Engine Build Thread - 427ci FE Big Block
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**** BUILD UPDATES / TABLE OF CONTENTS ****
-> 08/07/12 (post #64-67) – Oil Pump & Oil Pan: Prep, Pickup Clearance, Final Install
-> 05/27/12 (post #60-61) – Cylinder Heads: Cleaning & Paint Prep, Painting, Blueprinting, Final Install
-> 03/10/12 (Post #54-56) – Exterior Components: Front Cover Prep & Install, Balancer Install, Oil Filter Adapter
-> 03/03/12 (Post #53) – Camshaft: Degreeing the Camshaft & Final Timing Set Install
-> 01/29/12 (Post #51-52) – Rotating Assembly: Final Bottom-End Assembly
-> 12/20/11 (Post #47) – Rotating Assembly: Blueprinting & Balancing
-> 10/29/11 (Post #46) – Piston Prep & Blueprinting
-> 08/27/11 (Post #45) – Rods: Rod & Rod Bearing Blueprinting
-> 07/24/11 (Post #44) – Piston Rings: Filing & Fitting Ring Sets
-> 05/25/11 (Post #37) – Crankshaft: Final Install of Crank & Main Bearings
-> 05/07/11 (Post #28-29) – Crankshaft: Cleaning & Prep, Blueprinting, Main Bearing Clearances
-> 04/23/11 (Post #24-25) – Camshaft: Additional Components, Cam Install, Measuring Endplay, Final Assembly
-> 04/13/11 (Post #16) – Engine Block: Oil Galley Plugs | Camshaft: Selection, Cam Bearings, Blueprinting & Prep
-> 04/04/11 (Post #14) – Engine Block: Cross Bolts
-> 04/02/11 (Post #9-10) – Engine Block: Casting Flash Removal, Core Plugs, Cleaning & Paint Prep, Painting
-> 03/31/11 (Post #4) – Engine Block: Oiling System, Oiling Mods
-> 03/21/11 (Post #2) – Engine Block: Selection, Identification, Machine Work
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Engine Build Thread - 427ci FE Big Block
Figured I would start a thread to document the buildup of my 427ci FE motor during the next few days/weeks/months. Hopefully I’ll be able to cover most of the steps during the build and have a little fun in the process. :cool:
The concept for this project is simply to build a reliable 427 cubic inch FE big block without having to mortgage the house or take a second job (i.e. this build won’t be based off of a new-casting $3-5k side-oiler block). By boring a readily available seasoned FE 352 or 390 block, and filling it with newer modern componentry, the finished motor should be just as powerful as the original and more street friendly, all the while looking nearly identical on the outside to how the 427’s came out of the factory in ‘65/66.
Goals
~ Displacement of 427 ci (achieved via 4.060” bore & 4.125” stroke)
~ Visually Authentic to the ’66 S/C 427 FE Motor
~ Reliable & Low Maintenance Street Motor (via Hydraulic Roller Cam & Lifters, etc.)
~ Weigh less than an original-spec 427 FE (via Aluminum Heads, Aluminum Intake, etc.)
~ 6200 PRM Redline
~ 9.5-10:1 Compression Ratio
~ Horsepower & Torque = 450+
Parts & Components
~ 1966 Ford 390 FE Block (Bored/Honed to 4.060”)
~ SCAT 4.125” Stroker Crank (Internally Balanced for custom rotating assembly)
~ SCAT Forged I-Beam Rods
~ Speed-Pro Main Bearings & Rod Bearings
~ Diamond Forged 4032 Aluminum Pistons (Custom - Dished)
~ ARP Bolts: Mains, Rods, Intake, Heads, Cam, Damper, etc.
