356 top cruising speed critically viewed.

[Super90speedshop]

I've owned and run pushrod 356s for over 40 years. I've always done most of my own work apart from body and paint and on the odd occasion when I've had work done professionally I've never been happy with it. At the moment I'm running a 58, a 63 and a 65. They are all fully restored and spot on. My query us about reader/owner comments on the top speed of the pushrod 356. All the ones I've had over the years have been pretty well done in practical by the time they get to 80 mph or so ( in top gear ). They will go faster but the increase in noise of all sorts really makes pushing harder extremely impractical. I've just be re-re-reading the various and highly interesting Brooklands Books publications based on reprints of 356 road tests of models ranging from 1952 to 1964. Some of these road tests are English and some are American, all are from well established specialised motor journalists. There are many common comments on the 356 of course but the " ease of cruising, without fuss, at 100mph" comes out time and again. I know that many readers/356 owners will have exercised their cars on the track, the German Autobahnen or even the Isle of Man and may be able to comment from experience on the pros and cons of 100 mph cruising in a pushrod 356? Thanks in advance. Phil at the Super90 Speedshop, mid Wales.

[neilbardsley]

Some people, mostly in the states, fit Vic longer 4th gear which makes higher top speeds possible. I don't know about 100 but mine is happy to run near 90 in cool weather. I guess it depends on how happy your car is sitting at about 5k rpm.

[Ashley James]

All old cars are undergeared by modern standards, my Merc is doing under 2000rpm at 80 so I find it worrying to be doing around 4000 at the same speed in a 54 year old car. Therefore I cruise mine at seventy five.

Back in the sixties I drove my Healey at over 4000 all day in top, but now and quite apart from the dopey slow drivers everywhere, I rarely exceed 3000 because it’s making such a row.

[jb]

My 59 1200 beetle used to hold 90 without any trouble and I can't remember my 356s being any slower.

[vwgillybilly]

I’m not sure ‘cruising’ in excess of 75mph for a sustained period of time is possible anymore in the UK anyway...

Gill

[Hendrik Moulds]

In the PreA I like to go 60-65 and just cruise along. Yes it will go faster, I just don't feel like it or enjoy it much.
The '59 A I had was pretty much silent (like a modern car) at 80 and certainly could have gone faster, although the acceleration from that speed wouldn't be much. So I can well imagine that the original road tests would easily go to 100, the modern traffic environment would suggest to me that such high speeds in these older vehicles would not be prudent.

[neilbardsley]

I’m not sure ‘cruising’ in excess of 75mph for a sustained period of time is possible anymore in the UK anyway...

Gill

Only possible on the France 130 kph toll roads and the German Autoban

[simon james]

So many different opinions!
I always try to stick under the 70 limit, mainly because my 356 tends to run hot, well, it does in the recent heat we’ve been having! I would say 75 is about right, but my car does seem happier the nearer to 100mph it gets!
Interestingly, the faster it goes the more responsive it gets!
My limiting factor is noise, the boxer sound is loud in this particular car and is probably a combination of transmission mounts and “bottom end” (main and big end) deficiencies caused by the previous owner fitting a big bore kit!
It keeps going though, so for now so will I!!!

[roy mawbey]

Been running my 356A super 75 for almost 50 years. These days for sure don't exceed the max speed anymore. In the late 60's I had an indicated 108 mph from my engine with long empty straight and flat road. The top speed has been mentioned as around 112mph. Thats the super engine bit more grunt than the normal 60hp. My car is easy to get to 70 much more left especially if you work the gears more than usual.

I remember the RPM being well round the scale at near to top speed but not in the red.

My 356C was much the same in response and I would imagine the S90 would be that much faster too.

Certainly my ' A ' never feels it running out of power in fact I do feel like pushing it more at 70 mph as its very unstressed there. ( I might be wrong or forgetful but at 70 its at around the 3K mark on the rev counter in 4th )

These days I just want the engine to continue running and I enjoy my pottering around. No way can you compare speed and the 356 to say my 3 series BMW thats just not possible.

Roy

[richkaz]

Not sure if this helps but from an old road test book a Super 90




The following info specifically and strictly only for the eyes of Graham - 911 hillclimber

[mycar]

That's a great find... and funny.

