Section XXVII 2 Litre Pinto Engine Rebuild

Introduction

My Robin Hood 2B as built was fitted with a bog standard 1.6 litre Sierra Pinto. The reasons for this were simple. a) I was given one by a member of the NW RHOC&R) I felt that just building a standard Robin Hood was enough, without the extra complication of fitting a nonstandard or fuel injected engine.

I always wanted a 2 litre but they are not that easy to find, and the thought of just getting that solid cast iron lump home was bad enough, I hold the Cheshire and World record for Hernia operations.( 5) Imagine my surprise when the local carpet fitter said he had one in his garden not 1/4 mile away. A quick visit and sure enough with 205 cast on the block and P stamped on the head I had a 2 litre Pinto with hardened valve seats to boot. Engine code N4 September 1988

To reduce the weight, the Cylinder Head and Flywheel were removed on site, unfortunately the Inlet and Exhaust manifolds c/w carbs were missing, this lot was loaded into the back of my Passat and hey presto, I had a very dirty 2 litre Pinto sitting on the floor of my cramped garage.

A quick examination showed why it was 'free' The camshaft was worn on the crests by about 1 mm, and the cylinder bores the best part of 0.20 mm. It was pretty obvious that if the car was to be 100% reliable a full rebuild was needed. God knows what the crankshaft will be like. Fortunately as long as the block is sound, and the crank and head are not cracked, it is possible to rebuild to almost as new. Plenty of money is also required. Re-bore £60.00, New pistons 4 x £18.00 Crank Grind £160.00 and other bits no doubt. A new camshaft is £160 from Ford's Is it worth it !!

When dismantling make sure you keep all nuts and bolts, these are best put back into the holes they came out of. Keeps all the crap out. Watch out for special bits like the Rocker cover washers. It is not the cost, it's the aggro of sourcing bits you have lost or misplaced.

Cylinder Block

After draining the oil, plus all the accumulated water acquired after standing in the open for 5 years, my first job was to remove the crankshaft pulley, as this was an ex Fuel Injection model, the pulley was very tight and a bit of heat (watch the rubber damper) and a puller were required. Next job was to fabricate a low castor trolley and get the engine onto it, upside down, after removing the oil level pipe. (in the end I broke it off!!) Now the dirty work, a combination of wire and rotary brushes, Gunk, Paraffin and a high pressure lance removed all the 20 odd years crap and rust. The outside was then given a coat Kurust, this gives the paint a chemical key and kills any rust as well. This was followed by a coat of high temperature engine paint, more or less to stop it going rusty again, as no doubt it will require a second coat at the end of the rebuild. The sump was removed and then the alloy castings on the front of the engine were removed for special attention. Next the Distributor and Oil pump drive shaft, Oil pump, strainer and feed pipe, Oil filter, Temp and Pressure sender were removed, and any other items not part of the casting, Place everything away carefully for later inspection. The crankshaft timing pulley was very tight, but a dose of penetrating oil and a blowtorch finally shifted it.

The sump was placed to one side as it will need be shortened.(see the RHOCaR article) Keep all the bolts and washers in a bag. Do not be tempted to refit the standard sump. See also the Section XXVIII Fitting an Oil Cooler

Before you remove the pistons etc. note how far down the bore the piston crowns are at TDC. Mine were 0.70mm or 27thou. This is nearly the maximum you should plane off the block face suitable for normal road use. It is recommended that you keep the piston crowns 30thou off the face of the head, with your chosen gasket. If we assume a compressed gasket is 40 thou, then you could take a further 10thou off the block. i.e. total 37thou. Do not remove any material off the head unless it is warped. .