~ Comp Cams Hydraulic Roller Camshaft & Lifters (Survival Motorsports Custom Grind)
~ Blue Thunder Bronze Cam Thrust/Retaining Plate
~ Edelbrock 60069 Aluminum Cylinder Heads (w/ upgraded Dual Valve Springs to match Cam specs)
~ Blue Thunder 427 S/C Reproduction Intake Manifold – Aluminum (#IM-427MR-4)
~ Fel-Pro Performance Gaskets: Head (#1020), Intake (#1247-S3), Exhaust (#1442), Misc Completion Kit (#2720)
~ PRW 17-4ph SS Roller-tip Rocker Arm Assemblies w/ Billet Aluminum Stands & Hardened Shafts (#3239022)
~ ARP Custom Rocker Stand Stud Kit (Precision Oil Pumps)
~ Head Oil Restrictors to Rockers (TBD)
~ Pushrods – Trend Custom Length (TBD)
~ Chrome “Pentroof” Valve Covers
~ Blueprinted Melling High Volume Oil Pump (Precision Oil Pumps)
~ 1/4" HD Chrome-moly Oil Pump Driveshaft (Precision Oil Pumps)
~ 427 Road Race Oil Pan Repro w/ Windage Tray, Pickup, Custom Temp Bung (Armando Racing Oil Pans #408)
~ Milodon Crushproof Premium Oil Pan Gaskets (#40450)
~ Ford Racing Double Roller Timing Set (#M-6268-A390)
~ Cast Aluminum Timing Cover (Reconditioned OE FoMoCo)
~ Remote Oil Filter Block Adapter (Trans Dapt #1015)
~ Cast Aluminum Remote Oil Filter Housing & Steel Mounting Bracket (reproductions of Originals)
~ Crank Oil Slinger (OE Ford N.O.S.)
~ Crankshaft Damper Spacer (Billet Steel Repro)
~ Professional Products 427-FE Reproduction Damper (7-1/2") & Single-Sheave Pulley (6-5/8")
~ Carter Mechanical Fuel Pump - 120 gallons/hour (#GM6905)
~ Ford Racing Fuel Pump Eccentric (#M-6287-C302)
~ Fuel Filter Canister & Bracket (reproductions of Ford “B7Q-9155-A” & “C0AE-9180-A”)
~ 1x4v Fuel Log (reproduction of Original)
~ Carb (Holley - TBD)
~ “Turkey Pan” Cold Air Plenum
~ Stelling & Hellings 8.5" Chrome Air Filter Assembly
~ High-Volume Mechanical Water Pump (FlowKooler #1642)
~ Ford Water Pump Pulley - Single-Sheave 7-1/4” Diameter (Reconditioned OE FoMoCo)
~ Radiator “Surge” Tank (Black, Driver-side Outlet)
~ Alternator Bracket Set (Reconditioned OE FoMoCo ‘65-'67)
~ 61-amp Autolite Alternator (Repro of “C5TF-10300-F” w/ Red Autolite Stamping)
~ 2.62” Alternator Pulley & 13-Blade Alternator Fan (prepped & painted black)
~ Distributor & Coil (TBD)
~ Plug Wires (TBD)
~ Autolite Spark Plugs (#3924)
~ Powermaster Mastertorque Mini-Starter (#9606)
~ Quicktime Bellhousing & Block Plate (#RM-6056)
~ And more to come ...
- John
Block Selection, Prep Work, Machine Work
Block Selection
With this FE build being based on a readily available and cost effective seasoned 352 or 390 block, I needed to turn to the aftermarket in order to pick up the extra displacement and achieve my goal of having a 427ci big block FE. I had long ago decided I wasn’t going to try and reuse a 40-50 year old factory crank and set of rods with an unknown history ... too much risk in my opinion if I wanted to be able to spin this motor up over 6k and not worry about something letting loose. Plus, the cost to acquire, re-furbish, and upgrade (ARP bolts, etc) those factory pieces is nearly as much as a brand new aftermarket rotating assembly with higher quality pieces. And with the aftermarket, I could take advantage of available stroker cranks and custom piston diameters to get to my 427ci goal. A low mileage or service 390 block can be power-honed to a 4.060” bore diameter (a 352 block can also be used and easily bored/honed out to that same diameter). This is a very small over-bore, leaving ample thickness in the cylinder walls for proper strength and cooling (and can even be over-bored again in a future rebuild if desired). The 4.060” bore spec combined with a 4.125” aftermarket stroker crank creates the target displacement of 427 cubic inches.
