Crank journal sizing....

[user-23911]

New crank now after grinding is .0005-.0006 bigger on the mains, up to .0003 taper. Rods journal low spec is .001 bigger + .0002 taper, which I'm not concerned about, but still not really enough clearance.

Have you got the bearings, checked the rods for round(old ones NEVER are), measured the clearance?
How can you say there's not enough clearance otherwise?

I think you're just being too fussy?
Have you checked the factory specs?

[202ci EH]

Plain ol blue 3.3 Tony.

Of course I've measured the rod bores and the tunnel, which check out good.

Trial and error is telling me I don't have enough, been there before, .0018" rods and .0021 mains ain't enough.
Factory spec is pretty well useless, 2 different applications. The factory tolerance is .0007" - .0027" clearance.

[benno318]

pm sent eh

[user-23911]

The factory tolerance is .0007" - .0027" clearance.

So it's a Holden Blue

Factory spec is anything between 7 and 27.

You've got 18 and 21, but you want more?


I can't see what the problem is?
Normally depending on the bearings used , you'll get roughly those numbers.
Unless you want something else in which case you get the bearings first and custom grind the crank to suit.

New crank now after grinding is .0005-.0006 bigger on the mains, up to .0003 taper. Rods journal low spec is .001 bigger + .0002 taper, which I'm not concerned about, but still not really enough clearance.

I've always had a problem reading a mic to that level of accuracy, but I've only ever used metric micrometers, converted the inches to mm first.
Maybe it was ground in winter and you're reading it on a hot day?

[202ci EH]

Can't quite tell whether you're taking the piss Joe?

The factory tolerance is .0007" - .0027" clearance.

So it's a Holden Blue

Factory spec is anything between 7 and 27.

Not a stock rebuild.

You've got 18 and 21, but you want more?

Yes

"Custom grind the crank to suit."


That's exactly what I asked for.


Maybe it was ground in winter and you're reading it on a hot day?

You can compare them at anytime..

[user-23911]

But where's the problem?

I've done a lot of crank grinding.


In reality, they never come out perfect but the only time you're going to have a problem is if it's too tight, you'll spin a bearing.
If it's not too tight anywhere , it's OK.

It'll run and it'll work.


Reality again is that a regrind is always going to be acceptable but never the same as a factory finish due to the difference in machinery, I probably know so many ways to cock up the job, only because I've got first hand experience, that's due to using a machine that's older than me.

Afterall, it's only a crappy old holden?
It's not a race engine.

Are you going to give it 40 pounds of boost and make 1500HP at 10,000 RPM or just settle for 200HP?



So maybe you should be stating your expectations ......RPM and HP?

[cjperformance]

Doesnt really matter if its a victa lawn mower a holden or a rolls royce, if he wants the crank at a particular measurement and the grinder says OK then thats where the crank should be at when he picks it up.
Anytime I ask for a crank to be at a particular measurement thats how it comes back. A GOOD crank grinder can work to an extremely close tolerance.

[user-23911]

Get 10 different people to measure the same thing on 10 different days with 10 different measuring sticks and you 'll get 10 different measurements.

Or more.

[cjperformance]

Get 10 different people to measure the same thing on 10 different days with 10 different measuring sticks and you 'll get 10 different measurements.

Or more.

Ok, I'll just have to politely disagree there.

[Geoff2]

Joe,
Is your micrometer older than your crank grinding machine.......Just joking!

[steve cowan]

hi 202,
i have been using PLR performance engines at brendale for the last 12 months phone # 07 3881 1342
i have been to everyone in brisbane for the last 30 years and sometimes things go wrong from time to time
these guys did some block torqueplate hone and crank cracktest and linish for me on a scat steel crank,it was done within a week and cost was very fair
i am going to get them to do a valve and seat job for me soon and i am confident they will do a good job,i dont know who you previously used and dont need to know but i am happy with the service PLR has provided to me so far,like paul (tuff xf) said you can try performance wholesale (bill mann) but i doubt you will get it done quickly
i suspect you are going to warwick next month,and if so i hope you get er done

steve c

[KnightEngines]

Got a couple of 3.3 Black cranks, one is 10/10 - I wouldn't trust the grind, dunno about the other, it's under a bunch of heavy shit.

Can't be that hard to get a blue/black crank over there can it?

[Racerrick]

Plain ol blue 3.3 Tony.

Of course I've measured the rod bores and the tunnel, which check out good.

Trial and error is telling me I don't have enough, been there before, .0018" rods and .0021 mains ain't enough.
Factory spec is pretty well useless, 2 different applications. The factory tolerance is .0007" - .0027" clearance.

Its not enough? All you need is .001 per in of diameter for hp use. Holden 3.3 rods journal dia is 1.900 so your good there but the main is 2.4978 so I would dust the block with a line hone and run it.

[carmakerevive]

Who did you use that ground it out of whack?

[202ci EH]

Ended up taking it back to him, he really wanted to see it. Got it back and it mic's up good!

hi 202,
i have been using PLR performance engines at brendale for the last 12 months phone # 07 3881 1342
i have been to everyone in brisbane for the last 30 years and sometimes things go wrong from time to time
these guys did some block torqueplate hone and crank cracktest and linish for me on a scat steel crank,it was done within a week and cost was very fair
i am going to get them to do a valve and seat job for me soon and i am confident they will do a good job,i dont know who you previously used and dont need to know but i am happy with the service PLR has provided to me so far,like paul (tuff xf) said you can try performance wholesale (bill mann) but i doubt you will get it done quickly
i suspect you are going to warwick next month,and if so i hope you get er done

steve c

X2 PLR does good work!

Got a couple of 3.3 Black cranks, one is 10/10 - I wouldn't trust the grind, dunno about the other, it's under a bunch of heavy shit.

Can't be that hard to get a blue/black crank over there can it?

Thanks for looking tony.
Most of the time its a 1.5 2 hr round trip to pick up a core engine, and only 1 in 5 are useable, the rest go in the scrap bin.
Then a 1 in 5 chance the bores sonic test nicely.