Next the Connecting rod end caps were removed after taking care to ensure that the whole lot can be reassembled in the same order in 12 months time. Are they all marked as to location and orientation. It is almost certain you will fit new shells etc. but keep the caps and shells together until later. Then the crankshaft caps were lifted, complete with shells and any seals, thrust washers etc. Before you remove the crank, note the end float. All this is being kept rather brief as it has been covered in the Haynes manual and the two other good books on the subject. See links page. Lift out the crankshaft and tape the old shells to the main journals, wrap in an oily rag and place in a safe place. Make sure the main bearing caps are marked as to orientation and position. They are numbered and marked with a cast arrow showing 'Front'. The pistons have an arrow on the top face, together with the size, the end caps are stamped and the Connecting rods have an F cast on the front face. Take notes and photo's if needed. Now pull out the Piston c/w rods. Wrap up well and place aside. Large plastic boxes make ideal containers.

Clean up the inside and outside of the block as best you can, and ship the block and rods c/w pistons off to your local re-bore house. You may at this stage wish to consider having the block planned to raise the compression ratio. See above. There is an awful lot more you can do to the bottom end before you get this far, but if you are considering other work, such as better rods, pistons etc. I doubt if you will be reading this in the first place !! All this work is covered in the Sierra Haynes Manuals and How to Power Tune FORD SOHC Pinto Engines by Des Hammill also Rebuilding and Tuning Ford X-FLOW and PINTO Engines by Peter and John Wallage. The last two are very good books, fully recommended.

If you live in the North West and are going down the re-bore route you cannot do better than give Headshop (UK) Ltd a ring. Headshop specialise in Motorsport Engineering and can offer Pistons, Piston Rings, Shells & a full engine machining service to full race standards. Re-bores, Crank Grind etc. Tel 01925 851166/77 See links page for more details.

The machine shop who can re-bore your block will almost certainly be able to regrind the crank if required. But check it first, as a new set of shells may suffice. Do not skimp here as to strip and regrind a crank later on if you do have a problem is not to be taken lightly. If in doubt regrind, or at least seek the help of an expert at the machine shop. Pick one used to this type of work. My crank was very good, still within the makers tolerances, not bad for a 1988 engine, and no oviality at all. A new set off standard shells will suffice. Any scoring on the journals is a regrind. Some time later, and after a lot of money has changed hands, you will get your block and crank back. With a bit of luck the machine shop can fit the new pistons to the rods. Not easy for the home builder as they are an interference fit. The block goes direct onto the engine stand, and will not come off until it is virtually ready to go into the car. Refit the crank and pistons c/w new shells. Use plenty of oil or that special rebuild grease. Keep as clean as an operating theatre. Always fit new seals and gaskets. New connecting rods and mains bolts are advised.

If you intend to lighten the flywheel and possibly fit one or even two dowels, now is the time to do it. It can be ready to fit when the engine block comes back. It is a good idea to buy a complete new clutch unit, using the flywheel as a pattern to avoid errors. Use new flywheel bolts and Loctite. Make sure you get the correct number of splines on the clutch to suit your gearbox and that the small bearing inside the end of the crankshaft is the same diameter as the end of your gearbox input shaft. It may be a good idea to fit a new bearing into the end of the crank while it is stripped or at least give a good clean and grease.

Strip the oil pump, and if you have any doubts as to its condition, fit a reconditioned unit. You will need to shorten the oil pickup and strainer at this stage. Once this is done you can refit the pump, recheck all the work and carefully fit your shortened sump. This will keep all the dust out of the crankcase. Once the water pump and auxiliary drive shaft are refitted this more or less finishes the bottom end and we can turn to the Cylinder head. The bottom end may be vital, but all the power is produced in the cylinder head.

Cylinder Head

Stripping the cylinder head revealed a number of problems, the valve stem seals had gone hard ** and the camshaft spray bar was blocked, however the most serious fault was a very badly worn camshaft, caused no doubt by the blocked spray bar. Surprisingly the valve rockers were not too bad and the valve guides were in quite good condition. Perversely, bad valve guide oil seals allow more oil into the guides. The guides are cast into the head and replacing the guides means boring out the worn guide and fitting new pressed in liners then re-cutting the seats. You may also feel the need to fit new valves and springs. If the seats are soft, hardened inserts should be fitted. At the very least new oil seals and a valve seat regrind are a must. All this is very very expensive and not really worth the cost when there are good heads to be picked up at a reasonable price. Check the bearings in the camshaft pillars, these can be replaced if worn. Replace with Bronze bearings. It is surprising what Pinto spares can be bought on eBay. Never use any dealer who does not use Pay-Pal. If you buy from a local vendor ask if you can collect and pay on collection. No phone number supplied is a warning bell.

