Alcohol and our V12’s.

Reply Subscribe

Thread Tools

Search this Thread

Dec 7, 2021 | 11:25 AM

#41

Mguar

Thread Starter

Veteran Member

Joined: Aug 2019

Posts: 1,240

Likes: 426

Quote:

Originally Posted by JayJagJay

Cool and,,,.
Yeah, the weather has been nice.... strangely nice
Please do!

Ok. So, just because all of what I have heard (but don't completely understand) a out ethanol, to the best of my ability I have avoided it.

I have a 30+ yo car. I have replaced some, not all, of the soft fuel lines in the car. Are folks saying that for rubber old school non barricade hose, today's ethanol ladened gas will weaken and eventually melt the older lines? And, if so, what to do? Some of my lines in the trunk, the more factory-ish ones right off the tank say, what are THEY made of?

Also,,,, This past Friday I got on the highway at 10.30pm. For us here in NYC finding nice looooong stretches of road, ANYWHERE, is not easy. BUT, as soon as one enters into 278 and the BQE at that time of night chances for ya are GOOD to have some open road...

Anyways, when I got on I did what I never do. I FLOORED it... She stayed in second for longer than I was comfortable with, over 4 - 4.5k rpms... When she shifted, I swear the car JUMPED oft the road accelerating (I pooped a lil) and then, there was a whole NEW spirit. Little puff of smoke out of the back, both sides, and THEN it was time for MORE fun. A dude in an Infinity noticed this and pick it up. He shifted lanes and came up my left hand side... I leaned into it a little more with nearly the entire length of the Verrazano bridge ahead. I KNOW I surprised him! We stayed right together up thru 85 90 where ol cherry pie started WINNING, lol. I'll be damned. I let off. Satisfied, pleased and completely surprised...

Brothers!!! Y'all have never lied to me about this ol car!!!!

Now what, 😂 ?
Drag strips?

Well the car was never designed for drag racing but it’s kinda fun to go on a test and tune night. You don’t have to abuse your car but running it up to high RPM will never hurt it.
No special gear or preparations required. It’s not fast enough to require rollbar etc.
You might also take it to SCCA Track nights. All that is required is a helmet and often they will rent you one. It’s not wheel to wheel racing. Just high speed driving on a race track. You go as fast as you feel comfortable. One at a time. As long as the car isn’t worn out or have bad tires you can enjoy yourself without risk of a ticket.
Fill your tank up, because it’s addicting fun. Everybody goes the same direction, no drunks or kids playing. Nobody is texting or distracted. They will go over how to do it safely and then you can go out by yourself or get one of the instructors to teach you how to go faster safely.
Go to a Vintage race for the noontime “parade”. Basically you drive around the track somewhat briskly but it’s really really not racing. You get to see the track from a drivers perspective.
( and you might see me getting my Jag ready to go racing. Vintage racing is real racing with one absolute rule. No Contact.!!!! My car will be a tribute to Group 44 and it will be on track for about $7000. Making close to 600 hp and providing me with a lot of grins. So much so my face hurts for a couple of days after.

Dec 8, 2021 | 12:05 PM

#42

icsamerica

Veteran Member

Joined: Apr 2012

Posts: 2,291

Likes: 1,466

From: New York City

Quote:

Originally Posted by JayJagJay

... When she shifted, I swear the car JUMPED oft the road accelerating (I pooped a lil) and then, there was a whole NEW spirit. Little puff of smoke out of the back, both sides, and THEN it was time for MORE fun. A dude in an Infinity noticed this and pick it up. He shifted lanes and came up my left hand side... I leaned into it a little more with nearly the entire length of the Verrazano bridge ahead. I KNOW I surprised him! We stayed right together up thru 85 90 where ol cherry pie started WINNING, lol. I'll be damned. I let off. Satisfied, pleased and completely surprised...

Brothers!!! Y'all have never lied to me about this ol car!!!!

Now what, 😂 ?
Drag strips?

"Jumped off the road"... Sounds like you need trailing arm bushes. That's what the XJS does on abrupt shifts when the cage can move around. In any case save that nonsense for the Porsche. Carrying on like that in a convertible is certain death if something goes awry.

Last edited by icsamerica; Dec 8, 2021 at 01:07 PM.

Dec 8, 2021 | 01:07 PM

#43

JayJagJay

Veteran Member

Joined: Sep 2016

Posts: 4,277

Likes: 1,314

From: New York New York

Quote:

Originally Posted by icsamerica

"Jumped off the road"... Sound like you need trailing arm bushes. Thats what the XJS does on abrupt shifts when the cage can move around. In any case save that nonsense for the Porsche. Carrying on like that in a convertible is certain death if something goes awry.

