them for years without a problem. I remember using them for 400 runs. Then when I freshened the engine I checked them for fatigue cracks then changed the rod/bolts and resized the big end. Then ran them again. There are also (X) and (O) castings at the parting line near the rod bolt head. Chevy also made some very good HiPo Rod bolts.
  When you use your crank and stock rotating assembly for drag racing, whenever you tear the engine down for maintainence always have the crank checked for cracks.
 
  Now that I see what you have. 6,500 would be okay. Get a picture of that crank, or the numbers.Have fun...

Bob  

skyeking skyeking
Addict | Posts: 2738 | Joined: 08/09
Posted: 01/24/13
05:13 PM

Hi There,
What model HEI??
I would not belt a std one over 5500
very often.  Hi Gang..Anybody making
any money these days??..Good Luck to all..  
skyeking

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