Our '91 LX has been running...
Our '91 LX has been running very well in unmodified trim. True, we have skinnies on the front, a BBK X-pipe and header arrangement, a Maximum Motorsports suspension system and a K&N air filter (with 15 degrees of ignition timing) but the engine itself is untouched. Although a 13.86 at 97.11 mph with a worn out AOD is impressive, we desperately want to run in the 12-second zone.
We began our intake/head/cam...
We began our intake/head/cam project by removing the cover plate on the top of the stock HO intake so we could gain access to the two center bolts that route through the upper plenum.
Before removing the upper...
Before removing the upper plenum we first removed the stock 58mm throttle body so that we could transfer the four studs to the new Trick Flow plenum.
We'll be scrapping the stock...
We'll be scrapping the stock throttle body for a bigger 70mm BBK unit and will need these four studs to attach it.
With the six plenum bolts...
With the six plenum bolts removed we lifted it off of the stock lower intake. Note our adjustable BBK fuel pressure regulator. We installed this a few weeks ago to help adjust the extra flow that we gained from our BBK 190-lph, in-tank fuel pump.
Before we could remove the...
Before we could remove the fuel rails, injectors and lower intake we first had to disconnect the supply and return lines from the rails. To do this you will need to purchase fuel line-disconnect tools such as this one that we found at our local auto parts store.
The stock rails are snapped...
The stock rails are snapped into position with round springs that act like o-rings and the tool slides under the spring, permitting you to pull it free from the notch in the rail.
With the stock lower intake...
With the stock lower intake removed the next step was for the BBK 1 5/8-inch shorty headers to be unbolted. With the headers out of harms way we began to loosen the 10 (per head) cylinder head bolts.
Last month was a very hectic time for my latest project car, a '91 LX with a stock engine and an AOD transmission. As mentioned in my previous articles, I made the purchase with the intention of modifying it, but I still want to keep the fun level high. Super-fast, 9-second race cars are just awesome to watch and/or drive, but racing at that level can get very expensive very quickly. This '91 LX may not be the fastest thing on four wheels, but it's affordable, reliable and a blast to drive. I purchased it from a friend for $3,200 and swore that my total spending limit would not exceed $10,000. With a BBK exhaust system and a Maximum Motorsports suspension kit, I am just now creeping over the $5,000 mark. With a tick under $5,000 still to play with, I knew tackling the engine would be a wise next move.
I ran the car with the engine in stock form, save for a K&N air filter and 15 degrees of timing. With a set of drag radials and 4.10 gears, it clicked off a strong 13.86 at 97.11 mph. We accomplished this feat with the transmission in "D." We tried manually shifting it, but to no avail. Although a 13.86 from a high mileage stocker is impressive, like most gearheads we want more. This is where an aftermarket set of heads and an improved intake manifold come into play.
Most high performance engine builders will admit that the cylinder heads are where the power is made. True, custom cams and headers, among other things, help but high performance cylinder heads are everything. If you're racing with out of the box stock heads, you're not running anywhere near as well as you could. To remedy this, we contacted Power Heads in Fullerton, Calif., and wanted to find out about its ported stock iron E7TE castings. There are a host of aftermarket companies offering high performance aluminum heads for 5.0s, but the Power Heads versions are quite affordable and that sparked our interest. The Power Heads units are heavily ported on a CNC-machine and are fitted with bigger valves and matching seats.
"Our 5-liter heads are stock E7TE castings that we take and CNC-port in-house," explained Ralph Pici of Power Heads. "We port them, stuff them with bigger 1.94-intake and 1.60-exhaust valves (1.78 and 1.46 are stock) and mill the deck surfaces to add compression and restore the flat deck finish. We also replace the weak, stock valve guides with bronze racing guides, helping to reduce the overall wear of the valve stems. Our heads are very affordable and can be completed in no time at all." The Power Heads castings have very smooth intake and exhaust ports and that should pick up our performance level considerably.
"Our CNC-ported heads flow 215-cfm on the intake and 175-cfm on the exhaust side," explained Pici. "To give you an example of how good those numbers are, stock heads flow 160-cfm on the intake and 110-cfm on the exhaust side, a ton more airflow than stock. These numbers were generated on a SuperFlow flow bench with a 28-inch reading."
