Very Quick B & P question please

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marcher

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evening chaps, i'm going to strip my engine next week.

Question, will i notice the the extra CC if i go for new 1641cc B & P or will 1600cc ones be ok?????

I'm also fitting twin 40's at the same time??

I have found a cheap set of 1600cc for much least then half price :eek: :eek: :D :D :D are 1641cc B&P going to be worth the extra £150???
 
0.3 BHP i believe is the increase. a similar increase in torque. if your 1600 bzzznpzzz are good dont bother. spend the money getting some head work done to make the most of the carbs or a cam set up.
 
I wouldn't bother with Dell 40s on that set up either, they'll just be thirsty and you'll get better low down torque (where you need it) from a pair of Dell 36s.

Spend time porting and polishing your heads and put the money you save towards a nice flowing exhaust or 110 cam if you don't already have them, instead.
 
Cheers chaps.

There kadrons i'm fitting. Already have a quite pack. Dont really have the skills/time to split the case.

Anymore info on polishing and porting the heads??? could it be done by a DIYer like myself???
 
Yes! I've done a few (actually I don't know why I didn't do my new bus heads!).

The polishing bit is pretty easy, basically using a dremmel or similar you just need to smooth out all the little lumps and bumps in the inlet manifold and heads. Best to do it all when the heads are off to stop swarf getting stuck in hard to reach places.
One of the main areas to hit is the lump around the valve stems as you look down into the head inlet. I always think it looks and feels a bit like an adams apple. So you need to make that man a lady and get rid of the adams apple!

Porting is a bit more involved. Basically out want to open out the inlets so everything flows a bit smoother. So open out the holes of the base of your inlet manifolds a few mm with the dremmel, but make sure you still have material seperating the two inlet tubes. When you're happy and it's all smooth, get a piece of card, like a cereal box, and a soft hammer and lay it over the end of the manifold then tap it so it embosses the card. Now get your scalpel and cut it out so you have an accurate template of your inlet manifold.

Next take the template and transfer it on the inlet ports, you should have a bit of material showing through the template, so colour it in with a magic marker, then bust out the dremmel again and open up the ports. You need to make it so there's a smooth transition between the inlet manifold and the port. Finally you need to cut your inlet manifold gaskets the same as the templete, otherwise it'll all have been in vain. That's how you match port heads.
 
Good write up Slammed 8)

I'm sure this months Practical Classic mag shows you how to do it too.
 
Cheers Slammed vvvvvvvvvvvvvvvvvvvery helpfully. :D

Going to get PC this week and have a look
Cheers gninnam
 
I think places like John Maher Racing and VW racing can do them for £150+ a set depending on what you want. Dont hold me to that but these men have done more than id care to think of and PROPER knows their stuff.

Personally id get them done proffesionally by someone with a flow bench as a DIY job may result in cylinder imbalance also in some case removing material from the wrong places can reduce flow and therefore BHP/Torque.

I am a mechanical engineer with a full engineering workshop can easily accomplish most machining jobs but i dont think ill be doing mine myself. Its too hit and miss without the right set up IMHO.


Im building a similar engine to you at the minute, mines a 1600 TP i think my heads will be done by John Maher im also going for a merged system (home built to save on the wonga :lol: ) an engle W100 OR W110 cam (Not made my mind up) and a set of 36 dellortos.

Just hope it works. :lol: :lol: :lol:
 
Slammed said:
I wouldn't bother with Dell 40s on that set up either, they'll just be thirsty and you'll get better low down torque (where you need it) from a pair of Dell 36s.

If the 40s are choked & jetted the same as a set of 36s I wouldn't have thought it would make much difference?
 

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