Preparing a 375 inch Y-Block Ford for the 2009 EMC Competition.

By the time this is published, the 2009 Engine Masters Challenge (EMC) will be history and the final results very likely posted all over the internet.  Because this is being written as the engine is still being tested and before the competition takes place, I’ll do a followup article on the actual competition and what took place there.  But in the meantime, here’s the short version of what was involved to get a Ford Y-Block engine readied for the EMC competition.

I had intentionally kept the displacement of this years EMC project under wraps as it was treading in some territory not normally being explored for a Y buildup.  The original plan was for a four inch bore along with a four inch stroke to give a 403 CID.  This combination likely would not have given the best overall score but was going to give some impressive peak numbers.  After assembly, the four inch bore block broke in fine and running the engine up to 150 HP to seat the rings exhibitted no problems.  It wasn’t until a low rpm full throttle pull was made that some water issues came to the forefront.  These were only discovered after shutting the engine down and doing a general checkout.  With the single dyno pull that was made, the block took a twist and that allowed water to seep in at each cylinder where the head gasket sealing ring comes off of the sleeves and onto the deck surface.  The block had filler in it at both the tops and bottoms of the bores but to no avail.  When the engine was disassembled, it became evident that the camshaft tunnel had also taken a serious twist thereby making the block unusable for any future work.

Due to the four inch bore scenario being a no go (for the time being), plans went forward to build another four inch stroker but this time utilizing a fresh block with a smaller bore.  No sleeves this time.  Custom pistons were reordered August 31st and received Sept 11th.  Block work commenced again during the interim.  This time the bore was going to target for 3.859” giving a claimed cubic inch of 375.  That’s still a respectable cubic inch value by Y standards but not the 400+ I was really targetting for.  Most of the other parts from the 403 incher such as heads, crank, rods, and camshaft would be reused.  The 375 CID Y engine was cranked back up on September 19th and looks to be a solid performer.

Now that I’ve brought the whole EMC Y program up to date, I’ll step back a bit and give some additional information on what it took to get to this point.  For the 2007 & 2008 competitions, I was looking at a 0.022” over 312 with stock stroke (316 CID) and this looked to be a very good combination for the rules for those years.  But for 2009, there were some major rules changes.  Of significance was the  increasing of the rpm range for the competition dyno pulls, engines were now being allowed to deviate from factory supplied bore and stroke  combinations, and the static compression ratio could now be increased up to 11½:1.  Although the 316” Y looked to be a very good combination and especially at the prior 2500-6500 rpm test range, the rules for 2009 would have this same Y placing much lower in the field simply due to the allowance of roller camshafts thrown into the fray and the upping of the rpms to a 3000-7000 test range.  I was already at a disadvantage by having to use oem iron heads as the rules do allow aftermarket heads with some given guidelines.  But regardless, I did go forward with a plan to use a Y as my basis for this year’s competition even though I had last years Ford 427 Tunnelport backup engine still sitting here. Also available was a very stout 455 Buick engine being built for a customer with the latest in technology that was also offered up for the competition if so desired.

With the 312 engine that had been built for the 2007 and 2008 competitions being deemed unsuitable for this years competition, a new plan came to the forefront.  And that plan kept shouting “Go BIG!”.  And not talking about the 352 inchers that surface from time to time for a Y build but going witB Mockup Crankshafth 402+ inches with a 4X4 bore & stroke combination.  Although 3.75” and 3.80” strokes had been used successfully in prior Y builds, it was time to see what a 4.00” stroke would look like within the confines of a Y block.  A stock cast iron Y 292 crank was ground to a 4.00” stroke on one journal for mockup purposes.  Playing around with this combination found that by using a Honda rod journal (1.889”) and experimenting with the base circle of the camshaft, everything could be made to clear with a 4.00” stroke.  Camshaft to connecting rod clearance is typically the issue when stroking the Y but the smaller rod journal size in conjunction with an aftermarket connecting rod that utilizes 3/8” rod bolts instead of  7/16” bolts helps significantly in this area.  But a smaller base circle cam was not going to help here in that I was already planning on using a camshaft with ~0.376” lobe lift to get in the 0.600” lift neighborhood at the valve. As a point of reference, the base circle of the cam could be no smaller than 1.150” and still have the lifters not falling out of their bores from the bottom side.  Using the 1.150” base circle with a reduced lobe lift would help in the rod to cam clearance department only if the lobe lift was maintained at 0.337” or less; but I am wanting to keep the lift at the valve in the 0.600” gross lift neighborhood which does put clearance issues between the rods and tips of the cam lobes back to the forefront.

