Category Archives: Y-Block

Unported Iron Heads Can Still Make Over A HP To The Cubic Inch

By using just the right combination of parts, exceeding that magic 1HP to cubic inch ratio is indeed possible while still doing it with a pair of unported iron Ford Y-Block heads. The key here is in using a modern piston ring design and maximizing the compression ratio while still being able to have an engine that will run on available pump gasoline.  Not to be left out are the intake, carburetor, camshaft, and cylinder head choices which are also just as important.

For this build, the engine is going back into Karol Miller’s 1956 Ford Victoria with a T86 3 speed/overdrive.  The rear gearing is currently 3.22:1 which is going to drop the rpms significantly when the car is in overdrive mode. This makes low rpm torque production even more important.  Because this car is not going to be sitting dormant in a garage very much, fuel efficiency needs to be reasonable so the camshaft choice becomes critical in making power while still being efficient.

Because the block that comes out of the car is already 0.110” over and is badly worn, another block is picked out.  The C1AE block selected for this build has a May 25, 1961 casting date and while it had already been previously bored 0.040” over, it is heavily worn again at this point.  The block is sonic tested and deemed a good candidate for an additional over-bore.  Prior to doing any machine work to the cylinders, the two center ‘steam’ or vent holes in the decks were plugged.  The cylinders clean up at 0.070” over the stock bore size which will have the cubic inches coming in at 303 using a stock 3.3” stroke crankshaft.  The center cam hole in the block is modified with an interconnecting groove between the three holes there to insure adequate oiling to the top end of the engine.  Adding that groove has become a standard activity on Y engine builds at this shop as it alleviates any concerns about the new cam bearings pushing babbit into the camshaft journal groove and subsequently shutting off the oil supply to the top.  While there are a couple of other fixes for this, the machined groove is my own preferred option for increasing the oil supply to the top end of the engine.

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As an upgrade to the performance and efficiency, it’s decided to go with a modern ring design.  For this engine, 1.2mm metric rings will be used for both the top and 2nd grooves with a 3.0mm oil ring finishing up the ring package.  The original 2nd ring thickness was 3/32” which equates back to a 2.4mm ring.  The new ring package cuts this in half which in theory cuts cylinder wall drag in half.  But the metric rings also have less radial thickness which further reduces the ring drag.

The connecting rod choice could have gone with either the longer 292 rod or the shorter 312 rod.  While the shorter rod tends to allow for more torque production by lieu of an earlier piston movement from TDC, the drawback is an increase in the cylinder wall wear.  The longer rod on the other hand does allow for an increased dwell time at TDC which in turn will help to deter any detonation issues that could be encountered as a result of maximizing the compression ratio for both power production and fuel efficiency.  Piston skirt friction will also see a reduction with the longer rod versus that with a shorter rod.  Because fuel efficiency is being considered, a set of ‘longer’ C2AE rods will be used for this build and are prepped and resized with new ARP rod bolts being installed.

Diamond Pistons supplies a set of custom flat top pistons for this build which permits the use of the aforementioned 1.2mm rings.  These pistons have a wrist pin height of 1.792” and use a stock dimension 0.912” diameter wrist pin.  The piston to wall clearance for this combination is maintained at 0.004”.  The final deck height for the block after all the machine work is complete is 9.750”.

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The remainder of the short block build presents no problems.  The crankshaft comes from a 272 and is still a flawless standard on both the main and rod journals.  In fact the clearance on the rod journals is still on the snug side with the replacement standard size bearings which is where a set of the red/blue bearings that use to be available from Ford would have come in handy.  While the rod bearing clearance is on the snug side, it’s not so tight that it will be a problem.  Once the engine has been mocked up and the decks machined for a zero piston to deck clearance, the rotating assembly is precision balanced with the crankshaft being balanced to an 1890 gram bobweight value.  A small amount of overbalance is also included in the bobweight calculation which tends to extend the overall engine life. The oil pump is a stock gerotor oil pump that has simply been disassembled, examined for problems, and reassembled.

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The cylinder heads came off the original worn engine and had been worked on not that many miles ago.  They are a set of 113 castings which already had hard seats previously installed.  While the exhaust valves were okay to reuse, the intakes were replaced with a new set of 1.92” stock sized valves.  In measuring the pads at the exhaust side of the heads, it was found that both heads had had ~0.080” removed from them in the past.  While that sounds extreme, the heads are factory posted and looked to have been running okay like this.  In cc’ing the heads after reinstalling the valves and hardware, the combustion chambers are averaging 62.3cc’s.  Calculating the static compression ratio for this combination has it at 9.57:1.

