LT1 cranks fires, then smokes and quits

(Carl Hutchins, Jr. ) #1

Yesterday began well. One project finished and works better than expected. Rustic post topped by a little solar powered lamp!

I had the Jaguar out of the shop and in the drive to make working room in my shop garage.

When the morning work as done and I ready to go in a fix lunch. Twisted the key in the car. It fired instantly. It ran for about 1/2 minute or less. Not even time for me to shift from Park to Drive. Then shut down and a brownish cloud of smoke came from behind or under. It quit running.

I tried a couple of times to refire. It cranked with energy. But no start.

Not having energy, I left it to another day. today, much later perhaps a cursory look…

Fuel ?



(Carl Hutchins, Jr. ) #2

Oh the mysteries of life !

Late yesterday morning, I drove the Jeep to market. On the way home the radio was on a sports news station, Then it went silent !!! The time of day appeared on screen. I messed with it just a bit, trying not to divert to much attention from where I was going. .Upped the volumn. Music, Marty Robbins!! A tape had kicked in…

Stashed the groceries and began project two. Another rustic drive marker with solar lamp atop.

Cranked the Jaguar, still in the drive. Cranked nicely, but no fire. Looked under the hood/bonnet. Only one thing astray. The air cleaner element off the pipe. Backfired, for sure…

Son dropped by. Decided I could use a fresh belt on my sander and carve that way to get the 3/4" I needed. “Tom, I have belts”. Well, these are coarser, use 'em…

I mentioned the Jaguar’s illness. He an accomplished master in making things and making them run. A couple of efforts and it started!!! repeated !!! Drove it into my shop as I was done for the day.

Two guesses:

  1. Jumped timing chain.
  2. An oddity not likely to reoccur.

He put the air cleaner back on and on is well, so we hope…

Oh I am invited to a traditional thanksgiving diner at their house… Yum.


(Roger Mabry) #3

After owning LT1/700R S1 Jag…my first guess would be Optispark starting to fail…was most horrible thing GM ever did to the SBC.

(Carl Hutchins, Jr. ) #4

Thanks, Roger.

That was amongst the “guesses” by my son. should have mentioned that.

I knew of that weakness at the time of the install, circa 2001. I installed a new genuine unit at the time. Not easy as the Lt1 was in the chassis.

So, it is aged in time, but young in miles !!

Am I up to the install f another? Probably not,
I just turned 89.

Will I ask my son to do so. same answer.


(Roger Mabry) #5


It is a PITA…use a genuine unit if you do. Had to replace mine four times before getting a good one…still working for new owner.

Roger Mabry

Cell 626 806-1755

(Carl Hutchins, Jr. ) #6


The one I installed at the time I installed the LT1 was a new genuine unit.

How long did the ones you had issues with last? Were those genuine?

What were the symptoms?

How did you decide they were Oprilite failures?

And, were the failed ones the genuine or after market.

I think my son has a source for both.

But, I am not going to ask him to install another.
He has enough on his plate.

Will I tackle it. More than likely not.

So, the future is cloudy at best…

Thanks for the advice…


(Roger Mabry) #7


I attached the document that tells very clearly how to test the unit. I bought a Dynaspark or supposedly improved version… it failed three times… I have it on my Wall of Shame. Be sure to test the short section of the harness as mine failed once during the ownership.

I had a Meziere water pump and that made changing much easier. After doing it several times I could change it out and have it running in a hour.

Roger Mabry


(Attachment Opti testing.docx is missing)

(Roger Mabry) #8


Send me your email address directly to mine. I tried the one I had but it was rejected.

Too bad you live so far away or I would come by and help…


(Roger Mabry) #9


Send me your correct email address… I sent two documents to the one I had and they were rejected.

Roger Mabry


(Carl Hutchins, Jr. ) #10

For the record.

Attachments received PM. printed out perfect with the use of my Libre Office program.

Unfortunately, not on J-L for the benefit of others.

And, whee, the LT1, has fired up two days ion a row sans incident…

A fluke??

For the record, when the air is better, I’m going to do a harness test and the coil harness included. Just good jaguar mantra…

Thanks, Roger…


(Carl Hutchins, Jr. ) #11


All checks well as t the harness connections. Skipped the Optispark test. Spark is good.

No repeat of the “episode”. Starts and runs fine.

Son has a theory. The LT1 has a sturdy double row timing chain., They do wear and a blip might cause a mistime for just an instant. but, unlike the cheaper single rows, not likely to jump a tooth and remain out of time.

The “real” mileage of the LT1 is not known.

As to why it did not start up at the time, but did later. A sensor detected the oddity and tie allowed thing to return. Suspect. The knock sensor did it’s job. And the PCM responded, but with time, reset itself… “artificial intelligence”.

So, will we swap in a new chain. Not likely. Just drive it. Keep my cell handy and road service paid.

Good archive food.


(Carl Hutchins, Jr. ) #12


The Jaguar is still fine, no repeat of it’s "hissy fit’.
A timing chain episode seem most likely.

(phillip keeter) #13

Merry Christmas Carl,

(Carl Hutchins, Jr. ) #14

Status of the lump.

Almost a month into 2019. all seems good.

Did errands in the Jaguar yesterday. Nice weather. odd, one would think that a rainy day would be best for a car built in a country where those are prevalent !!

Purred as need and moved on out with alacrity as needed…

Carl .

(phillip keeter) #15

I could use some of that.