Engine Part 3 - Ancillaries

The first 2 installments on the engine build for the car should have the reader seeing that this motor is something like the Ford Racing crate engine, the 514. My motor gets to 520 cubic inches because of the 0.030" over-bore.

With the major components covered in the last 2 "engine" posts, this entry concentrates on what parts are needed to complete the motor.

Lets start with the block - here it is all wrapped up as delivered after machine work.


Aftermarket (performance) "385 series" blocks are hard to find here but imported stock "rebuildable" blocks are certainly around. I found a supplier relatively local to me in Melbourne and found what looked like a very rugged block with hardly any lip (worn away by the rings) in the top of the bores. This block had extra castings compared to the others and seemed heavier - all good I thought. Unfortunately, while the block looked good, a crack was found in the valley quite late in the machining process. Not a big one but it would eventually have caused a problem. Thank you machining shop for not just completing it and supplying it to me!! The same shop knew the block supplier and got another one sent over. This time the surface rust in the bore was just too deep (after machining) and some of the elements added to make the casting hard would have been leeched out - making the bore softer. So a third block was sourced and this proved good. Sonic checks of the walls after the 0.030" overbore were good too - I finally had my foundation. Patience pays.
A bare and machined block is just a starting point though. I de-burred and stress relieved all the casting flash I could find and smoothed the oil return passage-ways and internal oil junctions. See below.


I also installed a Moroso oil restrictor kit I retrieved from the 351C. Having a roller-cam and roller rockers means you can safely limit oil going to the lifters and subsequently the whole valvetrain. This ensures the crank & big-ends get priority oiling while the valve-train still gets enough oil for lubrication and heat dissipation. Here is a shot of an oil passage where I tapped and installed a restrictor into. The restrictor is simply a grub screw with a specific sized hole drilled thru it.


Restrictors are installed in bearing saddles 2 thru 5, but only where oil travels from the crank main journal to the camshaft journal - you can see one here in the smaller oil passageway. The larger passageway in the saddle is the main oil supply port from the pump. Be sure to tap a thread deep enough to seat the restrictor below the saddle bearing face. No restrictors should be put in the front main saddle.

While on the oil system, I decided a long time ago that I needed a dry sump. This may sound overkill but I was always having problems with my distributor cam drive gear in the 351C. The steel gear on the roller cam ate up the bronze drives and kept fouling my oil system. I also had the usual oil-surge problems (even with a top of the range baffled sump) that I attributed to the the front oil pickup on Fords. Any right turn while under hard acceleration brought the oil-pressure warning light on! A dry-sump oiling system solves all these issues.

A 3 stage dry-sump pump removes the need to drive a stock oil-pump from the bottom of the dizzy and ensures I scavenge oil from the front & rear of the sump as well as supplying full-pressure oil (no matter what the car is doing) from a remote oil tank. On top of that, I can remove the deep "bucket" area of the sump to lower the sump profile height. This now gives me room at the bottom of the motor to drop the engine slightly lower in the car - if bonnet clearance for the big-block in the early Mustang becomes an issue.


The pump and related pulleys are shown above. Details are: JRP (Jones Racing Products) drive-hub, spacers and pulleys. The drive hub has a serpentine drive-pulley for the future alternator & power-steering pump as well as a radius-tooth drive-pulleys for the dry-sump pump. The 3 stage dry-sump is from Stock Car Racing. All 3 stages (2 scavenge, 1 pressure) are 1.5" wide sections. The vacuum created by the scavenge sections should give me some negative pressure inside the block to help me with ring seal.

You can see the home-made dry-sump I built above. I'm yet to plumb in the scavenge outlets and I am mounting the pump itself on the "oil filter" side of the motor. Fine stainless-steel mesh (from tea strainers) cover the scavenge outlets as a first line of defence from metal particles. A mesh windage-tray is mounted to the crank girdle to trap flying oil - so it then drains down the angled bottom of the sump and pools towards the scavenge outlets.
The piston-rings themselves are "medium tension" to help reduce friction and increase available power. The engine bearings are Clevite 77, non hardened - to suit the cast crank. Hardened bearings would have been used if I had a steel crank.
As for the cooling system, I thought about a stock and then even an electric water pump bolted to the front of the motor, but in the end I decided on 2 remote-mounted Davey electric water pumps. This approach frees up the whole front of the block so the camshaft belt-drive will effectively be the front of the motor. This saves a lot of weight at the front of the engine and keeps the centre of gravity well back behind the front wheels. I will have to TIG weld some coolant manifolds to cater for the twin pumps connecting to the single radiator inlet/outlet pipes.

Other items of note are the Felpro "1028" big-bore head gaskets needed to suit the A460 heads (to clear the large valves actually) and the ARP head studs ("SVO" type) to suit the raised inlet and exhaust ports on the A460 heads. You can see that the studs are actually longer on the exhaust side of the block to cater for the much raised exhaust ports!

The cam (mentioned in a previous post) has more than 0.7" lift. I'll keep the specific lift & duration to myself for now until I get the dyno numbers.

As added insurance against harmful engine harmonic, a neutral balance Fluidampr is used and I have had the crankshaft internally balanced. Stroker engines need all the help they can get in this area, but I believe my setup should ensure as smooth a rev range as I can get!

You can see the round slug of mallory-metal pressed into the crank weight at the lower left area of the picture below.

