Those cams are not in the right position. Suggest you check your cam timing.
Hi JayâŚyou need to have a look at how you are trying to find TDCâŚdont use cylinders 2 & 3 to find TDC on 6 âŚhave a look here https://youtu.be/VHH36crKwkQ just concentrate with no6 piston⌠mark on the crank pulley when on compression stroke the no6 piston comes up and stopsâŚthen continue to turn the engine, it will move a few degrees befor no6 starts to move downâŚat this exact spot mark again on the pulleyâŚyour TDC is the point inbetween these 2 marks⌠Steve
Those cams are WAY more than 6 degrees out of position: DO NOT rotate the engine until they are correct, WRT to TDC.
Far to lateâŚhe,s been trying to start the car for a few days
Hereâs a pretty foolproof way to find TDC. From Dick Mauryâs web site.
YepâŚi knowâŚ
I used Dick Mauryâs method last night which is how I got the new readings for TDC#6.
=> Once there, using a depth micrometer or a screwdriver with your fingers, check the height of the #2 and #3 cylinders. As one is going down and the other is rising when the front cylinder is at TDC, this will help get the timing right on the money.
In the following thread Dick goes into a little more detail:
=> Actually it is #2 & 3 or 4 & 5 cylinders as the pistons are going
in oposite directions when #1 or 6 are at TDC. # 3 & 4 go up and
down together. As there is some arc at the TDC mark, a dial
indicator on #1 or 6 will only get it within a few degrees of TDC.
When the other cylinders mentioned are at the same height, then you
are exactly at TDC. It is amazing how sensitive this is and allows
a really good setting. In fact, when a car is in for a tune up, I
check to make sure the timing mark is centered using a screwdriver
and my finger. As the timing marks are adjustable, it should not be
surprising that a lot are off. Most anything adjustable gets
adjusted whether right or wrong
Jay
Theyâre supposed to be evenly positioned as mirror images of each other about the long axis of the block as ârabbitâs earsâ from memory, on our XJ6? Paul
Yep: slots lined up with the â1â in the casting number.
Secret: I only ever used the setting tool once.
If I may be permitted to offer inexpert advice what you should do now, Jay, is remove the cams, accurately set #6 to TDC in compression and only then zero the pointer, though you may not need to. If you do this you will establish TDC as a benchmark and, as Wigs says, wonât have to find TDC again.
Your shimming looks good so you may not need to fiddle with it. Remount and set the cams using the gauge, chain very snug but not dead tight, replace covers and then do your compression test. If you have any bent valves youâll show localised low to zero compression. If youâve got good compression in all six youâre golden, otherwise will be learning new stuff when you pull the head. If no damage your engine should start right up.
It is what it is. Wishing you the best.
Edit: since youâve already removed and replaced the cams this is likely unnecessary but do take care to gradually even the load in the process to keep from snapping one.
Far be it from me to question a method recommended by Dick Maury but I think there is an issue, particularly with 4.2s⌠The method of finding TDC on #1 & #6 using equal length âprobesâ into cylinders #2&3 (or #4&5) will only be completely accurate if the center of the spark plug holes for #2&3 are directly above the same point on the dome of the corresponding pistons (it doesnât have to be the top of the dome, but it does need to be the same distance from the top). Maybe this is true for the 3.8âs - I donât know. However, on the 4.2s the cylinder bores were moved while the hemispherical chambers in the head remained in the same positions as for the 3.8s. As a result, the bores arenât concentric with the head chambers on all cylinders - I think only #2 and #5 are concentric. So I would expect that some error would be introduced into this method of finding TDC. Whether the error is too small to worry about, I donât know.
Personally, I just put a bambo stick into the plug hole of #1 and place a ruler perpendicular to it resting of the tops of the cam covers. With #1 as close to TDC as I can make it by eye, I then put a band of painters tape around the bambo so the lower edge of the tape is about 1/32" above the point where it intersects the top surface of the ruler. I then nudge the engine around until the tape is edge is precisely on the edge of the ruler and record the position of the damper. Nudge the engine in the other direction (through the guessed TDC point) until the tape edge is once more precisely on the edge of the ruler. Note the position of the damper. TDC will be halfway between these two positions. I repeat the test several times to verify repeatability. I only use this to verify TDC for ignition timing, so itâs accurate enough for that purpose. I think I can get within 1-2 degrees this way. When setting valve timing, you may need something better. As has already been commented, those camshafts look a long way off if the engine was really at TDC. My fingers are crossed for youâŚ
-David
Dick,s artical for setting TDC is for anyone that has the head offâŚit says so on the first sentance.
I think you have instilled enough doubt in me about using piston 2/3 to find TDC on the 4.2 engine. Its probably close but want to be sure it spot on so I am going to use the dial indicator or piston stop method to make sure.
This was the best video I found showing this method:
Jay
Mgcjag,
Thanks for pointing that out. Iâve just read Dickâs article, and as you say, he is describing setting up TDC with the head off. However, in the forum thread highlighted by Jay, Dick says âWhen the other cylinders mentioned are at the same height, then you are exactly at TDC. It is amazing how sensitive this is and allows a really good setting. In fact, when a car is in for a tune up, I check to make sure the timing mark is centered using a screwdriver and my finger.â I donât think Dick removes the head for a âtuneupâ, so I presume he also uses this method with the head on. Using âa screwdriver and my fingerâ as a measure also suggests that weâre not talking fraction of a degree precision here either. I guess I must be missing somethingâŚ
-David
following alongâŚand as said there are problems with 2-3 being evenâŚwith head onâŚas domed pistons,spark plug hole location in the head can make the measurement not true. Finding TDC using #6 on compression only is the best wayâŚwhether piston stop at each sideâŚthen half way pointâŚor carefully checking the dwell at the top which can still end up 1-3 deg off as movement at that point is miniscule. Once TDC on 6 is setâŚthen line up camsâŚyes in removal and install tighten caps evenly across them all to the proper torque and no more. I like to put a little new cam lube on lobes. If the pointer is off for some reasonâŚwell it is offâŚmake a new mark. A TDC mark on the damper could be placed anywhere that you can easily see it as long as a corresponding mark on block or whatever is made at the exact same line up. On engines having a view hole to the flywheel teeth, then degrees is easyâŚie say on a 132 tooth flywheel it is 2.73 deg per tooth. There are other teeth variationsâŚ133, 104âŚyou need to know what you have.
Nick
69 Coupe
Very interesting. I am going to start re-assembling my engine in the next 3-4 months. Maybe I missed it, but how do you determine the âlengthâ of the plug that serves as the cylinder stop? Do you measure (however you choose to do it) what is the DTC and then make the rod a little longer, so you have the separation on each side of the stroke?
Mark
Murrieta, Ca.
I experimented with a wood dowel before deciding what depth to go with my piston stop. You want to be fairly near TDC as you rotate each way.
It is probably obvious but Iâll mention - you must be very gentle with the piston approaching the stop as this is a metal to metal contact. All other plugs are out so you should be able to gently wrench the crank for a light touch.
One trick I came up with was to use a digital camera to photograph the timing mark as the piston touched the stop in each direction. I then combined the two photos to have a composite that showed exactly where TDC would be (midway between the two stopping points). An example (TR not Jaguar):
In that case the pointer proved to be spot on. This was especially useful on a TR as the plugs are at an oblique angle to the piston making the dial indicator method something of a problem
69 Coupe
Excellent, thanks Geo
Mark
Murieta, Ca.