Here is some info from Wikipedia. I know that World Products heads would be easier, cheaper, and accomplish the same differance on hte OHV 2.9. However, my idea was more to the Cosworth. I like the idea of swaping to the 24V heads, however I wouldn't think modifications could be made since it is an DOHC engine could it? Would that be feasable? More reserch... MJ
North American 2.9 Reliability
The North American version of this engine suffered from several serious reliability issues over its lifespan.
Cylinder head cracking was very common in early models, but affected all model years. Compared to the relatively stout European heads, the North American 2.9 had apparently been subject to a reduction of material around the valve stem guides and rocker shaft mounting pedestals. Some engines would suffer from this failure after overheating only once, while some would fail without overheating at all.
The cylinder heads underwent a redesign for the 1989 model year, receiving additional material in some problem areas. This helped to reduce the chances of this specific failure, but it was still an issue. Some of these head castings are supposedly printed with the "89TM" designation, but there has been no verification of these claims as the "86TM" designation is usually found on the 1989 and newer heads as well. The redesigned heads also have larger diameter bosses for accessory mounting than the 1st design heads.
2.9 Cosworth
A special DOHC version of the 2.9 was created by Cosworth Engineering in 1991 ( Code BOA ). Although it shared the same block as the standard 2.9 (with a few machining operations left out to improve strength), power output was up to 195 PS (143 kW) and torque was boosted to 203 ft·lbf (275 N·m) at 4500 rpm. This engine was used in the Ford Scorpio Cosworth 24V. It was always mated to an improved A4LD ( A4LDe ( small e)) automatic gearbox. No manual versions were available.
The engine used an almost 3 meter long duplex chain to drive the camshafts, tensioned by a hydraulic tensioner. The oil pump was driven by a shaft located where the camshaft previously was. The ignition was replaced by a distributorless EDIS-6 system which had no moving parts at all.
The engine was known for its substantial increase in power delivery above 4000 rpm relative to the unmodified version; in recent years the engine has become a popular choice as a replacement engine for Ford Sierras.
An improved version of this engine ( code BOB ) was available in the restyled 1995 Ford Scorpio. Differences included two simplex chains with two hydraulic tensioners and the addition of a variable length intake system called VIS. Power output was increased to 210 bhp (157 kW). This was mated to a fully electonically controlled A4LDE (big E) Autobox.
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I have been throwing around the idea of swapping in either a 2.9 from a Merkur Scorpio or even better 2.9 Cosworth (DOHC). Anyone tried this? Figuring this would be a way around emissions (still a 2.9, right?) and get some HP and TQ boost before the upgrades, which are more widely available for these motors. MJ
