4.2 conversion. Bis toruble or what?

[Banjo]

I've located a possible motor donor car for my 58 Mk VIII.
It's a rough but running late 79 series 3 XJ6.
My Mk VIII has power steering and an auto tranny already, so how much trouble am I bringing on myself to drop that 4.2 and tranny in where the 3.4 resides?
I already know that I need to get the wiring to suppourt the fuel injection, that's not an issue. I can do that. I'm more concerned about the external differences between the two motors. I.E. motor mount locations and such.

 

[DrEntropy]

Ben, is the old engine that worn? My question is really: if you're going to do the thing anyway, why not go thru the engine too? Hard to weigh the alternatives, but even tho it'd ba Jag-to-Jag it'd still be taking away from the car's "heritage." Jag sixes are a commitment in any form, but you've the necessary skills and knowledge to go thru the original mill and make it NEW as it is. I'd vote for the rebuild, frankly.

 

[kennypinkerton]

Yeah, the engine is the fun part! Why dump a crappy 70's/80's engine into it? Tear that sucka down and make it beautiful again! A 58 Jag doesn't want a flaky fuel injection system... It wants carbs and a newly rebuilt 1958 engine! /ubbthreads/images/graemlins/thumbsup.gif

Jeez, if you, me, and Doc lived in the same town... we would be dangerous!

The bottom end should be the easy part... New rings, seals, and bearings. The top end... That's the expensive one... Hardened valve seats, maybe a couple new valves, new valve guides, a complete seal and gasket makeover, magnaflux (just to check for any cracks), Carbs rebuilt, Cam checked for specs - welded and reground if necessary, and several other odds n ends.

Just gotta remember, it's not a "performance" Jag. This thing was built to cruise smooth and slow with the rich guy either inna back seat, or behind the wheel!

 

[Banjo]

Well the ol' 3.4 has gotta come apart anyhow. I'm definatly going to investigate whats wrong in there, but I'm very concerned about how badly corroded the pistons and cylinders are.
This thing (according to legend) has been locked tight for at least 10 years, probably many more. and even with my "stew" in the cylinders, it ain't budgin.
My other option would be to use the good 4.2 block and put my 3.4 carburated head on it. Then I'd have estra displacement, and it'd look identical to the 3.4.
I guess I gotta look inside the monster before I do anything else.

 

[Marvin Gruber]

Banjo,
I have a 3.8 with auto still bolted up, out 60 sedan. Car was wreaked with 22K miles on it. I have had it sitting in barn for at least 25 years. I am sure its stuck but if you can use it, we will work something out.

 

[Banjo]

Thanks Marvin, That's a very generous offer. But I don't think it'll be in the cards to go to Alabama to get another engine that needs to be rebuilt. /ubbthreads/images/graemlins/frown.gif
Sometime this week I'm gonna drop the pan, pull the head, and have a look. It may not be as bad as I think.
'Course I'll keep you in mind if my tranny winds up being bad /ubbthreads/images/graemlins/grin.gif

 

[tony barnhill]

Ben - you're getting very sleepy, you're nodding off, the first thing you hear when you awaken will prompt you to load the Jag on a trailer and take a road trip....

Now, when I count to 3, you'll be awake and alert and not remember this conversation

1 - 2 - 3

 

[tony barnhill]

Hey, Ben - north Alabama is great this time of year!

 

[Banjo]

Don't tempt me Tony. It's spring, I'm gettin antsy for something to drive, I'm realising I have too many projects at once, and I really don't have the proper funds for any of them.
I'm still determined to stick with it for now.
I dropped the pan off the bottom of the 3.4, It looks pretty clean up in there. It's gotta be stuck rings.
So I might get lucky, and get away with rings and a gasket set to get it running.
Next step is pulling the head.

 

[DrEntropy]

THAT will be an adventure! They usually get "stuck" pretty well if left to sit. Lots of PB Blaster and playin' the headbolts like a xylophone.