Tensioner lockdown question
#1
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Hey guys quick question. I've checked Google and on here for my answer but have had no luck. If I have my cams locked and my drive plate locked with the setting plug through the access hole, can you then rotate the cams whithout casing damage to the timing whilst having the sprocket to camshaft bolt off? I was thinking about it and just couldn't make sense on how it would damage timing if the drive plate is locked with the setting plug at TDC? And made me believe even more so that no damage can occurs since in black onyx's DIY he clearly stated you can loosen the sprocket to cam bolt and rotate your cam accordingly if the flats don't line up with each other? Someone please clear this up for me.
And one other thing, with the new eurospare primaries I read a comment that mentioned you're not supposed to use the old backing plate, correct me if I'm wrong. When I installed the tensioner the small groove under the tensioner looked as if only a small portion of it lined up with the groove on the block where the oil is supposed to travel from to the tensioner. Am I just being paranoid or will the oil reach the new tensioner groove?
And one other thing, with the new eurospare primaries I read a comment that mentioned you're not supposed to use the old backing plate, correct me if I'm wrong. When I installed the tensioner the small groove under the tensioner looked as if only a small portion of it lined up with the groove on the block where the oil is supposed to travel from to the tensioner. Am I just being paranoid or will the oil reach the new tensioner groove?
#2
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You can't rotate the camshafts with the lockig tools in place... That is why they are lockig tools. If you remove the tools, then yes, you can turn the cams.
Regarding the rear back in plates: once you have the lower tensioners off, you'll notice that they are a different shape. They are also thicker. That is because the backen plate has been integrated into the body.
Regarding the rear back in plates: once you have the lower tensioners off, you'll notice that they are a different shape. They are also thicker. That is because the backen plate has been integrated into the body.
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Don B (02-11-2018)
#3
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I guess you mean can you unlock the cams and rotate them, while the crankshaft is locked. If this is what you mean, then the answer is no. With the crankshaft locked, you can only rotate the cams a small amount around the position of their flats up (the position where the flats are when locked). If you rotate the cams too much away from the flats up, you risk bending the valves as some will come in contact with the pistons.
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Don B (02-11-2018)
#4
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When the crankshaft locking tool is installed the timing is set at 45° ATDC. With the pistons in this position the valves will not come in contact with the pistons if the cams are rotated.
You cannot rotate the cams with the cam locking bars installed.
Here is a link to Motorcarman's engine repair manual.
http://www.jagrepair.com/images/Auto...Code%20168.pdf
You cannot rotate the cams with the cam locking bars installed.
Here is a link to Motorcarman's engine repair manual.
http://www.jagrepair.com/images/Auto...Code%20168.pdf
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Don B (02-11-2018)
#5
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You can't rotate the camshafts with the lockig tools in place... That is why they are lockig tools. If you remove the tools, then yes, you can turn the cams.
Regarding the rear back in plates: once you have the lower tensioners off, you'll notice that they are a different shape. They are also thicker. That is because the backen plate has been integrated into the body.
Regarding the rear back in plates: once you have the lower tensioners off, you'll notice that they are a different shape. They are also thicker. That is because the backen plate has been integrated into the body.
The new tensioners I understood that they had the backing plate integrated. My question was that the little groove on the underside where the oil travels didn't look like it mated with the galley on the engine block. I was just uneasy and thought what if the oil doesn't travel inside the tensioner and the oil pressure doesn't tension the tensioner.
I guess you mean can you unlock the cams and rotate them, while the crankshaft is locked. If this is what you mean, then the answer is no. With the crankshaft locked, you can only rotate the cams a small amount around the position of their flats up (the position where the flats are when locked). If you rotate the cams too much away from the flats up, you risk bending the valves as some will come in contact with the pistons.
#6
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Thanks, that's very good to know as I am just about to start installation of the camshafts on my Super V8 engine. I have the manual you attached but (obviously) did not read it in detail.
#7
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#8
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Does anyone here know if the sprocket to cam bolt is a stretch/angle bolt? On JTIS it mentioned to torque the bolt down to X amount and 90 degrees. Or is this not true in which case I can go ahead and reuse the bolt?
Last edited by PORNO; 02-11-2018 at 11:54 AM.
#9
#10
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"carry out the intake camshaft retaining bolt tightening sequence.Tighten to 40 Nm + 90°."
I am not sure if by it saying carry out tightening sequence, it means to carry out the same torque as the exhaust sprocket bolt, then torque it again to 40nm PLUS 90 degrees. indicating its an angular bolt. Correct me if I'm wrong and I apologize for all the annoying questions. I guess I just suck at yielding good search results
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![Tensioner lockdown question-3geidk5.jpg](https://www.jaguarforums.com/forum/attachments/xj-xj8-xjr-x308-27/225944d1683067180t-tensioner-lockdown-question-3geidk5.jpg)
#11
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The Workshop Manual specifies 115-125 NM for both, exhaust and intake, camshafts on supercharged engines. It specifies the same torques in the case of NA engines (with VVT) but the torque of the bolt through the VVT was later amended by the TSB. There is no reason to have different tightening torque and procedure between exhaust and intake camshafts on supercharged engines as the bolts are identical (the same length). Probably an error in the JTIS (copy and paste from the "Vehicles without supercharger" and forgot to amend the "Tighten to..."