Because the four inch bore block essentially failed, I’ll not go into much detail on how it was sleeved to get to that final bore size.  For the latest smaller bore block, a B9AE-F casting 292 non-steam hole block was selected.  Like the four inch bore block, the water jackets were partially filled to increase cylinder wall rigidity.  With the thin piston rings that are being used, it’s important to keep cylinder wall flex to a minimum.  This block was then fitted internally with the main support girdle from the 4” bore block which fits within the inside of the machined pan rails and at the same time crossbolts to the outside of the block.  After align honing the mains, the cylinders are then bored and torque plate honed to a 3.859” bore.

In the midst of all the work that was being performed, there was the ordering of the various parts of which lead times were a major consideration.  With the stroke figured out, a Moldex billet steel crankshaft with a 4.00” stroke and the aformentioned Honda rod journal sizes was used.  Rather than stay with a Y-Block flywheel flange at the rear of the crank, the flange was made the same as the FE and 460 Fords which solved the problem of locating the required SFI approved steel flywheel that’s mandated for the competition.  PRW supplied the necessary flywheel.  The connecting rods are manufactured by Oliver and are parabolic beams in design while being 6.750” long.   Being longer increases the dwell time at TDC and helps to make the engine less susceptible to detonation.  While the pistons for the 403 incher were by Wiseco, the pistons for the 375 entry are manufactured by Diamond.  Both sets are ceramic coated on their tops while the skirts have a special friction reducing coating.  The compression height (wrist pin location) is at exactly 1.000” which puts the wrist pin in the oil ring area and subsequently requires oil ring support rails to minimize any oil ring flex in the wrist pin area.  The wrist pin itself is 0.866” in diameter while a 9cc convex dish is used in the pistons to keep the static compression ratio at 10.1:1 for the 375 incher.  The dynamic compression ratio is 8.0:1 with the camshaft installed 1½° advanced and with the valve lash set at 0.025” hot.  This engine has to live with 91 octane fuel and oem iron heads which is why the static and dynamic compression ratios remain on the conservative side.  In theory, aluminum heads had they been available in time for this competition could have allowed for an increase in the static compression ratio while using the same 91 octane fuel.

C Moldex Crankshaft
The Moldex crankshaft as usual looks like a work of art.  Their craftsmanship as always is superb.  I deviated this time in crank design as the crankshaft is not fully counterweighted as I’m going for an overall lighter mass.  The 4” stroke fits within the confines of the block but some light massaging on the connecting rods was still required to insure adequate clearance to the camshaft.  Rod bearing clearances are held to 0.002¼” while the main bearing clearances are opened up to 0.0035”. The crankshaft was balanced to a 1630 gram bobweight value and this includes a considerable amount of overbalance or an increase in the percent value used for the reciprocating parts.  For harmonics control an ATI damper is fitted to the front of the crank.  I’m still working at this point on all those little details that will insure this engine revs freely to 7000+ rpms.

The piston rings are by Total Seal and were given considerable thought.  For the 375 incher, the top ring is 1.2mm wide with a 0.130” radial thickness while the second ring is 1.2mm wide with a 0.143” radial thickness.  The oil rings are 3mm wide with a 10lb pull.  The plan here is to keep ring drag on the low side without spending a ton of money on a set of custom rings.  Both the top and second ring end gaps are set at 0.018”.

