Category Archives: Engines

New Life for a 1955 ‘P’ Code 292 Police Engine

When David Church acquired a 1955 Ford Customline two door sedan, it was found that it was originally ordered as a law enforcement car with the P code 292 and a three speed standard transmission. A little back tracking finds that the car was purchased new in North Carolina and when found by David, still had the 1967 North Carolina license plates on it but was now sitting in a South Carolina field.  It had been well over 40 years since the car had been last registered and state inspected.  Although that car had been sitting in a field for a number of years, a bit of fuel poured into the ‘Teapot’ 4V carburetor and a battery boost gets it started.  It drives itself up and onto a trailer for the trip back to Mississippi.  The odometer is showing 60K miles but when looking at suspension, pedal wear, and general oil and grease build up at various parts of the car, the assumption is the car has 160K miles instead.  More time elapses and now the car is undergoing a complete restoration including an engine rebuild.  The engine rebuild is where I come into the picture.

In researching the old sales literature, it’s found that the advertised horsepower for the standard transmission equipped police engine is 188. Looking at some of the other 1955 year model 292 horsepower ratings finds that the Thunderbird standard shift engine is rated at 193HP while the Mercury standard shift engine is rated at 188HP just like the Police engine.  Delving deeper into the differences does find that the Thunderbird 292 has 8.1:1 compression ratio versus 7.6:1 for the Police and Mercury engines.  Going through the parts manuals does find the Thunderbird engine using the ECL heads while the Police and Mercury standard shift engines uses the ECK head castings.  It would appear the only difference between the Ford Police engine and the Mercury engine when equipped with the standard transmission is just the valve covers as both are identical otherwise.  The 1955 Ford Police cars using the Mercury engine is no surprise as the 1954 Ford Police cars used the Mercury 256 engine rather than an upgraded 239 version.

Click on pictures for larger images

Teardown of this police engine finds that it’s still a standard bore engine with all appearances that the bottom end had never been into before. The block is an ECK casting with a June 4, 1955 casting date while both cylinder heads and the intake manifold have July 6, 1955 casting dates.  Deciphering the stamped build date on the front valley cover rail finds the engine being assembled on July 7, 1955 on the third shift. If those dates are correct, there’s obviously no inventory of parts sitting loose for these engines as they are being assembled almost as fast as some of the parts are being cast and machined.  The crankshaft journals looked pristine but the rear thrust surface at the center main journal was wasted (badly worn).  While the crankshaft could be potentially welded up in that area and re-machined, it was decided to simply replace the crankshaft with another and start fresh.  As it works out, another standard journal crankshaft with minimal wear was sourced and used without having to grind the journals undersize.

The ECK-C heads have the 1.78” intake valves which was the intermediate intake valve size for the Y engines. The guides and valves are replaced along with new valve springs and valve locks.  The original two piece retainers are replaced with single piece units.  There was a problem with the early production Police engines dropping valves when being aggressively driven (over-revved) so there was a service bulletin issued instructing dealers to replace the valve springs on any police engines being brought in for service.  Now that more than sixty years has past, the aged valves and especially the exhausts are noted for their propensity in coming apart.  With that in mind, retaining the original valves is risky and putting a warranty on the engine if retaining them is out of the question.  The desire is for this engine to last at least another sixty years so it’s a no brainer in replacing all the valves.  The new valve springs are set up at 76 lbs closed pressure and 230 lbs. pressure at 0.410” valve lift.  No port work is being performed simply to keep the engine in a close to ‘as delivered’ state as would have been supplied from Ford originally.

All the combustion chambers are cc’ed and while it’s found that both cylinder heads are similar in chamber volumes, they are very much on the large side in that they are averaging 83.4cc’s. Some reverse engineering finds that the ‘as delivered’ compression ratio was 7.53:1 with the original steel shim head gaskets in place.  Before coming across the appropriate sales paperwork and service bulletins, it was initially believed that the engine was suppose to have 8.5:1 compression ratio.  Service Bulletin #973 and the sales literature for the Police car option puts this to rest as it states that the standard shift Police 292 was indeed rated at 7.6:1 CR.  The automatic transmission equipped 292 Police engines were rated at 198HP and with 8.5:1 CR.