Additionally, I wanted to source a ’65+ block to take advantage of all the minor upgrades to the FE line that occurred during the early 60’s (additional motor-mount holes, alternator mounting hole, wider #3 main thrust bearing, deeper head & main bearing bolt holes, etc).
The last requirement on the list was that the block needed to have provisions to run the hydraulic roller lifters being used in this build (meaning the block must have the two factory drilled longitudinal oil galleys necessary to feed hydraulic lifters).
With all of that decided on, and since I only needed a seasoned block for this project (not an entire donor or pullout motor), I had Barry at Survival Motorsports source the block and spec the machine work for me.
Prep & Machine Work
The block prep consisted of a bake cycle, then a media blast, followed by a hot-tank wash; it’s amazing how the block looks nearly brand new when it’s all done.
Block machine work consisted of the following:
~ Bore & Hone all cylinders to 4.060” (w/ torque plates installed to replicate distortion from cylinder heads & hardware)
~ Line Hone the main bearing bores (to create round and in-line bores for all the crank journals)
~ Mill & Parallel both deck surfaces
And here's how the machined block showed up at my door:
http://i628.photobucket.com/albums/u...k/IMG_4534.jpg
Now free from its container:
http://i628.photobucket.com/albums/u...k/IMG_4540.jpg
And finally, up and mounted on the engine stand:
http://i628.photobucket.com/albums/u...k/IMG_4622.jpg
Casting Codes / Block Identification
Now for the decoding ...
On this block, underneath the oil filter pad is a “6D27” casting date code; the “6” represents 1966, the “D” represents the fourth month of the year (April), and the “27” represents the day of the month in which the block was cast; meaning, this block was cast on April 27th, 1966.
http://i628.photobucket.com/albums/u...k/IMG_4589.jpg
The other code of interest is the “C6ME-A” casting number located on the passenger side of the block. In this instance though, the number doesn’t provide much info. Theoretically, with this code the block could be a 352, 390, 410, or 428 FE block ... or even a 330 or 391 FT truck block). Ford definitely didn't make it easy to identify these engines.
http://i628.photobucket.com/albums/u...k/IMG_4593.jpg
In the end, this particular block is indeed a 390 and was verified by the “drill bit test”. This simple check of the spacing between cylinder walls in the water jacket is considered the most reliable way to find the true identity of any particular FE block.
http://i628.photobucket.com/albums/u...k/8066f720.jpg
There are plenty of good write-ups already out there on how to perform this test, so I won’t go into detail here. In short, this block was confirmed as a 390 because a 15/64” drill bit shank was the largest I could fit between two cylinder walls in the water jacket. And that 15/64” spec makes it a relatively thick-walled 390 too, which is great news for overall cylinder wall strength in this motor.
Additional photos of the block here: http://s628.photobucket.com/albums/u...ngine%20Block/
Next installment ... Oiling System Mods.
- John
Oiling System / Oiling Mods
Side-Oiler vs Top-Oiler
Figured I’d toss in a quick history of the two different styles of oiling systems in the FE family: side-oiler & top-oiler. The difference lies simply in the sequence that each of the engine components receives its lubrication.
The “top-oiler” design was used on the vast majority of FE blocks produced by Ford (352, 360, 390, 410, etc) - even the 428 motor that powers most of the “427” Street Cobras was a top-oiler block. With this lubrication strategy, oil is primarily fed via a longitudinal center oil galley (located just below the lifter valley) and is dispersed from the top of the block to the bottom, meaning the lifters and cam bearings are the first to receive oil, as lubrication then makes its way down to the main bearings.
