Crossover? Crossflow?

[Ondergard]

The guy who is doing the skilled work on Betsy Blue has completely replaced the brakes (which I was assured were great) with a new Riley/Wolseley 1.5 system, and done the welding her previous owner also assured me wasn't needed. (Quote from Gary the engineer: "How did those brakes get through the MOT last year? It's no wonder you had to stand on them to get any braking - all the wheel cylinders bar one were totally seized, and clearly have been for ages, the horn doesn't work, and hasn't for ages, and there is structural welding needed. As for the paintwork, it's beyond amateur...")

Anyway, he is now turning his attentions to the engine compartment. New distributor cap, rotor arm, HT leads, plugs, fuel pump (NOT electrical), fuel lines, windscreen washer reservoir and pump (non-standard... in fact, very non-standard!), air filter, oil filter. I asked about tuning the engine, and then he lost me. He mentioned doing something called... well, I think he said something about crossover, or crossflow, or something like that, and how it would give the engine a bit more poke by being more efficient in some way. I nodded sagely, but understood nothing!

So, can anyone help me by explaining what he might have been talking about? He said it would be too expensive, so he wouldn't be doing it because he wants to keep my costs down, but I'd like to know what he was talking about, and Google doesn't appear to be my friend!

[PSL184]

Crossflow heads for the A series are available but are mega expensive. Basically it means the inlets and exhausts are on opposite sides of the head rather than the same side as standard. Cheaper route is to fit a 1275 Marina / Midget / Ital engine...

[Ondergard]

Crossflow heads for the A series are available but are mega expensive. Basically it means the inlets and exhausts are on opposite sides of the head rather than the same side as standard. Cheaper route is to fit a 1275 Marina / Midget / Ital engine...

Okay... and that means what, exactly? I mean, I still don't understand the significance of the positioning of inlets and exhausts (being a complete ignoramus on the subject of engines and engineering!).

[WPR678B]

See the head in the pictures in this link. I dread to think what the final price will be!!

http://cgi.ebay.co.uk/WESLAKE-WORKS-MIN ... 4cf04dc7f6

[Peetee]

Looking at your engine you will see two sets of pipes coming in at the right hand side at the top. One set supply the fuel the other remove the waste gas. On most engines the supply is on the other side of the engine to the waste. This is done to create the ideal flow to perform both functions, produce the most power and reduce the energy wasted by just keeping the engine running. You can liken it to running on an athletics track. Doing 1 circuit round an athletics field you cover 400 metres. However if you were to run up and down the 100m straight 4 times you would cover the same distance but you would also waste a lot of energy reversing direction at the end of each straight.

[bmcecosse]

The crossflow head makes a big difference - to your wallet! The main advantage is that each cylinder gets it's own inlet port and exhaust port - doesn't have to share with others ! But in fact - just as much power can be obtained these days using a highly modified 5 port head, including 'dry decking' the engine. Some however are fitting BMW motorcycle engine cylinder heads to their A series engines - doesn't half make them go well. I think your mechanic has been gently pulling your leg - talking about crossflow heads......... This is of course a Mini - but same engine -same idea.[frame][/frame]

[Ondergard]

What do you mean, he's pulling my leg? In what way?

[bmcecosse]

Because - the cost is massive.............. There are ways to pep up your engine that don't cost very much - but crossflow will be well into 4 figures!

[charlie_morris_minor]

could your garage be the person selling the head

[Ondergard]

Because - the cost is massive.............. There are ways to pep up your engine that don't cost very much - but crossflow will be well into 4 figures!

You missed something in my original post... ie, as I indicated, he actually said words to the effect of, "I'm not going to do that, though, it's really expensive!"

[bmcecosse]

No - I noticed that alright......... He was just gently, but not seriously, pulling your leg.......... If you do want to increase the power a bit - do come back and ask!

[Ondergard]

No, I think he was actually teaching his apprentice, who knows nothing about classics and is eager to learn, because Gary and I have already got plans to put a 1275cc with a five speed gearbox and a 3.77 diff, which would by the sound of it totally obviate the necessity of crossflow.

[bmcecosse]

Oh no - a good crossflow head with twin Webers will give you a genuine (but v fragile) 120 bhp! Your standard 1275 will be ~ 55 bhp. But will be plenty for a ran around car - and the 3.77 final drive is well suited to that sort of power - although I wouldn't bother with the 5 speed box ! It will provide an 'overdrive' top gear - so with a 3.77 final drive you will be seriously overgeared. Do one or the other - the diff is obviously very much less expensive - and works well.