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FOUNDING MEMBER
1995-2002 Range Rover P38A
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Discussion Starter #1
Some time ago a question regarding Callaway-specific gaskets came up. Technically Callaway gaskets exist as part numbers, but good luck in finding new stock. Will existing stock items work?

I decided to replace my head gaskets to find out. Turns out the current stock gaskets will work. The differences are minor.

Descriptions are for the image below the text.

Here's the (dirty) engine bay. Unique Callaway stamped plenum and carbon-fiber intake elbow. The Callaway air filter element (not pictured) is cotton-type (like K&N) with Callaway molded into the rubber gasket sides:
Callaway_EngineBay01.jpg

Intake plenum off. I don't have a stock 4.6L to compare to, but here are the intake trumpets off the Callaway, something that are supposedly different:

Callaway_Intake01.jpg

Intake valley gasket area. I was getting a some leaks from the rocker covers and intake heater plate. Possibly even some valley gasket leaks. I know my block was pretty coated in oil.

Here you can see how the Callaway gasket matches up with the Callaway-machined ports in the heads. The gasket is still a tad larger than the ports, particularly vertically:

Callaway_ValleyGasket01.jpg

Stock replacement gasket laid on top of the old Callaway gasket. Port openings match exactly:

Callaway_ComparisonA01.jpg

Side by side valley gasket comparison. I've circled the only really relevant differences. The Callaway bolt holes are all shaped/rounded, there's a slight difference between a bolt hole and a notch, but none of these details affects the way the gasket works. So the stock gasket is a perfectly adequate replacement. Note the faded "Callaway" sticker that brands all Callaway modified parts (plenum, intake, gaskets, gasket clamps, heads):

Callaway_ComparisonB01.jpg

Gasket to intake manifold comparison. New, stock gasket, obviously, doesn't impede the airflow of the Callaway ports in the intake manifold. But note, that while the head to gasket match is pretty close to the gasket cutout dimensions, the intake ports are smaller. That should be OK, though, as a step down/out from the intake manifold to the heads is preferable to a restricting step up/in.

Also note the end of the gasket closest to the camera. The gasket has been stamped for a water passage, the head has this passage open, but the Callaway intake manifold (as pictured here) doesn't have the same passage. It's just blank. It's also interesting to note that even the Callaway-specific gasket had the passage stamped out:

Callaway_Match01.jpg

Here are some noticeable machining marks to the corners of the head ports:

Callaway_MachiningMarks01.jpg
Callaway_MachiningMarks02.jpg

To be continued...
 

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FOUNDING MEMBER
1995-2002 Range Rover P38A
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239 Posts
Discussion Starter #2
... Con't.

And for those interested in just geeking out on some history, here are some pics of the Callaway identification markings on some parts.

The first is a 'Callaway' stamping on the side of one of the heads:

Callaway_Stamp01.jpg

Inside the rocker area on the heads are two plates stamped with 'Callaway':

Callaway_Stamp02.jpg

Every Callaway-specific part has a sticker that looks kind of like this (head example):

Callaway_Sticker01.jpg

The block is stamped for the increased 9.6:1 compression ratio of the Callaway spec:

Callaway_Compression01.jpg
Callaway_Compression02.jpg

That's about it.

One thing I forgot was to document the comparison between the stock head gasket and the Callaway head gasket. Worry not. They, too, are pretty much the same design both in stamping and thickness.

It all makes me wonder why there are specific part numbers for Callaway gaskets? Are the gaskets even really different from what came out of the factory on non-Callaway 4.6s at the time? Perhaps it's an accounting or administrative thing. Who knows...
 

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Thank you very much for the post/pictures, not exactly earth shattering modifications but perhaps will put an end to the (understandable) "...but, Callaway this...Callaway that" confusion.

Those trumpets are indeed different to stock, still looks like stock though just much shorter (cut down), you'd have to measure the i.d or o.d to be sure but given the very light nature of the modifications it seems unlikely.
 

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Premium Member
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thought i had a photo from long ago...and here it is, this was one trumpet i found had worked its way completely loose - so i thought i'd measure it (perhaps with the view to making some carbon ones) before i silicon'ed it back (O2 safe silicone i might add).

Its from cyl.4, if you can't make it out its 100mm long and i've written on it 40mm OD 37.5mm ID.

DSCF2118.jpg
 

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1995-2002 Range Rover P38A
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239 Posts
Discussion Starter #6
220 Callaways were produced for the 1999 model year. They are actually modified GEMS-based, late-98s. They were tuned by Callaway Cars in Old Lyme, CT for Land Rover North America. There were three colors available.

More details can be found here: http://www.rangerovers.net/modelspecs/1999.html#special
 
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