The camshaft selected for this build is an Isky grind with the following specs:

Duration at 0.020”: 264°I, 272°E

Duration at 0.050”: 228°I, 238°E

Lobe lift: 0.298”I, 0.320”E

Valve lift: 0.459”I, 0.493”E before valve lash

Ground on 110° lobe centers

Installed at 105½° intake lobe centerline

(4½° advanced)

With a stock link style timing chain set in place, the camshaft was sitting more than nine degrees advanced which was unacceptable in this case.  Instead, a Rollmaster roller timing set with the multi-indexed crank gear is used which makes camshaft phasing much simpler.  The dynamic compression ratio calculations when taking into account the 4½° of cam advance and using the 6.309” long connecting rods is 7.99:1.  This engine will like premium fuel which is typically recommended anyhow simply due to the reduced amounts of ethanol in premium fuel versus that in the lower grades.  The valve train is topped off with a set of rebuilt 1956 1.54:1 rocker arms and a set of 7.964” effective length tubular pushrods.

The intake manifold is the old reliable ECZ-B intake found on the 1957 and up four barrel equipped Y’s.  The four holes at the carb base were opened up so it was dual slots and the transitions going to the lower ports ground on to open up the flow some.  While it took about forty minutes to machine the dual slots at the carb base, the porting on the inside of the manifold took less than five.

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With engine assembly now complete, the engine is prepared for running in on the dyno.  Six quarts of Valvoline 10W-40 conventional oil fills the pan and a Wix 51515 oil filter completes the package.  The engine is initially started up with the shop’s 750 cfm HP Holley in place as this is a proven performer.  The carburetor sits atop a 1″ tall four hole phenolic carb spacer.  Once the engine is started up and run in, the valve train is checked for any problems and there are none.  After the engine has been allowed to thoroughly cool down to put a completed heat cycle into the new valve springs, some dyno pulls are made.  The engine immediately makes 308 HP and with some timing adjustments, jumps to 316 HP with the HP Holley on it.  Karol’s 1956 Lincoln Teapot carb is put on the engine with an appropriate adapter and after jetting adjustments, it’s making 294 HP.  But that carb simply has a hard time idling with this camshaft and has other issues with it that will require some serious work.  There’s an older model 4010 750 cfm Holley sitting here that is tried and that carb runs nicely and clicks off a 315 HP number without any jet changes.  Based on Harry Hutten’s recent performance with the Summit 750 carb that he is using on his ’60 Merc, a similar Summit 750 carb is ordered for this combination.  Two days later the carb arrives at which point it’s immediately installed on the engine which is still sitting on the dyno.  The engine idles well and with a three number increase in jetting on the secondary side only, another 315 HP number pops up.

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At this point, the engine is deemed good to go and reinstalled back in the 1956 Ford Victoria chassis.  The engine was dynoed on a Friday and is back in the car and running on the following Saturday.  That’s a quick turnaround.  Since then the car has been driven around and drives without issue even with the 3.22 rear gears.  Starts up good when cold and actually runs on the cool side with no heating issues at all.  The exhaust lets you know that this is not a stock Y though.  There’s a nice rumble from the pipes and that hard rush of air hitting the pants legs lets you know that the compression is there also.  While it hasn’t been driven around enough yet to get an accurate mpg number, the fuel mileage doesn’t appear to be bad though based on the 120 miles it was driven around locally before going back home.

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The sonic test sheet and dyno sheet are also included at the end of this article.  Until next time, happy Y motoring.    Ted Eaton.

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This article was previously published in The Y-Block Magazine, Jan-Feb 2015, Issue #126.

Stock Ford Y build or modified? Here are two different approaches.

I was recently given the opportunity to rebuild a pair of Ford 292 Y-Block engines with each going into 1963 F100 pickups.  While both engines started life out as 1963 two barrel pickup engines, one was a restoration project while the other was to be a mildly hopped up version.  The engine for the restoration pickup was to be built as close to stock as possible while the other engine was to use the normal performance upgrades such as four barrel intake and carburetor, larger valved heads, and a better than stock camshaft.