Unfortunately the aluminum heads were not available in time for testing on the EMC engine.  As a result, a set of oem ‘113’ iron heads were ported and prepped for the engine.  It’s undoubtedly an understatement to say that it’s going to take some really good flowing heads to provide an adequate amount of air to feed 375 inches of Y-Block at 7000 rpms.  Valve sizes are 2.02” on the intakes and 1.56” on the exhausts and were originally configured for the four inch bore.  Too late to reconfigure valve sizes at this point.  No flow numbers on the heads simply due to a flow bench not readily available to work with.  This particular pair of heads are already heavily milled and are at 65cc’s and that’s simply due to the needs of the prior engine and not this one.  On the flip side, the smaller combustion chambers are expected to help from a performance standpoint as expanding gases that are the result of combustion can be more easily directed into the piston dish rather than reside in the head where the heat gets misdirected back into the water jackets.  Much taller than stock valves are ultilized which has the rocker shafts being relocated ~0.315” higher than stock in order to get the valve train geometry correct.  Both Dove and Rocker Arm Specialist 1.6:1 roller rockers are still being tested as of this writing so more on this in another article.

Various intakes that were tested.

As of this writing, seven different intakes have been tested on the 375 incher.  The new Mummert intake has so far proved itself superior to the various Blue Thunder intakes that were tested.  Evaluated on a separate engine was the Cain intake manifold that was made in Australia but the torque numbers being on the lower end of the scale left this intake out of the testing being performed on the 375 incher.  Special thanks goes out to Peter Royale for sending the Cain intake and to Gary Burnette for sending a collection of Blue Thunders and a modified iron intake for testing.  Intake manifold testing will resume after the EMC competition on a +060 over 312 for a more detailed look at how the various manifolds compare to each other on a Y engine that’s more representative of what the majority have.

Balancing the camshaftNo deep pockets here so the camshaft was going to be a one shot deal.  I would preferred to have tried several different grinds but lifter pricing made it out of the question.  After much debate, the camshaft was custom ordered from Iskenderian Racing Cams with the following specs:  Duration at 0.050” is 254° Int and 258° Exh with the cam being ground on 109° lobe centers, lobe lift is 0.0370” Int and 0.376” Exh.  Before installing the camshaft at 107½° intake lobe centerline, it was balanced.  There will be more on camshaft balancing in a future writeup.

The oil system was kept simple.  Karol Miller had donated a new old stock iron gerotor style oil pump and other than being dissassembled and deburred, is essentially stock except for a 0.095” thick shim behind the bypass spring.  I still believe there’s a horsepower advantage to the gerotor pump over the spur gear design and will eventually get around to testing that assumption as an individual test somewhere in the future.  A rear sump design is being used for the oil pan in order to keep the inlet tube to the oil pump itself as short as possible.  The oil pan itself was made from sections of three different truck pans.  Rules were reasonably open in this area with the main restrictions being that the pan is not wider than the pan rails and no deeper than 12” below the crankshaft centerline.  Nothing trick in oil pan construction other than just making it deeper and adding some directional screening to keep the oil from being pulled back up into the engine due to crankshaft windage.  Seven quarts of oil including the filter is the plan.  There was debate about running with four or five quarts of oil but it’s simply not worth the risk.  Prior testing on a Ford FE showed no power level detriments with oil levels up to 9 quarts on an oil pan originally designed for 7 quarts.  There’s too much invested at this point to be taking risks with minimal oil levels that could lead to a premature or catastropic engine failure.  When this is all said and done, I’d still like to have a usable engine on hand.

Header testing took place on several different Y engines early on which gave a good feel as to what the EMC engine was going to need.  Jerry Christenson and Royce Brechler stepped up to the plate and provided a set of 1¾-1 7/8” stepped headers to work with while David & Robin Church at Metal Finishing Services contributed the JetHot coating on these headers.  Also being used as test headers are the 1¾” tuned headers from my 23T Altered racecar.  A future article will go into detail on the header testing as there are some interesting insights that were coming out of this in regards to what the Y engines were preferring in regards to header design.

Special thanks goes out to all that went out of their way to contribute parts, funds, and other support to make this happen.  Because some have requested anomymity, I’ll not publish the list at this time but it is lengthy.  At this point, I’ll just say “Stay tuned for the next installment”.   Ted Eaton.

This article was originally published in the Y-Block Magazine, Sept/Oct 2009, Issue #94.