The heads bolt onto the engine in the same manner as the stock versions, but the fun didn't stop there. To complement our new castings, we scrapped the factory intake manifold for a Trick Flow Street 5.0 intake, a BBK Performance 70mm throttle body and spacer, Crane Cams 1.6-ratio roller rocker arms and an Anderson Ford Motorsport B-21 hydraulic-roller camshaft. As mentioned, we ran the 13.86 with the engine mostly stock and couldn't wait to get to the track to retest the car with the new engine components. By the end of the day, with the engine work completed, we were able to generate a best time of 13.55 at 102.88 mph. You may be surprised that the car didn't run better, but let us say that we have a major problem that's hurting our on-track performance and it goes by the name of AOD (more specifically, the stock torque converter). When Rick Anderson of AFM shipped us out the B-21 cam, he mentioned that the true potential of it would never be achieved with the stock torque converter in place. "This cam needs a 2800- to 3000-stall converter," stated Anderson. "Our B-21 cam is designed to operate up to 6000 rpm but the stock converter will never let that happen, even with 4.10 gears out back. The car will be dead off of the line with the tight converter and that will kill your elapsed time." Ralph of Power Heads agreed. "Our CNC-ported heads are so much better than stock. They need to be revved to at least 5800 rpm to generate the results that they're capable of. With the stock converter and unmodified transmission still in use the performance of the engine combination will be severely hampered." Our converter struggles to stall to 1200 rpm on the line and, because of this and the fact that our AOD is shifting at 4600 rpm, we can't get off the starting pad to save our lives. The stock engine could turn 2.00 60-ft. times all day long but with the bigger Trick Flow intake and improved heads we lost torque below 3000 rpm and could do no better than a 2.07 60-ft. This is why a looser converter is so important. It will allow the engine to reach its higher rpm range sooner and should also help get the LX off the line much quicker, reducing our elapsed times quite a bit. Even though the stock converter and abused tranny are killing us on the track, they should have no bearing on the chassis dyno. With that in mind, we cruised over to Crazy Horse Racing in South Amboy, N.J., and strapped the car down to the rollers. With the stock engine combo we came in at 197.2 hp and 256.6 lbs.-ft. torque at the wheels. On the first pull with the new hardware in place, we jumped to 238.4 hp and 273.4 lbs.-ft. torque--a gain of 41.2 hp and 16.8 lbs.-ft. torque. If you read our BBK Performance story last month you are aware of the fact that we still have the stock mufflers in place.
One of our old projects, the Stone Pony, made 255 hp with Edelbrock aluminum heads and a matching intake and cam but it had a set of aftermarket mufflers strapped underneath it. We figure that the stock mufflers are hurting us by approximately 15 hp. If you add that 15 hp to our total of 238.4, we come in at 253.4 hp, right where the Stone Pony was. This tells us that the engine is solid and is making power. The transmission is now the culprit. All in all, our white '91 LX is making the steam but as expected, our stock AOD transmission and way-tight converter are holding us back big time. These are some of the prices you pay when real-world testing takes place. We could lie to you about the results but that is not what die-hard MM&FF tech is all about. We'll do it the right way and address the worn out trans.
Next month we plan on taking care of that with the installation of an Art Carr Performance Products Extreme AOD and matching 2800-3000 stall, 10-inch converter. This will allow us to use more engine rpm to get off the line and should keep the engine in a higher rpm band, right where it needs to be in order to run at its best.
Hopefully, after our AOD nightmare is addressed, our first 12-second timeslip will become a reality.
After loosening the cylinder...
After loosening the cylinder head bolts with our trusty breaker bar we lifted them from the stock block. The block looked better than we expected and the cylinder walls had virtually no scratches on them at all.
We coated the walls with a...
We coated the walls with a thin film of fresh oil prior to bolting up the new head castings.
Now is a good time to inspect...
