crossflow

[techbod]

I'm starting a rebuild of my xflow at the moment - its out the car so if you want any measurements from a to b or x to y now is the time to ask. Also if it helps, its stating the obvious but will a different inlet manifold length help clear - for example: http://www.burtonpower.com/im4242a.html or http://www.burtonpower.com/im4250a.html

>I don't do fragile engines, and still want road driveable, so a 135HP A Series is out.
>Having looked at all options the best compromise would seem to be a Ford X-flow or Pre-flow.

Some random thoughts that may or may not be useful...

My xflow was dynod at 133bhp after the last rebuild (I know, lies, damn lies and dynos) so is around what you are looking for. This was based around a 1600cc with +0.090" rebore, 1300cc +0.090" pistons (modded for higher CR), Kent 234 cam, twin dcoes', some head work, 4-2-1 exhaust manifold and careful building by a known xflow specialist - pre my ownership I should note. This is an established route to approx 1696cc and 130+bhp. But the bad bits - standard pistons and rings aren't really up to the job at these sort of outputs, the rings can wear and the piston lands between the rings can break up. Mine appear to have lasted about 10K miles (which why the engine is out now to check) but there are those that have worn them out in well under that and those that don't seem to have an issue. YMMV. If I was doing it all from scratch with a higher budget I would fit forged pistons which should eliminate the problem.

Bear in mind the xflow is a Heron head - comparatively heavy pistons and if you decide to change the head to something with bigger valves later or a cam with higher lift you may end up having to get the piston top cut outs machined to accommodate. This may or may not be an issue but worth noting. If you can find an decent engine with an AX block get it! Otherwise a 711M block is probably the best of the rest.

There seems to be some debate but if you want 'road driveable' it seems to be between the kent 234 or 244. The 244 should produce more power but some say its a pain on the road lower down the rev range. I've stuck with the 234.

If you haven't come across it already do a search for the Roger King spec xflow, supposed to be a very decent mix of reliability, good manners and power (approx 150+bhp) by a very well respected xflow builder.

Xflows make a great noise but I've taken to wearing ear plugs for journeys with mine - they are quite loud induction noisewise.

At the moment I have a daily debate with myself - heart says rebuild the xflow, head says put in a zetec. The xflow is the right engine for the cars age and style (not a W11 BTW) but that wasn't a consideration I'd go with the zetec in an instant. It is slightly heavier than the xflow though, it has to be said.

Right bored myself silly....

[Westfield 129]

I have a 125 HP A series, and I have over 16000 miles on it. No problems at all. I built it myself, using a Longman race head, scatter pattern cam, 73.5mm pistons (the AE cast ones, as I was not going to spend $800 USD on a set of pistons and pins). Running 10.6:1 compression, I have no problems at all, with anything. Oil consumption is about a pint per 1200 miles. I change oil at 2000 miles.

I did cut back on the power slightly, using a rev limiter set at 6500 RPM, rather than the more insane 7200... I am installing a 3.9 final drive next week, dropping another couple of hundred RPM, and getting a cruise RPM of 3600 at 80 mph. This will be even better with the tall 15" Dunlop race tires.

Since my Datsun transmission has a very low first gear, I wont have any problems with acceleration.

With my current setup, I have useable power from 2500 RPM. I just about never have to down shift to pass anyone.

The only problem I see with using the X Flow is that the engine is heavier, and there is not that much more power available if you like road going engines.

My luck with the A series has been quite good, and I have built a few like mine for friends. They seem to work fine. After all, my XI does 101 mph in the quarter mile. That puts it right at about 110 HP at launch weight (1,200 lbs with driver).

[jonclancy]

Off topic, but what sort of 0-60 and 30-70 times would you see with 110hp in a W11, Jan?

[erictharg]

