Alfa 105 Berlina Engine Rebuild

Follow along as the expert mechanics at Clydesdale Classic Cars carry out a full engine rebuild on this classic Alfa Romeo 105 Berlina 1750 from 1969.

Classic Alfa 105 Berlina 1750 Engine Rebuild

Lovingly looked after and maintained by its owner, this classic 1969 Alfa 105 1750 Berlina saloon model is a rare car.

Based on the Alfa Romeo Giulia saloon all be it with a shortened floor pan the 105 and 115 series Coupe was produced from 1963 until 1977.

Designed by Giorgetto Giugiaro who borrowed heavily from the 2000 Sprint and 2600 Sprint, it had innovative features for the time such as the flat grille with integrated headlamps.

This stunning 1750 Berlina model came to us suffering high oil consumption, poor cold starting, and exhaust smoke which the client asked us to investigate and report back.

The client had reported the vehicle was running great but noted an increase in oil consumption, around 4 Litres in the past 1000 miles.

Alfa 105 Engine Rebuild and Repairs

Fault Diagnosis

We started the investigation with a short test drive to confirm the issues as described by the client.

Our first check on the engine was to carry out a compression test on all four cylinders which would quickly tell us if we had any wear issues.

The compression test will inform us if the cylinder bores, piston rings, intake and exhaust valves, or cylinder head gasket are sealing properly.

We found all 4 cylinders to have lower-than-expected compression with cylinders 1 and 2 the worst for wear.

Results of the compression test measured in pounds per square inch (psi):

    • Cylinder 1 – 145 psi
    • Cylinder 2 – 142 psi
    • Cylinder 3 – 155 psi
    • Cylinder 4 – 165 psi

We would expect to see the pressures somewhere in the region of 170 psi per cylinder on this type of engine.

We then carried out a leak-down test to find out where the engine is losing its compression. This test is an excellent way to pinpoint where problems are before tearing down the engine. In this instance, the majority of the leak down was through the crankcase so we suspected piston ring or cylinder liner wear.

As a last check prior to disassembly, we used a borescope to check cylinder bores and verify previous tests, at this stage we could clearly see the oil contamination in cylinder numbers 2 and 3.

Engine Removal and Strip Down

With the diagnosis complete and after consultation with the client the decision to remove the engine was given.

Removing the engine from an Alfa 105 saloon is not a difficult task and so with all ancillaries disconnected and fluids drained it was time for removal.

With the assistance of an engine hoist and a second set of eyes, the engine assembly was carefully removed from the car.

Once removed it was quickly transferred to the engine stand where the strip-down commenced.

Once fully stripped all the parts were then organised and then cleaned and carefully inspected for signs of wear.

Identifying Faulty Parts

After the engine was carefully cleaned and stripped down for inspection, we began creating a list of worn parts for replacement.

Top of the list was a complete engine and cylinder head gasket kit as the original ones couldn’t be refitted.

With excessive wear in the piston bores, it was necessary to replace the liners along with a matching set of pistons and rings.

Luckily the piston liners and pistons are readily available as a complete kit and are available at a reasonable price.

A new set of big end bearings, crankshaft main bearing shells, and thrust washers were all added as replacing these items are recommended as a precautionary step.

The upper and lower timing chains as well as the tensioner were all added to the list as the chains were worn and stretched.

Further items added were a new oil pump, due to moisture corrosion, a set of exhaust valves as the originals were pitted, again also due to corrosion, and a new water pump.

All four of the exhaust valve guides also required replacement due to excessive wear. We opted to replace these with inlet valve guides, this will enable us to use valve stem seals on the exhaust valves as Alfa Romeo designed these engines with valve stem seals on the intake valves only.

A new oil filter and manufacturer-recommended specification of engine oil rounded off the list.

New Parts Required

New quality parts were sourced from one of our trusted classic Alfa Romeo parts suppliers and then shipped out to us.

Below is a list of the main replacement parts to allow us to carry out the engine rebuild on this classic 1969 Alfa 105 Berlina 1750.

We opted to install a new lower timing chain tensioner which originally was never fitted to this engine but could be easily added at a later date.

Fitting a lower-timing chain tensioner greatly helps with keeping the chain tensioned correctly and ensuring camshaft timing is accurate.

The replacement parts list:

    • Engine and Head Gasket Set
    • Big End Bearing Shells
    • Main Bearing Shells
    • Crankshaft Thrust Washers
    • Cam Cover Nut Fibre Washers
    • Lower Timing Chain
    • Lower Timing Chain Tensioner
    • Upper Timing Chain
    • Timing Chain Tensioner Spring
    • Washers for Cylinder Head Nuts
    • 1750 Piston & Liner Set
    • Exhaust Valves
    • Inlet Valve Guides
    • Valve Guide Seals
    • Oil Filter
    • Oil Pump
    • Aluminium Carburettor Mounts
    • Radiator Expansion Tank
    • Radiator Expansion Tank Cap
    • Water Pump

All ordered parts arrived on schedule and are ready and waiting for the rebuild to commence.