With the head fully stripped it was cleaned and mods. carried out the the valves/gas flow as per How to Power Tune FORD SOHC Pinto Engines. Once all this work was done the head was skimmed up 5thou. on the gasket face and re built with new seals, rockers, springs and a new camshaft.

** Note: some builders have suggested the use of Ford CVH valve stem seals as giving a better seal than the standard Pinto type.

Rebuilding

Note:- While the cylinder head is off now is a good time to do an accurate check on piston TDC. Fit the crankshaft pulley you intend to use and rotate the engine until No.1 piston is at the very top of its stroke. Perfectionists can use a "clock gauge" but it is not that critical. Note the position of the TDC mark on the crankshaft pulley. If it is in line with the marker on the crankcase, fine. If not you will need to remedy this by remarking the pulley etc. Finding TDC once the head is in position is not easy to do with any degree of precision. If you do find an error check again, as mistakes are rare, unless of course pulleys have been used off another engine etc.

When FULLY OPEN the valves on a Pinto DO NOT protrude below the cylinder head face, so a broken cam belt is not a disaster, just an inconvenience, but check to make sure. Also check the spark plug electrodes. They can they foul the pistons at TDC. If you have stuck to the guidelines, the pistons should still be at least 30thou. below the cylinder head face. i.e. At TDC the top of the piston should be a max of 10thou above the cylinder block face. (this assumes a 40thou head gasket thickness) Give the bores a final wipe with a lint free cloth, squirt fresh oil down the bores and refit the head c/w new cylinder head gasket. Use new head bolts and torque up to the required figure. (Ford advise a final tightening after 10 - 15mins running, followed by a final check of the valve clearances) Carefully check the valve clearances and fit all the external bits, Distributor, Fuel Pump, Breather, Timing Pulleys and Water Pump etc.

All the above is rather brief, but rebuilding and tuning Ford Pinto engines has been covered in great detail by engineers far better qualified than myself. See the Sierra Haynes Manuals and How to Power Tune FORD SOHC Pinto Engines by Des Hammill also Rebuilding and Tuning Ford X-FLOW and PINTO Engines by Peter and John Wallage.

The engine is now more or less ready to fit into the car.

Warning:- There are at least two Engine backplates. Early ones had a smaller hole for the Starter Motor mounting register. Later versions had a 3" dia hole. Before fitting the engine make sure that the Engine/Backplate/Starter Motor/Gearbox set up is correct. Will the Motor fit and will the pinion engage fully on the flywheel ring gear. Will the clutch work? See the chart on page 118 of "Rebuilding and Tuning Ford X-FLOW and PINTO Engines" by P and J Wallage. All this is best done before you fit the engine as it is very hard to see what is going on once the engine is in the car.

Shell Bearings & Piston Rings seem quite hard to source but Federal Mogul still offer Sierra parts as below. Mine were sourced thro' Headshop, Warrington.

All these part numbers are for standard dimension. Rebores or re-grinds will need other numbers.

Big End Shells AEB91349 STD (8)

Crankshaft Mains AEM 5466 STD (10)

Crankshaft Thrust Wahers AEW 2198 STD (4)

Piston Rings R40230 STD (set of 4)

Below is a chart of Ford Pinto Engine Serial Date Codes.

All Pinto's built after January 1989 are suitable for Lead Free Petrol. See also Wiring Appendix II Technical Notes, Head Codes.

Data by kind permission of Ford Customer Services.

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© Colin Usher 2007