One of the things you find when dummy assembling an engine is shown above. The crank counter-weight is too close to the crank girdle. The girdle will need to be ground away wherever there is less than 0.060" clearance with a moving part.
In summary, what I have tried to do is put a package together where the component parts are complimentary with each other. I will not perform final assembly of the motor until I am nearly ready to fire it up. I want to avoid cylinder and bearing surfaces drying out - which can happen with an assembled motor just sitting around for a long period. As I have no way of knowing exactly when the Mustang will finally be completed, the engine will sit in pieces for now.
I will create another post that details the engine assembly, creation of brackets so the pulleys line-up, installation of the 8 coils that will run in "wasted spark" mode, etc, etc.

Engine Part 2 - Bottom End

With the induction taken care of (at a high level) I had to make sure the reciprocating combination would be up to the task. The great thing about selecting the 460 big block is that parts are comparatively cheap. For example, I found 4340 H-beam conrods cheaper for the 460 than what I could get for a local 351C. Same for the crank and many other parts. Sounds crazy but it is true. I did however find a machine shop who imports without putting a silly uplift on prices. This helps a lot!


For this motor I figured there wasn't going to be any half-measures - I may as well stroke it to gain maximum advantage of the induction. But while stroking an engine builds torque, it lowers the available rev limit because of the mechanical differences it introduces. To counter this I wanted the longest conrods possible to offset the long-throw of the crank. This is needed to minimise the angle of the conrod in the piston at "half stroke" (half-way up or down the bore). The more you increase the stroke the more this becomes a serious consideration. By doing plenty of searching on the internet I came up with the following combo....

• Cast Scat "460" crank with 4.300" stroke.
  
• Crank conrod journals ground down to big-block Chev size - 2.200".


• Big block Chev, 4340 Chrome-moly' 6.800" H-beam rods with a 0.990" small end (to suite Ford).


• Probe SRS 4.390" bore forged pistons with a 1.350" deck height.

Here are some shots of the goodies......

Above - the Probe SRS pistons.

The Eagle 6.8" H-beam rods.

The cast 4.3" stroke Scat crank.

The Canton crank girdle - good insurance for a stroker engine.

And the "AustralianMuscleParts" 460 belt drive - a top quality unit. This allows me to modify cam timing in a flash.


Bore & stroke size brings the displacement up to 520 cubic inches (or 8.5 litres).

The crank is just a high-nodular cast iron unit as I saw no huge need to go for anything stronger. It is a very strong unit as is, but yes - a steel crank would have been nice (but much more expensive). Grinding down the conrod journals gives two advantages. 1, allows the use of "Chev" rods - which are cheaper because of the higher manufacturing volumes. 2, the smaller circumference around the smaller conrod journal means a lower velocity across the bearing surface - reducing heat and wear.


The pistons have a short deck height and the gudgeon pin hole cuts into the lower oil-ring land - but this is a trade-off as I wanted the longest rod possible. I guess we will see how much oil control I lose with this setup later (not too much I suspect).

I had to fly-cut the pistons to make the valve-relief required to suite the TrickFlow A460 heads. These heads put the large intake valve in a different position within the combustion chamber so the standard Ford valve reliefs do not match. I initially investigated some machine shops for pricing (quite expensive!) but after researching on the internet I decided to do it myself. The basic principle is this..... Weld a chopped up file onto the head of an exhaust valve, grind it down to size and then use it to fly-cut the pistons. You need to "dummy assemble" the piston and head so your new "fly cutter" cuts the piston crown in exactly the right spot. Here are some shots of the process......


Above - here the file has been cut and welded. The gaps ensure the shavings wont clog things up.

I loosely ground it to shape and then span it in a drill and ground it with an angle grinder to get an approximate shape.

To finish (above), I put it in a Cleveland head (same valve-stem diameter as the 460) and span it in one direction with the drill while using the big grinder which span in the opposite direction. The 351C heads had bronze guides and plenty of lube to ensure a "true" foundation.


Once the new tool was complete it was time to machine the pistons. I setup the tool in just one inlet valve guide in the head and progressively installed each piston in that cylinder. I used masking tape to minimise where the piston shavings could spread - even though the whole engine will be completely dismantling and cleaned before final assembly.


Here is the sequence - but this took quite some time to do for all 8 pistons!

Above - piston installed and masked. Note that I cut away the tape where the cutter would start so it wouldn't clog the teeth on the file.

Lots of filings result after a cut. However, each cut was remarkably quick and easy. Pistons are SOFT!

Above shows the result. You can easily see the inlet valve location difference for the A460 heads.

All done - and each piston is cut the same. The trick to getting them the same is to put in a cutting "stop" on top of the valve guide. This lets the drill only push down a certain distance until it hits the "stop" (a bunch of washers that gives the inlet valve at least 0.060" clearance in the valve relief). And how do you measure that gap?....... You put plasticine on the piston, put the cam in the engine (with a lifter, pushrod, roller rocker and make sure it is timed correctly) and give it a couple of revolutions. Then pull off the head and slice into the plasticine with a razor and measure the plasticine thickness right where the intake valve squashed it. If no slice is less than 60 thou' then you should be ok. I gave myself a little extra room in case I put in a bigger cam, change the cam timing and/or have a longer duration cam later.


Needless to say, this all takes time! Oh - and you have to check the exhaust valve for clearance too. Thankfully, no cuts were needed for them.

That just about wraps it up for the bottom end. There are still a few bits to fabricate in the sump and for brackets to mount the alternator, etc - but these will be done when the engine sits in the car so I know exactly what room I have to work with.