The “side-oiler” design on the other hand, was born out of racing necessity where the oiling priority needed to be to the main bearings first and foremost; this design has a main oil galley running lower along the side of the block to feed the mains, then galleys going upwards to feed the cam, etc. Many of the 427 motors were of this design (there were 427 top-oilers produced though). This side-oiler design was advantageous in theory because with any oil-pressure fluctuation or drop, the mains were still the first to receive oil and hopefully wouldn’t be starved (i.e. spun bearing). In practical application for a well built and blue-printed street motor, the difference is minimal to none; and with a few small oil-system modifications made to a top-oiler block (plus the addition of a high-volume oil pump), the main bearings stay very well lubricated and are completely protected. In an all-out racing application (such as 7-8k RPM, 650+ hp drag/road-racing), the side-oiler definitely has its merits, but for my purpose in a mostly street-driven Cobra, provides no quantifiable advantage. Also, most original side-oiler blocks were for use with solid lifters only and cannot be converted; in order to run a hydraulic roller cam, I would have most likely had to spring for a new-casting block (Genesis, Pond, etc) that has the necessary oil galleys drilled out for use with the hydraulic lifters. Unfortunately, the extra $3-5k for that block isn’t budgeted in my build; and truthfully, just flat out isn’t necessary for this project.
Oiling Mods & Upgrades
As mentioned earlier, by performing a couple small modifications to the block, the oiling system is vastly improved and becomes nearly bulletproof. And again, there are a plethora of great articles and books already out there on how to perform these mods so I won’t go into a lot of detail in this post.
Here’s the list of mods done on the block for this particular build:
~ Main Saddles: On FE blocks, there is a small misalignment between the oil supply holes (in main saddles # 1, 2, 4) and the oil supply openings in the main bearings themselves. To correct this, the entry portion of the holes on these three saddles were enlarged with a die grinder and blended to match the corresponding openings in the bearings.
http://i628.photobucket.com/albums/u...k/8e3bc516.jpg
~ Oil Pump Mount: There is a single opening in the block here, and is where the pump feeds oil up/over to the block’s oil filter mounting pad. This hole was enlarged with a die grinder (gasket matched to the new Melling oil pump), and the bowl/transition feeding into the passageway was opened & blended to aid oil flow.
http://i628.photobucket.com/albums/u...k/4b143e17.jpg
~ Oil Filter Mounting Pad: There are two openings in this area; the first is the one exiting from the block (containing oil from the passageway connected to the pump) and heading out to the remote oil filter; the second one is the opening coming back from the remote oil filter that feeds back into the block to lubricate the engine. Both of these holes were enlarged and blended with a die grinder to aid in oil flow to/from the block; machinist’s dye was used to create an outline of the gasket (for the remote oil filter adapter) on the block, serving as a template to insure the holes weren’t enlarged too far.
http://i628.photobucket.com/albums/u...k/ce58131c.jpg
http://i628.photobucket.com/albums/u...k/e3828450.jpg
~ Oil Galley Plugs: Depending on the particular year/type of block, some of the galley plug openings were tapped (1/4" NPT) by the factory, while others were left as a standard “press-fit” type plug. For a little extra security against one of the plugs popping out and the engine losing oil pressure, all of the remaining press-fit openings were tapped to accept the same 1/4" NPT plugs. A quick note: the one plug behind the distributor isn’t at risk to go anywhere and is fine to leave in stock form; so, it remained as a press-fit plug in this block.
http://i628.photobucket.com/albums/u...k/dea92dd9.jpg
~ Oil Drainback Holes: The drainage holes at the front & rear of the lifter valley were opened/deburred with a die grinder to help aid in oil flow back down to the pan.
http://i628.photobucket.com/albums/u...k/ed688747.jpg
~ Blueprinted High-Volume Oil Pump: To help move more lubrication through the oil galleys and provide a boost in oil pressure at idle and low RPM’s, a high-volume Melling oil pump (M57HV) was chosen. And to insure that the pump was set up to spec and working as efficiently as possible, it was blueprinted by Doug at Precision Oil Pumps - he does an awesome job with these and the work is top notch. I also decided to run one of his upgraded chrome-moly 1/4" oil pump drive shafts for a little extra peace of mind against the possibility of an oil pump drive shaft failure (thus starving the engine of oil and ruining my day/week/month/year).