Now is a good time to inspect the cylinder walls and pistons for visible damage. Our pistons looked very good and had less carbon buildup than we expected. Before placing our new Power Heads E7TEs on the block, we used a tap to clean up the threads and then placed a new set of Rol head gaskets over the four head dowels.
We replaced the camshaft as...
We replaced the camshaft as well. To do this, we removed the 16 stock lifters. The lifters can be removed from the block with the heads on or off the engine and come out by unbolting the retaining plate. This plate keeps the lifters from rotating in the bores and, with it removed, the eight (one per two lifters) lifter guide bars can be removed. We soaked our lifters in oil while the cam swap was taking place but it is a good idea to squirt oil down the pushrod holes after reinstalling them to help pre-lube the lifters.
The new heads that we chose...
The new heads that we chose to run on our car are from Power Heads and are ported stock E7TE castings.
The heads are professionally...
The heads are professionally CNC-ported and have a milled deck surface of .015-inch for more compression. New (and bigger) 1.94-inch intake and 1.60-inch stainless steel exhaust valves replace the factory ones and work with bolt-down roller rockers.
Power Heads also offer a screw...
Power Heads also offer a screw in stud and guide plate option for stud mounted rocker arms.
With the two Rol head gaskets...
With the two Rol head gaskets in place we lowered the two heads onto the block dowels and tightened them down to 85 lbs.-ft. torque. The upper (long) bolts do not protrude into the water jackets on the block but the lower (short) bolts do hit water. For this reason you will need to use a sealer on the threads to prevent them from eventually leaking. We used a slight amount of black RTV on ours.
In order to replace the camshaft,...
In order to replace the camshaft, the timing chain (and water pump) will first have to be removed. We noticed that our timing chain was extremely stretched and was hitting the side of the cover when the engine was running. This was wreaking havoc on our camshaft timing and could have been disastrous had it not been caught in time.
Another problem that we came...
Another problem that we came across was our hollow cam dowel pin. Our pin that keeps the timing chain sprocket in place was bent slightly, which also wasn't helping matters any. Our new cam was treated to a solid dowel pin and a new Ford Racing double-roller timing chain.
With the timing chain and...
With the timing chain and cover out of the way we slid out the stock (and small) cam. Care must be taken when doing this or you will risk the chance of scuffing the camshaft bearings.
The camshaft that we chose...
The camshaft that we chose to go with is the Anderson Ford Motorsport B-21 grind (see an AFM catalog for specs). The cam is based around a blower combination but Rick Anderson of AFM said that, due to our AOD transmission, the extra overlap of the B-21 (112 degrees) should work to our advantage. We slid the AFM cam into the block and lubed it up with fresh oil before installing the new timing chain.
Our new Ford Racing timing...
Our new Ford Racing timing chain is fully adjustable and a ton stronger than stock. We installed it in the "straight up" position as opposed to advancing or retarding it.
With the new heads on and...
With the new heads on and ready to go we complemented them with a new set of Crane Cams "Gold Series" Magnum roller rocker arms. The new 1.6-ratio rockers are much stronger than the stock flexible versions and will reduce internal drag with a full roller tip and body.
We also have a set of 1.7-ratio...
We also have a set of 1.7-ratio (stock Cobra) rockers, which have .030-inch more valve lift. We'll try them out in the near future.
We wanted to see if all was...
We wanted to see if all was good with our valve lift and installed a dial gauge on the tip of the retainer to check it. With a .015-inch shim under the rockers (our heads were milled .015-inch and so a .015-inch rocker shim was needed to prevent the lifter from collapsing), our gauge showed .500-inch lift, right on the money. Our single spring valve springs are rated to .525-inch lift so all is good there.
Our new heads did not come...
Our new heads did not come with the threaded inserts that are needed to install the power steering and alternator brackets. The inserts thread into the front (and back) of the heads and reduce the thread size of the hole for the accessory bolts. They can also be used to plug the two holes that will be left over if you choose to eliminate the air pump tube in the rear of the engine.
The next step was to bolt...
The next step was to bolt up the lower Trick Flow intake. Before doing that we placed our Rol intake gaskets onto the two head surfaces and used blue RTV sealer on the block ends.
With the intake gaskets in...