Machine work for the stock engine includes boring the cylinders 0.040” over and grinding the crankshaft 0.010” undersize for both the rod and main journals.  The 3.790” bore puts the cubic inches at 298.  The C1TE heads are upgraded with hardened seats for the exhausts with the new replacement valves remaining the stock sizes. The combustion chamber volumes for these heads after milling are 76.2cc.  The 1.43:1 rocker arm assemblies are rebuilt using new Schumann rocker arm shafts while the camshaft is a stock replacement grind with the following specs:

Duration at 0.020”: 211°I, 228°E

Duration at 0.050”: 195°I, 195°E

Lobe lift: 0.258”

Valve lift: 0.369” before valve lash

Ground on 113° lobe centers

Installed at 104° intake lobe centerline

The connecting rods are reconditioned with new ARP rod bolts, the big ends being resized, and new wrist pin bushings installed. The replacement cast pistons are fitted to the bores with 0.0025” clearance and sit 0.020” below the decks at TDC after a cleanup mill had been performed on the decks.  The static compression ratio for this engine is 7.8:1 while the dynamic compression ratio calculates to be 7.5:1.  The rotating assembly is precision balanced using a 2100 gram bobweight value once all the basic machine work was complete.

Topping off the engine assembly is the original two barrel intake manifold and the Autolite 1.02” venturi two barrel carburetor.  The stock distributor is retained and is upgraded with a Pertronix electronic ignition conversion.  The engine is filled with six quarts of Valvoline 10W-40 conventional oil along with a Wix 51515 oil filter and is readied for running on the DTS engine dyno.

After the engine has been broken in on the dyno, the valve covers are removed with careful attention towards any premature valve train wear.  There is none so all is good.  The valves are ‘hot’ adjusted to 0.019” lash and some power pulls are made to insure that the timing and jetting are where they need to be.  After making minor tuning adjustments, the horsepower peaks at 153 at 3800 rpms and the torque peaks at 267 lb/ft at 2500 rpms.  It becomes evident that the original two barrel carb is a major player in holding back any serious rpm capability.  On the flip side of this, the engine idles very smoothly and at a very low rpm.

I will add that the engine was tested with a set of headers feeding into dual mufflers.  The installation of the original crossover pipe with a single exhaust pipe system being used will cut the HP power numbers and torque values back a bit further based on previous exhaust system testing results.

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The second F100 engine has the cylinders bored 0.050” over stock thus putting the cubic inches right at 300.  The cylinders are sized so that the piston to bore clearance is 0.0035” and the decks are machined so that the pistons are level with the decks (zero decks).  A flawless standard journal crankshaft is available so no grinding of the shaft is required in this instance.  The connecting rods are reconditioned with new ARP rod bolts being installed and once this is done, the rotating assembly is precision balanced using a 2070 gram bobweight value.

The camshaft selected for this build is an Isky grind with the following specs:

Duration at 0.020”: 264°I, 272°E

Duration at 0.050”: 228°I, 238°E

Lobe lift: 0.298”I, 0.320”E

Valve lift: 0.426”I, 0.458”E before valve lash

Ground on 112° lobe centers

Installed at 108½° intake lobe centerline

(3½° advanced)

The cylinder heads are the ‘big letter’ ECZ-G heads with one of them being posted and the other is not.  The heads are rebuilt with hardened exhaust seats and lightly milled with the combustion chambers measuring 69.2 cc’s when all is done.  The static compression ratio using the Best Gasket composition head gaskets is 8.75:1 while the dynamic compression ratio calculates to be 7.17:1.  This engine will run fine on the lower grades of gasoline if necessary.

The rocker arms are the original 1.43:1 units that have been refurbished and mounted on new Schumann rocker arm shafts.  The pushrods are oem style tubular units measuring 7.940” effective length.  The engine is topped off with an iron ECZ-B four barrel intake and the carburetor selected is a new Summit 600 cfm unit which sits on top of a 1” four hole spacer.  This carburetor is similar in construction and appearance to the older flat top Autolite carbs that were popular on Ford engines in the Sixties.

The crankcase is filled with six quarts of Valvoline 10W-40 oil along with a Wix oil filter and readied for run in.  After running for a given period of time on the dyno, the valve train is thoroughly checked over for problems and none are found.  Once the initial tuning is completed, the engine is peaking at 269 HP at 5400 rpms and 306 lbs/ft torque at 3300 rpms.  While this engine does exhibit good idle characteristics, the exhaust is still letting you know that the camshaft is no longer stock.

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So there you have it.  Here are two engines that started life out similarly but went two different directions on the rebuilds; one being stock and the other being modified for additional performance.  While the stock engine was less expensive to build, many of the extra costs incurred on the hopped up engine was in obtaining the four barrel intake, G heads, and the new carburetor.  The Isky camshaft is also slightly more expensive than the stock camshaft but the costs for the machine work, pistons, rings, bearings, and gaskets for each engine were very similar.  The addition of ECZ-G cylinder heads, ECZ-B 4V intake, 600 cfm carburetor, and Isky camshaft to a stock engine in this case makes for a 76% improvement in power.  The stock engine is making 0.51 HP/CI while the modified engine is making 0.90 HP/CI.  That’s quite an improvement by just adding the right combination of parts.  The dynometer sheets for each engine are at the end of this article.

