Super-secret 356 Coupe Project

[Spyder-finder]

If you want 150bhp you need at least 2270cc.
I suggest these parts:
78mm DPR crank, 5 dowelled and mated with a lightweight 200mm flywheel and fully balanced.
H beam rods with 22mm pins
Keith black 96mm stroker pistons
Webcam 86b cam.
I would advise you not to reuse the heads and go for new cores with 44mm inlet and 38mm exhaust.
I would not use a deep sump as you will get ground clearance issues. If you intend throwing it around a track go dry sump.

[smallspeed]

Perfect! I think this is basically the conclusion I'm coming to..

Flog the near-new AMC heads on ebay for as much as I can get
76 or 78mm DPR crank, dowelled/wedgemated to a 200mm flywheel
New rods - was thinking about type 1 rods, but I don't think there's enough in it to justify saving a few quid so might as well go for H Beams (at which point there's no point in a 76mm crank - might as well go 78 and have the extra capacity)
96mm KB pistons/barrels set with the fancy rings

Need to think about heads, but coming to the conclusion that for 1400 quid a set, the new 914 heads P&P'd with uprated valves, seats and springs are looking like a good purchase for peace of mind and performance/reliability
Regards cam, the 86b keeps coming up again and again - while its poss not brilliant in a bus I think the ability to produce decent enough power/torque lower down, but also run to the red line (prob in the 5750 - 6250rpm range) would probably make it a killer option in this light weight 356 rep. Also I have the ability with EFI (using a MAF and ICV) to maintain drivability and decent idle at the lower end with a more wild cam so the 86b should work well

thanks for the input

[smallspeed]

So, been a while since I posted in this thread, and things have moved on a bit, i've just not really documented it..
I have checked the type 4 case over and partially cleaned it - ordered and test fitted a 78mm crank. Its a "no clearance" crank/rods but its a bit tight around one of the case bolt holes at the top, so I've removed a small amount of material either side from the lowest point and gained around 1mm or so clearance. Its not much, but it was about 3-4mm from the case at that point, and so I was a little happier removing some material and making it 5



I decided against the fancy 914 heads for the time being - I have a decent set of heads which I've replaced the guides in and cleaned up. I've CC'd them and done some light porting - mostly concentrating on blending valve seats, tidying up the castings so they're consistent and port matching to manifolds and gaskets. There's quite a bit of benefit to be had I think which will work well on this car where outright power isn't really the aim - its more about having a decent amount of grunt and good drivability. Heads are something that can be updated another time if its deemed "not enough" by mrs smallspeed!





My makeshift workbench..



I don't have any pictures of the next bit, but I've also done some work on the case
All of the oil gallery plugs have been removed, drill and tapped for aluminium threaded plugs. The case insides have been cleaned with gunk / brake cleaner, and all the galleries flushed and cleaned out with gun brushes / pipe cleaners. The case will be dry ice blasted outside and in (mostly outside) and then washed in a parts washer ready for reassembly in a couple of weeks

I'm travelling with work next week, so prior to leaving I have "everything that moves" packed up ready to drop off to my balancing guy - while everything is supposed to be good out of the box, id rather spend a few quid and have him cast his eye over it all. He's done all my other engines and a few for other people I know and the price is well worth the peace of mind.
He'll be getting..

- The crank (forged / counterweighted)
- 200mm lightened flywheel
- forged h-beam rods
- 96mm pistons
- kennedy stage 1 pressure plate

The whole lot will be sorted while I'm away, then packed ready to sit on a shelf for a month until I can start re-assembly!
The plan (as always with Billy) is thorough..

- balance the crank, pressure plate and flywheel
- fit flywheel to the crank and balance as an assembly
- fit the pressure plate and balance as an assembly
- weight match the pistons, end-to-end weight match the rods, pair everything up so they're as close as possible weight matched as piston/rod assemblies

By the time I get back from the US I should also have a web cam, cam gear and lifters and I can get on with putting things back together! They're currently sitting on my desk, so just need to mule them home in my luggage

[mdmax72]

Will you be adding the crank pulley and holder for balancing. Seems odd to have it all balanced and leave those out of the process.

Which webcam did you end up going with?

[smallspeed]

Oops! I’ve had to modify a pulley as I couldn’t find one that worked with upright cooling and accepted a timing wheel off the shelf.
The timing wheel, pulley, screws, etc and the holder are in the box too just missed from my list above This is the problem working from memory when there's 1000 other things going on!