With the intake gaskets in place we lowered the intake onto the engine and tightened down the bolts in a cross-cross pattern. When finished, we tightened them down to 40 lbs.-ft.
With the lower intake on and...
With the lower intake on and buttoned up we reinstalled the two (freshly painted) valve covers and remounted the stock 19-lb. fuel injectors and rails. The 19-lb. injectors should be more than adequate for now, but we may upgrade to a set of 24-lb. versions soon, depending on how our post dyno testing goes.
Our Trick Flow intake manifold...
Our Trick Flow intake manifold (part No. TFS-51500001) is designed to work in the idle to 5000-rpm range and has a much bigger, improved upper plenum design. It can move a ton more air than the stock unit and should really work well with our ported heads and bigger cam.
With the stock distributor...
With the stock distributor back in the block we were able to install the upper plenum assembly. The Trick Flow upper plenum bolts to the lower intake with four stud-mounted bolts (at the corners) and two longer bolts that protrude through the center of the plenum.
We complemented our improved...
We complemented our improved intake design with a 70mm BBK Performance throttle body and spacer kit. The new body is quite a bit bigger than stock and should be matched well to our bigger plenum.
With all of the work that...
With all of the work that we did it would be a real shame to cap it off with the stock mass air meter. We jettisoned that idea and went with a C&L Performance 76mm mass air sensor. The new sensor is much bigger than stock and will be needed in order to feed the hungry plenum and head ports. The C&L meter bolts into the stock location and can be used with either a factory or open-element air filter. We tried both but it seemed to run better with the closed off (stock) box design and flat K&N filter arrangement.
With the engine completed...
With the engine completed we dropped the old oil and filled it up with a fresh dose of coolant before resetting the timing to 15 degrees BTDC. It is very, very important to replace the old oil whenever the timing cover has been removed. No matter how careful you are, some coolant from the water pump holes will work its way into the oil pan. The coolant will come out with the old oil but if left alone, severe engine damage will likely follow. Our engine indeed had a small amount of coolant in the pan but that was taken care of when the old oil was drained.
With the engine looking and...
With the engine looking and sounding as awesome as ever we headed over to Crazy Horse Racing in South Amboy, N.J., for a little fun on the chassis dyno. Our stock numbers (with timing and air filter improvements) came in at 197.2 hp and 256.6 lbs.-ft. torque at the wheels. Our first pull with the new engine combo saw a jump to 238.4 hp and 273.4 lbs.-ft. torque--an improvement of 41.2 hp and 16.8 lbs.-ft. torque at the wheels. As mentioned, we felt that the stock 19-lb. fuel injectors could possibly be too small for the new engine combination but the air/fuel monitor on the dyno told us otherwise. We were actually way rich below 3000 rpm. After removing only 3 psi of fuel pressure from our BBK regulator, we picked up 20 hp and 25 lbs.-ft. torque at 2800 rpm. The peak power numbers stayed the same but we gained a ton of hp under the 3000-rpm range. Our air/fuel readout showed a way-rich 7:1 ratio (14.7:1 being ideal) but after the adjustment, it shot up to 12:1--still a bit rich but a much better improvement. It looks like the stock 19-lb. injectors will work just fine for now.
Counting My Pennies
Our goal is to construct a simple, 12-second street machine that can be driven to and from the track with no trouble, one that the average racer can afford. We set out to accomplish this with a budget of approximately $10,000 and have already spent $5,519.27 on a Maximum Motorsports suspension kit, a BBK Performance exhaust system and, of course, the Mustang itself (which cost $3,200). With $4,480.73 left to play with we addressed the engine and installed the following components:
1. Power Heads ported stock iron cylinder heads $881.64 (with shipping)2. Trick Flow intake $395 (Summit Racing) 3. AFM B-21 cam $2694. BBK throttle body $189.95 5. C&L mass air sensor $2296. Engine gaskets and oil/filter approx. $100
*These prices do not include tax and shipping.
So with the engine components totaled up they come in at $2,064.59. After adding that to our old total of $5,519.27 we arrive at a new total of $7,583.86. We are on a budget of around $10,000 and are still left with $2,416.14.