Increased power in type 1 1584 AE engine

[uladk84]

Hello everyone. I've recently bought a T2 so now can offically ask all the experts for advice about my bus!

I have a 72 crossover model (Floss), with a type 1, single carb 1584 AE engine, that I got for pleasure and also a business project I'm working on. I will be doing a lot of towing, and travelling in the Alps, so I want to increase power for that to be more comfortable. I've been reading around on many sources, but I'm still confused on the direction to go in.

If I stick with the single carb 1584, what modifications can be done to increase power? Can I convert to a dual carb setup? What kind of work would be involved? Modified tinware? I've been looking at this kit: http://www.justkampers.com/top-end-engine-rebuild-kit-vw-beetle-1600cc-1971-on-vw-t2-bay-1600cc-1971-1979.html

Or would it be better to switch to a 1776/2L type 4 engine, and upgrade the gearbox at the same time? What kind of engine bay modifications would be needed for my 72 crossover? New engine/trans mounts?

I'm not interested in adding fuel injection, or any other kind of engine swap, just an extra aircooled boost. I want to be able to do most of the work myself to reduce costs and learn about my bus, but if the engine bay would require a little modification, then that is fine.

Any help is appreciated.
Cheers,
Lewis

 

[StuF]

We had a very similar discussion at Skeg Vegas the other week ref increasing usable torque and power mainly to improve the buses pulling power.
Speak to Graham at Midland Early Bay!
I think the figures banded around were roughly £2k to utilise your current block and get it rebored to a 1776 - no need to modify tinware or engine bay.
No real need to go for twin carbs as they really only affect the power at the higher revs which wont be required when towing.
Single carb will need rejetting for the larger fuel requirements and an upgraded exhaust would be required over the standard one.
Vintage Speed is a good solution.
2L type 4's are great engines but spares can be very hard to come by and their heat exchangers and tinware are like unicorn tears!

 

[uladk84]

Thanks for the replyy StuF.

I've seen kits for 90.5mm pistons and cylinders that replace the stock 85.5mm ones. Can the crankcase be modified in such a way to safely accept those?
https://www.coolairvw.co.uk/Item/Shop_by_Product~Engine_Products~Barrels-C-_Pistons_and_Heads~Barrels_and_Pistons~Big_Bore_Barrels_and_Pistons/AC198910/T1-P-T2-P-T3-P-KG-P-T181_1776cc_Stroker_Barrel_And_Piston_Kit_-OB-90.5mm-CB-_-_Mahle_Forged.html

They use the existing 69mm crank, but that can be upgraded to 74mm later if I wanted to get 1904cc.

If I was to overbore my existing cylinders, I would end up with the exact same product in that kit right?

Apart from rejetting the single carb, would I need to modify anything else? The heads, timing, etc?

Thanks again

 

[atafonso]

The case and the heads needs machining. Your cylinders cannot be bored for 90.5mm for there is no enough meat in them and also no machine shops can do it due to cost and a special fixture needed to simulate the torqued condition of the cylinder in the engine to be bored correctly round.
If you buy the 90.5mm pistons and cylinders, machine case and heads; everything else can be reused if in good condition, including the exhaust. If you plan to make more power(instead of torque), then you can change the cam, add dual carbs and choose a more free flowing exhaust.
Keeping all stock parts and only increasing capacity to 1776cc will make the engine considerably more torquey, perfect if all you want is to improve driveability.

Abel

 

[K@rlos]

We had a very similar discussion at Skeg Vegas the other week ref increasing usable torque and power mainly to improve the buses pulling power.
Speak to Graham at Midland Early Bay!
I think the figures banded around were roughly £2k to utilise your current block and get it rebored to a 1776 - no need to modify tinware or engine bay.
No real need to go for twin carbs as they really only affect the power at the higher revs which wont be required when towing.
Single carb will need rejetting for the larger fuel requirements and an upgraded exhaust would be required over the standard one. Vintage Speed is a good solution.
2L type 4's are great engines but spares can be very hard to come by and their heat exchangers and tinware are like unicorn tears!

That's false, a properly jetted and tuned set of twin carbs will increase power and torque across the entire rev range FACT. Vintage speed are quite frankly overpriced. They are in essence a stock exhaust which is as you say restrictive plus the quality is rather poor for the cost, yeah the outside is stainless but the guts are all mild steel so after a while the baffles break upside.

Get twin carbs and a 4 into 1 exhaus then get them set up properly, Ideally for a torquey little towing motor I'd go 1776, twin 36's or maybe 40's, and some ported stock head and Engle 100 or 110 depending on your driving style and a quite pack or similar. Will be vastly more torquey than a stock motor and scoot along with traffic nicely too

 

[StuF]

Cheers for the info - nice to know twins are effective throughout the engine range not just at higher revs as I was told.
Glad I went to the trouble and expense of fitting them.
Wasn't a cheap conversion though using decent parts. Twin 36's with all the gubbins won't give much change if any out of a grand once carb linkages, manifolds, fuel pressure regulators, fuel pipes, vac lines and jetting is taken into account

Advantage I found a VS has over a 4 into 1 is that installing a tow bar is remarkably easier with VS.
Or to be a little more precise all the exhausts I looked at that incorporated equal length headers and heat exchanger connections wouldn't fit with a tow bar in place.
However as I'm no engine builder just an Aerospace biased Mechanical Engineer I'm sure I didn't find every single model out there. And I do like the VS burble 8)
What exhaust would you recommend that works with a Gadget Tow Bar and performs well with a torque centric engine?

