1929 Bentley 4.5 Litre Engine PL3497
Highlights
- Believed to be the only original 4½-Litre Bentley engine not currently fitted to a car
- Comprehensively rebuilt and ready to use
- Well-known history of the engine and the chassis it has powered over the years
- Video below showing engine running
The Appeal
To ensure the survival of his beloved company, W.O. Bentley had to prove his cars were the fastest money could buy, and to do that, he had to win races.
Despite the immense competition success of its 3 Litre models during the early 1920s, Cricklewood’s competitors were hot on their heels, and it became increasingly apparent by the middle of the decade that a more powerful car was needed.
To make matters worse, and much to W.O.’s annoyance, many of Bentley's wealthy customers insisted upon fitting heavy saloon bodywork to their cars, further slowing them down. So with weight shedding off the cards and W.O.’s well-known dislike of forced induction ruling out supercharging, Bentley resorted to its only other option. It was going to need a bigger engine.
As American drag racers would later proclaim, “There’s no replacement for displacement” - and indeed Bentley upped the capacity of its new powerplant from 3 to 4½ litres. After successful testing in the 3 Litre chassis, a new car dubbed ‘Old Mother Gun’ was built around the engine and immediately entered Le Mans in 1927 where it would go on to set the fastest lap at an average of 73.4mph before being involved in the infamous ‘White House Crash’ eight-car pile-up.
We have the honour of bringing to market an original 4½ litre engine built by Bentley in 1929. This represents an immensely rare opportunity for W.O.-era Bentley owners, racers and enthusiasts, as original examples seldom emerge. In fact, the vendor believes this to be the only original 4½ Litre engine (excluding those built-up from non-factory parts) not currently fitted to a car.
It was originally fitted to chassis no. PL3499 - a Vanden Plas Open Sports Tourer supplied in July 1929, cited in several publications and understood to be still in existence. In around 1960, our engine was installed into a 1928 4½ Litre chassis no: AB3351 until the then owner managed to source the original engine in Australia - commendably complete and well-preserved. That engine was whisked back to the UK in 2018 for fitting to AB3351. Engine PL3497 was removed and entrusted to marque specialists for a full rebuild.
The work is now complete, the vendor demonstrates that it runs superbly and now it’s time for this engine to go back in a car where it belongs. We hope to see it powering a 4½ Litre Bentley down the Mulsanne Straight in the not-so-distant future!
The Mechanicals
- The rebuild included a complete overhaul of the bottom end using the original crankshaft with new Arrow rods
- Line boring and white metalling were carried out by the renowned marque specialist R.C. Moss with the invoice for the work available for inspection
- New pistons, valves, and numerous internal parts were refurbished re-machined and fitted
- The complete unit is still to be run in
- We’re informed that it can be installed in a car and run immediately
- Correct original factory stampings are easily legible
Ancillaries include:
- Correct original inlet manifold.
- SU Carburettors (post-war)
- Correct the original 4½ Litre exhaust manifold
- 2 x ML GC4Magnetos - (Standard fitting on 3 Litre cars, but suitable and often fitted to 4½ Litre engines)
- Flywheel suitable for a plate clutch
- Pre-engage CAV Starter Motor
The vendor welcomes any inspection during the auction, and it can also be heard running at their workshop in Hampshire.
BEFORE YOU BUY
This sale is subject to the Car & Classic Terms and Conditions. By bidding and/or making an offer, you also agree to the following:
✓ The seller of this vehicle is registered as a business seller. And you are covered by Car & Classic’s Terms and Conditions.
✓ We request that a non-refundable fee be paid if you are the lucky winning bidder at auction or if your offer is accepted. Please refer to our helpful FAQs and T&Cs for specific rates.
✓ This vehicle is “Sold As Seen”, on an “As Is Where Is’ basis and without warranty. Photos and descriptions are solely for guidance purposes and it's customary to carry out a full inspection of the vehicle prior to purchase for your own peace of mind.
✓ VAT is included in the buyer's deposit. VAT may or may not be included in the final bid or offer price, as specified in the listing.
✓Buyers are responsible for vehicle collection
or delivery. Importing vehicles may result in additional customs duties and import taxes so it's worth checking beforehand. If requested we may refer you to a third-party shipping company who can help. For more details and to speak to the team, email [email protected]
Vehicle specification
- Year 1929
- Make Bentley
- Model 4 1/2 Litre
- Colour
- Odometer 1 Miles
- Engine size 4398
Listing Details
- Seller Type Trade
- Location Hampshire
- Country United Kingdom
The Gallery
Make an offer
This seller is open to offers. Enter the amount you'd like to pay and if your offer is accepted, a member of the team will be in touch.
Under offer
This seller has accepted an offer.
Click the star to watch the listing and keep an eye on it in the favourites section of your account, or search for something similar.