Lol... Easy man! Let a brother - fish story,,,
The arm bushes are new-ish. Jus like me

Dec 15, 2021 | 03:29 AM

#44

Mguar

Thread Starter

Veteran Member

Joined: Aug 2019

Posts: 1,240

Likes: 426

Quote:

Originally Posted by Greg in France

JJJ
An "oversquare" short stroke engine is one where the diameter of the cyclinder (90mm on the 5.3 HE) is bigger than the length the piston travels up and down the cylinder (70mm taking ICSA's word for it).
The original XK 6 cylinder Jaguar engine is a long stroke engine, that is the length the piston travels up and down the cylinder is longer than the cylinder diameter.

Now, for a given number of revolutions per minute for two engines of the same capacity, the distance a long stroke engine piston will travel in one minute (cumulatively up and down the cylinder all strokes added togther) MUST be longer than the distance an oversquare engine piston will travel.
Therefore, taking Mgar's point that an oversquare engine's piston travels a shorter distance than an identically sized undersquare piston would, it MUST logically follow that the oversquare piston is travelling more slowly.
But, and here I depart from Mgar's point to a degree, I do not believe the difference is significant as far as the engine getting gummed up is concerned. The mean piston speed of a V12 engine at (say) 2500 rpm is pretty high - although I am too lazy to calculate it for you. Sadly, in this day and age, the fact is that very very few owners give their cars and thus their engines a decent caning. Partly because they feel the engine is fragile (whereas actually it is bulletproof) and partly because speed restrictions make this hard to do. This, I believe, is the reason, if they do, that V12s get gummed up and need the famous Italian tuneup!
I feel certain that the XK engine, or any engine, babied in the same way that V12s are, would gum up just as much.

We absolutely agree on the need for regular brisk acceleration (canning in your words, Italian tune up in mine) on the XJS v12. That will indeed prevent carbon build up. At least on the piston rings. Deposits on the back sides of intake valves is more dependent on how often they are driven a short distance before shut down.
As many Jaguar engines as I’ve been into over the past 40-50 years I will respectfully disagree with regard the old Iron Block six with a 4.17 stroke. It was not unusual to have significant piston ridge after only 50-60,000 miles. Indicating wear, caused by high piston speed. Nor was carbon build up of the rings ever a problem.
However in the 50+ V12’s I’ve been into I have yet to see visible wear ( piston ridge) even with 100,000 + miles on them. We are all aware ( or should be) of that problem on our V12’s. Rarely was an engine carbon free on all 12 cylinders.
Finally, I too am too lazy to do the math required to document piston speed at various Engine speeds. However realize that a piston goes from a dead stop to a dead stop at the stop and bottom of the stroke. And accelerates to peak speed somewhere after mid stroke. During the power stroke. The rings are exposed to both flame, unburnt fuel and oil. For a given engine revolution the long stroke piston has to go dramatically faster than a short stroke engine. At peak RPM (5500 with a 4.17 stroke) the piston is approaching 3100 ft per sec. While the 2.75 stroke piston speed is approximately 1450 feet per sec.

Dec 15, 2021 | 03:46 AM

#45

Mguar

Thread Starter

Veteran Member

Joined: Aug 2019

Posts: 1,240

Likes: 426

Quote:

Originally Posted by icsamerica

Each cylinder of the 5.3 v12 has a piston stroke of 70 mm. Which is about two and three quarter inches. That's kind of short but it's not Ferrari short. 60mm or so. No one should get too excited about running ethanol in an XJS. The lack of any ethanol compatible rubber, steel line and tanks all makes running ethanol a bit of a Gamble without upgrading everything. Furthermore all fuels are extremely clean these days and most include some detergents. Deposits come from oil burning which is independent of fuel. Ethanol also does not have the same specific energy density as a gasoline therefore you would need to reprogram the fuel system to deliver more fuel. On modern cars that are known as flex-fuel there's a sensor that reads ethanol content and runs a modified fuel map. The only Fuel That should be used in an XJS is what it was designed for... Regular old gasoline. Sure a tiny amount of ethanol mixed with gasoline probably won't do much harm but running significant amount of alcohol is foolish without major accommodations.

The fuel of today is different than the fuel of 40 years ago. Please do a little experiment. Take a small amount of your favorite brand of petrol. Put it in a heavy glass bowl and light if. After it burns off completely ( and the glass cools back down) hold it up to the sunlight and notice the deposits from just one burning. Imagine the deposits from all the gallons of petrol your car has used in its lifetime.
Now clean that same bowl up and fill it with alcohol now lite that off. Caution; the flame is invisible in daylight. Once cooled off, Notice the difference?