Cylinder/piston letters.

Post by **GreenyUK** » Sat Oct 25, 2014 3:29 pm

Afternoon folks.

Can some explains the difference between the AAAA and BBBB blocks. I know when replacing pistons you need to match these up. I guess it's because one set is bigger or smaller than other, is this the case? Does anybody know which is which?

If a block takes the smaller type for instance, could I just get the cylinders honed? Which would allow the bigger ones to fit?

Thank you in advance

Post by **Drax** » Sat Oct 25, 2014 4:23 pm

http://www.ludegeneration.co.uk/post235 ... AA#p235700

mentioned here

vtecmec says "It's to do with the variance in cylinder sizes. The B's are slightly larger and have slightly larger 'B' type pistons."

Post by **Vtecmec** » Sat Oct 25, 2014 5:17 pm

Yes, but I then corrected myself

, the B's are the slightly smaller ones.

Post by **4thgenphil** » Sat Oct 25, 2014 6:08 pm

Vtecmec wrote:Yes, but I then corrected myself , the B's are the slightly smaller ones.

Really?

Post by **GreenyUK** » Sat Oct 25, 2014 6:37 pm

Thought so, and if the Bs are smaller than that's good lol
As spare engine is ABBB, and i have found some pistons but they are all As
If the Bs are smaller I can just get my block honed out for the As then??
Do you know how much 0.2mm or something like tha?
Cheers.

Post by **4thgenphil** » Sat Oct 25, 2014 6:40 pm

Of the top of my head its .02mm .

Sorry i haven't replied, currently in a state of perpetual drunkeness.

Post by **GreenyUK** » Sat Oct 25, 2014 6:42 pm

Thought so, and if the Bs are smaller than that's good lol
As spare engine is ABBB, and i have found some pistons but they are all As
If the Bs are smaller I can just get my block honed out for the As then??
Do you know how much 0.2mm or something like tha?
Cheers.

Edit* 0.01mm I see, blimey that is not a lot to remove lol
Edit** oh lol I just got te above from that linked thread.. Lol
Lol fair play that's quite a bender lol

Post by **Vtecmec** » Sat Oct 25, 2014 7:38 pm

4thgenphil wrote:Really?

Yes, I really did correct myself.

It is weird that the B's are smaller though.

From the manual:

Bore diameters:

A's - 87.010-87.020
B's - 87.000-87.010

Pistons:

A's - 86.990-87.003
B's - 86.980-86.993

Post by **GreenyUK** » Sat Oct 25, 2014 7:56 pm

Vtecmec wrote:
4thgenphil wrote:Really?

From the manual:

Bore diameters:

A's - 87.010-87.020
B's - 87.000-87.010

Pistons:

A's - 86.990-87.003
B's - 86.980-86.993

Thank you very much for this vtecmec

Do I need to get anything balanced ? I'm just installing standard PDE parts into a spare H22a I dont understand when the need for balancing crank etc is required. Am I right in think it's already done, as I'm just using standard crank in h22 so everything should plug and play so to speak after the hone.

Post by **4thgenphil** » Sat Oct 25, 2014 8:29 pm

Vtecmec wrote:
4thgenphil wrote:Really?
Yes, I really did correct myself. It is weird that the B's are smaller though.

From the manual:

Bore diameters:

A's - 87.010-87.020
B's - 87.000-87.010

Pistons:

A's - 86.990-87.003
B's - 86.980-86.993

I owe you a hand job