I went with the 86b cam, with web lifters and timing gears - seemed the best balance for the 2270cc / 2256cc type4 in a beetle, for decent power and torque while maintaining drivability. I know some of the camper van guys find it too peaky and want more torque lower down, but I think the requirements for delivery of torque/power is different in a "sports car" and its still not exactly the wildest cam out there. Seems to also be a good balance of performance vs. wear and tear on the drivetrain

The heads will obviously be the bottle neck in this engine as-built, but for the time being I think they will be OK - the valve seats are staked per factory and not going anywhere, I've had new guides fitted and the seats re-ground, and everything else is in good shape.
Further down the line if the car needs a top end rebuild or a power hike, I can swap the heads for something a bit more exotic such as the 914 style and just tweak the mapping to suit. Everything else will carry over. Its 1500 quid I can spend getting some of the other big chunks done in the meantime

[Bruce M]

AA Parts do a brand new bare 914 2.0 head for $280. Has been out of stock after the initial batch but maybe now back in stock. If the casting quality is good, that would be a good buy (now or in the future).

Avoids the significant modifications needed to the AMC heads to move the spark plug bore and such like to the 914 spec.

[smallspeed]

yeah i saw those - i think they're AMC heads too, but they seem unavailable everywhere. these are the bare castings stateside take, port/polish and build up with better valves and springs than stock I believe, so by the time you take $280 x2 plus shipping and import, you're prob at 650-700 quid. Suddenly £1400 for the completed pair of heads from stateside doesn't sound like too bad of a deal. I think as soon as they became available just about every "head builder" brought boxes full of them!

The 914 plug location is worth quite a jump in power i think over the standard type 4 location - i don't think its worth the hassle though of moving them on these heads though
the heads i have are basically "standard" AMC 2.0 type-4 heads but they (by all accounts) have slightly improved ports and chambers and a little more material in places where the stock heads were lacking. I don't have a standard VW head to compare with. The AMC heads have "staked" valve seats (seen it called all sorts - hash peened, clinched, etc - I've always referred to it as staked) which supposedly increases the life due to the dropped valve seat issue significantly.

I found the CC's to be pretty close - within 1cc, which wouldn't be enough to bother me much in this application. After i tidied the chambers a little I re-checked and balanced them all out to within 0.25cc. I've then blended the casting into the valve seats, matched the ports to the gaskets, and tidied up in-between; working a few of the areas where there's plenty of material and some good improvements to be made but without going crazy. Its a case of making the most of what I have without going crazy because at some point it will end up with some of those tasty 914 heads I'm sure

The inlet manifolds have been matched to the gaskets too, but some more work is required at the "carb" end as they're designed for 45 or maybe 48 IDA/IDF carbs. I'll be using 40mm throttle bodies as thats plenty big enough, so there will be quite a step here. As the manifold goes from sort of 48mm diameter to about 42-43mm diameter, I don't want a sudden velocity/flow drop at this point from the 40-48mm step. Fortunately the top part of the manifold is fairly straight so I will bore this out a bit, cut a counter bore in the top of the manifold surface, sleeve them, then flycut the top again. This will be a fairly simple thing to do, to help keep inlet velocities fairly constant. It should help smooth out the transition from 40mm throttle body all the way through to the combustion chamber which is about maxed out for the cam with the bigger heads. As I say, these heads (particularly the spark plug location) will be a bit of a bottle neck, but if everything else is optimised its something that can be swapped out in the future

[mdmax72]

I’ve got a brand new pair of LE-200 heads with match ported manifolds that l may let go if/when your in the market for some.

[smallspeed]

For a type 4 or type 1?

[mdmax72]

Type 4.

Here’s a link

https://type4store.com/cylinder-heads/le-200.html

[smallspeed]

I had seen them actually - I think the price scared me off

[mdmax72]

Yes not cheap, hence why l bought them second hand new.

I bought them of Simon who had a Raby built 2270 type 4 prior to when these heads were available. His engine was around 145bhp and these heads was to be a straight replacement to give an extra 30hp or so just by swapping the heads. Although Simon never got round to fittting them, then sold his car.

I was going to use them for my engine build but changed my mind on a few things which wouldn’t suit my build.

My engine is at 170bhp but still curious as to what these heads would produce if I’d had used them.

[smallspeed]

What is the spec of your engine for 170bhp?
I’d be interested on your thoughts on performance- I’m thinking somewhere around 150bhp but a few people have said that’s way too much for a 356 rep for my wife
Not sure she’d agree..

[mdmax72]

Can’t remember full spec, will need to dig file out. Most of the spec is in my 914 engine build thread. If you doing the 2270 l think your heads will be the difference from 150 to 170.

[smallspeed]

Yeah I think you’re right, maybe 140 to 160 but definitely worth a big jump