Adam - The MX5 engine is pretty small once you strip off all the standard injection bits. Iron block. But taller obviously with the twin cams. The reason it was on my list is that they are easily available for little money and come ready attached to a nice light gearbox with not too bad ratios (not race ratios but OK for a bigger torquier engine in a light car). The 1.6 with a little work (nothing internal) would give 130hp, or the 1800 makes that out of the box. Plus it's already set up for an in line installation. Happily revs to over 7000 as stock. Magajolt for the ignition and twin 40's. Stock exhaust manifold isn't bad and would probably package OK as is. Probably the best overall option in terms of power / cost / hassle. But needs a bump in the bonnet.
Top choice for power would be a 1.8 or 2 litre Zetec S. But bigger again. However, 180 HP pretty easy to achieve without any major internal mods. That's the great thing about the modern engines - the internals tend to be very robust and the heads efficient, meaning that although you need quite a bit of external kit to fit them (different sumps, water rails, usually a different inlet set up, ECU's) they can make good power and be pretty bullet proof without changing internals or even the head. But if you are up to those power levels you probably also need major changes to brakes and rear end to cope. So it gets seriously expensive - again.
Your car shows what an Eleven can do with close to the class limit power (with a decent driver, of course!), often beating Class C cars. So I'd be looking for a way to get to that limit but without stressing the engine too much.
Jan - I agree there's more to come from the A Series, and mine is still only at 1330. 1380 or 1430 being possible (what does the 73.5mm bore give you) with offset boring, and I can either run a hotter cam and / or go for 1.5 rockers and end up with similar output to yours. Touch wood the only problem to date has been the need top change the valve springs mid season to regain the last 500 revs lost after Spa (6500 to 7000). I do have a spare Marina 1.3 engine sitting under the bench to play with...
The Crossflow isn't perfect either. Quite a bit of money to get 130hp +, as Marcus says. Plus more engine weight and a relatively heavy Ford g/box.
It's a nice "problem" to contemplate. I also don't know for sure what my current set up gives (Peter Baldwin's rolling road still being very optimistic). I'll take it to Northampton Motorsport for set up this time to get a good number. Then see how we do this season.
Mark - did you look at leaning the K Series over a bit further to get enough clearance, or do different things foul then? Or maybe it screws up oil draining back to the sump...?

[adamwilkinson]

During our discussions about the MX5 engine we decided that if we were to go down that route we'd have a new chassis made so we could incorporate the rear end too.

Just to throw another engine into the mix, what about a CVH. Very tunable, although quite tall - i raced an Eleven a few years back with a 1600 dry sumped CVH and the bonnet still required a bulge.

Can i make one small suggestion, try and stick with the same rolling road (who ever you use) as you'll be able to judge how your developments are working. I've used other roads when Pete has been busy (i know people say his road reads high) and one company had very similar results and another were so far off the mark i'm glad i was only using them for a quick tune up and not a development test.
I have heard good things about Northampton Motorsport so you wont be going wrong going there. Plus, if you have any issues with your weber, they stock all the parts for them!! Saved me at Silverstone one year!

[Westfield 129]

With a 120 HP engine, my XI does 0-60 in about 6.5 seconds. The quarter mile is passed in 14.6 seconds, at 101 mph. The LSD helps at the start, but has no bearing on the trap speed.

In a drag race with a Subaru STi, I had cleared 60' before the STi got rolling. He could not catch me for a full quarter mile. The STi is quite a bit faster in ET, but in every race, he lost at the start. While I may be better on the lights, remember that both cars have about the same power to weight ratio.

73.5 mm pistons are used in a 1380 conversion, offset bored block. I don't know about going bigger, but I can. That poor block swinging that long stroke crank. I can see it flexing...

[adamwilkinson]

Jan,

Have you heard of Swiftune?
At race retro last year they unveiled this http://www.swiftune.com/NewsArticle/80/ ... eries.aspx
Very interesting but a tad expensive...

[techbod]

>The Crossflow isn't perfect either. Quite a bit of money to get 130hp +, as Marcus says. Plus more engine weight and a relatively heavy Ford g/box.

If you are happy with 4 speeds then the type 2 gbox is lighter than the 5 speed type 9 (even if you fit an alloy bell housing) and should be able to handle anything up to 155ish bhp, so basically anything you are likely to get from a xflow without spending £££ on it.

[erictharg]

So Marcus, purely out of curiosity, how tall is a crossflow from crank centreline to top of rocker cover (excluding oil filler)?

[Westfield 129]

Yes, I am familiar with Swiftune. I have their roller rockers in my engine, and a few other bits as well. I also have parts from MED Engineering and Peter May as well.

With the coat of a good 1388 approaching $8000 or more... Say, £6000~6500... Adding a crank shaft for more than a couple of grand USD is out of the question at the moment, but the idea is a good one. If I had a cost is no object budget... YES! Maybe when I bore this one to a 1400... Now, if I could only figure out how to put that 7 port head on the engine, and clear the frame at the same time.

Meanwhile, my engine works great at 6500, though it is still a bit strange to shift when it is still pulling so strongly. It is lasting very well, and it goes well, too.