I continued the cleanup of the 1987 XJ6 4.2L donor engine that I am transplating into my 1984 XJ6 Vanden Plas and I removed the core plugs to inspect the base of the head studs and clean out the debris deposited at the base of the studs inside the water jacket. Attached are some pictures of what I found after I removed the core plugs and then after I removed the debris. The studs appear in pretty good condition and I suspect that removing the debris may help even out the cooling the engine and perhaps extend the longevity of the studs. I have r
You should take the plate at the back of the block off too. You’re likely to find more goop behind it. It will cost you a new gasket on reassembly but is a much easier job with the engine out of the car.
Regards,
I have absolutely no interest in finding out!
What exactly is that sludge - casting sand, silica, rust, oxide,…? The studs are pretty though. The plate would hide most of the debris - it should be at the lowest point…?
The XK engine is well known for bad water circulation , that’s why they added 2 extra water ways on the later engines ,as you now know it did not help much , I have replaced my drain tap with a straight pipe connector and added a electric water pump , to help circulation !
I just turn it on , once or twice on a run for 10 mins or so !
I removed that blanking plate from the rear of the block, as well as the water pump, and used a garden hose several days ago to spray water at a high pressure through all the water jacket openings to clean out as much of the debris as I could. I had one of those blanking plate gaskets, as well as some water pump gaskets, in my “big box of miscellaneous Jaguar gaskets” that I acquired over the past 18 years, so I didn’t even need to order them.
I plan to install the blanking plate, water pump, and core plugs today as I continue to build up the engine for installation in my 1984 XJ6 Vanden Plas.
David,
The debris is all of that and possibly some of the Bar’s Stop Leak that Jaguar dealerships added during routine cooling system service as well as calcium from tap water use. The accumulation of denris is at the lowest point inside the water jacket.
With the engine out of the car and on my engine test stand it is relatively easy to remove things to clean out the debris. I have done this water jacket cleanup before on an engine outside the car and also on an engine still mounted in the car when I had the cylinder head off. With the engine inside the car I did not go as far as remove the blanking plate or water pump.
I knew what I would find behind the core plugs from past experience, so I could not with a clear conscience leave the debris in place especially with everything so easy to access and spare gaskets on hand. I also waneed to check the condition of the head studs to make sure they looked OK before installing this engine. I did have to get a few more core plugs from one of the usual suppliers since I didn’t have enough on hand for the job.
Paul,
I highly recommend removing the core plugs if you have an engine removed for a transplant. In addition to clearing out the water jacket debris you get a good look at the base of the head studs. I have found badly corroded core plugs and badly corroded head studs in the past that might have failed unexpectedly on me had I not inspected and changed them out. The corroded head studs looked like a beaver had been in there and chewed all around the circumference of the stud leaving very little metal remaining. There have been head stud failures reported on Jag-Lovers where the stud failed while the car was being driven and the dome nut with part of the stud still attached went straight up due to coolant system pressure and damaged the hood.
Tony,
I don’t know how effective doing what you suggested would be. The debris behind the core plugs at the bottom of the water jacket around the head studs can be scraped out or blasted out with a hose aimed directly at it. I don’t know how much of it you will remove from the blanking plate or just the front core plugs removed.
I got a lot of debris out with an engine still in the car years ago, but that was with the manifolds, cylinder head, and core plugs removed.
In my opinion the best way to clean out that debris is with the engine out of the car and the core plugs removed, like I just did on this engine. But that is not practical most of the time.
I suspect that the debris in the water jacket results in some localized heating and overall reduction of cooling system efficiency in addition to corrosion of the head studs. The bigger cooling problem is more likely when there is blockage inside the radiator tubes.
Others will have to chime in about engine flush products and techniques. I am just trying to do all the right things during this engine swap to extend the performane and life of the engine and cooling efficiency of this car.
BTW, I took the radiator into a local radiator shop and it was seriously blocked. I had it recored and it is ready to install. I am hoping that when I am done I will have nicely running engine in my 1984 XJ6 Vanden Plas that operates well in high ambient temperatures like my 1987 XJ6 Vanden Plas did, even with the air conditioning on, after I completed much the same work on it last year.
Yep, a lot of crud from running tap water without rust inhibiting anti-freeze.
Could even be sand from the molding cores that was not fully cleaned out at the foundry.
Not an XK, but here is what I found behind the core plugs in my Mark V head.
These wires were to hold the sand cores together before the iron was poured into the mold at Midland Motor Cylinder Co. They either forgot or didn’t bother to pull them out afterwards.