Additional photos of the block here: http://s628.photobucket.com/albums/u...ngine%20Block/
Next installment ... Finishing up the block. :)
- John
Finishing Up The Block (continued)
Paint Prep
~ Solvent Cleaning: To eliminate any residual WD40 or other oils on the exterior of the block, I used a couple cans of brake cleaner to completely clean and decontaminate the surface for the next step.
~ Etching Solution: POR15 will be used as the basecoat on this block, so the recommended next step in the surface prep is their “Prep & Clean” solution - this stuff neutralizes any remaining surface rust, creates a light etch in the metal, and leaves a zinc phosphate coating behind ... all of which evidently help the POR15 adhere to the block like mad. When using this solution, make sure to keep if off of any surface that won’t be getting painted (especially the machined surfaces like the decks), because you don’t want those places to get any type of etching at all. I used a small spray bottle and carefully applied it only to the areas of the block that were going to receive paint. It is a very slow acting etch, so if any of the solution does happen to hit a machined surface, if wiped off quickly, it won’t do anything to the metal. After the solution sat of the block for about 15 min, it was then rinsed off with fresh water and the block was blown dry with compressed air.
This is what the metal finish looks like after the etching solution step is complete:
http://i628.photobucket.com/albums/u...k/779c6fd1.jpg
~ Solvent Cleaning (again): As a final step, just to make double and triple sure that the surface is 100% ready to receive paint, I took a lint free cloth along with a can of acetone and wiped down every single surface that was to be painted.
~ Masking: A tedious and time-consuming process, but the effort put in here will pay dividends on the final product. Everything that wasn’t getting paint was completely covered and taped up (decks, lifter valley, bottom end internals, galley plug areas, cam plate area, etc). I used a fresh razorblade to trim the tape edges around all the deck surfaces and other critical areas. Additionally, all of the exterior bolt-holes and exposed galleys were plugged to keep paint out.
http://i628.photobucket.com/albums/u...k/15896ab8.jpg
Block Painting
For this project, I decided to use POR15 (semi-gloss black) as the basecoat on the block. This stuff is not only unbelievably strong and chip-resistant, but also does an amazing job of sealing and bonding to the metal to prevent ANY rust issues in the future. It also is resistant to high temps (up to 600 F), so is perfect for engine block applications. I applied two thin coats a couple hours apart using simply a paintbrush - this stuff is self-leveling and absolutely no brush marks show up, especially on a rough texture cast iron surface like this. The one downside to POR15 though, is that it isn’t very UV stable and the color can fade over time. Because of this, it is recommended to apply a topcoat over the POR15. And, if you apply the topcoat before the POR15 basecoats cure, there is no need for a primer or tie-coat in between. For the topcoat in this application, I’m using a semi-gloss back ceramic engine enamel from Duplicolor. Per instructions, I sprayed on two light coats, followed by a final medium coat ... allowing about 10 min flash time between each of the 3 coats. And the beauty of having the POR15 underneath, is that if the ceramic enamel topcoat ever does happen to take a hit and chip, the POR15 layer underneath (in semi-gloss black to match the topcoat) isn’t going anywhere.
After the 2 basecoats of POR15:
http://i628.photobucket.com/albums/u...k/d3329fa5.jpg
After the 3 topcoats of Ceramic Enamel:
http://i628.photobucket.com/albums/u...k/c4687281.jpg
After everything was unmasked, here is what the final product looked like:
http://i628.photobucket.com/albums/u...k/f754812b.jpg
http://i628.photobucket.com/albums/u...k/5944bc40.jpg
http://i628.photobucket.com/albums/u...k/5258329e.jpg
Additional photos of the block here: http://s628.photobucket.com/albums/u...ngine%20Block/
Next installment ... Camshaft selection & prep.
