Deck height of Aussie 250
- Thread starter L6
- Start date
Yes, the OHC was decked 160 thou to give it bonnet room when the OHC went in.
The early 1966 seven bearing 170/200's were 7.808", the 1968-1970 188/200's were 8.425". In 1969, the 250 was released in America with a 9.469" deck. The Aussie 250 of 1971 was similar looking, but ran the 9.38" deck, and a narrower block and a cam spaced closer to the crank tha the US version.
The 1984 -1995 US HSC OHV fours got 8.66 or 9.38" decks, and came in 2.3 and 2.5 litres.
We talk about modular engines today, but Ford Engines have been modular since 1960, and todays 4.0 DOHC engines still bear the same architecture of the first 4.08" bore centre sixes
The early 1966 seven bearing 170/200's were 7.808", the 1968-1970 188/200's were 8.425". In 1969, the 250 was released in America with a 9.469" deck. The Aussie 250 of 1971 was similar looking, but ran the 9.38" deck, and a narrower block and a cam spaced closer to the crank tha the US version.
The 1984 -1995 US HSC OHV fours got 8.66 or 9.38" decks, and came in 2.3 and 2.5 litres.
We talk about modular engines today, but Ford Engines have been modular since 1960, and todays 4.0 DOHC engines still bear the same architecture of the first 4.08" bore centre sixes
Thanks for all the info.
That does not seem the smartest decision. Surely there was some way they could have cribbed 4mm by lowering the engine mounts or putting a bulge in the bonnet line. If they had maintained the higher deck height then with a slightly lower piston the "long rod" AU could have used the same length rod as the 200.
xecute®™© he he":2bt5imoe said:
That does not seem the smartest decision. Surely there was some way they could have cribbed 4mm by lowering the engine mounts or putting a bulge in the bonnet line. If they had maintained the higher deck height then with a slightly lower piston the "long rod" AU could have used the same length rod as the 200.
I no longer believe in long rod, tall deck engines becasue of the wieght constraints.Mathematically, they don't work out on a wieght for power basis. The only time they work is in a turboed open wheeler, like the old 1000 hp 1.5 liter BMW engines which had short strokes, long rods and tall BMW318i-based engine blocks.
The idea from year dot is that unless it has 1.8:1 rod ratios, you are loosing power. In effect, that is still true, but the parent cars then has punative drag, weight, resource consumption restictions compared to short block engione. I'm certain somewhere at Ford, the cost implications of long rod engines have been added up, and decided against. Imagnine the weight, bonnet height and drag implications of making the current 5.4 quad cam engine have a 1.8:1 rod ratio, rather than the pitifull 1,58:1 it is now. I'd bet the Falcon would need to be 2 mters wide just to fit it!
Background on the EA 26 engine project is facinating.
When the decision was made in 1986 to go with the EA 26 programe, Ford CEO Bill Dix had to decide on upgrading the old I6 or the Colonge 4.0 or Essex 3.8 engines were to be used. In a Wheels articel of 1983, he called the engine choice "the 64 million dollar question". The astronomical interest rate rise of 1985 put paid to US import V6's, and even 5.0 V8's were looking at being A$10 000 imports when Dick Johnston was looking at one for the SVO Falcon XF. The cost of retooling for an engine line already being made in the States was too significant. Ford Oz has a general ledger the envy of the US becasue it has huge amount of local content from a very small list of suppliers, and it tends to be very much against retooling because of the cost.
Five reasons I can think of got Ford down to 9.22:1
1) The OHC was to have a short stroke price leader version 3.2 already with 6.27" rods.
2) The bonnet line was limited by the XF XG Longreach ute. Simplist option was to reduce engine deck and resulting weight to fit.
3) Cab forward was coming in vogue, and the tall deck X-body was getting hard to sell because the car felt big with a tall hood.
4) Engine weight on a six is proportional to deck height, and the Broadmedows guys looked at the cheapest way of getting the 3.2 and 3.9 OHC project running and fitting. Although 160 thou is only 5 kilos, the block is stiffer and less vibration ridden with all the gussets over it.