To compound issues with the compression ratio already being to the low side, the wrist pins in the replacement pistons are 0.023” closer to the piston tops and when also taking into account for switching to a composition head gasket rather than the original steel shim style, the compression ratio lowers another full ½ point making it 7.05:1. Zero decking the block only brings the compression ratio back to 7.5:1 so it’s going to take some head milling to get the compression ratio back up to the original advertised 7.6:1.  But at this point, the plan does deviate in that the desired compression ratio should at least be what the automatic transmission cars were.  To that end, the new target compression ratio is 8.5:1.  To attain that, the decks are milled an average of 0.035” to get the pistons level with the decks.  The amount of milling required to reduce the chamber volume 1cc on the ECK-C heads is ~0.0056”.  A little bit of math indicates that the heads must be milled 0.070” to get the chamber volumes down to 71cc.  Internal bracing within the coolant areas of the heads is sufficient enough to permit this amount of milling on these particular heads.  To insure that the intake manifold fits correctly, the intake sides of the heads are milled 0.080” which pretty much puts the intake gasket surface parallel with the valve cover rail.  As a side note, It’s always recommended to mill the intake side of the heads when possible rather than the intake manifold as this still allows the intake manifold to not be cylinder head specific and can be repurposed later on another set of heads.  All this machine work gets the calculated compression ratio back up to 8.5:1.

The block is fresh bored and honed for a replacement set of Silv-O-Lite 0.030” over cast pistons, the mains are align honed, and the decks are fresh machined so that Best Gasket composition head gaskets can be used rather than the original steel shim head gaskets. The piston to wall clearance is 0.0025” when all the machine work is finalized.  The pistons are sitting level with the decks at TDC which essentially gives a quench clearance of 0.046” which is the head gasket thickness.  The connecting rod big ends are resized with a new set of ARP rod bolts torqued in place while the wrist pin ends get new bronze bushings. With all the block machine work complete, the rotating assembly is dynamically balanced.  The bobweight value is 2070 grams and includes the 14 grams used as an oil value.

The camshaft is replaced with a NOS FoMoCo replacement supplied by David Church. It’s still in its original round cardboard tube but the part number is long faded away.  The center journal is cross drilled for upper end oiling rather than the grooved journal found on the 1956 and newer replacement camshafts.  The specs on this particular camshaft are as follows:

Advertised duration: 231½° Int / 235½° Exh

Lobe lift: 0.256” Int / 0.263” Exh

Calc valve lift: 0.366” Int / 0.376” Exh

Lobe centerline: 112½°

Duration at 0.050”: 196½° Int / 198° Exh

Cam is installed at 111½° Intake lobe C/L

Once the new set of Hy-Lift Johnson lifters are lubed and placed in their respective lifter bores, the pre-lubed camshaft is gently slid into place. The camshaft turns freely within the new bearings so all is well.  With the cam retainer bolted in place, the camshaft end play is at 0.006” which is within spec.  A note here about lubing the cam and tappets; the moly lube is used only on the lifter faces and camshaft lobes but the shanks of the lifters and cam journals are lubed with a quality engine oil.  It’s important that the lifters turn freely in their lifter bores and using oil instead of the moly lube insures this.  The moly lube if used on the lifter shanks can actually inhibit lifter rotation which then potentially brings a lifter/lobe failure to the forefront.  What happens in the first sixty seconds of running pretty much dictates the ultimate life expectancy of the cam and lifters.

Before installing the Hastings single moly piston rings on the pistons, they are placed and squared within the cylinder bores to check ring end gaps. The replacement rings are not a ‘file to fit’ set but ring end gaps are checked as a safety precaution against being too tight.  With some tweaking, the ring end gaps are finalized at 0.018” for the top rings and 0.014” for the second rings.  Once this is done, the rings are removed from the individual bores and placed on the pistons going into those particular bores.  The rings are installed on the pistons using a ring installing tool rather than twisting them on to the pistons.  Using a ring installation tool minimizes the chance for breakage while also eliminates the potential for any ‘twist’ to be imparted into the rings when installing them without the aid of a ring tool.