#12
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Just for comparison, M12 x 1.5 Grade 12.9 bolts (like the bolts for the camshaft sprockets) are / can be, according to the general fastener torque tables, tightened to 147 NM. As it is probably unnecessary to go to this full torque in the case of clamping the sprockets to the camshafts, Jaguar specified somewhat lower torque. Both torques, 147 and the Jag's 115-125 NM, are certainly not cases of torque to yield (stretch).
#14
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Just for comparison, M12 x 1.5 Grade 12.9 bolts (like the bolts for the camshaft sprockets) are / can be, according to the general fastener torque tables, tightened to 147 NM. As it is probably unnecessary to go to this full torque in the case of clamping the sprockets to the camshafts, Jaguar specified somewhat lower torque. Both torques, 147 and the Jag's 115-125 NM, are certainly not cases of torque to yield (stretch).
#15
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Workshop (factory) manuals almost always have errors and some can be catastrophic if followed. A couple of examples:
- XJ8 Workshop Manual gives, in the table of engine torques, the torque for the head bolts as just 35 NM (no mention of +90 +90 deg.)
- Ferrari 348 Workshop Manual states 0.8 NM for the M6 bolts on camshaft caps (a little more than finger tight).
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PORNO (03-19-2018)
#16
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Are there different head designs used on the sprocket bolts? (ie, Torx, Hex, Ribe.) I ask as I used the 10mm ball head on my AJ27 engine and it didn't work too well. I got the bolt out after modifying a 12mm Ribe bit to fit properly, but the bolt head is too mangled to reuse. (It looks like an ARP 256-1001 might be a good replacement.) My first XJR was a '98 and it seems that the bolt heads on that engine were more of a torx style head. I say 'seems' as it was 15 years ago when I took a look at the timing gear to see if the upgrades had been done, which they were.
Mark
XJR-100
Mark
XJR-100
#17
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Are there different head designs used on the sprocket bolts? (ie, Torx, Hex, Ribe.) I ask as I used the 10mm ball head on my AJ27 engine and it didn't work too well. I got the bolt out after modifying a 12mm Ribe bit to fit properly, but the bolt head is too mangled to reuse. (It looks like an ARP 256-1001 might be a good replacement.) My first XJR was a '98 and it seems that the bolt heads on that engine were more of a torx style head. I say 'seems' as it was 15 years ago when I took a look at the timing gear to see if the upgrades had been done, which they were.
Mark
XJR-100
Mark
XJR-100
#18
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Thanks for the reply, PORNO. When I did a full chain job at 100k miles (73k ago) I got a 10mm hex and the 10mm ball head. Got the same results as you, but I wrapped some duct tape around the 10mm hex and was able to R&R all 4 bolts. There was a little damage to the bolt heads, but it all worked out. This time around, my diagnosis is the A-bank secondary tensioner. What caught my eye was slack on the tension side of the secondary chain. When I put the bar across the cams, the slack was still there, so I needed to do a little tighten up there requiring the bolt to be removed. Using the same technique as before (with the duct tape), I managed to really mangle the head on the cam bolt. Also, while perusing the Jag tool website, I came across tool number 303-1077A, Ribe Socket M12 x 1/2. The description of its use is "Removes the exhaust camshaft sprocket retaining bolt and nut" and is applicable to X200s and X350s. Well, that X200 would include 4.0L engines, so that all made sense. Instead of bying the Bosch tool for $37.99, I ordered a full set of Ribe bits for 24.99. When that arrived, the 12mm was too big and the 11mm too small. So, I put the 12mm on the drill press and got a cheap file to wear down some metal. I was able to get both the A and B bank bolts out, but I was very concerned about stripping out the remaining material in the bolt head. Summit Racing has a retail store near here, so I went and got the ARP bolts that I mentioned, and they work great. The only difference is that they have a larger flange with an 18mm 12point head. I can't get the 1/2-inch drive torque wrench on them, but I did find a short socket that allows the 3/8 drive torque wrench to get on there inside the timing cover. So, I used 20NM and 90 degrees of turn from the JTIS torque spec tables in the JTIS.
Here are some pics: the first one is the totally mangled bolt head from the A-bank; the second is the half-mangled head from B; the new bolt; short socket with 3/8 breaker bar.
Mark
XJR-100
Here are some pics: the first one is the totally mangled bolt head from the A-bank; the second is the half-mangled head from B; the new bolt; short socket with 3/8 breaker bar.
Mark
XJR-100
Last edited by hispeed42; 03-20-2018 at 04:33 PM.
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