- John
The Cam Goes In (continued)
And finally, bolting the cam plate down for good:
- Everything was removed from the front of the cam again (timing gear, retaining plate, etc).
- With everything out of the way, assembly lube (Max Tuff) was applied to the camshaft's thrust face, and the cam retaining plate went back on.
- The two retaining plate fasteners (ARP 7/16”-14, half-height 12-pt heads) were treated with a dab of blue Loctite (new #243, which has good tolerance to oil and long-term heat exposure) to keep the bolts from backing out down the road, and to serve as a thread sealant for the two oil galleys that terminate at these bolt-hole openings. Bolts were torqued to a final spec of 250 in/lbs (approximately 21 ft/lbs) - I’ve read specs ranging anywhere from 12 ft/lbs, all the way up to 35 ft/lb. But, between 20-25 ft/lbs seems to be the recent consensus.
http://i628.photobucket.com/albums/u...t/f8e92cfe.jpg
- Assembly lube (Max Tuff) was applied to the backside of the timing gear (on the shoulder where it rides against the retaining plate).
http://i628.photobucket.com/albums/u...t/cd6ca610.jpg
- The timing gear, fuel pump eccentric, cam bolt and washer all went back on again - these parts are being mounted temporarily until the complete timing set is installed later on in the build.
http://i628.photobucket.com/albums/u...t/4d921d25.jpg
- I did one last check to make sure the assembly rotated smoothly and there were no tight spots. Again, everything was good to go and the cam rotated like proverbial butter. For curiosity’s sake, I threw an in/lb torque wrench onto the end of the cam bolt to see how much effort it took to rotate the assembly – the number would barely even register on the dial and came out to a mere 5 in/lbs.
http://i628.photobucket.com/albums/u...t/bbd9ef09.jpg
Cam Lobes
Since the cam for this build is a roller cam, the lobes luckily do not require any special break-in lube. Comp Cams actually recommends just regular motor oil to be used on all of the lobes; so I’ll wait to oil the cam lobes until I’m getting ready to install the lifters later on – I can easily get oil to the lobes by going through the lifter bores with my oiling can before I drop in the lifters.
Additional photos of the cam install here: http://s628.photobucket.com/albums/u...lock/Camshaft/
Next installment ... Crankshaft & Main Bearing blueprinting.
- John
Crankshaft & Main Bearing Blueprinting
The crankshaft selected for this build is an aftermarket SCAT “Series 9000” Lightweight Pro-Comp stroker crank with a 4.125” stroke length (standard Ford FE 390 & 427 cranks have a 3.780” stroke, while 428 cranks have a 3.980” stroke). The SCAT crank is internally balanced and weighs in at 60 lbs, which is about 5 lbs lighter than an OE 390 cast crank and about 15 lbs lighter than an OE 427 steel crank. The crank’s main journals are machined to a standard FE size (2.748”), while the rod journals have been designed and machined to accept 2.200” diameter big-block Chevy rods (standard Ford FE rod pins are a 2.438” diameter). For an FE stroker application, using these BBC rods provides several unique advantages: first, the smaller rod pin diameter creates the extra room inside the bottom-end of the block to allow for stroke lengths of 4.125” & 4.250” without any block clearancing required. The smaller bearing journal diameter is also more efficient by creating less friction and heat; plus, BBC rod bearings are more readily available in under/over-sizes (if needed to obtain the desired clearances).
First order of business in this part of the build was to thoroughly clean the crankshaft. The cleaning started with a spray down of brake cleaner to remove any machining oils and gunk, and was followed by a good scrub down with hot soapy water; the oiling passageways needed special attention and were cleaned with a small bore brush from the block cleaning kit I used earlier in the build. After a rinse with clean water, the crank was blown dry, sprayed down with WD40 to prevent any corrosion, and finally wiped down with a microfiber cloth to remove the excess WD40 and pick up any remaining gunk or other oils that the WD40 had lifted from the metal.
