Before I spend more money, I want to confirm this all works.
1967 4.2 block (MkX)
- 4.2 133t flywheel
- 4.2 hi-torque starter
- 9.5 clutch
- 1966 3.8 4 speed (full synchro O/D) and bellhousing
Thanks!
Hi Joe,
Sorry but The 3.8 gearbox/ bell house Need a 104 teeth flywheel and according starter
Regards Roger
Will a 104 tooth flywheel work on a 4.2?
Other thoughts:
- Are all 4.2 flywheel/bellhousings the same from the 1960s through the end of the XJ6 run in the 90s(?)? In other words, would a manual trans/bell from an xj6 fit my 4.2? (I know of a conversion kit)
- Will the manual trans from the 3.8 fit a 4.2 bellhousing (assuming I can find one
)?
Is that also true for a 3.8 full synchro box as in 3.8 S-type?
Does it matter if my trans came from a 3.4 rather than 3.8?
Moss notes the following, but lists a 104 tooth wheel for the 3.8 XKE
“Please note that, originally, 4.2-liter cars came with a 133-tooth flywheel and the 3.4/3.8-liter engines fitted to the XKs and MK VII-MK IX were fitted with a 132-tooth version”
I believe starter flywheel combo need to match. Must use matching clutch parts. Whether it’s a 9.5 or 10 inch. The bellhousing size is the same 3.8 or 4.2. I measured my 4.2 bell to my 3.8 bell and they are the same.
So, I could bolt my 3.4/3.8 bellhousing with the 104 tooth flywheel to the 4.2 and it would work? I just need a 3.8 starter. The flywheels aren’t balanced differently or anything like that?
Balanced is Balanced, but the 3.8 flywheel is usually lighter than a 4.2. If you use a 3.8 flywheel, you need a 3.8 starter. The flywheel may or may not be drilled for a 9.5 in clutch.
I advise do a really good search of the archives, as this subject has been written up before ( a few times). I seem to remember an excellent guide by @PeterCrespin
I believe the 4.2 bellhousing is different at the centre bearing where it bolts to the gearbox.
When I did this search using just the authors name and bell housing as the search term, there was over 50 entries, including this sample
[E-Type] Bell housing advice please - E-Type - Jag-lovers Forums
Tony, thanks for the suggestion. I am not familiar with Peter and, as you pointed out, there are a lot of bellhousing posts.
I’m not sure that post is germane because it refers to swapping a 3.8 to a 3.8, and Peter’s comments seem to just say that I need to match the starter to the flywheel, unless I’m missing something.
To be clear, my RHD 1966 Mk2 came with a complete bellhousing/4 speed/OD unit plus a 104 tooth flywheel, 2 9.5" pressure plates/friction discs and 1 10" set (but that doesn’t seem to be correct). The trans is #JCN3331 which I was told makes it a full synchro unit. The Laycock is 28/61740/ 001580
I do not have a starter, so will buy a hi-torque unit for a 3.8 104 tooth flywheel and probably an aluminum flywheel. What I need to know is if the set of parts I have will work with the 4.2.
You are right there is a lot of posts and I did not find the one I meant, nor did I look through them all, but I seem to recall it did say the 4.2 to 3.8 bellhousing requires machining in the centre, as @Allrand mentioned
Seemed like it was fairly straight forward…search again using that phrase
It will be good when our computer expert @admins get AI working on the search function
If I’m reading this correctly, the Moss 3.8 bell needs to be machined to fit the All Sync trans, which doesn’t apply to my situation since I have an all sync trans & bell. Allrand is referring to a 4.2 bell, which I don’t have.
I’ll search again, but the first few dozen results seemed to refer to different scenarios.
I have a MKX 4.2 block with a MKVII (3.4) SH gearbox on the back
Its still in the car but will be out in a few days
At that time I will be able to see what Bell is in there, I think it has the older style starter
I think you misunderstood me, I was referring to a 3.8 bell matching to a 4.2 box.
Been away for a few days I see passing all right information !. As I supplied as a hobby many Getrag 265 sets for the classic Jaguars , and before that build a 4.2 box in my Mk2’s I had to research a little bit . Got also some experience .
-Use the right flywheel to the box with its bell house, or you get trouble with the starter, the latest of course need to be also the right one. . This means a 104 teeth to the mk2, the S type and the 3.8 E type. A 133 teeth to a XJ, 4.2 E type . 132 Teeth to a XK 120-150.
-"4.2 box "to a 3.8 bellhousing requires indeed machining in the centre. Its done a lot of times and no problem . Of course you create than new match.
- Another clutch diameter is if the holes are there , or good machined (!) no problem . I use for the mk2 the XK150 and the XJC the 9 1/2 "diafragma , but aware for the right realease bearing. Try it in case of doubt , before assembling the box in the car .
Hope above gives some extra overview.
Regards Roger
forgotten: All boxes with its bell houses fit mechanical to the XK engines, but the bell houses are absolut different in dimensions regarding the starter unit: a 3.8 isn’t the same as a 4.2 !
The back of the 3.8 bellhousing has a smaller bore cut for the front gearbox bearing. It can be machined to fit.