Are camshafts interchangeable?


(HOLDEN) #1

I have tried to research this but have found conflicting answers. I have a 1986 XJ Series 3 Engine that I am putting in my project. The cams have the same numbers on them, P31818A and LYD 4. I might add that I have had them reground. One cam has a threaded female end, which I was planning on using for a rev counter. It looks as if this would fit better on exhaust side as the rev counter’s seal and make up seem to fit better with the relief that is on that side of the head. The other Cam has no threads and no plug, which leads me to the question, does it need a plug? I have had this motor together but had problems getting it running well. So I took the head off and am starting over. I am learning on the go. I am wondering if the cams were in the wrong position before I took the head off?

I appreciate any feedback.
Thank you in Advance!
Holden
holdenwallace@hotmail.com


(Rob Reilly) #2

I can’t imagine the engine running at all with the intake and exhaust cams switched. Unless you ignored the normal cam timing procedure and set the timing by some other unknown method.
Look for C.xxxxx part numbers stamped on them in very tiny numbers, which are the actual Jaguar part numbers.
Do you have a service manual?
What is the engine serial number stamped on the bell housing flange?



(Paul M. Novak) #3

Holden,
Jaguar XK engine intake and exhaust side cam shafts are not interchangeable. If you put an intake camshaft on the exhaust side and the exhaust cam shaft on the intake side and rotate the engine you will bend some valves.

The casting numbers cast into the cam shafts may be the same, but the part numbers of the intake and exhaust cam shafts are different because their shapes are different. Some of the cam shafts have their part number stamped in the face of tge sprocket end.

Working on an XK engine cylinder head can be complicated and should be done using a proper shop manual. These manuals are available used on eBay for less than the price of a replacement valve.

Paul


(HOLDEN) #4

I will find out the engine number and look more closely for the numbers again. The service manual I have been looking at only talks about valve clearance and how to install them with the proper tool. I have other manuals and will look at them as well. It is always possible that with my ADD brain, I over looked that important part of the equation!

Thanks


(Paul M. Novak) #5

Holden,
If you are wondering where to find the engine serial number on your Series III XJ6 4.2L engine, it is located at the left rear of the engine where the block meets the transmission bell mouth. The serial number of one of my engines is circled in red in the attached picture.

Paul


(Ian) #6

You do need a plug at the end , or all the oil will come out the hole at the end of the cam shaft , I fittead a tacho drive on the rear of a XJ6 engine , when fitted to my MK2


(HOLDEN) #7

Paul,
I cannot thank you enough for your pictures and suggestions. I did find all the appropriate number, I think!
Engine number is 8L 115271-S as well as another number next to it, AH-904.

The Camshaft numbers were on the flange end. they are C37582 and C37583. Would you be able to tell me which one is Intake and which one is exhaust?

And the info on your the camshaft end clear that up, I think!

Holden


(Paul M. Novak) #8

Holden,
The intake cam shaft is C37583 and the exhaust cam shaft is C37582.

Paul


(HOLDEN) #9

Thank you! I got it all shimmed up now and feel more confident that I can’t screw that part of it up. My intake cam already had threads to accept the rev counter. I see you have some sort of oil slinger on it as well and I am guessing no plug behind that drive.

So on the other cam, I plan on putting a plug and no slinger or anything else.

Thanks again!
Holden


(Ian) #10

I guess your talking about my pictures Holden ?
The bolt is the plug !
On the older XK cams , they both have a oil thrower , on the later heads they are not fitted , not sure what they do , as I had it , it went on .
I was going to change the cam shafts over first , but found out the XJ6 cams have a diffrent profile for quieter running !


(HOLDEN) #11

I Appreciate the great pictures. I hope I can get my engine running well this time. I am bull headed and will continue tripping but I am learning by my mistakes!
Thank you
Holden


(HOLDEN) #12

Paul,
Another question if you don’t mind. I am installing the oil pump pickup tube and delivery tube. I put in the appropriate seals, (I think). There are four seals that came with Lower Gasket kit. one smaller thicker seal, one smaller thinner black seal, one larger green seal and one thinner black seal. when I insert the pickup and delivery pipes there is still some play and the pipes can fairly easily move. I am concerned air will leak through these and prevent the circulation of oil. Is this normal? It seems the seals should be just a hair bit thicker?
Thanks
Holden


(HOLDEN) #13

Ian,
Another question if you don’t mind. I am installing the oil pump pickup tube and delivery tube. I put in the appropriate seals, (I think). There are four seals that came with Lower Gasket kit. one smaller thicker seal, one smaller thinner black seal, one larger green seal and one thinner black seal. when I insert the pickup and delivery pipes there is still some play and the pipes can fairly easily move. I am concerned air will leak through these and prevent the circulation of oil. Is this normal? It seems the seals should be just a hair bit thicker?
Thanks
Holden


(Paul M. Novak) #14

Holden,
Sorry but I can’t answer your question because I have not done that work. Others will have to help.

Paul