187 replies to this topic

[Heath]

Stroking a Holden six makes the balance factor seriously bad. Low down torque is good but you won't break any records with a motor that can't be spun out smoothly.

[FastEHHolden]

On that question about breathing capacity of V8 heads....whats the bore centres of a red 6 compared to a v8? has someone got a v8 and a red6 head gasket in the shed to lay over each other? I'm have a crazy and very economical thought.

[Steve TPF]

I'd like to hear more about that. What's a BF head?

[Com_VC]

I'd like to hear more about that. What's a BF head?

Ford BF Falcon i'm guessing... I'd love to see some pics

[Steve TPF]

Sounds promising!

[FastEHHolden]

EEEEKKKK my Ford loving brother would have a heart attack especially if I stole the heads off his 5.4lt 260 Boss engine!!!

I can just see the glee on his face:

Ford 221 Crank
Boss head
toploader gearbox
9 inch diff


lucky there is a badge to tell everyone its a Holden!!!

Edited by FastEHHolden, 20 February 2010 - 02:47 PM.

[Stinga]

I'd like to hear more about that. What's a BF head?

Ford BF Falcon i'm guessing... I'd love to see some pics

+1 for pics

[Heath]

As above

[rodomo]

I'd rather come last than bolt a F@RD part on my Holden engine!...............But that's just me.



Though, I might log on anonomously from time to time to check out the pics.........

[Heath]

I don't believe that Holdens are that limited by the heads, and even if you believe they are, you can always just go J-ZED. The issue seems to essentially be the single plane counterweighting of the crank... and possibly crankshaft material. That's why I think these strokers are a kinda mediocre idea.

Remember that a Holden 6 isn't exactly SMALL in a Torana - it's just because we are used to them having V8s. There are plenty of cars the size of a Torana that have only been optioned with four cylinder motors. I wouldn't get too caught up in chasing cubes

If you want BIG POWER, you are not going to make it with a stroker, period.

Edited by Heath, 20 February 2010 - 05:35 PM.

[FastEHHolden]

It depends on what your version of "Big power" is...and considering the block metalurgy is really the limiting factor I am absoluty sure you can find the limit with a stroker.

I always planned having a high compression/low boost turbo system with my 234...from that I was pretty sure of getting the result I was after.

I just need to spend more money...on manifolds...Either "Extrudehone" a VK EFI and get an exhaust manifold to fit with it...or start from scratch...and yes Oldjohno I know your feelings on VK EFI manifold..but I reckon ported how i want them , with boost, it would work great...might need a bigger plenum though.

[Heath]

Fair enough Heath. I think enough people have successfully used strokers in relatively mild builds to prove they can last - so long as you're prepared to accept their limitations regarding the rpm ceiling and maximum output.

Absolutely, and they have heaps of low down torque. They are great street motors but using a Holden crank with offset ground pins, it will never be a race motor without SIGNIFICANT modifications to the counterweights.

Compare early and late Ford in-line six cranks to see the counterweighting changes, it's quite interesting

I should state here that I don't actually know what the 221 crank is like - what crank it is exactly, how that is weighted and what processes are involved in putting it in the Holden motor. It probably provides a shithouse rod ratio but beyond that I don't know.

But if something like a jzed head (or some sort of blower) was used, and you wanted to fully utilise its potential to make power, then it's gonna take more than a girdle and a bit of grout to keep it together. The crank would have to be billet steel for strength as well as ability to be properly balanced, and you'd want ultralight pistons and custom rods to get a decent ratio that would be gentle on the bores. Even with all this you could probably still kill the block if you rattled it hard or for too long.

Yeah I don't disagree with any of that. You can spend as much time as you want strengthening shit up, and even if you get it so good that nothing will come loose or break, the imbalance that you've ignored is still going to rob huge amounts of power and limit your motor's operating speed. Essentially you need to sort out your balance before anything else happens - there are no two ways about it. I just think that making an offset ground 202 stroker crank is just shooting yourself in the foot if you wanna get to the engine speeds where real power gets made

The balance factor on a standard 202 crank is woeful (that's why everyone is having huge vibration issues). Offset grind stroking them makes the balance factor even worse obviously

But if all you wanna do is have a Torana that pulls bloody hard down low and doesn't rev any harder than a standard red 202, then ignore my arguments (or just put a supercharger on your car lol!)

[Heath]

that's why everyone is having huge vibration issues

mmm might need to look out for them now........hehe are they more proment with the use of red cranks.

Yeah definitely more prominent with a red 202 crank than a black 202 crank, but I can assure you that neither are great! But the closer the crankpin is to the axis of the main journals, if nothing else changes, the better the balance factor.

Is yours a late model 202 crank? What balancer? I don't know what effect a flex plate & stally have (extra weight probably has some advantages). What do you rev it out to?

Edited by Heath, 21 February 2010 - 09:35 AM.

[biga064]

...The balance factor on a standard 202 crank is woeful (that's why everyone is having huge vibration issues).

And it's also why so many people using knife-edged cranks are breaking blocks...
The only solution with a factory crank is to use lighter rods/pistons and/or mallory metal.

Old Johnno , What do you recommended for a lightweight piston rod Combo ? If you already have your red crank ? Cheers Biga064

[Heath]

http://www.gmh-toran...opic=40831&st=0