5.0 Stroker

[gremlinsteve]

i port heads and assemble them all day long....its aluminum...if you damage it it can be welded.

i am not in agreement with the large valve thoughts either. if not needed..why run them?

i would like to get my hands on the hesco head and rework one..see what i can do.


steve

[Plechtan]

The engine is deing built for a land speed record, so we are looking for maximum hp at WOT. The desktop dyno started to show a limited airflow above 6000 rpm, but peak HP around 7,500 rpm. I have seen similar HP curves on chevy and Ford I6 motors of similar displacment. The motor is not ment ot be a daily driver or a street machine.
Some of my discusions with Hesco it was stated that the larger valve would not flow more because of the cylinder bore size, when we went to a 4" bore, that changed. Lee at Hesco is confident that his head out of the box will flow more air than the valves can handle, and does not even offer polishing services on the head. So if the restriction is the valves, why not try to go a little bigger.

[Plechtan]

A question came up about just bolting togather off the shelf parts for the LSR motor, Here is a Summary of what will be stock and what will not be:

Off the shelf:

Engine bearings
Flywheel (Fadanza)
Clifford header
injectors
Fuel pump (holley)
Head gasket
other gaskets

Custom

4.0" bored block
Hesco custom aluminum head with oversize valves and chamber
Pistons (diamond custom)
Rods
Custom ground crank
Custom ATI damper
Custom belt driven oil pump
Custom oil pan
Timing belt drive
Custom intake
Custom Roller cam
Custom Shaft Harland Sharp Rockers
Custom ECU
custom exhust
Custom throttle boddies and linkage
custom wiring harness

I may have forgot somthing, but tht is a basic overview

[Mgardiner1]

i'm not familiar with clifford headers, but if you are going through the work to make a max flow cylinder head, wouldn't a custom fabricated, large tube header be the real deal?

[TurboTom]

What is the C/D on your truck and how much HP will you need to meet your goal?
How much down force will you need to create, to get that HP hooked up on the salt, and how will that effect your C/D?
Other than the" Hey look what I did" (my personal drive with the drag car) why not use an engine with a better design?
We have 3.2 liter BMW I6 engines that make 450hp at 8200rpm..and will do that for 12 hours....road racing.
What is the 183 cu-in record?
There is a very good possibility we can build and LOAN you one of these engines for your LSR attempt.
Can't promise anything...I have to talk to the higher up's.
Trust me, I wonder why I am not running one of these, and throw this old Rambler stuff in the trash
How much do you plan to spend on Dyno time to get the oil pan right?
How much dyno time do you have planned to get the intake tuned?
Why the belt driven oil pump?
Are you going to dry sump the engine?
I looked at some comp eliminator classes my car would fit into. It is just not going to happen...the head sucks too much.
I like what you are planning, but just like me you have to determine when you are just...
If I were you I would start off with a better head design (cross flow) since you can not run boost.
$2000 buy's alot of welding!
Not sure of your rules...but you need to start with an engine that works best for the rules and cheat from there!

[1bolt]

I don't know which record Plechtan is specifically looking at breaking, but one of the things with land speed records is that the actual Engine and the chassis used, are how the record is classified... so a BMW I6 Engine probably already has some pretty high LSR attached to it... I don't know how they work it in terms of putting a BMW I6 in an AMC/Chrysler Comanche. But I think its a safe bet that the MJ and 4.0 have not gone so fast that he needs 100,000 dollars and 5 years of R&D to break that record.

So as I said earlier, one of his handicaps in working with a Jeep engine is also a huge assest in that the current record for fastest Comanche with a 4.0 is probably an attainable one without needing a corporation behind him... Anyway that's what I'm assuming, I wont pretend I actually went and looked up the record or rules, but I am a casual (very casual) Bonneville fan. I like oddball engines and creative ingenuity and the salt flats are brimming with those.

As far as the head ports, with boost and 280-300 CFM ports are you really that limited? I recognize that the more restriction your turbo needs to overcome the more your intake temps will climb, but with ice water intercooling, and some nitrious (mostly for charge cooling) you should be able to overcome the ports.... Especially if you got one of Lee's Aluminum diamond encrusted numbers... With a turbo and a high stall converter/Trans brake I'm sure you could get all the CFM you need out of one. Hell with a little work probably get enough out of iron heads.

Tom if you give me your target hp and RPM, and all your specs that differ from the stock 4.0 in a nice neat PM I can run your combo through EApro and produce some numbers that might be helpfull in terms of how much charge cooling, boost, and port size you need. A theoretical launch RPM might help too... I realize that some or those are still up in the air.