Short block assembly goes together without any issues. The bearing clearances were previously micrometer checked and it’s verified that the rod bearing clearance is ~0.0015” and main bearing clearance is ~0.0022”.  The rod bearing clearances were tightened up by using a std bearing in one half the rod and a 0.001” oversize bearing in the other half.  The rod side clearances are checking out at 0.018”-0.025”.  As a tip here, when the rod bolts were being torqued to their respective journals, a feeler gauge was being used between the rod pairs to take up all the clearance or ‘slack’. This prevents the rods from twisting during the torquing operation thus preventing the bearing from being unseated and/or sitting crooked within the rod bores.

With the short block together, the camshaft is degreed in and with the stock link timing chain setup, the cam is sitting at 1° advance or at 111½° intake lobe centerline. In keeping with the original intent of having this engine make it’s advertised horsepower rating, the camshaft is left at 1° advance rather than broaching a new keyway slot in either the cam gear or crank gear in which to further advance the cam timing.  While advancing the camshaft in this particular case would help low end grunt and idle, it would be counter-productive to making the rated horsepower ratings.  At the conclusion of degreeing in the camshaft, the crankshaft is rotated to put the #1 piston back on TDC before removing the degree wheel.  The timing cover, timing pointer, and damper are then installed to insure that the TDC on the damper is aligned accurately to the pointer.  Any discrepancies between the two are taken care of by simply bending the pointer accordingly in which to compensate.  The damper (freshly rebuilt by Damper Doctor) is then removed so that the remainder of the engine can be assembled and painted.  The damper is to remain flat black so it’s off the engine when the remainder of the engine is painted with high heat primer and then final coated with Bill Hirsch Ford ‘T-Bird’ Red.  A little bit too orange for my taste but it is the right shade of Ford Red for this application.  After engine painting is complete, the damper is reinstalled.

It’s now just a matter of taking care of the little details before installing the engine on the dyno. Some of those details include checking out the Load-O-Matic distributor with its new breaker points and related parts, new spark plugs and wires, replacement wire looms, the addition of six quarts of Valvoline 10W-40 conventional grade oil, and a Wix 51515 oil filter.  The original cartridge oil filter goes to the wayside and is replaced with the newer spin on style.  In this case, some items simply don’t need to remain original.  A 4oz bottle of ZDDPlus is added to the crankcase as additional insurance that the Zinc/Phosphorus amounts are sufficient for break in.  Before installing the distributor, the engine is pre-lubed to guarantee that oil has filled the oil filter and various passages as well as having adequate cranking oil pressure.  The original List #1074-1 Holley Teapot 4V carburetor looks clean and usable so it’s not taken apart at this point and is installed on the intake along with the original ½” phenolic carb spacer.  Fuel in poured into the top vent hole in the carb so that the fuel pump does not have to work at filling the carb when attempting the first start of the engine.

With the engine on the dyno, it starts up immediately without any fanfare and is brought up to a fast idle for both the camshaft and piston ring break in. The engine is being run with a set of headers instead of exhaust manifolds as this provides a more accurate way to monitor the air fuel mixtures.  While the camshaft is being broken in, the engine is repeatedly being loaded and unloaded against the dyno water brake so that the piston rings can seat in much more quickly.  After allowing the engine to completely cool in which to put a completed heat cycle in the engine, it’s then restarted for some power testing.

The first series of dyno pulls nets a best of 181HP and 266 TQ. The original List #1074-1 Teapot carb is being troublesome with the accelerator pump having a weak shot and the numbers are down from what was expected so the carb is changed out to a List #1164-2 carb off of a 1956 Thunderbird with a 312 engine.  The Thunderbird carb had been freshly kitted and with it installed on the engine, it makes a clean pull netting 191HP/267TQ.  The original ECK-T 1074-1 carb is then disassembled, cleaned, and rebuilt using a Daytona Carb Parts #603 ethanol friendly carburetor kit.  With the rebuilt carb reinstalled on the engine, the engine is now responsive when winging the throttle with no hesitation or dead spot.  The dyno likes it too with 192HP/280TQ numbers coming to the forefront.  The carb jets remain stock as 50’s in the primaries and 86’s in the secondary sides.  The engine is making its best power numbers and idles well with the Load-O-Matic distributor set at 12° initial timing and the valves set at 0.019” hot.  At this point, the engine comes off the dyno and is ready for reassembly back into the chassis.

While a horsepower rating of 188 doesn’t sound like much by today’s standards, this was a serious performer back when it was new. This engine was just the precursor of things to come as the following year started seeing larger valves and experimentation with more aggressive camshaft grinds.

