Hi all,

Well, I picked up an EBay deal and the car arrived with the engine seized up tight. They told me it was running fine when the parked it but it's been sitting a while. sure...Sure...lol

Anyway, the car is a 99 and I'm expecting the rings are rusted in the bore or something equally awful.

My question is one about a replacement block. Are there any differences between the 4.0's in the different platforms? Is the block in XJ the same as in the S type or XK.

I believe I'm looking for a block manufactured after August of 2000 but if I have that wrong please correct me.

Thanks in advance....

 

BW-
The first thing you need to determine is if the engine is a AJ26 or AJ27. If you have a MY 99 XJ8, it should be an AJ27. If it is an XJR (SC) it should still be an AJ26 in MY99. You can swap parts but it is not trivial to swap engine series. The AJ 27 NA was used from MY 99 thru MY02. The ones after MY00 are steel linings rather than Nikasil, but it is subject to argument whether steel or Nikasil is better at this point. It would help if you put the car model in your signature.
As to the other platforms, I do not know. I suspect there are some differences, but no doubt someone else will chime in.

 

If you have it in writing in an email then Ebay will make the seller refund your money because it was not as advertised.

 

Thanks, I'll edit my signature this evening.

I believe it's an AJ27 as it's the normally aspirated XJ8.

I do have it writing...twice...but I suspect EBay will be useless. We'll see...chuckle.

I like the car...I had a 95 XJ6 and loved it....and would like to get this one rolling again. But if that's not possible, I should be able to at least break even parting it out...

Thanks for the responses......

Take care,

 

Here are some of the infomation from forum thread about using throttle body to identify A26 and A27 engines - both NA and SC types -

https://www.jaguarforums.com/forum/x...er-help-72032/

S/C cars were AJ26 ones up to 11/1999 VIN 878717, but N/As were AJ27 already from late 1998 VIN: 853936

You will also notice two distinct fetaures that designate the engine type.
The AJ26 engines use a TB with a large round black vacuum actuator for the cruise control and the VVT units on 4.0 litre NA cars stick out the front of the timing cover.
3.2 and super charged engines do not have VVT operation.

AJ27 engines use a throttle body that does not have the black vacuum actuator as the later cruise control is fully electronic.
Also, the VVT units have their operating solenoids sticking vertically from the cam covers.

These features are the quickest visual identification of the two engine types.

Jim Lombardi

 

Also worth mentioning, if you paid via credit card, your credit card company WILL get the money back if it is not as advertised, and they are much more reliable than Ebay.

 

Well, Ebay was a fail so it's down to what the CC company will do. Either way it isn't a big deal.

So, after checking pictures and number and descriptions, it is an AJ27 engine. I haven't found anything informative on the differences between AJ26 and AJ27 blocks. Are they interchangeable? I would swap over the heads, intake, etc, etc if I go that route....

Been perusing this site for a while now..lots of great information I wish I would have had when I restored that '78 XJ12L. Lots of fun but I probabkly spent more than I could have with htis sort of information available...

Take care,

 

I've done the swap, as have a few others (Moscow leaper etc.) If you can build a top end on an engine you can do it. It's also a great opportunity to have a "fresh" engine.

Is it LOCKED up or locked up? As in, can you turn it by hand either direction? Is it possible that the piston is interfering with a valve? Maybe the engine is salvageable.

 

I bought an XJR that was "overheated I think by my wife on the freeway" that was CLEARLY locked up at a high rate of speed judging by the hole created when the broken connecting rod lodged itself halfway through the block. I made a profit on the part out though.

 

..And to answer your direct questions (I would swap in a used engine if the rest of the car is good FYI)

Any S, XK8 or XJ8 motor will work- You will have to swap out the bed plate, FLEX PLATE, heads and other assorted parts covered in other posts if you use the S-type or an earlier engine (AJ26). Look for a about a day to rebuild and a day to install moving at a shade-tree pace.

 

Thanks for the reply. I think the engine is more LOCKED up than just locked up. I put an 18" breaker bar on the crank bolt and couldn't budge it a fraction of a gnat's eyelash. I pulled the plugs and squirted in some PB Blaster, hoping to breakdown any ring rust...it that's even possible with a nickel plated bore.

The oil, plugs and coolant all look pretty normal. I think it may have just routed sitting still.

I plan to pull the heads and see if ther es a dropped valve or something. If it's just stuck pistons I'll rebuild what I have..assuming the bores are good. If the bores are shot I'll try to find a good block...for a reasonable price, of course. I've thought about getting the block sleeved but that's a last resort.

I've probably rebuilt a dozen various engines over the years so I'm thing I have the required skills to fix this one. we'll see, of course. The Jag V12 was probably the most time consuming...just getting parts.

Thanks for your help!

 

Ok- looks like you are good to go- let us know what you find when you pull the heads and chime in with any questions!

 

I would pour some atf in the spark plug holes, let it sit for a couple days and then try the breaker bar. I'm betting that will free it up.

 

Hi Bruce
My older son has been restoring a 1957 Chevy Belair Hardtop convertible for the last 10 years. The chevy V8 has had the seized engine issue at last 3 times over the years.
He has always been able to unseize it using Marvel Mystery Oil. Sometimes at least 3 times of spraying it into the spark plug holes and took a couple of weeks to free it up.

Then he was able to use a breaker bar on the crankshaft bolt to turn it over as a first step to getting to run again.

Since you have no knowledge of the engine repair/maintenance history, you probably also will have to at least get a look at the timing chain tensioners to make sure your timing has not jumped over more than 2 positions on the spockets and bent any of the valves or damaged other parts of the engine.

Jim Lombardi

 

I am guessing removal of the cam covers and a flashlight in the spark plug holes will reveal alot....

 

Thanks for all the suggestions. I've already put PB blaster into the spark plug holes so adding something else is certainly OK.

interesting note. about 35 years ago I analyzed Marvel Mystery oil in an organic chem lab I was taking at the time. The analysis indicated that it was very similar to ATF. Wolfs Head AtF to be exact. since then I've used ATF to clean top ends by introducing into the intake tract, to free sticking lifters by soaking them in it for an hour or and cleaning carbon off old pistons. ATF works great and I'll try it in this engine as well. What do I have to lose?

Even if this engine would have started and run I was planning to do timing chains and tensioners after reading the forums. I was, I admit, going to use the Ford parts..at least for the tensioners.

I'll update with what I find and will include pictures if I find something weird.

Take care,

 

Have no fear of the "Ford" parts. A careful examination of the Ford die castings show the exact casting as the Jag tensioners. The only thing different is the box they come in.