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| markr154 |
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Can someone explain to me WHY JMM's camshafts seem to cause timing chain rattle and worn / broken chain guides and timing covers?
I've got a full DEV 5 set-up ...and recently had 2 chain guides replaced because of bad wear / breakage resulting in chain rattle (timing cover was worn too) ...but now the rattle seems to have come back ...and I get an annoying ticking sound at idle that seems to be coming from the bottom of the car AND the engine between the Rocker cover and BBM? NOTE: Can't be the lifters ...had all of those replaced last week, also had belt tensioner pulley replaced. I want to boost my engine shortly, and just want this problem fixed.
_________________ Hot Chilli Red EL XR6, 5-spd, JMM DEV 5 enhanced (161 rwkw custom tuned), Eliminator Switch Chip, 18" BA GTP rims, Pedders Superlows, BA XR6 badges, BA Sunroof, Pioneer Stereo, Splits, 6x9's, 10" sub, 700W 6-ch Viper amp.
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| badcooky |
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How new is the cam chain Mark?
_________________ BA XL ute. |
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| GeZza200 |
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could it be wrong size shims?
_________________ EL Futura: CVE head, Wolf V500, ICE Ignition and Coil, 36lb injectors, Walbro 255lb, Paci comps, 3" exhaust, T5, Harrop Truetrac with 3.9s. Now with 198.9rwkw, (~185rwkw and 13.80 @99.1mph) with more power to come |
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| markr154 |
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The cam chain is less than a year old, recently replaced.
Apparently it was noted that there were 3 shims per lifter when lifters were done last week ...and all replaced same way they came out. Pain in the a** this is..
_________________ Hot Chilli Red EL XR6, 5-spd, JMM DEV 5 enhanced (161 rwkw custom tuned), Eliminator Switch Chip, 18" BA GTP rims, Pedders Superlows, BA XR6 badges, BA Sunroof, Pioneer Stereo, Splits, 6x9's, 10" sub, 700W 6-ch Viper amp.
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| markr154 |
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Just spoke to Jim Mock himself ...he reckons it's likely that the Hydraulic Tensioner needs to be either replaced or adjusted.
He also said that not many people ever set up the Tensioner correctly ...even using a couple of washers if necessary. Are there any other performance cams I can use that will still work ok with my JMM head, but not have the rattle problem?
_________________ Hot Chilli Red EL XR6, 5-spd, JMM DEV 5 enhanced (161 rwkw custom tuned), Eliminator Switch Chip, 18" BA GTP rims, Pedders Superlows, BA XR6 badges, BA Sunroof, Pioneer Stereo, Splits, 6x9's, 10" sub, 700W 6-ch Viper amp.
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| markr154 |
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Booked in again at BPT next THURS.
Terry was saying that when a sticky lifter is replaced, the 'cap' thingy associated with that lifter will have to be machined, and the shims removed. They're also gonna do a diagnostic scan & dyno power run for me, to check for any faults or power loss probs. I haven't got the foggiest about what he's REALLY saying, maybe someone here could enlighten me?
_________________ Hot Chilli Red EL XR6, 5-spd, JMM DEV 5 enhanced (161 rwkw custom tuned), Eliminator Switch Chip, 18" BA GTP rims, Pedders Superlows, BA XR6 badges, BA Sunroof, Pioneer Stereo, Splits, 6x9's, 10" sub, 700W 6-ch Viper amp.
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| racer |
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Nice looking car.
I have read that the dev 5 kit gives these problems but i don't know why. I've read it on another thread. I would be looking at another cam from another company like WADE CAMS, CAMTECH CAMS, CREASENT MOTORSPORT. I have spoken to brenden mock & soory to say they are very rude & full of s**t. GOOD LUCK WITH IT BUDDY.
_________________ FORD EL 4.0L. Crow cam, T.I Performance J3 Chip, Vernier cam gear, SPR ported head, 68mm TB, AU head gasket + ARP studs, AU injectors, Pacey 4480, High flow cat, Shift kit, Stallie, 3:73 TrueTrac. |
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| ebxr82nv |
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it's. Cause all of their cams are regrinds if you get it measured and have a new one made froma billet you won't have any more probs. If you do post the specs up
_________________ 9/98 AU1 XR6hp-about to retire from the road and be reborn on the race track. |
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| XR6EB |
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I had the same problem with the DEV 5 cam. Broke the guides twice in under 11000KM. The cam is simply to big and causes back lash. This was confirmed by JMM, although not easily. It will continually cause damage, as it is stretching the chain cause it to rub against the guides.