All for now and until next issue, Happy Y Motoring. Ted Eaton.

Originally published in The Y-Block Magazine, Issue #147, July-August 2018

Degreeing in the camshaft – Part I – Finding TDC

Part of the blueprinting process during any engine buildup will include degreeing in the camshaft. This operation is performed to insure the camshaft is phased or installed at the desired position in relation to the piston sitting at TDC. While degreeing in the camshaft during its installation may seem to be an activity reserved just for the race engines, the fact remains that it’s just as important on the daily driver applications as it is for high performance engines.

Continue reading Degreeing in the camshaft – Part I – Finding TDC

Degreeing in the camshaft – Part II – Phasing the camshaft

Part I of this article went into detail as how to find exact TDC. With that now behind us, the actual process of checking the camshaft and how it is currently phased within the engine can begin. For this, a 1.000” travel dial indicator will be required that can measure the up and down motion of the lifters. While the number one cylinder is customarily the cylinder of choice in which to check the camshaft, any cylinder can be used to degree in the camshaft once TDC has been found for that cylinder. In fact, later in this operation another cylinder will be checked in which to both verify the results obtained off of the first cylinder check and also insure that the camshaft is at least consistent in values on two different cylinders. For now, the number one cylinder will be used as a reference.

There are two basic methodologies in checking the camshaft phasing. One would be to check the opening and closing events of the intake and exhaust lobes and comparing those to the camshaft specification card. Most checks performed with this method for aftermarket cams will be done with the lobe opening and closing events being measured at 0.050” off the heel of the camshaft. For instance, lobe lift is measured at 0.050” after the lifter starts to rise and again at 0.050” before the lifter comes to a rest at the end of its closing event. Some of the older oem Ford grinds use 0.100” for the check so be sure to know what the spec card or manual calls for when checking a camshaft using the opening/closing specs methodology.

Because of manufacturing variances and/or excessive lubricant on the lobes and tappets themselves, there tends to be some error introduced into this checking method that can make it difficult to obtain accurate readings. Be aware that most high viscosity cam lube is to be used only on the tappet faces and the lobes and should never be used on the lifter stems or lifter bores; also do not use camshaft specific lube on the engine bearings. While working with lobes and lifters that are simply oiled would give more accurate results, doing it this way would require that the cam lobes and lifter faces be removed to properly lube them for the final engine assembly. Doing this then increases the risk of the camshaft being reinstalled incorrectly if not re-performing the degree in process again.

Another method which is also my method of choice involves checking the lobes as measured from their centerlines. This method works for a majority of the camshafts out there and only gives issues when the lobes are special ground to the point they are not symmetrical on the opening and closing ramps at the top of the lobes. The following detailed instructions will be using the lobe centerline methodology.

Lobe Centerline Methodolgy –

At this point the camshaft, lifters and timing set are already installed. If the crankshaft gear has multiple keyway slots, then use the ‘zero’ position slot as a starting point. Many camshafts already have a given amount of advance built into them and in most instances starting with the ‘zero’ slot will have the camshaft much closer to its desired installed position. Second guessing the camshaft and pre-adjusting the crank gear more often than not ends up having the camshaft being installed way off of the mark when performing that first check.

With the dial indicator firmly attached to the deck surface and so that its stem can contact the intake lifter for the number one cylinder, the engine is rotated until that lifter is at full lift as indicated on the dial indicator. Placing the indicator stem at the outer edge of the lifter rather than in the pushrod cup hole tends to also give more consistent readings. With the lobe at max lift, rotate or adjust the dial indicator dial so that it’s reading zero. Now rotate the engine backwards (CCW looking from the front) so the lifter falls back down ~0.060”. Then rotate the engine forward until the lifter rise is at 0.050” before the top of the lobe. The reasoning for going back to a point more than 0.050” from lift peak and then coming back to the 0.050” mark is to insure that any slack in the timing chain is compensated for by loading the chain in the direction that the engine normally turns. At this point, take a reading from the degree wheel as the number of degrees from TDC. In this instance, we’ll use 49° ATDC for the example.