5) In any case, Ford Australia was working with AIT to turbo the EA, but everything when pear shaped. The bore was reduced due to head gasket issues with the heat from the overhead cam. The stock OHV Alloy Head could have the odd gasket failure.
Running the 3.68" bore rather than the eventual 3.613" bore the EA got was a good move for reliability, becasue alloy moves around a lot with the heat of the camshaft bearings and oil needed to quench the friction.
I'm not a mechainical engineer, and respect the cost strictures the brainy people at Broadmedows were under. Heck, we all wish our Ford engine was a Ferrari V12. Tecnically, the Ford OHC sixes from 1989 have done everything wrong.
If I was Ford Australia, I'd run
1) the small block bolt pattern (so you could standardise on one V8 spec transmission)
2) run a short storke engine with the old 221cube 8.425" deck height (reduce weight 22 kilos),
3) Have the 3.46" crank with 5.53" rods, for a 1.6:1 rod ratio. (With variable camshaft, weight and evirnonmental issues, the ideal rod ratio for modern cars is in fact no longer 1.8:1, so a thinking engineer could make the block as low as 8.1", and still have a sensational engine. Heck, drag engines never get over 1.5:1 rod ratios becasue it is counter productive to power to weight).
4) The bore would be increased to 3.68" with a fully jacketed base engine, and a diesel spec block with a siamese bore of 3.68" for a Teritory diesel. This could be sold as an aftermarket block for a low rent Australian Six-cyl Racing catagory. Or power boats. Or stationary engines....
If you've got an engine plant, its got to be running full tilt these days to recover costs.
When I was 17, I sat down, and decided the Lotus Charlton Turbo 3.6 engine was what Ford should be building from its existing Geelong factory. I went over a mock BMW M5 design with a turbo and no slant, and then screwed up the design and forgot about Fords for the next ten years when the Falcon Turbo failed to materialise.
These days, I see little Pug 407 diesel 2.0 Fours giving 135 hp and 235 lb-ft, and I see low sulphur diesels taking over.
I look at a siamese bore 3.6 litre DOHC cam Ford diesel. Turboed, common rail I6 diesel is enough to kill any V8. 244 HP (183 kW), 425 lb-ft ( 577 Nm)
And then cutting it down, and selling 2.4 I4 versions to the Japs and Chinese.
All it takes is someone to realise Ford has the best basis for premium grade automotive right in its front yard.
The idea from year dot is that unless it has 1.8:1 rod ratios, you are loosing power. In effect, that is still true, but the parent cars then has punative drag, weight, resource consumption restictions compared to short block engione. I'm certain somewhere at Ford, the cost implications of long rod engines have been added up, and decided against. Imagnine the weight, bonnet height and drag implications of making the current 5.4 quad cam engine have a 1.8:1 rod ratio, rather than the pitifull 1,58:1 it is now. I'd bet the Falcon would need to be 2 mters wide just to fit it!
Background on the EA 26 engine project is facinating.
When the decision was made in 1986 to go with the EA 26 programe, Ford CEO Bill Dix had to decide on upgrading the old I6 or the Colonge 4.0 or Essex 3.8 engines were to be used. In a Wheels articel of 1983, he called the engine choice "the 64 million dollar question". The astronomical interest rate rise of 1985 put paid to US import V6's, and even 5.0 V8's were looking at being A$10 000 imports when Dick Johnston was looking at one for the SVO Falcon XF. The cost of retooling for an engine line already being made in the States was too significant. Ford Oz has a general ledger the envy of the US becasue it has huge amount of local content from a very small list of suppliers, and it tends to be very much against retooling because of the cost.
Five reasons I can think of got Ford down to 9.22:1
1) The OHC was to have a short stroke price leader version 3.2 already with 6.27" rods.
2) The bonnet line was limited by the XF XG Longreach ute. Simplist option was to reduce engine deck and resulting weight to fit.
3) Cab forward was coming in vogue, and the tall deck X-body was getting hard to sell because the car felt big with a tall hood.
