How to make a XJ6 3.4 Engine look like and fit a MK2

Worth me saying why and how ? :writing_hand:

2 Pictures are of the same engine !


Yes!, if that’s a XJ6 3.4 going into a Mk 2 then I am VERY interested as I am going through this process now. I’ve seen the E book, but I have lots of questions. As these engines are long lived there are multiple combinations.
Thanks Phil

I didn’t know there was such a thing as a 3.4 XJ6 engine. I just finished swapping an '85 4.2 into my Mk2 so, but not sure how similar those two motors are.

Thanks for the reply, the motor I have is a 3.4 out of a S3. I doubt it will be that different to yours. What did you need to do to get it to fit? In my case the car body is at a different location to the engine so I am trying to get as much sorted prior to a trial fit. This is the list I have from reading what I can find:

Engine mounts from old motor should fit on XJ, but need to fabricate alternator bracket?
If I use pancake filters the carbs will clear the bodywork?
May be an issue with the XJ intake manifold fouling steering column on RHD cars?
Water pump too long

any help gratefully received

Phil

My 3.4 is out a 1975 XJ6 , so far I have
Fitted MK2 engine mounts , bolt straight on , I have the dynamo
Fitted a MK2 water pump , bolts straight on , may fit the impeller from the XJ6 as it has 8 blades , MK2 has 6 !
Drilled and tapped the back of the XJ6 cam , to fit the MK2 generator , you need the back baring housing as well from the MK2
Fitted 240 cam covers , bolt straight on .
Replaced the oil filter housing from the XJ to a 240 one , bolts straight on .
The HS8 and HD6 carb bodies are about the same size , but think the xj6 inlet manifold is wider ,
My engine is up and running on a test bed .

Ian covers most of it.

I used an oil pump and pan from the Mk2 3.8.

I used the black and silver cam covers from the xj6 and had my tach converted by Mike Eck (works great) to run off coil vs. cam generator.

Had to have custom alternator mount made since the moved motor mounts took the bolt holes otherwise used for my accessory mount.

I used a dual intake from a 420 and two HD8’s, which are very tight to the sidewall, but they fit.

Thanks guys for your help. Wil let you know how I go.
Cheers

I have about 3 4.2 inlet manifolds , waiting for a MK2 straight port head one to come to try , should be here by the weekend !
Still deciding what carbs to use .
I went for the 240/340 cam covers , look more attractive , with the Jaguar name on them , and the bigger alloy filler cap !
Think you could have used the MK2 Engine mount Theo , just would have needed some spacers on a long bolt to take up the slack !
Was there a reason for the 3.8 oil pump and pipes ?

Well, the pump and pan on my 3.8 were relatively new, I wasn’t sure of the condition on the donor motor. Also, I knew they fit around the subframes, I also have a rack and pinion and uprated sway bar both of which are very tight fits so didn’t want to have to mess with refitting or interference, easier to just use what already proved to work.

Hi Theo, I’ve been told the oil galleries are different on the S3 engines, what did you do regarding the oil filter arrangement?

The 3.4 Engine I am working on is from a 1975 Ser 2 .
The 240 filter housing was a straight bolt on job , I know Jaguar changed the filter housings a lot , but not the block , have you got a picture of a 4.2 se3 block , with out the filter housing bolted to it ?

I found this pic 4.2 Ser 3 , to me the filter mounting point looks like all the rest of the XK blocks !
Jaguar even left the same engine mounting points from very early on , so can’t see they would change the oil ways inside the engine , or the mounting points , some have 4 bolt holes some have 5 !

Ps , even the oil pipe from the 240 filter to the sump was a straight bolt on job , to the 3.4 sump !

This is a 3.4 Ser 2 oil filter housing block face , you can see its the same as the 4.2 !

Ian, thanks for the pictures. I’ll take my housing off today and compare. I need to send some pictures to parts suppliers here to see what I can dredge up.

Hi, here are the images, I’ve also seen the thread on the XK engine forum and from my uneducated viewpoint I think an older filter housing will work. My engine seems to be the ‘new’ 3.4 (engine # starts with 8Axxxx) but the block seems the same as the 240 image you showed on the XK engine forum. My engine had the oil cooler fitted but that seems to be all in the housing, not the block. All thoughts gratefully accepted.
Phil

Found this pic of the 5 hole housing , looking at your pic , the gasket goes over the mounting bolt hole , so looks like all the blocks are the same !
You just need the right gasket to match the housing !

Awesome, thanks Ian.

Ya I’m not sure about the specifics, but the shop who set up my 4.2 used the same kit that was on my 3.8 with no issues. Apparently some of the hoses had to be remade but everything bolted up without issue.

New Throttle return springs come yesterday eBay item number:
291965093186

3.4 XJ6 engines were offered on the series 3 cars, never in the US

Well just a update , plan on starting the engine change in a week or 2 , few more things to get .
Sort Garage out so there is room all around the car , will be taking lots of pictures , like this one , how to remove the 2 Dowels that hold the starter ring to the Crank , they are threaded , so they just pull out , as you tighten the bolt up !