Until next time, Happy Y Motoring.  Ted Eaton.


Click on dyno sheets for larger images.

This article was originally published in The Y-Block Magazine, Nov-Dec 2014, Issue #125.

Oil Viscosity and Its Effect On Engine Power

It’s pretty well known that engine oil with a higher rated viscosity tends to rob power from the flywheel end of the engine. It’s this mentality that has the new car manufacturers using lighter weight engine oils in which to increase the fuel efficiency of their engines as well as pick up some additional power. The oil itself is not so much the power robber as is the oil pump and clearances which simply makes the pump work harder to move a higher viscosity oil throughout an engine. Higher or heavier viscosity oil drives up the oil pressure which in turn makes the oil pump work against a higher resistance. In this vein of thought, the oil pump is ultimately just another horsepower robbing accessory similar to the alternator or water pump. In the case of the oil pump, using lower viscosity oil allows it to turn easier which simply frees up some horsepower. In some racing venues, the volume of oil delivered by the oil pump is intentionally reduced with an oil pump rotor size reduction to minimize the horsepower losses associated with an oil pump that’s simply larger than it needs to be. OEM oil pumps are generally engineered on the ‘large’ side of specifications to insure adequate oil flow under a variety of conditions and to also compensate for a given amount of long term wear within an engine.

While dyno testing a high horsepower Ford Y-Block engine (570+HP), a significant drop in the peak horsepower numbers was noted when the oil was changed out for one with a higher rated viscosity. That particular engine had been initially started up and broken in with conventional 10W-40 oil. At the conclusion of that break-in and after making the prerequisite baseline dyno pulls, the oil was switched out to a 20W-50 racing oil at which point there was an immediate loss of ten horsepower. For both of these oils, the water and oil temperatures had been maintained within the same ranges which eliminated those two items as potential variables. While it was anticipated that there would be a horsepower loss with the higher viscosity oil, that loss being as much as ten horsepower was unexpected. It was this particular instance that would prompt a more complete dyno test using the 312 dyno mule where several different viscosities of oil would be run in a back to back fashion to clarify the effect on both the oil pressure and the power production.

While the rated viscosity on the container is a quantifiable value that can be worked with, the unknowns in this series of test are the shear properties of the various oils. Based on the final results of the tests, there are some differences not accounted for in examining just the viscosity ratings. It can be assumed that some of these differences are related to the shear properties imparted within the various oils by the different additive packages used to derive the various viscosity ranges. Another variable is the cycle time or how long the oil has been used within an engine. The first oil used in this test was well used versus the remainder of the oils being fresh out of the can bottle.

The +060 over 312 dyno mule is prepped with a set of mildly ported ‘posted’ big letter G heads, a stock Mummert aluminum intake, and a 750cfm vacuum secondary Holley carburetor. It is base-lined with the existing oil that’s already residing in the crankcase which is Valvoline conventional grade 10W-40. This particular oil is well used at this point and the engine is already past due for an oil change as the engine is fast approaching 300 dyno pulls with this oil. In fact, the oil pressure had been dropping off in the upper rpm range which was first thought to be bearing wear taking place. Six new dyno pulls are made on the engine with this oil in which to record data at varying engine coolant and oil temperatures. Once this oil was changed out with a 0W-20 full synthetic oil, all oil pressure issues went away which then indicated that the original oil in the engine was just simply ‘worn out’. For this particular 10W-40 oil, a separate chart and graph is included showing how this oil performed over time as it was showing some serious degradation after dyno pull number 250. For comparision purposes though and because all horsepower numbers needs to be using the same cylinder heads, the baseline numbers for the first oil tested puts the average oil pressure at 44 psi and the peak horsepower at 310. This oil was actually averaging well over 50 psi earlier in its life.

To help maintain a level of consistency in the testing, the same brand of oil is used so that viscosity measurements are not as varied as would be if using different brands of oil. It has been found in the past that the viscosity measurements between oil brands within the same rated viscosity oils are not the same. While the baseline test would be the Valvoline conventional 10W-40 oil that was already in the engine, the other oils to test would include Valvoline 0W-20 full synthetic, Valvoline 5W-30 semi-synthetic, Valvoline 10W-40 Max Life (syn blend), and Valvoline 20W-50 VR1 racing oil. The oil filter is also changed with each oil change and the filter of choice for this test is the Motorcraft FL-1A.

