What to do with an 86 xj6?
Joined: Jan 2014
Posts: 28,386
Likes: 6,340
From: Delaneys Creek,Qld. Australia
Many accused purists are really just traditionalists, whereas true purists usually hang out in the concours arena - different breed altogether.
Seems like an unimportant debate, but hey, it distracts us from politics and all the other unsavoury garbage enveloping the world on a daily basis, so maybe not so unimportant!!
Seems like an unimportant debate, but hey, it distracts us from politics and all the other unsavoury garbage enveloping the world on a daily basis, so maybe not so unimportant!!
But if I had no other choice, either economically or availability of a quality XK rebuild I would have lumped mine to keep it on the road.
The rebuild wasn't cheap, and at other stages of my life lumping would have been a serious consideration.
Senior Member
Joined: Jan 2017
Posts: 282
Likes: 95
From: Kerkrade, South Limburg, The Netherlands
If you look at it that way, I'm rather a traditionalist too.
During the restoration I'll surely be finding some things that don't quite work on the actual car, though they might look good on paper.
Take the window rubbers for example. I don't think I'll be putting them back in like the factory intended to. They are the cause of all rust that I'm currently fixing, so I'll have to figure out something that works, without messing up the looks of the car.
The cooling problems on the V12, what do they actually consist of?
I hear a lot about blown head gaskets, but do they blow out just for no reason? On most engines they blow out because of a lack of coolant, steam build up in the cylinder heads. That is no design flaw, that is just plain and simple neglect.
During the restoration I'll surely be finding some things that don't quite work on the actual car, though they might look good on paper.
Take the window rubbers for example. I don't think I'll be putting them back in like the factory intended to. They are the cause of all rust that I'm currently fixing, so I'll have to figure out something that works, without messing up the looks of the car.
The cooling problems on the V12, what do they actually consist of?
I hear a lot about blown head gaskets, but do they blow out just for no reason? On most engines they blow out because of a lack of coolant, steam build up in the cylinder heads. That is no design flaw, that is just plain and simple neglect.
Veteran Member
Joined: Jul 2012
Posts: 6,796
Likes: 2,403
From: Walnut Creek, California
1. A modern alloy 427 or so Hemi? If those wide heads would fit, yes mam!!
2. Doug's mating of two cars with issues in to a single pleasurable one is attractive. The deed goes way back.
3. The Jaguar V12 at circa 350 CI brings it into Chev SBC territory. Older BBC's are at about 454. Hefty, but with a bark their own and tons of torque. At least one kit exists to make the mating simpler.
4. The XK engine complete with "interesting engineering features" is a beautiful engine. Actually a bit of an enigma. Longish stroke, good for torque development at lower engine RPM's. And a wonderful crossflow DOHC head. Great for breathing at high RPM's. Why, the mismatch ? I've read of two. Politics. Engines taxed on bore dimensions. Use stroke to get the CI's. Sales intrigue. The draw of a DOHC over a plebian OHV. I've always been attracted to the I6's. Properly "dressed" they look god and run good. My 94 Jeep's old tech infused with modern tech I6 performs reliably and well. And has done so for well over 200K.
5. The SBC came into the market in 1955 at a smallish 265 CI's. Light weight casting.
More bore than stroke. Light weight and simple valve gear. Stayed in the game til about 1998. Developing all along. Many applications from racers to largish trucks.
6. To lump or not to lump, that was my question, circa 2001. A major engine failure.
Heat related. The precise cause remains a mystery to me. Unexplained loss of coolant? I spent a lot of time in research. Although, my son operated his auto machine shop at the time, a rebuild involved a lot of $'s. Was the BW 66, although
working fine, far behind. The car came with about 115K on the clock. Not bad, I thought for a 83! No reason to disbelieve the number. It looked great, ran and drove well. After shopping I chose an engine take out from a 94 Cadillac Fleetwood Brougham. The yard threw in a lot of stuff. Including a brand new pair of after market ram horn manifolds. I bought an installation kit. A lot of the needed stuff there, albeit not quite all. My mistake was an after market harness. The "raggedy Jag wires" indicated that as a good idea. It almost but not quite fit. and at least two errors that caused me no end of consternation and $'s. Somewhere in my lore is the "White Paper" that I wrote about the journey. Imperfect and a bit incomplete, but runs and drives well. Except for the fact that it badly needs a bath, it looks great.
Looking over all the cars I've owned or driven, up top as a favorite.
Carl
2. Doug's mating of two cars with issues in to a single pleasurable one is attractive. The deed goes way back.
3. The Jaguar V12 at circa 350 CI brings it into Chev SBC territory. Older BBC's are at about 454. Hefty, but with a bark their own and tons of torque. At least one kit exists to make the mating simpler.
