Chris' Engine Building Info Page

A collection of information from engine builder and manufacturers


CYLINDER BORE REFINISHING

(copied from www.hastingsmanufacturing.com)

Cylinder bore refinishing is extremely important in the engine rebuild process. There are some basic rules and facts that will prevent common problems incurred when deglazing or refinishing cylinders.

CROSS HATCH ANGLES

The correct angle for cross hatch lines to intersect is approximately 45 degrees. Too steep an angle promotes oil migration down the cylinder resulting in a thin oil film which can cause ring and cylinder scufflng.

Too flat a cross hatch angle can hold excess oil which conversely causes thicker oil films which the piston rings will ride up on or hydroplane. Excessive oil consumption will result.

The diagrams will illustrate cross hatch angles.

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HONING METHODS

Two basic systems are used to refinish cylinder wall either rigid stones or a flexible brush.

Correct cylinder finishes can be achieved with either system if used correctly. In all cases the manufacturers instructions must be followed with respect to :

1. Stone grit

2. Honing oil

3. Stone pressure (Automatic equipment)

The vertical speed of the brush or hone in the cylinder Is what causes the cross hatch angle on the surface of the cylinder wall. Too slow a vertical speed causes too flat an angle, while too rapid up and down motion of the hone or brush causes too steep an intersecting angle. In the case of hand honing it will be necessary for the operator to experiment to learn the proper up and down movement in relation to the rotating speed of the one to produce proper cross hatch angle.

CYLINDER ROUGHNESS

Substantial controversy exists on the correct cylinder roughness for proper seating of piston rings, whether chrome, moly, or plain cast iron. It has been our experience that the use of 220-280 grit stones and achieving proper cross hatch angle produces a finish compatible to all three types of the above rings.

CYLINDER CLEANING

The single most critical factor of any cylinder refinishing job is the cleaning of that cylinder after the honing operation.

It can be stated, pistons, rings, and cylinder bores will forgive slight variations in roughness, cross hatch angle, etc. No engine component will tolerate dirt!

Honing cylinders leaves two types of "dirt" on the cylinder wall, honing stone residue, and cast iron dust. If not removed before the engine is reassembled, the world’s finest lapping compound is waiting to destroy all the hard work of assembly the instant the engine is started.

Proper cylinder cleaning consists of a thorough scrubbing of the block with hot, soapy water taking care to clean the surface under the cylinder facing the crankcase. Rinse with hot water, dry, and lightly oil to prevent rust.

For detailed honing questions it is wise to contact the manufacturer of your specific equipment. They are experts in metal finishing and of course completely understand their own equipment.

In general if the foregoing practices are used excellent engine performance will result.

(P76-77)

 

HASTINGS PISTON RING SET
COMPOSITION RECOMMENDATIONS

When asked if he wants a piston ring set with moly, chrome, or cast iron faced top compression rings the mechanic often returns the question to the jobber salesman by saying, "What should I use?"

There is some confusion in the trade as to what type ring set should be used. Hastings would like to offer some suggestions to help the consumer make the proper decision for his particular application.

The single most important factor to be considered in selecting the proper top compression ring face coating material is the service requirements the engine will be operated under. Will the engine be subjected to unusual speed or load operation, stop and go - short trip driving, or operating in a high dust or dirt environment? if, for example, the vehicle is a passenger car operated by family members for what could be termed the average driver, it really doesn't matter which type is selected from a standpoint of the life of the engine and piston rings. On the other hand if one of the above mentioned conditions is going to exist on a regular basis then no doubt one type of ring face coating will be more appropriate than the others.

The three popular types of top compression ring face coatings, chrome, moly, and cast iron, each has advantages of its own with respect to operating conditions. Moly has a very high resistance to scuff. Chrome has good resistance to scuff but does not exhibit moly's oil retention capabilities. Plain cast iron is a durable wear surface in normal operating conditions and is less costly than the moly or chrome faced ring.

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For typical light duty service where the vehicle Is not subjected to long periods of high speed or load operation and is run primarily on paved streets, plain cast iron is a good choice because piston ring cast iron Is very durable when not subjected to unusual dirt or heat conditions.

When faced with continuous high speed or severe load conditions, the engine will be subjected to long periods of high temperatures. Moly Is then a good choice because of its scuff resistance. Moly, which is an acronym for molybdenum, inherently is quite porous in its applied state which results in excellent retention of oil in the face of the ring. Moly also has the highest melting point of the three popular face coatings which results in its capability to live better under more severe operating conditions, or more specifically to resist scuffing and scoring.