 

[Zcat7]

I have to say that the first thing I did to my 1641 engine was fit twin carbs and the result was dramatic. These were the relatively maligned Kadron 40s but I have to say that they have been a cracking little set of carbs for me - very reliable and stable despite what some others report. Improved torque and fuel consumption (as you don't leave half the petrol stuck along the walls of the long inlet tracts of the stock manifold) and hills were no longer an embarrassment.
I did however build a 1776 later, after I split my AS41 case, with an Engle 100 cam and Vintagespeed exhaust but stock everything else apart from the Kadrons. Night and day difference over the 1641 (so even more so over a 1584...) once the Kadrons were jetted correctly.
I have now bought a set of Weber 40s (off of K@rlos ironically!) which I will fit once I have all the parts and I imagine that this will be my last upgrade unless something should go bang, in which case I might go for a longer 74mm crank to get 1904cc.
I use a Vintagespeed for similar reasons to StuF and I find towing with this setup easy peasy!

Finally, I have just fitted a set of Weber ICTs to my Sister's T25 with a 1600 CT engine - once again dramatic improvement and she is well happy that the bus will now pull up a moderate hill without dropping a gear!
As always though, make sure your base engine is healthy and has good compression etc as all these bolt-on mods are a bit of a waste of time otherwise and you won't be able to set things up to get best performance from the money you are spending.

 

[mike.s]

What Karlos says - twin carbs, 4 into 1 header exhaust get the heads ported and flowed, maybe some ratio rockers and you will have a noticable improvement in power. make sure your bottom end is in good condition first though.

You can further improve the torque, power then by machining your case out 90.5mm b + p, align bore, etc, maybe a stroker crank, cam, etc.

Of course, the more you want to increase the power, torque and keep reliability the more money you spend!

The first step alone above will cost in parts and head work around £1500-£2000 straight off.

 

[K@rlos]

Realistically the only decent exhaust to work with a tow bar is something made by turbo thomas or maybe a CSP python. But both of these aren't cheap, I don't have a tow bar fortunately and i run an old skool 1 5/8 merged header with a 'phat boy' muffler

 

[uladk84]

Thanks for all the great information, and my apologies for the very late reply. I have been caught up in other things.

Setup wise, I have decided to go with the following for my 1776cc:

- 90.5mm barrels and pistons
- stock 69mm crank
- stock heads: mildly ported with 3 angle valve job
- Engle W100 cams
- twin weber ICT 34s
- 26mm oil pump (30mm if I do full flow & filter)
- 55amp alternator upgrade
- deep oil sump
- stock exhaust size but still not sure which exhaust to use

What deck height / compression ratio should I aim for?
Would it be worth upgrading to a counter weight crankshaft?
Are 1.1:1 ratio bolt together rocker arms correct?

Spot anything that can be tweaked in my setup?

Cheers guys

 

[VeeDubMan]

Thanks for all the great information, and my apologies for the very late reply. I have been caught up in other things.

Setup wise, I have decided to go with the following for my 1776cc:

- 90.5mm barrels and pistons
- stock 69mm crank
- stock heads: mildly ported with 3 angle valve job
- Engle W100 cams
- twin weber ICT 34s
- 26mm oil pump (30mm if I do full flow & filter)
- 55amp alternator upgrade
- deep oil sump
- stock exhaust size but still not sure which exhaust to use

What deck height / compression ratio should I aim for?
Would it be worth upgrading to a counter weight crankshaft?
Are 1.1:1 ratio bolt together rocker arms correct?

Spot anything that can be tweaked in my setup?

Cheers guys

No need for a CW crank. You're not going to be racing it/revving it too high with a 100 grind cam. Stick with stock rocker ratios too and you won't need a 30mm pump either with that set up.

John Maher doesn't recommend going higher than 8.0:1 on a regularly street motor and will get it closer to 7.8:1

Sent from my SM-G920F using Tapatalk

 

[K@rlos]

No need for counterweight crank, as said not enough revs. Just get the whole rotating assembly balanced and no need for a 30mm pump. 26mm will be ample even with a remote filter and external cooler

 

[mr scoops]

I disagree, get a counterweighted crank and get it balanced. Although you may not be revving it high getting it balanced will make it a lot smoother running and will increase longevity.
I was led to believe a non cw crank couldn't be properly balanced.

 

[atafonso]

The finest crank ever made to an ACVW is the stock German one. The best performance cranks availabke today are simply stock German cranks welded for more stroke. And yes, they can be properly balanced and it's a great upgrade for longevity.
If you not revving past 5k you are ok with a stock non counter weighted crank.
Abel

 

[K@rlos]

I disagree, get a counterweighted crank and get it balanced. Although you may not be revving it high getting it balanced will make it a lot smoother running and will increase longevity.
I was led to believe a non cw crank couldn't be properly balanced.

:lol: who told you that? any crank can be balanced! I had the stock crank in my 1200 bug balanced when I rebuilt that. Why spend out on a more expensive crank when it isn’t needed? A balanced German crank is good for 5000 rpm. Get the pulley, pulley bolt, crank, flywheel and clutch all balanced as 1. Stateside tuning charge about £100 for that service. Job done