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Enkei74

250 Crossflow build

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Gday Everyone

 

I'm new to the forum so wanted to introduce myself

 

Ive been following this forum for awhile and appreciate the knowledge that everyone has dropped with 250 Crossflows that ive read so far. The only problem is I am pretty tech illiterate so cant find the info ive been looking for.

 

I have a 85 XF Fairmont, Alloy head, Carby crossflow all std.

 

I am trying to preplan how I'm gonna get  this to 300hp N.Aspirated with further potential for turbo.

 

I am planning on buying another 250 crossflow and stripping it down then rebuilding from the crank up. This way I can just keep mine running for now and build the next motor right until its ready.

 

Wondering is it better to start with crank regrind & 200 rod combo plus the correct pistons - I have read a lot of info on how to do this - but the info I have found is old so I don't know if 200 rods are available from anywhere else apart from ACL - Does anyone have a good set for sale?

 

Otherwise does anyone have a good combination that is interchangeable from other fords say EF Crank with AU longer rods & ? pistons as an example - tried & tested that will be a strong fit so I don't blow my motor to pieces in the long run e.g

 

I will make sure I sonic test the block for cracks to begin with and also more than likely cement aswell so I get this done right from the get go. Any other info would be highly appreciated such as any bearings and grinding work required and also info on doing it yourself.

 

Just thought I would start here & all help moving forward is greatly appreciated.

 

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i would suggest you read both of these threads.. then decide if the cost is justified? or in the budget.

there's a LOT of info, and heartache, and reality. 

My question would be.. why do you want 300hp NA if you are going to turbo it.. could probably turbo straight up for cheap and get 300hp relatively easy.
 

 

 

 

 

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i would suggest you read both of these threads.. then decide if the cost is justified? or in the budget. there's a LOT of info, and heartache, and reality.   My question would be.. why do you want 300hp NA if you are going to turbo it.. could probably turbo straight up for cheap and get 300hp relatively easy.

 

 

  

 

Yep with a stock valvetrain, just a decent set of valve springs, decent head gasket & fresh bottom end. Stock CR is perfect for a turbo.

 

 

 

 

 

 

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2 hours ago, deankdx said:

i would suggest you read both of these threads.. then decide if the cost is justified? or in the budget.

there's a LOT of info, and heartache, and reality. 

My question would be.. why do you want 300hp NA if you are going to turbo it.. could probably turbo straight up for cheap and get 300hp relatively easy.
 

 

 

 

Cheers for the info

Cheers for the info

 

It would be a bit of an expense but am trying to look at building this up reliably so when it revs with the turbo on it wont spit any rods.

 

I can see Slydogs ute was getting a forged bottom end - so I presume better rods & pistons? I could be wrong but thought this would be the way to go. I would like a stronger bottom end so maybe I could shot peen the rods that I have but I don't know if it will work for a turbo application and I may be wasting my money?

 

"there's a LOT of info, and heartache, and reality. " - Sounds like there would be so was thinking do you mean that the upgrades aren't worth doing?

 

Also yes was chasing 300RWHP / 220RWKW NA as then when I put a turbo on it will be even more powerful - but need it reliable

 

Cheers again for the help

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Hey XPT

 

"Yep with a stock valvetrain, just a decent set of valve springs, decent head gasket & fresh bottom end. Stock CR is perfect for a turbo."

 

Will definitely do the above just wondering what you refering to with Fresh bottom end?

 

Cheers

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9 minutes ago, Enkei74 said:

Cheers for the info

 

It would be a bit of an expense but am trying to look at building this up reliably so when it revs with the turbo on it wont spit any rods.

 

I can see Slydogs ute was getting a forged bottom end - so I presume better rods & pistons? I could be wrong but thought this would be the way to go. I would like a stronger bottom end so maybe I could shot peen the rods that I have but I don't know if it will work for a turbo application and I may be wasting my money?

 

"there's a LOT of info, and heartache, and reality. " - Sounds like there would be so was thinking do you mean that the upgrades aren't worth doing?

 

Also yes was chasing 300RWHP / 220RWKW NA as then when I put a turbo on it will be even more powerful - but need it reliable

 

Cheers again for the help

 

 

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57 minutes ago, Enkei74 said:

Does anyone know if the AU falcon rods/pistons will work as a possible alternative to the 200 rods from spool imports?

 

Cheers

i don't think you could have possibly finished reading those threads yet.

XPT means RECONDITIONED stock bottom end for FRESH.. 

i think you can go a long way with just ARP rod bolts but,  i'll ask what your budget is, because you won't get much change from $10,000 for that power level at a guess (reliably) 

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If you are planning to turbo, you are better off with stock or slightly longer than stock rods anyway. I would not use 200 rods, the benefit of the longer rods is for NA applications. There are pistons that exist for the AU rods that will work, but you will need to look. Just make sure the rod length + piston compression height add up to the same value as it does with the stock setup. If it is price that turned you off of the Spool rods, forget about 300hp NA + more later. If you have never driven a near stock crossflow and a decent sized turbo (say GT3582R) running 8-12 psi boost, you should try that first before committing to this build. 

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Yeah I agree, spending $ on an engine to make atmo power then boosting on top of that is pretty much building the engine twice.

You don't need a mega-dollar top end in turbo applications, the whole idea is that you're force-feeding it for the extra torque (and power) rather than making the poor thing scream its tits off to achieve the same goal.

A turbo setup needs slightly upgraded valvesprings, wide lobe cam, good pistons, and especially a good ignition system, programmable and with decent output. Anything less will be a massive compromise.

Making big power on what most would describe as an agricultural engine like the Crossy takes specialist knowledge and lots more dollars than the usual V8 build. The Crossy has 2 disadvantages in that regard. It has less cubes, and is undersquare so rpm is not something it likes.

A turbo fixes the breathing once the atmo torque drops off. Dollar-for-dollar, turbo wins. Build the engine solely with that in mind and bolt on the snail when everything is good to go

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I’ve got all the bits to do a Crossflow turbo build for my XF Ghia, time and enthusiasm are lacking...

However my goal has never been about max dyno numbers, more around how it goes and feels.

My build is exactly what all the above are giving advice on, fresh bottom end, MLS head gasket, small cam and valve springs. ECU is an EL with XG harness with a J3 chip.

It will toast the tyres all day long, probably make 300 and something HP...not bothered really.


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2 hours ago, gerg said:

and is undersquare so rpm is not something it likes.

that said, slydog's one revs past 7000.. far from stock though

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that said, slydog's one revs past 7000.. far from stock though
Yeah it costs a lot to defy the laws of physics, but some get a kick out of it.... Good on them, the world would be boring if everything was LS

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On ‎3‎/‎21‎/‎2019 at 1:38 PM, NZXD said:



However my goal has never been about max dyno numbers, more around how it goes and feels.




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And that's the great thing about a turbo

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Make your mind up!! 300RWHP aspo will cost serious dollars and in no way will you then be able to take that engine and add boost. If you think you can - your dreaming. Pure and simple. 

 

If you want boost, build it for boost straight away.  I have many customers who run boost and run fast reliable times with near stock components.  They have a good combination of parts, good tune and it works. 

 

You need to make up your mind and stick to the plan or your in for a world of hurt. Both will cost dollars to do properly. Both will cost even more if you chop and change and try and make NA change to boost. 

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I'm struggling to understand why anyone would make an already undersquare engine even more so. Maybe more off-boost torque? Crank harmonics would also get worse with smaller journals and less overlap. Hardly worth the trouble if you ask me.

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