In a dusty environment such as gravel pits, sand or rock mines, or operating on a dirt or unpaved roads, chrome is the best choice. As mentioned earlier, moly because of Its porosity holds oil on the O.D. face of the ring which helps inhibit scuffing. Pores on the material also can serve as a trap for foreign materials, however. Because of the incoming air/fuel mixture probably will contain some abrasive contaminant In a dusty environment, chrome with its smoother O.D. surface is a logical choice. Chrome's extreme density and hardness resists the Impingement of dirt Into the face of the ring which accelerates cylinder wear, and actually contributes to the exhaust gases carrying some of the airborne contaminant out through the exhaust system. Chrome has more resistance to scuffing and scoring than cast iron but somewhat less than moly.

All in-all when the engine experiences normal driving conditions and is properly maintained with respect to oil and air filter changes, any of the three coatings functions equally well. It is the installer's expert judgement in analyzing the primary use of the engine that should lead him in a direction of which ring set will be the best possible choice for that particular customer's engine.

(P68-69)

 

ENGINE BLUEPRINTING

Engine blueprinting has become standard procedure in many performance engine shops. Blueprinting is an absolute necessity to obtain maximum power and to insure the longest possible engine life and reliability.

Blueprinting an engine means hand building an engine with perfectly fit components using maximum recommended clearances, and minimum recommended volumes. These specifications should be determined using the engine manufacturer's tolerances for the engine being built.

All parts must be one hundred percent clean. The block should be boiled out making certain water jackets are perfectly clean. All bolt holes should be re-tapped, cleaned and oiled, as well as their mating bolts. Any surfaces being refinished should have all holes chamfered, and any casting burrs or irregularities should be ground away.

The V type block should be align bored exercising extreme care to maintain perfectly equal deck heights and keeping the crankshaft parallel to the decks. Any variation in these areas will result in irregularities in combustion chamber volume.

After align boring, the cylinders should be bored with the main bearing caps still torqued in place. The cylinders should be finish honed to their proper size using a 220-280 grit stone and taking care to obtain a good cross hatch pattern. After honing the block should be thoroughly cleaned, taking care to remove all honing grit from the bores and also from the lower end of the block. Be sure to oil cylinders after cleaning.

Some engine builders paint the inside crankcase area of the block. This is recommended as a detergent to carbon or sludge buildup, and also seals the pores of the iron preventing oil from washing deposits, left in the pores after cleaning, into the oil. Painting will help insure the absolute cleanliness necessary for top quality performance and engine life.

p23.gif (95060 bytes)The crankshaft must have correct angularity of the rod throws as well as be perfectly straight. It should be 100% inspected for cracks and have the journals ground to perfect angular index. Fillet radii should be held to recommended arc as well as having oil holes chamfered and bearing surfaces polished. The oil passages should be cleaned thoroughly with a good brush. Some builders use fully grooved main bearings or groove or cross drill the crankshaft main bearing journals. These procedures are also helpful in insuring longer engine life.

The connecting rods should be carefully checked for imperfections and Magnafluxed. All rods should be reworked so they are EXACTLY the same length from crankshaft centerline to wrist pin centerline. Performance builders recommend allowing from .002-.003 for rod stretch at high speeds. Generally the length of the rods will be controlled by working to the minimum manufacturer's clearance for piston to deck. Any burrs and irregularities should be removed from the rods, and always use new rod bolts and nuts. The rod alignment and side clearance are also critical.

The pistons should be individually and carefully fit to the respective pins. Chamfering any sharp edges on the piston reduces possibility of localized hot spots which cause pre-ignition and/or detonation. Each piston should be carefully matched for clearance with each bore. Too little clearance will result in scuffing and too much clearance reduces the effectiveness of the rings.

The compression rings should each be placed in the bore and straightened with the top of a piston to square the ring in the bore. Gaps can then be checked, with .0035 per inch of bore the minimum allowable gap. Staying as close to minimum as possible is recommended. Also be sure to check ring side clearance in piston groove. The maximum is .006 but .003-.004 is most desirable.

Now that the main reciprocating components are selected and fit, the engine should be balanced. It is recommended the balancing be done with all ring, S, pistons, rods, bearings, crankshaft and also flywheel and crankshaft dampner and pulley. Some engines

(Ford 427 for example) recommend an allowance for oil weight in the crankshaft when balancing. These specs are available from A.E.R.A. or from the manufacturers of balancing equipment. Additional weight is added to the bob weights in these cases to compensate for oil weight.