[Kneeslider]

I'm interested in this because I am a relative newcomer to 356 driving. I made the long trip from Yorkshire to Le Mans for the 24 hours in June, so max comfortable cruising speed is something I have found out the tough way! Now my engine is quite a way from stock, and given that I built my car myself, was wondering if I have done it right, and whether or not it is a good one.

My engine has a SPG roller big end crank and rods, a 616/16 cam (SC), and a set of new AA 1716 (85.95 x 74) big bore kit. My heads however are not the big valve ones from the SC, but 38.5mm inlets, and 31.5mm exhaust, and topped off with Solex Pii40s. Gasses are exited through a Dansk stock looking silencer. My piston to head clearance is 1mm, which by my reconing gives about 9.3:1 CR Largely the spec of my engine, thought not what I would choose, is as it came from the USA, so I decided to stick with what I have, being a tight northerner, and see what happens. My case is early B, as are the heads, but the 3rd piece has the larger oil pump.

On stock 741 / 2C gearing I can see 70mph at about 3,500rpm.

Sustaining this speed is really easy, even on long uphill sections of motorway, and the oil pressure and temperature stay pretty steady. The car seems to cope with higher speeds comfortably, but I find that the noise and vibration get intrusive at speeds higher than about 75mph. The whole experience is very similar to being in a small aeroplane. I have seen 5,000rpm in top which is just about 100mph. That seems plenty, and surprises people used to moderns who think that all old cars are slow and boring.

Is my car in any way typical?

I think that a higher top gear or diff ratio would be beneficial. Some folk in the USA are making 5 speed conversions using VW bits. That might be the way ahead.

[Ashley James]

That’s how I feel about mine, which is a 356C. I’ve no idea whether it’s standard inside but it has Zeniths and shoots round to 6000, even in top if you let it, but 3,500 feels max comfortable and a bit less might be kinder. It’s a fantastic car but undergeared like all oldies.

[Hendrik Moulds]

I get a similar feeling in the PreA, but at slightly lower speeds and there's no way I'm going anywhere near 100mph!
Never had any vibrations from the A I had at any speed, it was just a delight.

[neilbardsley]

I'm interested in this because I am a relative newcomer to 356 driving. I made the long trip from Yorkshire to Le Mans for the 24 hours in June, so max comfortable cruising speed is something I have found out the tough way! Now my engine is quite a way from stock, and given that I built my car myself, was wondering if I have done it right, and whether or not it is a good one.

My engine has a SPG roller big end crank and rods, a 616/16 cam (SC), and a set of new AA 1716 (85.95 x 74) big bore kit. My heads however are not the big valve ones from the SC, but 38.5mm inlets, and 31.5mm exhaust, and topped off with Solex Pii40s. Gasses are exited through a Dansk stock looking silencer. My piston to head clearance is 1mm, which by my reconing gives about 9.3:1 CR Largely the spec of my engine, thought not what I would choose, is as it came from the USA, so I decided to stick with what I have, being a tight northerner, and see what happens. My case is early B, as are the heads, but the 3rd piece has the larger oil pump.

On stock 741 / 2C gearing I can see 70mph at about 3,500rpm.

Sustaining this speed is really easy, even on long uphill sections of motorway, and the oil pressure and temperature stay pretty steady. The car seems to cope with higher speeds comfortably, but I find that the noise and vibration get intrusive at speeds higher than about 75mph. The whole experience is very similar to being in a small aeroplane. I have seen 5,000rpm in top which is just about 100mph. That seems plenty, and surprises people used to moderns who think that all old cars are slow and boring.

Is my car in any way typical?

I think that a higher top gear or diff ratio would be beneficial. Some folk in the USA are making 5 speed conversions using VW bits. That might be the way ahead.

Sounds pretty typical. I'm not sure about the noise although. Is the vibration coming the from engine? If so I would be a little worried. Are you happy the fan is balanced? Does the engine sound balanced when you run it at higher rpm? Have you checked that the carbs are balanced at 3k, 4k etc. When I do faster in my 356 most of the noise is air over the car. However, in the 912 it seems to vibrate a bit more between 80 to 90 but then goes away.

Your compress at 9.3 is what I seem a few recommend. I'm not sure about 38.5mm inlets, and 31.5mm exhaust. If you go on the 912bbs board Mike Horton and others are experienced engine builders and will help. They are a bit more forgiving then the 356 registry lot.