[Plechtan]

i'm not familiar with clifford headers, but if you are going through the work to make a max flow cylinder head, wouldn't a custom fabricated, large tube header be the real deal?

The clifford is setup up as a 2 sets of 3 into 1, it has long tubes. The chevy 6 cylinder guys liked 30" tubes from the cylinder to the collector, the cliffords are not that long but they are a good start. I may go with a custom header later, but the port in the head is less tha 1.5" in diameter. I will see how it works, the Intake and the head are my big concerns right now, if the exhust looks like it is a major limitation, then we will go with a custom setup.

[Plechtan]

What is the C/D on your truck and how much HP will you need to meet your goal?
How much down force will you need to create, to get that HP hooked up on the salt, and how will that effect your C/D?
Other than the" Hey look what I did" (my personal drive with the drag car) why not use an engine with a better design?
We have 3.2 liter BMW I6 engines that make 450hp at 8200rpm..and will do that for 12 hours....road racing.
What is the 183 cu-in record?
There is a very good possibility we can build and LOAN you one of these engines for your LSR attempt.
Can't promise anything...I have to talk to the higher up's.
Trust me, I wonder why I am not running one of these, and throw this old Rambler stuff in the trash
How much do you plan to spend on Dyno time to get the oil pan right?
How much dyno time do you have planned to get the intake tuned?
Why the belt driven oil pump?
Are you going to dry sump the engine?
I looked at some comp eliminator classes my car would fit into. It is just not going to happen...the head sucks too much.
I like what you are planning, but just like me you have to determine when you are just...
If I were you I would start off with a better head design (cross flow) since you can not run boost.
$2000 buy's alot of welding!
Not sure of your rules...but you need to start with an engine that works best for the rules and cheat from there!

Well to answer some of your questions, I have to look up the 183cid record, but it is probably around 130 mph. In the standard production class you have to run an engine from the same engine family that cam with the vehicle from the factory, but it cannot have a taller deck. They do have a modified class where you are required to modify the vehicle, and an engine swap could be one of the modifications. If the engine is changed i would think you need to swap the trans as well, then you have to get a SFI bellhousing, SFI clutch and flywheel, and deal with all the other stuff you need when you do an engine swap.

As to the HP question, hard to tell, the big factor is drag. I have the HP numbers for the 1986 truck, it was about 260. On the test track at sea level it had a top speed of 155, the best it did on the salt was 144mph( 4000 ft elevation) from these numbers I am guessing at a frontal area of about 17 sq ft, and a cd around .55 This would put the HP requirements in the 430HP range for 185 mph, and 534 hp to go 200 mph. If i can get the CD down to .5 then i would only need about 490HP to go 200 mph. I agree that the Jeep does not have the best head, and the jeep is not the best motor, a Supra motor would probably be nice.

As for the belt drive on the oil pump, the idea was to unload the cam as much as possible, and to get enough oil flow and pressure to support 7,500-8,000 rpm. Dry sump is an option, but because we ar going in a straight line , we will go with a wet sump for now. It will cost some money to dyno everything, but maybe we all will learn something from it.

A friend on mine once asked me "how do you tell who the pioneers are?" I said " I don't know" to which he replied " those are the guys with the arrows sticking out of their backs"

[1bolt]

The reason to go custom header is the ability to specify cross section and the exact length, The length of the ports and the header along with the intake runners and how they work with the Cam is the primary means to put your power where you want it and get the most out of it.

A program like EApro or Pipemax could help you a lot (serious sims not lightweights like Desktop Dyno), they're both very close for optimising inertial ramming and scavenging pulses so the intake and exhust work with each other (and the overlap and timing of your cam). EAP does complete engine simulation and Pipemax does Exhaust and intake tuning, both are popular among performance engine builders. On a well built motor there's lot of power on the table with resonance and inertia tuning. We're talking about taking the engine from 90-100% VE to 110% possibly more. Fortunately the 99+ intake is already strongly tuned for 4000/5000 RPM's... You're probably looking for a peak much higher though, but with something like EApro you can play with the plenum volume and the intake runner length (then just cut out runner or open up cross section, or add on an adaptor that lengthens the runner etc.) and header lengths to move the tuning pulses to exactly where your cam will use them. Of course you can also use it to select a cam that moves things around a bit to get what is already there (so to speak) but that's not the ideal by any means, it's useful if you've already got a lot of money in an exhaust and intake.

Actually I'll extend the same offer to you as I did to Tom, if you would like I can put your planned combo specs through EAP along with your goals for where you want your power to peak, your cam specs, etc. it can give you some starting points for exhaust and intake lengths, if you end up wanting to play with the program yourself I'll email you what I've input for you. PM if you're interested.

