Does anyone here have any familiarity with disassembling/reassembling the throttle body on an AJ26 engine?

I want to bore my throttle body DIY, but am more worried about taking it apart and putting it back together. Before I just wing it I'm hoping someone here has possible blazed this trail before.

 

https://www.jaguarforums.com/forum/x...ncerns-159443/

No pictures but a description. There’s some useful information.

 

Awesome, thanks for the link! So from what it sounds like it shouldn't be too difficult to tear down. I was imagining there may be a clock spring type mechanism or some other element that could fly out when taken apart.

 

Just takes time and patience. The question if you get to the point of boring out the TB is how do you know when to stop? If you are successful in the whole process, can a AJ27 TB be on the potential list?

 

I'm just going to sneak up on it. Once the the unit is disassembled I'm going to put the housing in the CNC, pick up the center of the hole, and start taking passes around the ID. Somewhere around 79-80mm it should start taking off material. Then I'll just increase the diameter in small increments until I've gone as far as I feel comfortable. The thin side just has to be strong enough to withstand a hose clamp, so the strength requirement isn't that high.

I did see in another thread that someone actually made an entirely new housing that was a much larger ID. Unfortunately the ECU didn't like it and I think that was the end of it. I have seen 82.5mm thrown around in threads discussing the service Maxbore used to provide. I will probably use that number as an upper limit to be conservative. Whatever I do I need the thing to work lol, so I don't want to to nuts.

Anyways, from there you just need to make a new butterfly plate which can be designed and machined pretty easily with a CAD program.

I don't see why this approach wouldn't work for an AJ27 throttle body as long as it can be disassembled completely in a similar manner. Unfortunately, I do not have enough access to the machines to do more of these than my own, but if successful I will document the process fully and it should be fairly easy to replicate.

 

If I’m not mistaken, the 82.5mm TB’s you are pertaining to is for 4.2 (later V8) engines?? Did you read about this in the X100 or the X308 section?

Just a bit of information in case you didn’t know.
USA SPEC:

1997 XK8 AJ26
1998 XK8 AJ26
1999 XK8 AJ27

1998 XJ8 AJ26
1998 XJR AJ26S
1999 XJ8 AJ27
1999 XJR AJ26S (I believe the second half of the 99’ XJR went to the AJ27S.

The AJ26 and the AJ27 do not have the same TB and cannot be interchangeable. There are similarities between the two but that’s it. The AJ26/27/S TB’s have no resemblance to any other Jag TB.

 

My late 2002 STR has a 75mm TB. Can't see Jag using different sizes across the 4.2 litre engines (XJR, XKR, STR).
The 82.5mm was what you 'might' be able to increase to from Maxbore.

 

I did know they were different, but I did not know the actual breakdown by year and model. When I referenced the AJ27 throttle body I just meant that as long as you can break it down to just the housing the process of boring it should be the same.

Yes, this is right. I'm not even sure I'm going to get that much, so we'll see what happens.