Now rotate the engine in a forward direction (CW looking from the front) so that the lifter crests at full lift and continue rotating so that the lifter is now at 0.050” down on the other side of the lobe. At this point take another degree wheel reading as degrees from TDC. In this instance, we’ll use 157° ATDC for the example. Taking the sum of the 49 and 157 values and then dividing by two, the resulting value is 103. This would be the number of degrees that the intake lobe centerline is from TDC. Now looking at the cam spec card, look for the number of degrees that the camshaft is ground on. For this example, the card says the camshaft is ground on 108° lobe centers. With the measured intake lobe value being less than 108° and subsequently closer to TDC, then 108 minus 103 would have this camshaft being 5° advanced. Some cam cards will include the manufacturers recommended intake lobe centerline installation value which can be compared to your measured value. Our card has the recommended installation being at 104° degrees intake lobe centerline which has the camshaft as measured having one more additional degree of advance. Had the intake lobe centerline value been a number greater than the advertised lobe centerline value, then the camshaft would be that number of degrees retarded. If the measured intake lobe centerline equals the advertised ‘as ground’ lobe centerline value, then the camshaft is installed straight up (no advance, no retard).

Click on picture for larger image.

Because of manufacturing variances, we are now going to go an extra step and check the exhaust lobe to get some real numbers on the camshaft and how it has been ground. This is being performed to both verify the checking procedure and also insure that the camshaft is ground as advertised at least for this particular cylinder. So with that in mind, move the dial indicator to the #1 exhaust lifter. Rotate the engine in a forward manner until maximum lobe lift is obtained on the dial indicator and then zero out the indicator dial. Rotate the engine backwards so that lifter falls back down approximately 0.060” and then forward so that the lifter is sitting at 0.050” before max lobe lift. Take a degree wheel reading as degrees from TDC. In this instance a 160° BTDC value is indicated on the degree wheel. Now rotate the engine forward (CW looking from the front) so that the lifter crests to max lift and continue forward until the lifter is sitting 0.050” down on the other side of the lobe. The reading on the degree wheel at this point is 64° BTDC. Taking the sum of 160 and 64 and dividing by two gets a value of 112° for the exhaust lobe centerline. Because we are now dealing with the exhaust lobe, any value greater than the advertised lobe centerline will also indicate degrees of advance. In this case, 112 minus 108 equals 4° of cam advance based on the advertised ‘as ground’ lobe centerline value on the spec card.

As determined by the individual lobe measurements, the intake is installed at 5° of advance and the exhaust lobe measurement says 4° of advance. Which is correct? To determine this, the two sets of degree wheel measurements must be combined. Add together the measured 112° exhaust lobe centerline and the measured 103° intake lobe centerline values obtained earlier and divide by two. 107½° is the revised or actual ‘as ground’ lobe centerline value rather than the 108° that is listed on the cam card. Revisiting the intake and/or exhaust lobe centerline values and recalculating using the actual ‘as ground’ lobe centerline, the camshaft is actually 4½° advanced instead of the 5° value that was determined earlier by only doing the intake lobe measurement.

SAME DRILL, DIFFERENT CYLINDER.

Because the #1 and #6 cylinders on most V8 engines share the same TDC on the degree wheel, the #6 cylinder will now be used to reaffirm both the checking procedure and any variances in the camshaft itself. (The Buick V8 Nail Head engines are a known exception to the cylinders 1 & 6 sharing the same TDC.)  Because the #6 cylinder is being used for the double check, the degree wheel can remain as it was for the #1 cylinder check. Any other cylinder can be used for the recheck as long as exact TDC for that cylinder is found and the degree wheel is adjusted accordingly.

In this case, the dial indicator is simply moved to the #6 intake lifter and the same procedure as used for the #1 intake lobe is performed once again. In this instance, the intake lobe centerline measures to be 104°. The dial indicator is then moved to the #6 exhaust lifter and that ends up being installed at 113° lobe centerline. Adding the 104 and 113 values together and dividing by two gives us a 108½° ‘as ground’ lobe centerline for cylinder #6. Taking the 104 value and subtracting from the 108½ value leaves the intake on this cylinder being installed at 4½° of advance. The check for the #1 cylinder also had the actual amount of advance right at 4½° so in this instance, both are identical. In the event there was a difference, then averaging the values would give the advance value to be used for this particular engine.