Balancing will provide insurance for engine durability, and will also help obtain maximum horse-power.

The cylinder head should be disassembled, cleaned and carefully inspected for cracks. If the surface is in questionable condition or the head is warped, it should be resurfaced. If resurfaced all holes and sharp edges should be carefully chamferred and deburred. Bolt and spark plug holes should be retapped and cleaned. The valve guides should then be checked and replaced or repaired as necessary. Remember to also check valve stems and replace those valves not acceptable. This is also the time to machine the valve guides if necessary for the installation of Hastings P.S. seals. The valve job should be done according to recommendations for the engine. Make sure valves and seats are not worn so as to sink the valves too far into head. A valve stem height gauge should be used to keep all valve stem ends the same height above the spring seat. All burrs and irregularities should be polished out of the combustion chamber. After this the chambers should be checked for volume in cubic centimeters. The chambers should be enlarged to the volume of the largest chamber. When all chambers are equalized the desired minimum CC's can then be reached by milling the heads carefully until the correct volume is reached.

In order to check the CC volume of the chamber a Plexiglas plate, light oil, and a chemical burette are needed. With the spark plug and valves installed the plate is placed over the combustion chamber and sealed with a light coat of lubricant. Using the burette it is then a simple matter to measure the amount of liquid needed to fill the combustion chamber.

Valve springs should be checked for tension and installed height, and replaced or shimmed as needed. If the head has individual rocker arms on studs the stud should be threaded or pinned in its boss.

In engine assembly be very sure to follow recommended procedures for bearing and ring installation. Torque main bearing and rod bolts slowly and in progressive steps to the proper tension. Use protectors on the rod bolts to prevent crankshaft scars, and keep rotating the engine as each step in the installation of the crankshaft and pistons is taken. This will enable spotting the exact location of any misfit or mismatched parts.The use of Plastigage here will serve as a double check on clearances.

Many performance engine builders are using support "girdles" for the lower end of the block. These girdles are readily available for most popular engines and are a very important aid in strengthening the engines lower end. The girdle supports the center mains and also serves to stiffen the engine block.

When installing the timing gears and chain the use of a camshaft degree wheel will insure perfect crankshaft to camshaft timing.

Offset keys or cam gear bushings are available to allow accurate adjustment of possible timing discrepancies.

After installing the heads, making sure they are torqued to the proper specifications, the valve train should be completed and checked. In cases where higher lift camshafts have been installed it is possible to have the valve spring bottom out, or the canoe type rocker be interfered with by its mounting stud. Where this happens the spring must be changed, and the rocker arm relieved to provide the necessary clearance.

The complete engine build must be performed as painstakingly and accurately as possible. Always keep in mind that dirt is the greatest enemy of engine life. Perform your engine build under the most antiseptic conditions possible. The blueprinted engine is the utmost in performance and durability possible, and its success is a real testimony to the expertise of the engine builder.

(P22-24)

CYLINDER DEGLAZING

The importance of cylinder wall deglazing cannot be overemphasized. The proper cylinder finish will provide the quickest possible break-in and greatly reduce the possibilities of ring or piston scuffing during break-in.

The glazed cylinder wall causes rings to "skate" on the highly polished finish and discourages the minute amount of wear which is necessary to mate piston rings with the bore.

The interrupted "deglazed" finish contains minute hills and valleys which carry a film of oil which will retard which will retard scuffing during break of as well as produce the type of cylinder finish piston rings can mate to very rapidly.

The finish produced by a 220-280 grit stone is most desirable. The cross hatch pattern should intersect at approximately a 450 angle. Too flat an angle leads to ring spinning which prevents seating the rings.

Probably the most critical part of the deglazing operation is the proper cleaning after deglazing. The residue of honing, if left in the engine, will rapidly destroy all moving parts. It is recommended that engines be cleaned thoroughly with soap and water. Clean with soap and water until the bore can be wiped with a clean white cloth without soiling the cloth. After clean up, oil the area to prevent rust formation. Waterless hand soap also serves as an excellent cleaning agent.

CYLINDER WALL GLAZE BREAKERS

This new Deglazer is fast, easy to use a real performer ever under adverse condit1ions. Cylinders can be deglazed and crosshatched in 30 to 45 seconds. Tests made on this tool have proven satisfactory operation up to 14 hours of continual running.

