Jump to content
Nath

Crossflow Build Advice

Recommended Posts

Solid advice going on in here. 250 rods arent the weakest thing going around, several turbo motors run them to great effect(300rwhp+)not to mention torque. And the ARP rod bolts are future proof and reliable. Goodluck with it all

Share this post


Link to post
Share on other sites

It's more than just a engine. TBH if you spend $3500 on a engine expect to spend that on a drive line and acc to suit it to do it right.

 

Build a big engine and run a stock geared stock driveline and you will loose every set of lights. If staying manual you will NEED a proper clutch around $600.Then you will kill T5's like no tomorrow. Then you will fit a LSD to the diff when you fit correct 3.7 plus gears,then you would realize all the auto car's are still beating you so you want a C4 and convertor which will cost as much as the engine almost.   

Share this post


Link to post
Share on other sites

Stick with the 250 rod real mate.  You can rev them to 6000 if you balance the engine, which I highly recommend if you are going the rebuild way as it is bugger all extra cost $350.  If you are getting new pistons its easier because they don't have to press the old ones off to balance them (read build a tool to stop them from breaking when they press them off).

 

The carton of beer motor has 250 rods and Brenton flogged it all last speedway season to 5500 every lap.  Yes it will not be doing it as efficiently as a 200 rod motor - but it is still doing it. 

 

No problems on the other head, cam and lifter package.  I'll txt Richard today and let him know you are keen.  I freighted the whole coffin to Brisbane for $134 so I would think a small aluminium head and the other bits  to cockroach county should not be that bad. 

Share this post


Link to post
Share on other sites

Perhaps I have commented on this before (I see my name), but if it is only ever going to see 5,000rpm I would go with the smaller 218deg Camtech cam with a 500 Holley or small 4brl either on a secondhand redline manifold, reco'ed and balanced standard bottom end and that's about it.

 

Or forget about going big (it seems your goals are not set that high) and build an engine with the manifold and carb you have, a 208deg camtech and a std reco'ed 250 bottom end (maybe slightly higher comp ~9-9.5:1) and have a nice car to drive. Will love the highway with 2.77 gears and no over-drive and will work well with as low as 3.27 gears. No race winner, but a nice engine

Share this post


Link to post
Share on other sites

Sweet.

 

Slydog - Good point about the rest of the driveline. The manual box is coming with an Exedy clutch. Never had any experience with them so can't comment on how strong they are. You're right though, I don't want to be blowing through T5s. Having said that though for arguments sake, if a new 600 dollar clutch will let me get away with an a fair bit more power then I'll pony up for one.

 

I haven't got around to sorting a new diff out yet. Keeping an eye out on gumtree/evilbay, and also the local wreckers.

 

Matt - I can pretty much guarantee I'll abuse it to whatever it can safely handle without grenading, whether that's 5 grand or 7 :D. Like I said in my first post, I would rather do the bottom end and head work to leave me somewhere to go later on if I go chasing more powahhhh (because I know I will). I'm happy to aim for as much power as I can that's within the budget and won't blow up the rest of the driveline.

Share this post


Link to post
Share on other sites

A 4brl manifold (redline is good enough and I am not convinced any worse than an Aussiespeed, both have different good points) with a ~500cfm carb (465 Holley, 525 Demon or similar).

 

You can use what you have, but it will cost HP.

 

If you use the 218deg cam, I'd try what you have already, but only because you have it.

Share this post


Link to post
Share on other sites

Yeah have seen that add before.  Don't know the business personally but that is a reasonable price for a machined block and piston set.  Your comp. will get up there quickly with flat tops and a C2 head so just be careful. 

 

I would think that freight to you may be a killer and to be honest if you had a good low k motor you could just zero deck it and achieve the same result for less $$$. 

Share this post


Link to post
Share on other sites

Don't plan on freighting anything - I'm driving up north to pick up the gearbox, extractors and a bottom end for a 4.1 from one of the guys here. Was hoping to get the head posted down to him as well to get it all at once.

 

Ipswitch is only a couple of hrs extra, if it's worth buying then I have no dramas making the trip.

 

Not fussed one way or another as I will have a 4.1 bottom end anyway. Just figured getting one that's already had work done would be a good route if a good one pops up. If you reckon it's not worth grabbing then I won't bother with it.

Share this post


Link to post
Share on other sites

Would anyone happen to have a part number for the ACL pistons to suit a 200 rod combo?

 

I'm not going to hold my breath but there is a chance I might know someone who has a friend who's cousins with a guy who knows someone who might have a set sitting at the back of a shelf in their workshop. Might be worth just putting the line out and seeing if anything bites.

 

Never know, might be an old speedway dude who has a dusty set sitting on his bench or something. Can't hurt to ask. Won't lose sleep over it if nothing turns up.

Share this post


Link to post
Share on other sites

They did make a couple of different sets - some even had just one compression ring (I have a set of 5 of those thanks to a useless local machine shop).