The crank then received an inspection to check for any nicks or scratches on the journals, or any issues with the oil hole chamfering. Everything looked good on this crank, and the machine work from SCAT appeared to be top notch. The blueprint work that follows will insure that everything is indeed in spec.
http://i628.photobucket.com/albums/u...t/5dfab264.jpg
Blueprinting
~ Main Journals: Examined the crankshaft’s main journals for roundness, taper, and overall spec. I measured each journal OD with a micrometer at several points: a forward and aft measurement, followed by forward/aft measurements taken 90 degrees from that first set of measurements.
Final blueprint measurements came out to:
Main Journal #1 Average = 2.7481”
Main Journal #2 Average = 2.7480”
Main Journal #3 Average = 2.7480”
Main Journal #4 Average = 2.7480”
Main Journal #5 Average = 2.7481”
Max “Out-of-Round” Observed = 0.0001”
Max “Taper” Observed = 0.0001”
~ Rod Journals: Examined the crankshaft’s rod journals for roundness, taper, and overall spec. Each journal OD was measured with a micrometer at several points: a forward and aft measurement, followed by forward/aft measurements taken 90 degrees from that first set of measurements.
Final blueprint measurements came out to:
Rod Journal #1 Average = 2.1990”
Rod Journal #2 Average = 2.1990”
Rod Journal #3 Average = 2.1988”
Rod Journal #4 Average = 2.1988”
Max “Out-of-Round” Observed = 0.0001”
Max “Taper” Observed = 0.0000”
~ Crankshaft Run-Out: This measurement was checked to insure the crankshaft itself was straight and in spec. With main bearings installed in the #1 & #5 main saddles only, the two bearing faces were lubricated with motor oil and the crankshaft was carefully laid into place. With the crank riding only on the front and rear-most bearings (in essence floating freely above the #2, #3, #4 saddles), a dial indicator was mounted on the block to measure overall run-out via the center #3 journal while the crank was slowly rotated. Total run-out for this crank measured in at a little less than 0.002”, which is completely within spec (0.000-0.004” is Ford’s spec).
http://i628.photobucket.com/albums/u...t/a1ae94ac.jpg
Main Bearings
The main bearing set I decided on is Speed-Pro part # Z125M; these are a 3/4 groove, standard FE sized, competition bearing set made from a Super-Duty H-14 bearing material.
http://i628.photobucket.com/albums/u...t/51be416c.jpg
Close-up photo of the backside of a bearing:
http://i628.photobucket.com/albums/u...t/e3fcb7f9.jpg
Crankshaft & Main Bearing Blueprinting (continued)
~ Main Bearing Clearances: The crank journals’ actual oil clearance inside the main bearings were next to be checked. This can be done with Plastigage, but that method truly isn’t very accurate. High-end engine building shops moved away from Plastigage a long time ago; they use a more precise method involving an outside micrometer and a dial bore gauge. These bearing clearances are crucial to the life of an engine, especially a motor going into a performance orientated car; to skimp out now and not use the proper tools to insure that everything is in spec, well, it’s just not a real option here. So for this build, Plastigage is out. And to make double sure I get accurate measurements, I bit the bullet and bought a super slick Fowler digital dial bore gauge that reads all the way down to increments of 0.00005”.
Here is a good article that demonstrates how “off” Plastigage can really be:
http://www.carcraft.com/techfaq/116_...ter/index.html
And here are a couple other articles explaining how to accurately measure bearing clearances using an outside micrometer and dial bore gauge:
http://www.chevyhiperformance.com/te...nce/index.html
http://www.bracketracer.com/engine/mains/mains.htm
Here’s the breakdown of how clearances were measured:
- The bearings were test fit into the block and into the main caps to check for any interference or other issues. I did find that the #3 topside main bearing had a locating tang that was slightly too wide and was keeping the bearing from fully seating. To remedy this, a fine file was used to remove the portion of the tang causing the interference against the saddle.
