87 Octane and the Aluminum E-Head

[Root Moose]

So, getting serious about a stroker build and thinking about the Edelbrock head to build around for 87 octane with a NVH block. Got a line on a workable block to work with.

Here's the configuration I put into the calculator:

+30 over, 4.6 litres.
Edelbrock head, 55 cc combustion chambers
1.6 rockers, H-S or Y-T - haven't decided, opinions on either?
Scat crank, options for new rods?
OEM Gasket @ 0.051" thickness
Custom Bulltear pistons: 22.5 cc dish, piston height to be flush with block at TDC
OEM cam (1999-2004): 253.3 intake duration, 107.3 LSA

Calculated values:

SCR: 9.69:1
DCR: 8.36:1
Quench: 0.051

Seem workable?

The 22.5 cc dish is arbitrary to get the DCR into the low 8s.

Are there other thicker head gaskets out there? I know about the 0.043 ones, just wonder about hedging my bets if this thing pings under hot load.

Is there such thing as a custom hyper-eutectic piston manufacturer?

Any input appreciated.

Thanks.

[jeepxj3]

Why use a stock cam in an engine that is 15% larger in displacement and has a better flowing head? That is like using a stock or even a 62mm TB on this engine.

Make the head a worthwhile investment and get a 68-70mm TB and a cam, something in the 200-210* duration and 0.475" lift.

Looking forward to any build using this head.

[Root Moose]

Thanks.

Can you recommend a cam(s) to look at?

[jeepxj3]

What year block?

[Root Moose]

What year block?

2000

[jeepxj3]

The 2000 uses a cam retainer plate which is better than the older style pin and spring or fitted pin/bolt.
All the popular aftermarket cams are the old style.
Only 'negative' is there are no double roller timing chains for cam retainer plate cams. Just use a single roller Colyes
Call Jones Cams. He is one of the few who will grind a new style cam retainer plate cam. About $250 + shipping.
You would probably want his 204/208* grinds.
That cam + F+B 68-70mm TB + Edelbrock Head + 4.6L + bulltear pistons =

[Root Moose]

The 2000 uses a cam retainer plate which is better than the older style pin and spring or fitted pin/bolt.
All the popular aftermarket cams are the old style.
Only 'negative' is there are no double roller timing chains for cam retainer plate cams. Just use a single roller Colyes
Call Jones Cams. He is one of the few who will grind a new style cam retainer plate cam. About $250 + shipping.
You would probably want his 204/208* grinds.
That cam + F+B 68-70mm TB + Edelbrock Head + 4.6L + bulltear pistons =

Thanks for that.

I have a 63mm TB currently (generic eBay piece). Recommendation/ source for larger?

Also, for messing around with the compression ratio calculator, do you know what the typical LSA would be for one of their cams? I want to get my "head space" in order before calling them so as to not waste their time.

[jsawduste]

http://www.fbthrottlebodies.com/products.htm#66jeep

LSA in the 112-113 range.

You can convert a retainer plate to a pin and spring if you want. The plate is better IMHO but there are plenty of engines running with the pin. Just set it up carefully.

Consider the Hesco RVOB cam. It is a spring and pin but a good grind.

[jeepxj3]

F+B for the 68mm, 505 for the 70mm. IDK if you can get the 70mm directly from F+B, I would try that as they are the manufacture. 505 is a hassle sometimes.
The Jones cam is 113*.

[Root Moose]

Spent some time messing with the calculator looking at CR's. Looks like the suggested cam will bump the DCR too high (9.1:1 or higher depending)- likely ping with 87 octane?

I'm shooting for low 8.x DCR to make certain this thing works when running hot under load. This is a workhorse Jeep, not so much a toy. It has to work properly when towing.

My thinking at the moment is to stick with the OEM cam, get it dialed in, then experiment with more aggressive cams afterwards.

What the new Al head will allow is an unknown so I'm being conservative (zero deck, OEM gasket, mild/OEM cam profiles). Is there a better approach?

[jsawduste]

F+B for the 68mm, 505 for the 70mm. IDK if you can get the 70mm directly from F+B, I would try that as they are the manufacture. 505 is a hassle sometimes.
The Jones cam is 113*.

F&B will make you a 70mm as a special order. No up charge. Lead time varies, sometimes they are on the shelf and other times a week or so out.

[jeepxj3]

The Jones cam numbers were for duration at 0.050" lift (200-210*) and they can't be used in the CR calculator.
Oops, sorry for the confusion.

For the Jones cam, you would want a split I/E
Cam profile H65295 260* 204*@0.050" 1.6:1-0.472" lift (Intake)
Cam profile H66299 264* 208*@0.050" 1.6:1-0.478" lift (Exhaust)

The closest cam selections in the CR calculator are- (with your build specs)
Comp 68-201-4 260* 110* DCR 8.26
Crane 753905 260* 111* DCR 7.87
Isky 133126 262* 108 DCR 8.1
Lunati 63501 260* 112* DCR 8.26
Lunati 63502 262* 112* DCR 8.1

The OEM '99-'04 253.3* 107.3* DCR 8.36 Is the worst of the selected cams.

The Jones cam should be right where you want it low 8's maybe even high 7's.
With the Jones cam, You might even be able to use a thinner head gasket 0.043" or less piston dish and raise the CR and still have low 8's DCR for more power and low chance of detonation.

Play with the CR calculator some more and see.

[Cheromaniac]

Calculated values:

SCR: 9.69:1
DCR: 8.36:1
Quench: 0.051

Seem workable?

The 22.5 cc dish is arbitrary to get the DCR into the low 8s.

Are there other thicker head gaskets out there? I know about the 0.043 ones, just wonder about hedging my bets if this thing pings under hot load.

Is there such thing as a custom hyper-eutectic piston manufacturer?

Any input appreciated.

Thanks.

That's workable but I suggest you use a 0.043" head gasket and add more volume to the piston dish.
Unfortunately there are no custom hypereutectic pistons so forged are your only option.
I agree with the others about using a longer duration cam to take advantage of the E-head's higher flow.

[Root Moose]

After looking up the relationship between the intake valve closing angle, duration and overlap I messed around with the calculator a bit more...

I'm not there yet though.

Can someone advise on how to think of the relationship between intake duration and overlap from an empirical, power delivery point of view?

In my simplified way of thinking about it the intake duration length kind of indicates the amount of air via length of time that can be sucked into the engine. Increases the charge O2 content.

How does LSA relate to this way of thinking about it? Wider LSA means what?

Lower IVC means higher DCR.

I came across and interesting quote on the this web page: http://www.crankshaftcoalition.com/wiki ... sion_ratio

It's worth mentioning that 8.5:1 DCR is considered to be the maximum for iron heads and 92 octane fuel (MON + RON divided by 2).

Alloy head and 87 gas might let one get away with 8.5:1 DCR maybe? I think I'm going to try to make something in the 8.25-8.40 range initially and see where it leads.

[BADASYJ]

I would stick with stock rods (more then strong enough)and stock rockers(stronger and more reliable).
Save your money they are not needed, it will be a waste putting them into the motor you will build.