Hi All,
I am a new member subsequent to the purchase of a very tatty '61 xk150 for restoration.
The car has a non original engine, being an early e-type 3.8, 9:1 compression triple SU etc.
The motor is completely seized and am yet to pull it apart to have a look.
I am just wondering what the forum’s view would be as to whether I should restore it or install something else (series 3, 4.2 with my triple SU carbs?) given I do not have a numbers matching car anyway.
Warm Regards
Haydn
End of the day its down to you , the E type engine would look more at home in the xk150 , but will cost a lot to put right !
3.8 E-type engine is worth a lot more money then a 4.2 , even seized up , so you could cash it in , buy a 4.2 and have some cash over for some other new parts !
Congratulations on your purchase and welcome to the forum.
If it was me I would first delve into the 3.8 and find out why it is seized.
It may be an easy fix or need a total rebuild or somewhere in between.
Does it have the correct attachments for a 150, oil filter head, intake manifold, water pump, etc? Correct trans?
This is the place to ask such questions.
The series 3, 4.2 engine has a different engine mounting arrangement , with cast mounting points on the block being different. The problem extends. The mounting being further back alters the Cof G of the engine , so you have to fiddle with gear box mounts to ensure tailshaft alignment.
And relative to the 3.8 it’s an ugly looking engine.
Far far better with the 3.8 engine .
This is a 3.4 XJ6 Engine 1975, Jaguar left the mounting point there for early mountings , I would think the 4.2 is the same !
,
I can’t comment on that in particular , But my S 1 XJ6 had the 2.8 engine replaced when i got it , With a 3.4 MK II engine and the engine mounts were fairly long complicated affairs that went from about the front of the block to the frame about centre of the engine.I presume it’s better to be sure first. I know the spring supporting the back had to be altered because of the different weight distibution
Thank you for your thoughts. The reason for considering the 4.2 series 3 motor ('79 to '92) is after seeing similar modifications over here, (Australia). My simplistic understanding is the 4.2 is basically a stroked 3.8 block with better cooling and large (inlet) straight ports and therefore a much better motor than the old 3.8, from a pure engineering perspective. The 4.2 series 3 motor is simply the final evolution of the xk engine as far as I am aware (albeit with my very limited knowledge) and there is about 50 BHP and excellent low end torque to be enjoyed as a bonus. Actually, we have a few e-type owners here who have installed the 4.2 head as best of both worlds (onto the original 3.8 block, and kept the original head aside for originality sake in case they sell the car) With a little fiddling, they keep the polished camshafts and triple SU’s to make the motor more aesthetically appropriate. Conversely I am conflicted about “modernising” such a beautiful car from the 50’s era and in principle, the 3.8 is probably more appropriate from this standpoint, given it is not a step too far from the original.
If I was you , I would keep the engine in the pic , would think its just a case of the rings sticking to the cylinders , take the plugs out and poor some fuel in , leave it for a day , then put a socket on the front crank bolt and try and rock it .
Its not straight forward putting a later head on a early engine , they changed the water ways to the head from the XJ6 ,if you go down the straight port head road , you need a head from a 240 , 340 , or the like , you can fit the XJ6 heads but you need to block some waterways up in the head !
Your have a problem with the inlet manifold as well , as the waterways are different there to !
Not stroked, bored. The 4.2L and the 3.8L engines both have the same stroke. Compared to XK era 3.4L and 3.8L engines, the 4.2L engines have larger siamesed cylinder bores. This required different center-to-center bore spacing, which then also required a different crankshaft. Although the cylinder bore spacing changed, the cylinder head combustion chamber spacing did not. This peculiarity allows you to put a late 4.2L head on an early 3.4L block. It also makes high compression 4.2L pistons an expensive proposition as you have to have different dome designs for the different combustion chamber offsets.
Same it’s not in the UK I have a lovely 3.4 engine and a 5 speed box available.
Nick
Thanks again everyone for your contribution and Ian/Mike for your clarification. I am clearly on a learning curve!
I totally agree it would be silly to detach from the 3.8 if it is a relatively easy fix. As stated it is a better option aesthetically as well.
I’ll keep you updated as to how it goes. Note if it is totally buggered my original question remains!
By the way, just thinking laterally for a moment, is there such a thing as a register of “missing” engine numbers? My original motor is probably out there somewhere and maybe there is a series 1 e-type owner wondering where his is?
Now for my next question…and thanks for bringing it up Nick,restoring the buggered moss box/overdrive or getting a 5 speed.
Given the moss box parts are difficult to come by, and it is an acquired taste as-is, what do you reckon?? (and sincere apologies in advance to all, for my naivety in messing with more of the sacred entrails)
You can search www.xkdata.com to look for your original engine and www.xkedata.com to look for the origin of your present engine.
For Moss box restoration, start a new topic. They are generally strong units. It may not be as buggered as you think, maybe only needing new seals.
Hi I,m looking at using a head off a series 3 xj 3.4 and replacing my 150 s head Could you post a pic of rear of head I need to know if its got the 2 extra water ports in the back like the 4.2 regards Terry hilton Australia or xkpartsoz@gmail.com