[Plechtan]

I would be very interested in seeing what these programs would come up with. One of my thoughts when i started the project was that technology had progressed somewhat in the last 20 years and maybe a guy like me with limited resources could build something that would perform at the same level the factory teams were able to achieve 20 years ago. The original Jeep record was set in 1986 and the Banks s15 record was set in 1989.

I have been researching the Chevy I6, there seems to be a lot of information available about them. The intake system is totaly different on the chevy, they have siamese ports, 1 intake port for 2 cylinders. You can't really tune that. My thoughts on the Jeep engine was to split it into 2 banks , Cylinders 1,2,3 in 1 bank and Cylinders 4,5,and 6 in the other bank. Most exhaust headers seem to be set up this way already. The basic idea is that a cylinder from bank 1 will fire alternately with a cylinder from bank 2. Since a cylinder fires once every 720 crankshaft degrees, 1 cylinder in each bank will fire every ( 720/3 = 240) 240 deg. Since this number seem similar to cam duration angle, depending on the Cam, a valve may be opening on 1 cylinder in a bank, just as another one is closing. On bank one the sequence would be 1,3,2,1,3,2 etc. on the second bank it would be 5,6,4,5,6,4 Etc. Each bank would have it's own throttle body. Not sure if a balance tube or plenum would help or hurt things. I think the airflow through each throttle body would be fairly constant, with 1 cylinder at a time on the intake stroke (minus the overlap). A plenum could reduce the effect of the pulses, and cause more turbulence than splitting things up. It is all theory, maybe your program can prove it one way or another.

[Plechtan]

I got a call from Lee Hurley at Hesco today, He said the head was done. I asked how the flow numbers looked, he said 260 on the intake at .550 lift about 181 on the exhaust with the same lift. He said that a 2" valve would have given me about 5 cfm more then the 2.02. He said the springs will support a .625 lift.

The chambers are 61.5cc . We talked a little about the price, he charged me about $900 over the price of a standard aluminum head, His normal shop rate is $95.00. I think he probably has allot more than 10 hours into the head.

The head goes off to Harland Sharp next for the shaft roller rocker setup. The rods and pistons are due in the end of next month.

The block is finished machining, but we wanted to stabilize the bottom of the block a little more, we put in about 1" of hard block. This should help with harmonics. It should also help strengthen the bottom of the #1 cylinder where we put the sleeve in. The hard block will make it impossible to use a water pump in the block. We had always planned to use a remote electric pump anyway, so no big deal here.

[5-90]

Here's a thought on the crank - how about an unmachined blank that will support anywhere from 3.500-4.125"? Final grinding to be done by the shop. Cast in nodular iron - since you'd have to remove too much to really have an effective forging.

Or even 3.440-4.125", which should give you stock to nasty...

[Plechtan]

Looks like everybody wants a much stroke as possible You can use a 232 crank to get strokes in the 3.5 to 3.6 range, I don't know if there is much demand there. If you did go with a 4" bore, a 3.6" stroke would give you lower piston speeds, probably be eaiser on the piston and rings.

A 4" stroke with a 2.1" Chevy journal would seem to be the product that everybody would buy. This could be ground down to 2" to achieve other strokes.

[Plechtan]

I finally got the Aluminum head from Hesco. They installed 2.02 intakes and 1.058" exhaust valve, chevy LS style. the head chamber volume was increased to 62cc. The head flows 249 cfm at 25" and .600 lift the exhaust flows 141 cfm. I will try to get some better numbers later, right now the head is at Harland Sharp to have a Shaft roller rocker setup installed. The airflow capability of the head seem to be the biggest issue with making more HP. With the restrictive head, it looks like forced induction would be the way to go to get big numbers out of the motor.

The Hesco head has a integrated valve cover spacer, which means that the head is thicker then the stock head, With this additional material it is possible to either move the intake ports up higher on the head, or make the intake ports taller. Chevy made taller ports on the heads when the went to the LS motors. Making the ports bigger will result in the loss of low end torque, but will allow larger intake runners. If you look at the total airflow into the cylinder, you have to take the losses of the intake runners into account. My engine will probably have runners 7" long or so. The less loss in the runners the more air available for the engine. On the chevy I6 motors the intake ports were siamese, 1 port for 2 cylinders, you could not tune it, but you could have a huge intake runner. Both intakes were never open at the same time, so all the airflow was available to 1 cylinder. Some of these motors made HP in the 480-500 hp range @ 7500 rpm.

[heartlandoffroad]

You should be able to get 330 or more out of that head with the 2.02 @ .600. I can get that out of a 0721 head ( with allot of work ). If the Hessco head can't get them numbers Lee needs to go back to work on it.