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No. 1733-37

GLAZE BREAKER HONE

Sturdily built deglazing hone breaks the glaze in any cylinder. Flexible drive shaft permits easy access to all cylinders. Cone expansion adjusts hone to cylinder wall with uniform pressure. Adjustable spring tension lets you select desired pressure.

Fits standard %" drill. Cylinder range is 3" to 6", no extensions required.

Supplied with 220 grit stones recommended for quick, positive seating of steel and chrome rings. Replacement stones and pads available.

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  (P31-32)

ENGINE PRE-LUBRICATION

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The importance of pre-lubricating overhauled, rebuilt or new replacement engines cannot be over emphasized. Many of these engines are badly damaged within the first few minutes of operation because of lack of lubrication to vital parts.

Parts such as pistons, rings, cylinder walls and bearings must have immediate lubrication to prevent scuffing, scoring and bearing damage. In some cases it can take as long as five minutes of engine operation for the oil pump to prime itself, fill the oil passages and oil filter, then deliver oil to the various parts of the engine.

These unnecessary failures can be prevented by lubricating the parts as they are assembled, then forcing oil under pressure to the oil galleries, oil filter and oil pump. This provides immediate lubrication to all pressure lubricated parts and eliminates the time-lag that occurs in the oil pump priming itself and filling the oil galleries when the engine is first started.

The oil pump for some engines is not self priming and when the oil pump cover has been removed for any reason, the pump gear cavity must be filled with petroleum jelly to aid priming.

The oiling system for any engine can be filled by the use of a bearing leak detector, which should hold at least two quarts of oil. Normal engine oil pressure, or about 40 psi, should be forced to the galleries.

The oil supply line from the leak detector can be attached to the engine at any convenient tapped hole on the outside of the engine block that leads to the oil pressure circulating system in the engine. Hook-up points are located differently, according to the engine.

 (P34)

BREAK-IN PROCEDURE

STARTING PROCEDURE

1. Set tappets, adjust carburetor and ignition timing as accurately as possible before starting engine.

2. Start engine and set throttle to an engine speed of approximately 25 miles per hour (trucks, tractors and stationary engines one-third throttle) until the engine coolant reaches normal operating temperature. Then shut down engine and retorque cylinder head bolts, recheck carburetor adjustments, ignition timing and valve tappet clearance. (Run engine at fast idle during warm-up period to assure adequate initial lubrication for piston rings, pistons and cylinders.)

BREAK-IN PROCEDURE

1. Make a test run at 30 miles per hour and accelerate at full throttle to 50 miles per hour. Repeat the acceleration cycle from 30 to 50 miles per hour at least ten times. No further break-in is necessary. If traffic conditions will not permit this procedure, accelerate the engine rapidly several times through the intermediate gears during the check run. The object is to apply a load to the engine for short periods of time and in rapid succession soon after engine warm up. This action thrusts the piston rings against the cylinder wall with increased pressure and results in accelerated ring seating.

2. Following the breaking-in, turn the vehicle over to the owner or operator with the following suggestions:

PASSENGER CAR AND LIGHT TRUCK

Drive vehicle normally but avoid sustained high speed during the first 100 miles.

HEAVY DUTY TRUCKS AND BUSES

If possible, place in light duty for first 50 miles. At no time should the engine be lugged. Lugging is said to exist when the engine does not respond to further depression of the accelerator.

FARM TRACTORS

Operate at one-half load or less for the first two hours.

DETONATION AND PRE-IGNITION

When an internal combustion engine is torn down for rebuilding and badly burned and distorted pistons and valves are found, it is very likely caused by extremely high combustion chamber temperatures and pressures from detonation or pre-ignition. Generally speaking, most machine shop men know that such damage is caused from abnormal engine operation. Too often, the customer does not know what causes the costly damage, yet the machine shop man may be unjustly blamed for an engine "that didn't stand up".

Detonation and pre-ignition are forms of abnormal combustion in the combustion chamber. During normal operation of the engine, the burning of the fuel-air charge produces a steady, smooth push on the pistons of each cylinder. At the instant of ignition by the spark plug, the flame of combustion moves rapidly outward from the plug very much like the waves when a stone is dropped into a pool of water (see fig. 1).

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Abnormal operation may allow combustion pressures to develop so fast that the heat and pressure will "explode" the remaining unburned fuel. This produces the knock, often called "ping", carbon knock, etc. Actually this is detonation. The knock results from the violent explosion when the normal flame front runs into the secondary flame front. Detonation will cause piston and ring damage, top ring groove wear, scoring, sticking rings, loose head gaskets and possible complete engine failure.