I left the cam in there after the first time it broke the guides [3000km], and learnt my lesson when the second time a pieces of the chain broke off and stopped my oil pump. That staops the dizzy, which left me strandard with my car for two days, 1 hour away from home. I will NEVER use JMM products again! Thats just my experience. It may not be the same for everyone else.
_________________ EB S XR6
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| markr154 |
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XR6EB wrote: I had the same problem with the DEV 5 cam. Broke the guides twice in under 11000KM. The cam is simply to big and causes back lash. This was confirmed by JMM, although not easily. It will continually cause damage, as it is stretching the chain cause it to rub against the guides.
I left the cam in there after the first time it broke the guides [3000km], and learnt my lesson when the second time a pieces of the chain broke off and stopped my oil pump. That staops the dizzy, which left me strandard with my car for two days, 1 hour away from home. I will NEVER use JMM products again! Thats just my experience. It may not be the same for everyone else. Which cam did you wind up replacing it with?
_________________ Hot Chilli Red EL XR6, 5-spd, JMM DEV 5 enhanced (161 rwkw custom tuned), Eliminator Switch Chip, 18" BA GTP rims, Pedders Superlows, BA XR6 badges, BA Sunroof, Pioneer Stereo, Splits, 6x9's, 10" sub, 700W 6-ch Viper amp.
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| MRESP8 |
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There is a simple rule that I am not sure all engine builders follow, as I had the same prob on mine, but was fixed when rebuilt.
The head was machined down so much for compression, that it needed spaces to lift it back up to correct specs. If the head is to low its always going to have chain/guide problems. Since that was fixed I have no problems with chains and guides, but down side is I lost a bit of compression. |
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| Waggin |
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I had this exact issue on my JMM Dev5a setup. JMM's response was the same - "replace your tensioner, or adjust it". Now, these tensioners can't be manually adjusted, right?
In any case, alot of time was wasted replacing the chain, tensioner, guides, etc - and it was just impossible to get rid of the rattle. Unfortunatley the regrinds that they do to produce the reasonably large cams mean you lose alot of meat off the cam itself, add this to the issue of shaving the head a couple of mm and you find the distance between the cam and the crank has decreased more than the tensioner can ever make up for. It may be possible to put shims inside the tensioner and build it up to make up for it, but I ended up selling my engine before I got to that.
_________________ WAG363: AUII LTD Supercharged 363 Dart Stroker [Supercharged 363 LTD Build] |
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| balizticbobo |
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Using a reground cam won't move the cam closer to the crank...
But skimming the head will. Please feel free to correct me if i'm wrong, but aren't most Dev5's out there complete engine rebuilds? Therefore, the block deck would most likely have also been skimmed, a s**t also skimmed off the head, and a timing chain that is now way too long. Which also means that the tensioner has run out of travel, and cannot take the slack out of the chain. Chain is now free to rattle about and slam into the guides and simply destroy everything in its path. How would you like being whipped thousands of times every minute by a hot oil soaked timing chain. How many kms would you be able to handle it for before you finally broke? The only way I can think of checking for this is to run the engine with the rocker cover off, also preferably over an unliked neighbours front lawn! And watch the timing chain to see if it's free to shake. If so, try a new tensioner, it may also be necessary to modify the tensioner with the addition of a spacer JB WELDED onto the end, or modify the guide itself. Remember the tensioner has the same operating characteristics as a hydraulic lifter. When it's run out of travel, it's going to make noise. Noise means increased wear = BAD! I have the Head, Cam and Vernier gear off a complete JMM DEV5 that spat the chain and guides, also cracking a piston and bending some valves. VL's are notorious to snapping off the cam belt tensioner when fitted with a decompression plate. Belt is too short = massive load on tensioner in fully released position.
_________________ 13.28@103.73mph |
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| balizticbobo |
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Also dont f**k about getting anything else done with the lifters at this stage.
And also try not to drive it unless you have to until you fix your timing chain problem to you could kill the whole motor just like the motor my head came off.
_________________ 13.28@103.73mph |
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| ebxr82nv |
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I wonder how you would go taking a link out of the chain or would it make it to short
_________________ 9/98 AU1 XR6hp-about to retire from the road and be reborn on the race track. |
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