View Full Version : Closed Deck engine block

23rd Aug 2010, 11:27
What is it, Mercedes use it on the E63. supposed to give increased rigidity to the cylinder block.

Does anyone have a diagram in comparison to a normal cylinder block.

23rd Aug 2010, 11:48
Modern aluminum block engines use steel cylinder sleeves inside to let the pistons ride in. Aluminum is just too soft and would quickly wear away under the abuse of piston rings.
Open-deck blocks have a space between the sleeves and the block at the top of the engine block.
Closed-deck blocks have some reinforcement between the sleeves and block at the top of the engine block.
In high-HP applications like forced induction, etc that can create much larger pressures inside the combustion chamber and more violent combustions.
An open-deck block is weaker because it cannot tolerate as much pressure. The head gaskets (between the cylinder head and block, right at the open/closed-deck interface) tend to fail due to the movement between the cylinder and block, and the pressure blows out the side.
Closed-deck blocks, being more rigid at that point, can hold in the pressure better and are more resistant to blowing out head gaskets.

Open-deck block:-


Closed-deck block:-


23rd Aug 2010, 11:50
Nice cut & paste!

green granite
23rd Aug 2010, 11:56
There are several photos on this forum showing the difference: Closed deck vs Open deck? - ClubWRX Forum - Subaru Impreza WRX and STi Community and Forums (http://www.clubwrx.net/forums/engine-modifications/38142-closed-deck-vs-open-deck.html)

23rd Aug 2010, 11:56
Nice cut-and-paste.

Simples! . . .

23rd Aug 2010, 12:00

If the closed deck block is so strong, why has it had to be welded up!;)

23rd Aug 2010, 17:43
Dunno, M8 . . .

(just an image gleened from Googoo)

Lon More
23rd Aug 2010, 18:22
Not exactly new technology. My Hillman Imp (c, 1967) had an open deck block IIRC, Derived from the Climax fire pump engine (also used in the Lotus Elite and many sports racers of the '60s) it dates back even further. Didn't the original Vanwall use 2 of those joined together, or was that the BRM? I had a book with a whole series of overlays of the engine when i was a kid. long gone now though

23rd Aug 2010, 18:37
For a very short period I owned a Renault 4cv (http://en.wikipedia.org/wiki/Renault_4CV).

It constantly flooded the sump with coolant as the liners 'floated' around. I never found a solution.
It was also (IIRC) an 'automatic' clutch operated by a switch in the gearknob (touching the gearlever disengaged the clutch).

23rd Aug 2010, 19:18
The closed block in G-CPTN's photo is probably welded because it has been converted from it's original open block design by fixing on a plate.

Strange how these things come and go; there is nothing new in engineering. The Reliant Robin 3 wheeler engine, designed 50 years ago, uses an alloy block and steel wet liners in a "closed block" design.

23rd Aug 2010, 19:30
I was told (by the owner of a Kitten) that shells for the Reliant engine are now sold 'per half shell' at a price of 9 each!

23rd Aug 2010, 20:07
The Hillman Imp's biggest problem with its open deck block was air getting into the coolant. With the engine being at the back and the heater matrix being at the front your feet would get cold. On the early ones this entailed leaving the engine running, slacking off the clamp holding the water hose to the heater and letting the air bubbles out. Later one had a purpose made bleed valve that made things easier.

Still the best thing in snow with a pair of snow tyres on the back. Towed many a Beatle out of the clag.

23rd Aug 2010, 20:36
these are also welded and slightly modified
Ah, now I see, Hermatite has obviously improved greatly over the decades..:}

And don't get me started on the "n'th" rebuild of the wife's Imp engine, lost count after 3...:ugh:

Was all that sort of mechanical purgatory supposed to be character building or wot?

23rd Aug 2010, 20:36
I used to work at a place that sold extractor exhaust manifolds for Imps. Little branched things made of 1 inch tubing!

Here's a lovely 'home-made' engine block...

DMD Australia engine block (http://www.dmdaustralia.com.au/block.html)

sled dog
23rd Aug 2010, 20:38
I too had an Imp: when faced with an engine problem, simply put supports under the engine, undid various bits and pushed car off engine. Easy. Fix problem, reverse procedure. Donk based on Coventry Climax fire pump engine, later to go onto better things thanks to a certain Jim Clark. :cool:

23rd Aug 2010, 20:50
Former Imp owner here too . . .

