Mustang Owners Club Australia Forum
Technical & General Discussion Area => Tech Torque 1979 to 2014 => Topic started by: jiffy on June 01, 2018, 03:33:43 pm
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So, a few years back I had John from ICES Performance replace the engine/gearbox/fuel system in my 2002 Cobra with a lightly used 2003 setup. While it's supercharged the design of the motor is very similar to the 2000/1/2 engines, it just uses a few different components. I had about 170K on the old drivetrain as I drove it every day from new and pushed it pretty hard, and it mechanically was faultless. The new setup now has about 60K on it.
Over the past few years I've noticed an annoying issue with the 2003 motor in my 2002 Cobra - about 2/3 time at startup from cold there is a 'rattle rattle' or 'tap tap tap' coming from the front driver's side of the motor for a few seconds (at first anyway, after a year or so it was 20+ seconds...).
I wasn't sure what it was but wondered if it was the lifters, a cam follower, exhaust leak, cam guides, cam chain tensioners etc. This noise would come back at idle when the engine was very hot on a hot day - when the oil had thinned out and the oil pressure was dropping..
So, tried the headers - all good, no leaks. Replaced the lifters and a little better. So, as I'm up to my nuts in investment in this car, it seemed prudent to find the cause and fix it. So, a buddy is a Holden mechanic and we'd discussed this a lot, and he agreed to pull it down and find the cause.
So, off with the all the bolt-ons and start checking stuff. There were a few cam followers that exhibited more play than the others, which would contribute to a generally noisy engine, so they've been replaced by cam followers from a 5.4 modular motor (similar but improved design). Pulled down the front of the motor and found 2 of the 4 cam chain tensioners had blown out the seal on the back of them. This is a known cause of these issues, and eventually the lack of pressure at start-up will break the top off the cam chain guide and then shit starts moving around.
Here's some pics:
(http://www.mustangphotos.com/photopost/data/500/medium/Cam_tensioner_2.JPG)
(http://www.mustangphotos.com/photopost/data/500/medium/Cam_tensioner_3.jpg)
So, I thought so long as the thing is apart, might as well replace everything - cam chains, tensioners, guides (new improved design that doesn't break), sprockets, oil pump - that could conceivably go wrong, and luckily there's a kit for that:
https://performanceparts.ford.com/part/M-6004-A464 (https://performanceparts.ford.com/part/M-6004-A464)
Oil pump:
https://performanceparts.ford.com/part/M-6600-D46 (https://performanceparts.ford.com/part/M-6600-D46)
Gasket set
https://www.modmaxracing.com/03-04-COBRA-4V-4-6-Complete-Gasket-Kit-p/felfs26187pt.htm (https://www.modmaxracing.com/03-04-COBRA-4V-4-6-Complete-Gasket-Kit-p/felfs26187pt.htm)
So, car is due back soon and I'm expecting the engine to be as quiet as a grave (even if the exhaust isn't) and run like a top.
The replacement tensioners do not have the little rubber seal on the back that bleeds off oil pressure when the motor is off, they're an improved design that seals to the machined surface of the block.
Cheers
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Good info Jeff. As discussed I will do a complete timing chain kit plus plus when the time comes.
:pepper:
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ok - got the car back and it's a missile. all good.
Just a cautionary note for any other 4.6/5.4 owners. These motors feature an oil restrictor in each head to keep oil pressure around the bottom end. The oil restrictors feed oil to each cam and lifter set and also to the front cam gears and tensioner. If a bit of silicon or gasket gets into the oil feed system then it may easily block the little holes in the restrictor stopping oil feed to one head or other.
This video explains it perfectly - https://www.youtube.com/watch?v=KCkBGDuw4sI&t=82s (https://www.youtube.com/watch?v=KCkBGDuw4sI&t=82s)
On a 2V head (shown in this video) the restrictor may come out easily. On a 4V DOHC head, the head normally has to come off to get to the bottom of the restrictor to force it out. Ask me how I know....
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Jeff, so if I buy the kits, I don't have to take the heads off? Only if the gaskets malfunction and block the oil restrictors?
I noticed mine makes the rattle at start up or when in a lower gear and you rev it a bit under load I get the same noise.
Im sure mine is the timing chain though...………………..hopefully.....
Glad yours is up and roaring... need some vids of it..
:pepper:
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Exactly!!
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So you reckon I need to do the same???
:ouch:
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Can’t say without hearing it. So, if this is the issue, it should be easier and cheaper than mine and you could just replace the tensioners which may solve the issue, but it all depends if this is the problem or not.
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Will try and do a video soon and put up. From what I have heard on youtube from the usual Mustang sites it sounds like tensioners..