Hey guys, I am putting a 6.0 out of a 94 XJ12 back together. I am rebuilding the engine, with crank, pistons, rings, bearings now assembled. I was going to put the sandwich plate, oil pan, etc back on the engine when it occurred to me that it may need those parts off of my 5.3 in my 89 XJS. Can anybody educate me?

 

You will not need any bottom end parts from the 5.3.
Sump design is very slightly different between the two but the sedan 6 litre design will actually give better access in the steering rack area. I assume both original and donor are full flow oil cooling.

 

Thanks!! When my 5.3 dropped a valve seat, I parked it. It has been sitting for about a year and a half, knowing it will need lots of work beyond engine work when I get it going again. I don't know when full flow came into place. I haven't removed the engine, but I presume it is?
My biggest concern was the sump fitting as it should. I had bought another 5.3 to build from David at EverydayXJ of unknown origin. That engine has a place for a oil line of some sort on the sandwich plate, whereas the 6.0 doesn't. Not sure about my 5.3 as I haven't looked under it.
Either way, I want to use full flow. I'm not overly concerned with things fitting exactly as original as I am adding a Whipple supercharger and 5 speed while I'm at it, so I know I am going to be re-routing things to fit as needed.

 

If the return line from the oil cooler goes to the front RHS bottom of the sandwich plate, the engine is a bypass flow engine. These engines also have only ONE steel pipe leading from the oil filter casting to the oil cooler.
The full flow engines have TWO steel pipes coming out of the filter casting, one going to and one back from the oil cooler, and nothing entering the sandwich plate in the RHS front bottom.


The sandwich plate design was introduced to the XJS to enable the engine to sit low enough in the XJS body, the plate enabled the engine to be lowered and the sump was pushed rearwards to clear the subframe. On some other V12 cars the sump is bigger than on the XJS version. Your only fitting problem from this point of view is whether the donor engine already has a sump layout that will clear the subframe or not. If not, just install the old V12s sandwich plate and sump, you can still use the full flow engine's everything else unchanged and just block the sandwich plate oil entry hole with a blanking plate and gasket.
Warning to converters of a bypass engine to full flow: As well as blocking off the sandwich plate entry hole and fitting the full flow oil filter casting and twin pipes to the oil cooler, you also need to block off the oil entry port in the oil pump casting directly above this hole into which the oil cooler cooled-oil used to go. The internal oil pump piece was different on the FF engine to eliminate this extra entry port. This is a relatively easy thing to do, as the piece that fits into the sandwich plate hole can be unbolted and just needs blocking up and replacing.
Greg

 

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thanks GREG, very good information, my oil cooler system is 1978 partial flow, so far been OK, but you never know what may happen!
i have a seprate trans cooler not connected to the radiator!

 

i have never done a 5.3 to 6.0L conversion, but if i have to i will do what has got me thru 65 yrs of car modifying!
use commonsense and logic.

and good luck on your project.
back when i was doing my restore, there where no 6.0L around, and found one they wanted $10K for it, had 3K miles on it.

 

Ron
Like you I have a bypass flow engine. I have an oil temp gauge coming for my birthday, and I have bought a sump plug that will take the sender in an extra holes in its centre. When the summer comes I am going to place some max temp-showing strips on the cooler exit pipe and the cam covers, and on a hot day do a long run, with hot stops, and record the sump temps at set intervals and note the max strip temps.
I have in stock all the bits to convert to full flow. If after my test the oil temps are OK, I shall not fit the FF system. If they are higher than I like I shall fit the FF system and exactly repeat the test and see what the differences are, if any. It is about time we had some decent data!
Greg

 

I live in Hot Florida...
my other British cars all had full flow... I would have thought it would have been a better design for a 10,5 quart engine oil car for the bypass flow to go to a coolant/oil heat exchanger than an oil cooler and that full flow with a thermostat bypass for when the oil is too cold...

hey just a winter day waiting for the oil to warm up so I can get into the REVs

v12 sales offers headers... but you have to do a oil filter relocation to use them... they supply that too I think in the kit...
so why not just plum the old bypass cooler straight to the sump (not using the OEM cooling unit) and replacing the OEM with the full Flow cooler piped from the relocated oil filter......

just going crazy...

and those crazies who would like faster oil warm up a heat exchanger on the bypass...

 

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some good ideas, food for thought if it becomes nessasary!