With the numbers obtained from the #6 cam lobes check, the variability within the cam lobes between cylinders 1 & 6 can now be observed. The 108½° value on cylinder #6 is compared to the 107½° degree value that was obtained on the #1 cylinder and there is a 1° difference. That is your lobe centerline manufacturing variance for these two cylinders. This is assuming your cam checking methodology is both consistent and accurate. While 1° of variance would be my own upper limit of variability, there are those cam manufacturers that are comfortable with 2° or more of variability. In summary, the more accurately the cam lobes are ground, the more potential power an engine will make once that camshaft is installed at its optimum position. If so inclined, the camshaft lobes for all eight cylinders can be checked for a better feel for how the camshaft is ground. In this particular instance, the camshaft that was just checked will be left where it is and ran.

The scary part of all this is if you only check the lobe or lobes on the #1 cylinder, the variability within the camshaft is basically unknown. That variability can be an engine performance issue all by itself once the engine is in the vehicle and being operated. The caveat to checking a large number of cams from the different manufacturers gives the installer a good feel for which cam grinders do a consistently better job in keeping variances to a minimum; or said differently, which cam companies to stay clear of.

HOW MUCH ADVANCE OR RETARD?:

As a general rule, most camshaft installations prefer a given amount of advance when being installed. Examining the spec card will give the manufacturers recommended installation specs but if not given those values, then 4° of advance covers most installations. Why advance the camshaft rather than simply install the camshaft straight up? Because a timing chain has a given amount of elasticity, the camshaft retards as the rpm increases so this initial amount of cam advance helps to compensate for this. Also, as a timing chain wears it stretches and as a result, the camshaft is also being retarded over time. All out race engines will break many of these rules in that the camshaft is simply being installed for the best power numbers in a given rpm range. Long term wear or stretch in this instance is not being compensated for.

Here is a word of caution regarding moving the camshaft phasing around. As the camshaft is advanced or retarded, the intake and exhaust valve relationship to the piston at TDC is changed. Depending upon the engine and the piston design, the potential is there for a valve to contact the piston resulting in a catastrophic failure if valve to piston clearances are not being checked. As the camshaft is being advanced, the intake valve becomes closer to the piston; as the camshaft is being retarded, the exhaust valve becomes closer to the piston.

A general rule of thumb for flat tappet camshafts is for each 4° the camshaft is moved, the valve to piston clearance is altered roughly 0.025”. If the camshaft is advanced 4°, the intake valve becomes ~0.025” closer to the piston; if the camshaft is retarded 4°, the exhaust valve becomes ~0.025” closer to the piston.

MAKING ADJUSTMENTS:

While the first part of degreeing in the camshaft is simply checking to see where it is initially installed, the second phase of the operation is actually moving the camshaft so its relationship to TDC is altered. If the camshaft has been found to be off enough to necessitate a change, then the camshaft phasing in relation to TDC will need to be moved. On some engines, one degree of change may be critical while on others it may take four degrees to be significant. Changing the camshaft phasing on some engines can be performed at the camshaft gear by lieu of using an offset key or offset bushings. Where the crankshaft gear has multiple key slots, then the appropriate slot can be used to move the camshaft a given number of degrees in one direction or the other. Where the crankshaft gear has only a single slot, then an offset key can be used at the crankshaft with the direction of the offset that’s built into the key determining either advance or retard. Another option where the crank gear only has one key slot is broaching an additional slot at a new position in the gear to also move the camshaft in the desired direction and amount. Likewise, a new key way slot can be broached into the cam gear or a new dowel pin hole placed at the appropriate spot on the gear.

To advance a camshaft, then either the cam gear is turned more clockwise (looking at the front of the engine) or the crank gear is turned more counter clockwise in relation to the opposite gear not moving at all. To retard a camshaft it’s the opposite scenario where the cam gear is turned counter clock wise or the crank gear is moved clockwise. Advancing the camshaft simply has the cam timing events occurring sooner while retarding the camshaft has those same events occurring later.

While part II of this article ended up being more complicated than I envisioned, I trust it is laid out in such a manner that the cam degreeing in process has been simplified. Part III will go into the specifics of the Rollmaster timing set for the Ford Y-Block and the nuances in moving that particular crank sprocket to achieve the desired results. Until next issue, happy Y motoring. Ted Eaton.

This article was originally published in The Y-Block Magazine, May-Jun 2015, Issue #128.