so i've dropped the engine and hope to crack the flywheel nut today and split the case (suspected cam lobe failure). I'd like to increase 'cc' while in there (type 1 1600 remtec engine from 2008). It looks like the cost of 90.5mm b&p (for 1776cc) is the same as 94mm (for 1914cc). Is there any downside to going bigger? Machining issues? Clearance with the cylinder head studs? Possible heat issues? I'm planning to keep everything else standard (single carb, standard exhaust) for now! Any thoughts. Cheers.
Pretty sure you will struggle to get a bigger bore engine to run right without going to twin carbs. I did once see a 1776 on a standard carb though.
Matt's 1776 runs on a single Webber progressive. I wouldn't want to go any bigger though I don't think.
both involve machining so it's not something you can do yourself without the proper tooling....neither option will give you the sort of power increase to put a huge smile on your face, unless you spend £££s on ancilliaries (reworked heads, exhaust system, manifold (s) carbs, full flow filtration, improved cooling, dowelled flywheel, cam, ignition improvements etc.etc.)....so for my money, I'd go with 1776 , dynamic balancing, 3 angled valve job, and full flow....twin carbs/exhaust system are bolt-on mods you can do at any time
1915 will have thin barrel walls so not great for a bus, You could pop a 74mm crank in with the 90.5s to give 1903cc !!! Not sure the carb would work though.
Yes case needs machining ,probably need case savers ,heads need machining ....why not keep standard barrels and just up the crank to give you more of a 'square' torque engine
1915cc is a great size bus engine and costs no more than a 1776cc, either way will involve machining so costs should work out the same. I have lots of mates with this combo and it works great in a van. You will have to upgrade the exhaust and carbs at the same time, you'll end up running it lean and causing majort issues if you try running it from a standard single carb or even a 32/36 progressive. You could run it from a central single twin choke 40 IDF, but that will be a struggle to fit in a bay engine bay so a pair of twin 40's would be your best option. Exhaust wise a vinatge speed system is a good bet, they are good for 125Bhp so about right for a mild cam'd bus 1915cc
I'd like to revive this thread instead of starting a new one if that's ok. I'm going to give my engine to Dave Wheatley in Armagh. I spoke to him on the phone and he said that a 1776cc would be as much as a 1915cc so why not go to that. I was asking about going for a stroker crank for the 1904cc option but then I'd have to change push rods and tubes. But then would a stroker give me better torque over the the 94mm piston and barrel upgrade for the 1915cc? He also said a 1915cc would run fine on a single carb.
Iwould have thought twin dell or kadron or weber 40's. Surely the stock carb is not up to the job of a 1915.
there is no replacement for displacement I don't know anything about specs for a 1915cc suitable for a bus, i do have info on specs for 1776 and 2110cc
The thing you will need if you decide for more power is more cooling. a 1776 might get away with stock cooling until you forget and fry it on a hot fast run. I can still make a 1641 get quite hot on the way to Techenders 140ish miles with a smaller 8 row off board oil cooler. Oxford bypass is the usual hottest place. Miles gently down hill then gently up hill.
I have a 1956cc T1 a slightly unusual choice using a 76mm crank and stock length rods and 90.5mm pistons. At the time I built it I spent a LOT of time reading up on the Samba but also non VW engine building forums because so much of ACVW engine building knowledge is based on drag racing/low mileage/short life engines. I've actually forgotten most of it now (Rod Ratios, Air Flows) but i can state my engine is very torquey with 044 heads and an Engle 110 cam. I'm nearly always in 4th gear and have a fully equipped Westy and also tow a trailer. Economy is the same if not better than the standard 1600. I'm running twin Weber 40 DCNF's with 30mm chokes but theoretically you could drill out the jets on a standard carb to get the mixture right on any CC engine but you'd really be holding it back. Originally it would get quite warm on long runs in high heat abroad mid 30's, but after re-doing the heads for a better compression ration and getting it rolling roaded it never runs above 90C on the oil temp without an oil cooler. Get the CR right, mixture tuned correctly and all factory cooling in place and your 1776cc shouldn't get too hot.
thanks @V.R.M. It's the 1915 I'm thinking of going for. so stock crank with 94mm pistons. I think a 1904 is stock size pistons with a 74mm crank which would be more torquey. what's a better option for improving cruising speeds and not acceleration?
Really, for higher cruising speed you want a higher ratio gearbox for which you need a torquey engine, so that would suggest a longer stroke crank. But a new gearbox is going to cost you a whole load more cash and if money was no object I bet you'd be building a 2.3 turbo and not worrying about the fuel and insurance! With your existing box the only way you are going to be cruising faster is to run higher revs and a standard length crank would probably be the best for revs, but its really not going to be nice buzzing away and isn't good for the life of the engine. You'd certainly want a counterbalanced crank too. I would caution against 94mm pistons because there is less cooling fin area around the barrels, 90.5mm barrels are established as a good compromise between power and cooling. It probably depends on your mileage and the reliability you want. Personally I'd go 1776cc and spend on the best bits I could get, fully balance everything, get it rolling roaded etc. Just a though, but if you have a panel van, it is possible you have lower ratio box than a standard bus - might be worth a check.
John Maher Racing has some good information on pros and cons of different bore size etc I've had 90.5mm barrels on a 1776cc and on a 2110cc bus engines http://johnmaherracing.com/2013/01/project-2110-part-2-bore-stroke/
Top bloke John Maher, I have a few bits from him in my engine from way back. I wish I could afford a complete motor from him! Think he's more busy with his camera these days though.
Thanks folks. Here's a thought on longer stroke engines. Correct me if I'm wrong but wouldn't more torque mean you could stay in the higher gears more often when not at motorway speeds therefore get a bit better economy in those situations by keeping the revs down which would also keep you running cooler more often?
You could stay in a higher gear for longer but the engine still has to produce the same power to push the bus along at the same speed so unless efficiency is improved there is still the same amount of fuel being used. Unfortunately with an air-cooled engine as the engine revs are reduced the fan speed is also reduced so there is less air trying to cool the engine. Same speed, same heat, less cooling.
Fan is at its fastest at 3500 rpm apparently. Bigger capacity engines can get you to desired speed at lower revs, so engine working less hard and therefore producing less heat? There is a thread somewhere on here about similar. I did the same journey with same engine but different ratio gearbox es, I measured temp and fuel consumption. Not very scientific but interesting. Temperature was cooler with gearbox with equivalent ratios to a 6 rib.