Close-up photo of the #3 topside main bearing and the minor clearancing work to the bearing tang:
http://i628.photobucket.com/albums/u...t/1aeda76d.jpg
The bearing is now able to fully seat into the saddle without any interference:
http://i628.photobucket.com/albums/u...t/eb3dd653.jpg
- After the test fit, the bearings were removed and then cleaned in an isopropyl alcohol bath to remove any traces of oil, dust, debris, etc.
- To insure the main caps didn’t have any small burrs or nicks remaining on them (which could keep them from fully seating and interfere with the clearance measurements), each cap’s mating surface was very lightly drawn over a fine flat mill file. No cap material was removed … just any possible small burrs, etc that may have happened to be protruding onto those mating surfaces.
- Next, all of the main caps were cleaned and prepped. They were sprayed down with brake cleaner to remove any machining oils and gunk. This was followed by a good scrub down with hot soapy water, a rinse and dry, then a light coat of WD40 was sprayed on after that. Finally, the cap’s saddles were wiped down with solvent to insure that there would be nothing to get between the bearings and their respective mating surfaces.
Photo of the cleaned and prepped main caps and their corresponding bearings:
http://i628.photobucket.com/albums/u...t/f065b839.jpg
- The main saddles in the block were wiped clean with solvent to insure that there would be nothing to get between the bearings and their respective mating surfaces in the block.
- Bearings were then re-installed back into the block and into the main caps.
Close-up photo of the installed #4 & #5 topside bearings:
http://i628.photobucket.com/albums/u...t/7114654c.jpg
- The #4 & #5 main caps were then seated into their respective locations in the block (the dial bore gauge isn’t long enough to reach these rear bearings if the other three caps are also installed, so caps were installed progressively from back to front as I went along taking the bearing measurements). The threads on the ARP main cap bolts were lubricated with ARP’s Ultra Torque Fastener Assembly Lube, then tightened down in three steps to an ultimate torque value of 95 ft/lbs (matching the spec used during the line-honing machine work).
- An outside micrometer (2-3”) was used to measure the crank’s #5 journal diameter; the micrometer’s spindle was locked in place at that measurement and the micrometer was then secured into a soft-faced vise to hold it for the next step. The dial bore gauge was positioned between the micrometer’s anvils and zeroed out so that it baselined off of the actual OD of that #5 journal. Now, when the dial bore gauge is placed inside the block’s #5 main bore, it will directly read the exact bearing clearance for that particular bore. And to insure that any possible bore taper was within spec, I took one measurement at the front portion of the bearing and one at the rear for each main bore. As a quick side note, all measurements were made 90 degrees from the bearings parting lines, as this is the spot where clearances will be the tightest; the closer you measure to the parting lines, the larger the actual bearing clearance is to form the oil wedge and keep the crank from catching a bearing edge (thus spinning a bearing).
- This whole process of bolting down each main cap, torqueing to spec, measuring the respective crank journal with the micrometer, zeroing the dial bore gauge to that micrometer, and measuring the bearing clearance was repeated for each bore as I worked my way towards the front of the block. The bearing clearance I was targeting is 0.0028”, with anything in the range of 0.0025-0.0030” being within spec and acceptable.
Close-up photos of the bore gauge measuring the inside diameter (and ultimately the actual bearing clearance) of the #1 main bore:
http://i628.photobucket.com/albums/u...t/e740397c.jpg
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Final blueprinted main bearing clearances were as follows:
Main Bore #1 Average = 0.0028”
Main Bore #2 Average = 0.0029”
Main Bore #3 Average = 0.0029”
Main Bore #4 Average = 0.0028”
Main Bore #5 Average = 0.0029”
The other critical blueprinting measurements for the crankshaft (crank endplay, rod bearing clearances, etc.) will be completed at later stages of the build.
Additional photos of the crankshaft here: http://s628.photobucket.com/albums/u...ck/Crankshaft/
Next up ... Crankshaft Install.
- John