 

There were flat tops and 8.5cc dish ones.  6MKRY9412 are the dish pistons. 6MKRY9413 are the flat tops.  They have not been available since December 07.

 

If they have them in a complete rebuild kit the part no. is RAC9412.

 

Good luck - but you never know what is out there in people's sheds.  I got my last set from a mates workshop.  They had them out the back with a heap of other good stuff.  Brand new in the box - sure the box was very crusty and dusty but there they were.  It does happen.

Share this post


Link to post
Share on other sites

Ando with the goods again! Cheers dude.

 

Not expecting a set to turn up but you never know. I found a bunch of NOS 70s Statesman parts in my garage despite the fact that no one who's lived here has ever owned a Statesman. Definitely wouldn't be the strangest thing.

Share this post


Link to post
Share on other sites

My sedan build is living testiment that shit can just pop up, but that cunt murphy and his shitty law generally means it wont pop up when your looking for it. And when the tooth fairy does find them they generally come from some one you knows uncles brothers cousins dads grandads moms sisters next neighbour friend.

Share this post


Link to post
Share on other sites

I may get flamed for this but ill say it anyway BOOOOOOOOOOOOOOOOSSSSSSSSSSTTTTTTTTTTT the fooker

It will pull the 2.77 gears like 3.9s and will put a built sub 5000rpm engine to shame, and if you keep it under 12 psi it will last and make more numbers and double the TQ

im all for a tough crossy I have heaps of them but a boosted stock engine will keep up with most of them and at less cost and if you lunch the engine get another one and go again

I did the NA thing for a long time but I now have a few boosted crossys and they will out pull any NA engine at half the RPM with much longer gearing, my white car pulled harder then my ute and under 4500rpm on a dead stock engine with valve springs. You can make them move NA but you will never have one that drives as good, my white thing off boost its like a stock engine and good on fuel, well gas

Just a option to think about and if you willing to put 3 4k into a engine bay its something to consider

 

Share this post


Link to post
Share on other sites

I have thought about that, and it is tempting, but wouldn't that mean I need to switch to EFI? I know you can box the carb but everything I've read suggests that's a right prick to get to work properly, could be wrong there though.

 

Then there's the whole engineering thing. Kind of hard to hide all the big dirty turbo gear.

 

It's something I considered but then put into the "maybe in a few years" box.

Share this post


Link to post
Share on other sites

Agree with Pro on the turbo as you cant compete with the torque and power. But if your on your P's you can do an NA crossy now but the boosted one will have to wait a few years which since your wanting to do it now figured turbo is out.

You can hide a turbo system pretty easy even an intercooler. Obviously once the bonnet is popped the games up but if its a low boost setup most of the stuff is pretty small. You dont need to run injection a boost referenced carby is all that is needed. If you put the car on straight lpg then you will have no drama getting it engineered until they realise your on your P's. Turbo is no harder than NA just different stuff required.

Share this post


Link to post
Share on other sites

Is it dandy engine builders that do a lot of boost through carbs?

 

If you did go boost, I'd leave the 3.3 in there. You could boost reference the carb you have, retard and lock the timing, mod the fuel pump or get an electric with a pressure regulator....I'm just going off memory as to what a guy did with a carb v8 commy a few years ago.

Share this post


Link to post
Share on other sites

Yes boost is the the way of the future but TBH it costs the same if not more to do it properly. Still needs H beam rods forged pistons balanced bottom end proper set up ported head and then you can decide on induction and either EFI or blow thru and the needed fuel and ignition systems then exhaust.Then gearbox and matching converter and diff then tuning.

 

I'd back it in to be dearer infact...especially if EFI but I doubt the path will be choosen here.     

Share this post


Link to post
Share on other sites

Tbh choo choo noises coming from an XD would just sound weird... fun as it may be.

 

Will give forced induction a miss for now. Later I might decide fuck it, I'll slap a turbo on it, but for now I'd rather just build myself a decent N/A engine. Can leave the boost for the fully sick VL turbos.

Share this post


Link to post
Share on other sites

You can make 300hp and 450nm on a stock engine theres no need to build one

Go for a run in a boosted crossy before making your mind up. The cost of a built basic 4 barrel engine with a cam rollers ported head would setup a turbo engine. My white thing would keep my ute and its a 5k engine just In parts and 100cubes bigger then a crossy

I was anti boost for a long time to, but its easy power and its something that should be considered that or a,,,, cough,,,, cough LS

Share this post


Link to post
Share on other sites

I'm not so much anti boost it's just that along with that there comes the extra stuff around of having to get it engineered and waiting to get off my Ps before I can drive it legally (still got like a year to go or something).

 

Besides that, I just want to build me an engine...

 

Theoretically if I want to boost it later couldn't I just put a lower compression head on it and a cam suited to the job?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×