this is a continuation of my 'no power top end' thread i started ages ago. i finally found out how to check correct cam timing on my car, so this arvo i pulled off the rocker cover and checked it as per instructions. they state that the timing mark on the cam must be level with the head or no more than 3mm above it (more distance=more 'retarded' cam) i measured mine and it is about 4.5mm - is this enough 'retard' to cause my car to loose power and not want to rev past 4700rpm under load?
I want to get a DEV 3 package from Jim Mock, but i want my car to be making its correct amount of power before i get it, just in case the problem is major and i kill the engine from the extra herbs. if the cam timing is the problem then will a vernier cam gear from the DEV 3 fit the standard cam and will it cure it, or do i have to get a new timing chain (AAARRRGGGHHH - that will be a pain in the butt to fit!)
here is a pic of the cam timing:
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your best bet try a dyno,best bet get them to check spark,a/f mixtures,exhaust temperture,compare dyno figures plent in threads,had my coil and vct soiloind replaced by myself $260 big ones, still looking for the turbo i put in also (lol) best of luck.
It looks to me that the timing chain has warn some, the tensioner is on the left which would retard the cam alittle..Agree with above though you MAY not loose performance..
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yes the cam is retarded (and so is my bloody car!!!) but im just wondering how much difference 4.5mm can make...ive heard that these motors are very sensitive to cam timing, im kinda hoping Grunt51 will give me some advice...how much is it for the vernier cam gear from the DEV 3? i was going to get the exhaust first, then leads cam cam gear etc later, but if my tax cheque is big enough it might stretch to exhaust and cam gear at the same time...
oh and i broke the passenger side engine mount the other night when i was being a rough bugger, does anybody in brisbane have a spare???
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197.4hp at the wheels, 14.505@152.46km/h Tuning in progress... *CLICK TO SEE MY XR6*
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How many Klms the engine done? I'd fix chain before vernier gear..Possibly be done same time as D3 iff it replaces the cam..There is a kit with gasgets, chain, tensioner/guids, Pulley etc..Reasonably priced...
I guess a well plained head will do this too!
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Don't be afraid to try something new. Remember, amateurs built the Ark...Professionals built the Titanic!
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Tuned & maintained by "Peppertree Perfmormance". Dart block, Scat 4340 steel crank, Custom C.P pistons.Oliver rods.. Mal Wood twin plate clutch.. Twin SC61/2's,482 rwkw/ 645 rwhp..
Passengers, myocardial infarction material..
R.I.P Possum...
well it had 110,000k on it when i got it, has 119,000k now, the owner reckons the engine has never been apart when he had it and he bought it with about 30,000 i think.
i havent asked him if he ever noticed the lack of revs issue, i highly doubt it, he was not a rev head at all, and i havent spoken to him since i bought the car - the head might have been off it before, people never tell the truth when they are trying to sell you something...
the manual says if you can lift the cam chain more than 2mm off the top of the sprocket with your fingers then you should replace the chain, but mine is still tight, maybe the head has been machined before, but i dont think it would make this much difference...
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Slick, Quick and Fulliii SIK!!!
Proud TQE Operator
197.4hp at the wheels, 14.505@152.46km/h Tuning in progress... *CLICK TO SEE MY XR6*
I can get new Genuine Holden/Ford/Audi/Land Rover/Honda parts cheap, PM me!
A Mock cam will come with excellent easy to follow timing instructions (wich include photos). You'll need to fit the variable cam gear and get hold of a dial indicator to be able to do it tho. I never "dialled" a cam in before in my life and had absolutely no problems doing it.
Variable Cam gear is about $100 on its own from anywhere like autobarn etc, not sure on how much Mock charge for it.
Is it possible that when the chain was put on, it was placed a tooth out, in the retarded position?
If this is the case, you could easily fix it by loosening the tensioner, and carefully moving the chain over a tooth. If it sits a little advanced it should still be ok. You can always give the dizzy a lil turn to compensate a little.
If it were my car, that's what I would try anyhow.
I have had my head decked on the EA, and chain still sits fine. I put in new chain guides, and was going to put in a new chain, but the chain was still in good condition, so there was no point.
Anyhow, God Luck.
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Originally posted by Bass Crazy .....If this is the case, you could easily fix it by loosening the tensioner, and carefully moving the chain over a tooth. If it sits a little advanced it should still be ok. You can always give the dizzy a lil turn to compensate a little....
Sorry Bass but CAM timing and SPARK timing (moving the dizzy) are completely different things (OK, related but different). Retarding one to compensate for the other being too advanced isn't what I'd be doing.
I may be a bit off track here as I have no I6 knowledge.
Lets assume your cam was installed straight up. Zero advance.
Most increments will run with a gear tooth. To use a V8 top timing gear as an example.. 3* up or down is usually several teeth on a gear and I would assume it would be at LEAST ONE on you rtop gear. Now if you were to move your timing gear by ONE tooth you would "consume" that 4.5 mm without doubt. The timing mark would not be visible above the head any longer given that your crank must stay still.
Therefore the change between 3mm and 4.5 is irrelevent to your timing as far as a seat of the pant measurement goes. You may be talking the difference between 0* and 1* retard. That will have no seat of the pants feel. Only a dyno/strip can pick that up and then at 4500 plus rpm most likely too.
Make sense?? Doesnt help you with cam timing but I think your problem is elsewhere.
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