4) Engine weight on a six is proportional to deck height, and the Broadmedows guys looked at the cheapest way of getting the 3.2 and 3.9 OHC project running and fitting. Although 160 thou is only 5 kilos, the block is stiffer and less vibration ridden with all the gussets over it.
5) In any case, Ford Australia was working with AIT to turbo the EA, but everything when pear shaped. The bore was reduced due to head gasket issues with the heat from the overhead cam. The stock OHV Alloy Head could have the odd gasket failure.
Running the 3.68" bore rather than the eventual 3.613" bore the EA got was a good move for reliability, becasue alloy moves around a lot with the heat of the camshaft bearings and oil needed to quench the friction.
I'm not a mechainical engineer, and respect the cost strictures the brainy people at Broadmedows were under. Heck, we all wish our Ford engine was a Ferrari V12. Tecnically, the Ford OHC sixes from 1989 have done everything wrong.
If I was Ford Australia, I'd run
1) the small block bolt pattern (so you could standardise on one V8 spec transmission)
2) run a short storke engine with the old 221cube 8.425" deck height (reduce weight 22 kilos),
3) Have the 3.46" crank with 5.53" rods, for a 1.6:1 rod ratio. (With variable camshaft, weight and evirnonmental issues, the ideal rod ratio for modern cars is in fact no longer 1.8:1, so a thinking engineer could make the block as low as 8.1", and still have a sensational engine. Heck, drag engines never get over 1.5:1 rod ratios becasue it is counter productive to power to weight).
4) The bore would be increased to 3.68" with a fully jacketed base engine, and a diesel spec block with a siamese bore of 3.68" for a Teritory diesel. This could be sold as an aftermarket block for a low rent Australian Six-cyl Racing catagory. Or power boats. Or stationary engines....
If you've got an engine plant, its got to be running full tilt these days to recover costs.
When I was 17, I sat down, and decided the Lotus Charlton Turbo 3.6 engine was what Ford should be building from its existing Geelong factory. I went over a mock BMW M5 design with a turbo and no slant, and then screwed up the design and forgot about Fords for the next ten years when the Falcon Turbo failed to materialise.
These days, I see little Pug 407 diesel 2.0 Fours giving 135 hp and 235 lb-ft, and I see low sulphur diesels taking over.
I look at a siamese bore 3.6 litre DOHC cam Ford diesel. Turboed, common rail I6 diesel is enough to kill any V8. 244 HP (183 kW), 425 lb-ft ( 577 Nm)
And then cutting it down, and selling 2.4 I4 versions to the Japs and Chinese.
All it takes is someone to realise Ford has the best basis for premium grade automotive right in its front yard.
Thanks for the explanation; the reasons behind a "simple" decision are often more far reaching than first appears.
There is one aspect I would like to comment on.
The dilemma any engine designer faces is that
power is proportional to
bmep x (piston area) x (number of pistons) x stroke x RPM
and this reduces to bmep x RPM x (engine capacity)
Other parameters being equal, a reduction of stroke and deck height has to be compensated by larger diameter pistons with the accompanying increase in engine length and width, entirely negating any weight savings, and increasing the difficulty in shoe-horning the package into available engine bay space.
If the 200 engine had been enlarged by to 250 purely by larger bore size, then the engine would have been about 2.9" longer.
Even in engine design the old adage of "you don't get anything for nothing" holds true.
xecute®™© he he":3s52vcet said:
There is one aspect I would like to comment on.
The dilemma any engine designer faces is that
power is proportional to
bmep x (piston area) x (number of pistons) x stroke x RPM
and this reduces to bmep x RPM x (engine capacity)
Other parameters being equal, a reduction of stroke and deck height has to be compensated by larger diameter pistons with the accompanying increase in engine length and width, entirely negating any weight savings, and increasing the difficulty in shoe-horning the package into available engine bay space.
If the 200 engine had been enlarged by to 250 purely by larger bore size, then the engine would have been about 2.9" longer.
Even in engine design the old adage of "you don't get anything for nothing" holds true.
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