Several water pumps and a transaxle

(not to mention the regular exhaust valves - I carried spare valves and a head gasket (as well as the necessary tools) wherever I went . . . )

23rd Aug 2010, 22:23
I was told (by the owner of a Kitten) that shells for the Reliant engine are now sold 'per half shell' at a price of 9 each!

G-CPTN, yes, the going rate is about 75 for a set of big-end shells. But I'd never heard of half a bearing being sold or priced separately.

Still the best thing in snow with a pair of snow tyres on the back. Towed many a Beatle out of the clag.

Ringo had no treads on his shoes and that drum kit was very awkward in the snow, it's true. :E

Lon More
23rd Aug 2010, 22:48
My tool box wasa the perfect height to support the Imp engine, Once had to change the clutch at the side of the road outside Blackbushe when it packed up going back to Luton from Bournemouth. I'd got the engine out and was fitting the new clutch when someone pulled up and started to remove the battery - If you're nicking the engine, I'm having this. Disuaded him with a gentle wave of the torque wrench.

One of the quirks of the original was a pneumatic throttle instead of a cable :ugh:

Twin Weber DCOEs and a 4-2-1 tubular manifold - a bit bigger than 1"diameter though - helped it go like the poverbial off a shovel, lowered suspension and a bag of cement in the front helped it go round corners. The radiator had also been moved up front with 2 long ally pipes through the interior it was always warm in winter but uncomfortable in summer

a thing of beauty, the V16. I'd confused it with this, the BRM H16 in an earlier post

and the Climax engine was a 1.5 litre flat 16, the FWMW (Feather Weight Marine)

24th Aug 2010, 09:53
Here's the basis of the Coventry Climax F1 engines - the famous Coventry Climax fire pump engine (this one is a 1939 model - looks like a sidevalve thermosiphon):


24th Aug 2010, 10:16
Once had to change the clutch at the side of the road outside Blackbushe when it packed up going back to Luton from Bournemouth.
Same-ish story, opposite direction: Bournemouth to Bracknell - except, I managed clutchless gearchanges all the way. Just a leeetle bumpy when starting off from traffic lights - only three in all, IIRC! but I was proud of myself. After that, didn't use the clutch much except for starting from rest... I learnt to drive in a '33 Austin Seven where the clutch wasn't up to much and double-declutching was de rigeur.

Irritating car: loved the little b*gger.

24th Aug 2010, 10:27
Once had to change the clutch at the side of the road

Luxury. We used to dream about changing clutch on side o't'road ...

I once drove a Mini Moke halfway across Australia (Sydney to South Australia), with no clutch, no starter motor AND inoperable windscreen wipers!

Just to clear it up, the BRM V16 appeared in 1949 and was used in front-engined cars. The rear-mounted H16 was far more ambitious and far less successful. The chaps at BRM were still mired in its complexities when BRM effectively folded. The final version, in 1968, had 64 valves. It raced only a few times, but enough to win the US Grand Prix with Jim Clark in a Lotus 43. I wish I'd ben there, not just to see Jim Clark drive, but to see the reaction of the Yanks to the engine.

Both engines sound absolutely magnificent, like someone tearing cloth next to your ear. There are plenty of soundtracks of both engines on Youtube. Treat yer ears!

IIRC, someone once took Jim Clark flying. After the learner had completed a few circuits, the pilot described Clark as having 'got it' quicker than anyone he had ever taught.

24th Aug 2010, 10:46

Drool. The H16 in a BRM chassis. 'Owen Racing Organisation' refers to the Rubery Owen company, which backed Raymond Mays and Peter Berthone in British Racing Motors aka 'British Racing Misery'.

24th Aug 2010, 14:30
Turn up the volume and scare your missus!


24th Aug 2010, 15:15
On the subject of racing engine sounds, I learned that F5000 cars have to be fitted with exhaust silencers now! There is an upper limit (I think he said 110dB).
Anybody confirm this?

24th Aug 2010, 19:03
It sounds likely.

Around here, we have dirt track 'speedway bikes'. They're large capacity singles that circulate in permanent oversteer, spraying gravel and dirt at the patrons who stand around the track with a pie in one hand and a beer in the other. You shut your eyes and cover your beer with the pie when the pack goes past. A great night out.

However, the bikes which used to have short, open exhausts now have to have giant mufflers bolted on. It not the same without the howling noise as well as the dirt.