*7M Crank RPM Limit*

I

IJ.

Grumpy Old Man
Mar 30, 2005
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Ash: I think (bit hazy here) that the Group A blocks didn't have squirters!

Not really sure how much the extra 9 psi is going to give as I'll be getting towards the limits of flow in my intake system by then so it may drop off.
 
I

IJ.

Grumpy Old Man
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Update!
As suspected there wasn't a lot left power wise after 25 psi as the 3540 just can't flow enough to fill a 3.0 litre motor at high rpm.

I tore it down and did an inspection and found the Rod bearings were showing signs of fatigue so am upgrading to a better quality bearing for the reassembly.

Mains show evidence of Crank flex but that was expected and there isn't a lot to be done about this! (I think/feel it would have been more severe with a 6M crank)
 
supra90turbo

supra90turbo

shaeff is FTMFW!
Mar 30, 2005
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Is there anything that can be done to reduce the flex Ian? I will be running a 7M crank as well, and wondered how reliably it can handle high revs.
There is of course, the point to which it must flex and if it's hardened it will become brittle...
So is it necessary to just leave it alone you think?
If I simply have to put new bearings in every winter, I can accept that.
 
I

IJ.

Grumpy Old Man
Mar 30, 2005
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Kurt: Not a whole lot can be done it's just part of running such a long crank.

I'd love to inspect some of the 7M's that have been running the non dampened front pullies!

I think if I can get a rod bearing to live the flex won't be a huge issue as it's only wearing the mains on their corners/edges so Oil pressure doesn't suffer.
 
Nick M

Nick M

Black Rifles Matter
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Is there anything that can be done to reduce the flex Ian? I will be running a 7M crank as well, and wondered how reliably it can handle high revs
Click to expand...
Crower, or any custom unit from a crankshaft manufacturer. They will be more than willing to take your $$$.
 
I

IJ.

Grumpy Old Man
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Nick: I can't really see an aftermarket crank making a difference in flex as it still has the same limitations in length and bearing diameter as the stock crank which is forged steel to begin with.
 
Nick M

Nick M

Black Rifles Matter
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I know Toyota doesn't cheap out as a rule.

If GM and Ford can run a crank(from Crower and Scat) that has a 3.5 inch to 4.00 inch stroke you can too.

Well, money doesn't grow on trees at my house so good luck. Hoping to see you dump some nitro methane in it.
 
NashMan

NashMan

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Aug 5, 2005
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IJ. said:
Funny when mine was NA I can't remember hitting a limiter at all!
(don't even know if NA's have one)
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na rev limt on my old 7mge was 7200 rpm at lest that is what i remember

and i think my 88 7mgte is like 6800 7000 don't remember
 
Boss302

Boss302

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May 2, 2006
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trydrew said:
Hahaha Well i have. Here we go,

I was cruising at ~60mph with cruise control. I came to a light so i went to disengage the clutch, thinking the cruise control would cancel like it should.
Well my car has a auto->R154 swap and the lazy ass second owner thought it best to leave out the clutch switch. Yes, that is the thing that cancels cruise control when you push in the clutch... And i didnt have one.

Sooo, I push the clutch and slowly begin to slid down in my seat with the "oohhhh shhhiiiittt" felling as my tach takes off. For a second or two i was as confused as my car was thinking, "WTH is goin on!" So i frantically swing around in a blur looking to stop this. I dont remember exactly but im sure i engaged the clutch 1000 times after putting it in neutral hahaha. Then i thought for a 1/2 sec and flipped the CC stalk toward me. The people i was passing must have been like wtf is that damn person doing.

All in all, I think my engine barked at me about 5 times as it bounced back of the limiter. To bad i was too busy looking for a way to make it stop i didnt look to see how high the needle went. lol not safe, not fun, and almost dramatizing. I was somewhat in shock the rest of the way home. I did pull in to a near parking lot to make sure that it was ok.

Im starting to think my engine has had a past rebuild... I wish i knew.
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:icon_bigg :icon_bigg hahahaha oh y gosh you remind me of a time when i had a bit of spirited driving and when i push the clutch in all of the sudden rev's SHOOT just fly away i flip trying to figure out what's going on and put it in gear and take it out and engage and disengage the clutch. fastest shifting i've ever done cause the thing kept wanting to go so i had to dance with tthe gears to keep it under control. the throttle linkage binded it sucked. man i look back and that was funny.
 
Adjuster

Adjuster

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Apr 8, 2005
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Was that over 900lbs of tourqe on that dyno sheet... Dang man, that engine is making the power. (Who cares about peak HP if your making that much tourqe.)

Interesting to hear about the rod bearings being worn. Your running the stock journal sizes with the Pauter rods right? I wonder if some molydisulfied coatings on your bearings would help? (I don't know what kind of bearings you were running, but I'm on a set of Clevite's now that are coated and so far, so good, no problems yet, but I'm not running my motor up to 7700rpm either. :) )
There is plenty of power where I'm at right now, and since I do not have upgraded cams, I'm going more for the low/mid power improvements with a nice healthy top end that ends at the stock rpm range. (Still might re-clock the TCCS for 7500ish rpm limits, but only if I think there is more power to be had up there on my stock cams.) Changing over to higher lift/duration cams and the shimless buckets would be a nice mod in a few years I suppose.

Any photos of the bearings and how they wore?
 
I

IJ.

Grumpy Old Man
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Greg: I'll get some pics in the next few days (the bearings are out in the workshop and it's too cold to go back out tonight!)

The Mains are nice and uniform just with a bit of wear on their edges from crank flex, the Rods bearings are fatigued as in "smeared" like if they were "soft" and you rubbed hard with a finger.

At first I thought they were contaminated as if something had gone through the Oil system but the Mains being spotless rule that out, I took them to my Crank Shop and got the owner to inspect each shell as he's been in the business for 40+ years and his verdict was "fatigued"

Interestingly he said If I'd used ACL's they would have failed totally, the bearings were Japanese NDC's and are meant to be quite a good bearing.

He suggested Clevite77's so that's what I have now!
 
suprarich

suprarich

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IJ. said:
Nick: LOL no where to dump any Nitro in my car! :)

Straight LPG fuel system here!

(Money doesn't grow on trees here either I work damn hard for every cent that goes into my car)
Click to expand...

I got just the set up for you IJ, we'll get some nitro in your motor. I even have 5 or 6 gallons sitting around. I would pay money to see that on the dyno!!
 
Boss302

Boss302

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May 2, 2006
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Originally Posted by IJ.
Ash: I think (bit hazy here) that the Group A blocks didn't have squirters!
group a supra said:
mine has ian but i put them in the block came with them blanked out with plugs
Click to expand...
some didn't
 
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