No additional additives are being used in this test although the zinc/phosphate amounts in the 0W-20 and 5W-30 oils are less than ideal for flat tappet camshafts. The zinc amounts in the remaining oils that are being used are more than adequate for flat tappet camshafts without the use of supplemental additives. I’ll add that at the conclusion of this test, there was absolutely no measureable wear to the valve train components although there were a number of dyno pulls made using oils with reduced amounts of ZDDP compounds. Here’s a chart showing the test results.


Oil Avg oil pressure Avg oil temp Peak Tq Avg Tq Peak HP Avg HP
Valvoline10W-40 conventional 44.19 psiSee Note 1 161.19°F 344.4 327.53 310.1 249.12
Valvoline0W-20 full synthetic 45.75 psi 170.16°F 346.4 327.92 307.9 249.26
Valvoline5W-30 conventional 48.84 psi 168°F 346.9 328.27 306.4 249.4
Valvoline20W-50 Racing 52.36 psi 169.32°F 342 323.11 301.9 245.52
Valvoline10W-40Syn Blend 51.77 psi 167.87°F 345.2 327.74 307.5 249.09

Note 1. This particular oil was nearing 300 dyno pulls on it and looks to be ‘worn out’ by the time this oil test took place. The following chart shows the oil pressure performance of the 10W-40 conventional oil at the different rpms during the course of it being in the engine under a multitude of different testing conditions. Of particular interest is how the oil is not maintaining the oil pressure in the upper rpm ranges after ~250 dyno runs have been made using it.

Ref # 372 409 447 492 541 599 624 649 662
Rpm Run#6 Run #43 Run #81 Run#126 Run#175 Run#233 Run#258 Run#283 Run#296
2500 53.7psi 51.6 46.3 50.9 50.5 47.5 46.0 42.5 42.5
3000 52.9 50.4 48.0 51.7 52.9 53.1 46.7 43.9 44.4
3500 54.2 51.2 49.0 51.3 53.2 54.0 48.6 44.6 46.4
4000 54.6 52.3 49.9 50.3 53.0 53.6 49.3 44.9 45.9
4500 54.6 51.9 50.9 50.8 53.0 51.5 50.2 46.3 45.3
5000 55.4 54.7 53.2 53.0 54.6 53.5 52.4 43.6 41.1
5500 57.7 56.9 54.0 55.1 55.9 55.3 53.5 43.5 42.7
Avg oil temp °F 149.3 146.0 159.1 144.7 138.1 139.2 149.8 165.1 161.2
Avg psi 54.7 52.7 50.2 51.9 53.3 52.6 49.5 44.2 44.0


But to put more emphasis on what was going on with this oil, the following graph shows the oil pressure on runs #81 and #296 on the same oil. These two runs were selected simply due to the oil temperatures being the most similar. The degradation in oil pressure in the upper rpms becomes quite noticeable on the well used oil versus the same oil that did not have as many dyno pulls on it.

Used versus well used oil

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In summary, that same significant drop in horsepower that was originally seen on the high HP Y when switching from 10W-40 to 20W-50 was also seen on the dyno mule. While it was a 10 HP drop on the high HP Y, it was still an 8 HP drop on the dyno mule. For the remainder of the oils tested, the range or difference from best to worst was only 3½ HP which makes all those oils reasonably close to each other from a performance standpoint. In this particular test, the best bang for the buck comes from using the 10W-40 oil which already has the prerequisite amounts of ZDDP for the flat tappet camshafts without the use of additional additives. The Y engines with their flat tappet camshafts does still require an oil with a sufficient amount of ZDDP or an additive to supplement the known lack of it in the oil. Most API ‘SN’ rated oils with 40W or higher in their labeling will have sufficient amounts of zinc & phosphorus compounds for flat tappet camshafts while oils with 30W or less in their labeling do not.

The surprise finding in this test was actually being able to see how the oil does indeed wear out or break down thus mandating an oil and filter change. This could very well be the results of contaminates that do not get filtered out. These contaminates then contribute to a reduced viscosity leading to cavitation issues not normally observed. A likely contributing factor is that this oil is being submitted to a multitude of full throttle power pulls which can put a more than normal amount of fuel past the rings and into the oil thus affecting the overall viscosity. If engine wear is to be minimized, then the oil and filter should be changed before the drop in oil pressure that was observed in these tests actually takes place. If I was to take a stab in the dark at how dyno pulls relate to real world vehicle mileage, then I’d say 250 dyno runs would equal ~3000 miles. Assuming the oil is not contaminated, then 250 dyno pulls on the same oil is the upper limit for this particular engine. More frequent oil changes sure will not hurt though.

As always, just consider this food for thought. Until next time, Happy Y Motoring.                              Ted Eaton.



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This article was originally published in The Y-Block Magazine, Issue #119, Nov-Dec 2013