ive got a 1500 TP. 1561cc to be exact (I think) i'm looking at upgrading the pistons and barrels to make it a 1641 as i hear this allows you to go up hills does anone know what size barrels and pistons i need. Im assuming that mine are 83mm and i need to upgrade to 85.5? or is it 85.5 as standard and i need to go up to 87mm? i need to take the cylinder heads off in the next few weeks to replace the pushrod tubes so thought i may aswell increase the power if i can. and is there anything else i would need to change or is it pretty straightforward? cheers in advance.
85.5 is used for a 1600 bus engine (well, it's actually 1584cc) 87 would give you 1641. There's also 1679 but you should steer clear of that because the barrel walls are very thin, and therefore not ideal for an engine in a bus (overheating issues is what I heard mention of when I read up on it). The next size up is 90.5, which is 1776, but that requires the case to be machined to accommodate the larger barrels, and you're getting into full rebuild territory there.
Dont try and get any extra power out of an engine unless your bottom end is in A1 condition The extra stress will quickly show up any wear in the bottom end most often in an expensive way
yeah just found some more info on another forum, i need an 87mm piston & barrel kit. is the move from 1584 to 1641 a noticable or worthwhile thing to do? and i take it i would just have to have my carb set up? but then again ill probably look at twin carbs in the future so thats not an issue either.
Splitting the case and doing a visual inspection and measuring up is the only guaranteed way to tell the condition of the bottom end
agree with all said. 1641 is the worst "upgrade" for a type1 engine that i know of. slightly bigger bang in exchange for a lot less reliability and durability. You can probably get the same rush just with a set of good carburetors.
As above. If you were thinking of getting twin carbs as stated that would give you more oooompphh than just 1641 p & b Probably a very small, but better MPG with twin carbs also. Keep the reliable 85s
Twin carbs,some polishing and porting of the heads and a free flowing exhaust will give you a noticable increase in power As it removes the inherent restrictions in the stock engine