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(Photo of detonation damaged piston). Fig. 2

Detonation can be caused by:
  1. Lean fuel mixture
  2. Fuel octane too low
  3. Improper ignition timing
  4. Lugging
  5. Carbon deposits
  6. Excessive milling of heads or block, which will increase compression ratio.

Pre-ignition, as the term suggests, is the ignition of the fuel-air mixture before the regular ignition spark from the spark plug. If the regular spark occurs shortly after the pre-ignition, the colliding of the two flame fronts will cause a pinging noise. Preignition causes loss of engine power and can cause severe damage to pistons, rings and valves.

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(Photo of pre-ignition damaged piston). Fig 3

Detonation and pre-ignition are so closely related that it is en difficult to distinguish one from the other by sound. Each can lead to the other and either condition can cause extensive engine damage. Inspection of damaged pistons and rings quite often indicate which caused the damage.

Damaged pistons and rings usually mean replacement. The same damage can occur again unless the cause of the detonation or pre-ignition is corrected.

Pre-ignition can be caused by:

  1. Carbon deposits that remain incandescent
  2. Spark plugs too hot a heat range
  3. Spark plugs not firmly seated against gasket
  4. Detonation or the condition leading to it
  5. Sharp edges in combustion chamber
  6. Valves operating at higher than normal temperature because of excessive guide clearance or improper seal with valve seats.
  7. Overheating
  8. Ignition crossfiring. Induced voltage in spark plug wires that run parallel to each other for long distances

  (P25-26)

PISTON RING INFORMATION BULLETIN

Detonation in a Gasoline Automotive Engine

Detonation is a form of abnormal or improper combustion. It is commonly referred to as "spark knock" or "pinging". When detonation is present cylinder firing pressures and temperatures are elevated with resulting engine damage. This engine damage varies depending on the degree of detonation.

With this in mind Hastings Manufacturing conducted testing using a 350 C.I.D. Chevrolet engine and developed a cycle where the engine drifts into and out of a detonation condition. The objective was not to destroy the engine, but rather to operate in what would be borderline abnormal combustion and stop before serious engine damage resulted. Oil economy was observed during the test.

The engine was set up on a dynamometer using premium unleaded fuel and S.A. E. 20W engine oil. The engine was cycled from 1200 - 2400 R.P.M. every 25 seconds. It was run with the ignition timing advanced beyond the factory specification.

During the acceleration part of the cycle light to medium spark knock was audible.

After 80 hours the engine was disassembled, one piston was removed, and the rings examined. There was distressing on the bottom side of the compression rings and the sides of the oil ring rails. The sketch below illustrates the shape the ring assumes from the pounding.

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The engine was re-assembled and the test was continued for another 80 hours at which time the test was concluded and the engine was torn down and examined.

Oil economy declined approximately 30% when the engine was operating under detonation conditions. The graph shows oil control deterioration, and the photographs illustrate the damage to the rings.

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All compression rings exhibited the pounded condition shown in the foregoing sketch. The oil ring expander had indented Itself into the lower oil ring rail. The upper rail also has indentations although to a lesser degree. The top compression rings had light to medium scuff on their O.D. face. No piston damage was apparent although some cylinder scoring was present on major and minor thrust sides.

Detonation can be caused by:

1. Lean fuel mixture.
2. Fuel octane too low.
3. Improper ignition timing.
4. Lugging the engine.5. Excessive milling of heads or block which will increase compression ratio.

Detonation is a form of abnormal combustion in the combustion chamber. During normal operation of the engine, the burning of the fuel-air charge produces a steady, smooth push on the pistons of each cylinder. At the instant of ignition by the spark plug, the flame of combustion moves rapidly outward from the plug very much like the waves when a stone is dropped into a pool of water.

Abnormal operation may allow combustion pressures to develop so fast that the heat and pressure will "explode" the remaining unburned fuel. This produces the knock, often called ping, carbon knock, etc. Actually this is detonation. The knock results from the violent explosion when the normal flame front runs into the secondary flame front. Detonation will cause piston and ring damage, top ring groove wear, scoring, sticking rings, loose head gaskets and possible complete engine failure.

The goal was accomplished in this experiment as testing did not destroy the engine but did piston ring damage and verify that oil control is adversely affected when detonation is present.

(P88-89)