4. The XK engine complete with "interesting engineering features" is a beautiful engine. Actually a bit of an enigma. Longish stroke, good for torque development at lower engine RPM's. And a wonderful crossflow DOHC head. Great for breathing at high RPM's. Why, the mismatch ? I've read of two. Politics. Engines taxed on bore dimensions. Use stroke to get the CI's. Sales intrigue. The draw of a DOHC over a plebian OHV. I've always been attracted to the I6's. Properly "dressed" they look god and run good. My 94 Jeep's old tech infused with modern tech I6 performs reliably and well. And has done so for well over 200K.
5. The SBC came into the market in 1955 at a smallish 265 CI's. Light weight casting.
More bore than stroke. Light weight and simple valve gear. Stayed in the game til about 1998. Developing all along. Many applications from racers to largish trucks.
6. To lump or not to lump, that was my question, circa 2001. A major engine failure.
Heat related. The precise cause remains a mystery to me. Unexplained loss of coolant? I spent a lot of time in research. Although, my son operated his auto machine shop at the time, a rebuild involved a lot of $'s. Was the BW 66, although
working fine, far behind. The car came with about 115K on the clock. Not bad, I thought for a 83! No reason to disbelieve the number. It looked great, ran and drove well. After shopping I chose an engine take out from a 94 Cadillac Fleetwood Brougham. The yard threw in a lot of stuff. Including a brand new pair of after market ram horn manifolds. I bought an installation kit. A lot of the needed stuff there, albeit not quite all. My mistake was an after market harness. The "raggedy Jag wires" indicated that as a good idea. It almost but not quite fit. and at least two errors that caused me no end of consternation and $'s. Somewhere in my lore is the "White Paper" that I wrote about the journey. Imperfect and a bit incomplete, but runs and drives well. Except for the fact that it badly needs a bath, it looks great.
Looking over all the cars I've owned or driven, up top as a favorite.
Carl
Veteran Member
Joined: Mar 2008
Posts: 25,529
Likes: 11,724
From: Pacific Northwest USA
The cooling problems on the V12, what do they actually consist of?
I hear a lot about blown head gaskets, but do they blow out just for no reason? On most engines they blow out because of a lack of coolant, steam build up in the cylinder heads. That is no design flaw, that is just plain and simple neglect.
I hear a lot about blown head gaskets, but do they blow out just for no reason? On most engines they blow out because of a lack of coolant, steam build up in the cylinder heads. That is no design flaw, that is just plain and simple neglect.
Actually. blown head gaskets are not all that common on the V12. Certainly not to the extent that such an occurrence was almost 'a given' on the later XK-6 cylinder engines.
Very briefly.....
The V12 cooling system is complex and weird. The radiator, for example, is partitioned internally to partially separate the flow from each bank. Thermostat *length* is a critical consideration...and many thermos being sold for the V12 are just wrong. It's not something the average owner or repair shop gives much thought to
Proper bleeding is essential; no room for error. Mistakes here lead to hot spots in the heads and, quite often, dropped valve seats.
Radiators are very often clogged, both internally and *externally*. This external clogging typically goes unnoticed until problems occur. Seemingly innocuous steam relief pipes are often clogged as well, causing problems. Too many owners (and repair shops) are not aware of how important they are.
Everything must be 100% spot-on or you'll have problems.
In my experience the system is OK as designed if kept at 100% but experiences vary, and many go through some elaborate modifications
Cheers
DD
Senior Member
Joined: Jan 2017
Posts: 282
Likes: 95
From: Kerkrade, South Limburg, The Netherlands
That's what I also thought, Doug. Thanks for the info...
Will be keeping this in mind when flushing the system soon.
The radiator will be taken out and cleaned in- and externally. Some goes for the steering oil cooler and the transmission oil cooler.
Engine oil was the first thing I replaced. It is now temporally running with 15W40 Diesel Engine oil, for the remainder of the rebuild. After that, I'll be switching to Castrol 15W50. Tranny oil and filter are next, then gear oil in the rear diff.
She has a huge crack in the distributer cap at the moment. Can't image she still runs, be she does....new cap has already been ordered...spark plugs are there as well, just need to find the time to swap them out...
Will be keeping this in mind when flushing the system soon.
The radiator will be taken out and cleaned in- and externally. Some goes for the steering oil cooler and the transmission oil cooler.
Engine oil was the first thing I replaced. It is now temporally running with 15W40 Diesel Engine oil, for the remainder of the rebuild. After that, I'll be switching to Castrol 15W50. Tranny oil and filter are next, then gear oil in the rear diff.
She has a huge crack in the distributer cap at the moment. Can't image she still runs, be she does....new cap has already been ordered...spark plugs are there as well, just need to find the time to swap them out...