Vapour Blasting

As the engine was now stripped down to its component parts, this was the perfect opportunity to send off various items to a local company, EK Blast and Powder Coating, for vapour blasting.

Parts sent for vapour blasting were as follows:

    • Cylinder Head
    • Valve Cover
    • Intake Manifold
    • Engine Block
    • Engine Sump Pan
    • Front Engine Cover
    • Oil Filter Housing

Having worked with EK Blast and Powder coating for many years on various restorations and mechanical repairs their attention to detail and quality of work makes them the perfect choice to refurbish the parts to the highest of standards.

Vapour blasting serves two purposes, it ensures the parts are thoroughly cleaned before the engine rebuild begins and provides a more aesthetically pleasing look once reinstalled in the car.

With all the components cleaned and vapour blasted as well as many spare parts to hand it was time to proceed with the engine rebuild on this classic Alfa 105 Berlina.

Lanoguard Rust Protection Treatment

With the car now sitting awaiting the cylinder head and carburetor refurbishment the client chose to take this time to tackle some “non-mechanical” issues, mainly the underside of the vehicle.

After a consultation with the client and running through all the options, it was decided to opt for the Lanoguard 1-2-3 rust protection treatment plan.

Essentially this involves an initial heavy treatment of Lanoguard grease and Lanoguard spray in year 1, top-up coats of spray in years 2 and 3, and then repeating the plan from year 4.

You can read a more in-depth article on this treatment here: Underbody Rust Protection for Classic Cars

In the images below you can see the further strip-down of the car and then (after a heavy degrease jet wash) the application of the Lanoguard grease followed up with the application of the Lanoguard spray itself.

Engine Rebuild

With all the components cleaned and vapor blasted as well as many spare parts to hand it was time to proceed with the engine rebuild on this classic Alfa 105 Berlina.

The cylinder head had been skimmed and checked for straightness, new exhaust valve guides fitted, the valve seats re-cut, inlet and exhaust valves, along with valve springs and new stem seals fitted and finally, the cylinder head was pressure tested.

Now that the twin Weber 40DCOE32 carburetors have been fully refurbished it was time to turn our attention to the engine rebuild proper.

Starting with the block securely attached to the engine stand the rebuild commenced.

We have condensed the installation procedure down to bullet points making it easier to follow:

    • Cylinder liners installed.
    • Crankshaft and main bearings.
    • Connecting rods, pistons, and piston rings assembled and inserted.
    • Big end bearing shells and caps.
    • Crankshaft oil seal
    • Lower timing sprocket.
    • Intermediate timing sprocket.
    • Timing chains.
    • Timing cover.
    • Upper sump pan.
    • Oil pump.
    • Lower sump pan.
    • Cylinder head and gasket.
    • Camshafts are installed in the cylinder head.
    • Camshaft sprockets and tensioner.
    • Upper timing chain.
    • Water pump.
    • Inlet manifold assembly.
    • Fuel pump.
    • Cam cover.
    • Ancillaries.
    • Carburetors.
    • Flywheel and clutch.

With the engine fully reassembled and engine mounts fitted the engine was transferred to the engine crane ready for installation.

Engine Installation

With the engine fully rebuilt, bolts torqued and checked and a thorough final inspection it was time to refit the engine back where it belonged.

With an Alfa 105 refitting the engine assembly is normally a relatively straightforward procedure.

After careful positioning, and with an extra pair of eyes and hands, the engine was carefully lowered into position.

With a few wiggles, shakes, and some minor foul language the engine was back in the car and work commenced on reconnecting all the ancillaries.

The engine was mated to the transmission, engine mounts bolted back to the chassis, the exhaust system reconnected, fuel, electrical and coolant systems re-instated and after a final check, it was time to start the engine.

After just a few short cranks the 1750 Alfa Romeo engine fired up and was running again.

With the engine running smoothly, ignition timing dialed in and a thorough check for leaks we can now move onto the checking and running in phase.

Project Completed

After a run-in period, this classic Alfa Romeo was given a final check-over to ensure all was well after its engine rebuild and passed with flying colours.

If you are looking to have any repairs, engine rebuilds, tuning or routine servicing carried out be sure to contact us to discuss your requirements.

Discussion

Feel free to join the discussion on this engine rebuild and share your thoughts on the ongoing work of this classic Alfa Romeo 105 Berlina.

Had similar work done on your Alfa? Why not share your experiences?

This Post Has 2 Comments

  1. Gareth McRae

    Scottish Borders based and very impressed with your process. I have a 1600 GT Junior with 80k miles and mayonnaise in the oil…

    Interested in a chat regarding a rebuild, with the ambition of upping power to a fast road spec. but retaining decent driveability. Needs to be complete by late spring 2024. Email is OK but even happier to take a call on 07900492164. Or we can arrange a mutually convenient time and I can ring you?
    Kinx Regards,
    Gareth McRae

    1. Kevin Gilmour

      Hi Gareth, I have passed your details on to our workshop manager Vladimir who will be in touch shortly. Please keep an eye on your spam folder just in case. Regards. Kevin

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