was told i need a new cam but..........
Discussion
so i have been told i need a new cam for my chimaera 500 by two different independent garages. Both told me it would cost in the region of £1000 to £1500 depending on what cam I get. a good friend of mine (Dave500) has been telling me for ages that
"the cam is fine, don’t listen to them",
but if two separate mechanics of good reputation tell me it needs replacing then to me it need replacing.
I decided though that at a cost of £40 I’d take the car down to a Rolling Road in Surrey to see what the power output is just to see how bad it was. I wanted at least 150hp but basically anything over 100 in my mind would be good. When I got there I told the lovely chap my story and he let me know that with a knackered cam it should still put out about 200hp. So after waiting for a 650hp Nissan skyline to finish the chim was backed up and let lose. To my shock and happiness it ran 301.7hp of fFtLb and 241.3hp of FtLb and was told in no uncertain words that the cam is fine and must have been replaced in the last couple of years.
Now I’ve owned the car for two and a half years the previous owner had the car for a year and only covered a fue hundred miles so it must have been the first owner that had it changed and never kept the receipt for it. So for a car that’s covered almost 115K miles and is running standard apart from a fully de-catted and sleeved exhaust and I think that’s pretty good.
Now which output do I look at realistically. I’m thinking the 301.7
"the cam is fine, don’t listen to them",
but if two separate mechanics of good reputation tell me it needs replacing then to me it need replacing.
I decided though that at a cost of £40 I’d take the car down to a Rolling Road in Surrey to see what the power output is just to see how bad it was. I wanted at least 150hp but basically anything over 100 in my mind would be good. When I got there I told the lovely chap my story and he let me know that with a knackered cam it should still put out about 200hp. So after waiting for a 650hp Nissan skyline to finish the chim was backed up and let lose. To my shock and happiness it ran 301.7hp of fFtLb and 241.3hp of FtLb and was told in no uncertain words that the cam is fine and must have been replaced in the last couple of years.
Now I’ve owned the car for two and a half years the previous owner had the car for a year and only covered a fue hundred miles so it must have been the first owner that had it changed and never kept the receipt for it. So for a car that’s covered almost 115K miles and is running standard apart from a fully de-catted and sleeved exhaust and I think that’s pretty good.
Now which output do I look at realistically. I’m thinking the 301.7
I think your figures are bit confusing, either you have 301bhp and 240 ft/bls of torque, or its the other way around, which is most likely on over 100k miles, if that is the case then time for a new cam, if the 500 lump is all in standard tune then 270bhp would be a good figure.
in which case have a new cam fitted as it is proably the original one with the 100k miles on it.
if you have 301bhp, but, only 240ft lbs torqe I`d still be worried as the cam has possibly been replaced, but badly timed in, your torque on a 5lt should be 320ftlbs plus I would have thought, with the cam timed in properly your bhp would be a more realistic 270`ish and torque over the 300mark.
if you are happy with it, an don`t want to spend out then leave it alone.
have you got the dyno graph that you can post up?
in which case have a new cam fitted as it is proably the original one with the 100k miles on it.
if you have 301bhp, but, only 240ft lbs torqe I`d still be worried as the cam has possibly been replaced, but badly timed in, your torque on a 5lt should be 320ftlbs plus I would have thought, with the cam timed in properly your bhp would be a more realistic 270`ish and torque over the 300mark.
if you are happy with it, an don`t want to spend out then leave it alone.
have you got the dyno graph that you can post up?
Clive I've attached a link for you to look at. To be fair i had to ask what it was i was actually looking at as i've not had a dyno done in many many years. if you can, just let me know what you think.
http://www.flickr.com/photos/69723961@N03/
http://www.flickr.com/photos/69723961@N03/
you`ve got no problems there mate, your graphs explian it clearly, your first graph being at the wheels figures, so 240bhp and the 3rd graph showing flywheel figures, so 301bhp and around 320 ft lbs torque is a very healthy motor.
the ft/lbs on the right scale is for the torque reading, and the bhp on the left is .....well for the bhp reading.
the ft/lbs on the right scale is for the torque reading, and the bhp on the left is .....well for the bhp reading.
Hi Shaun, Sorry I did'nt get to spend a little more time with you yesterday, I was a member of staff down and a little stressed.
The lower number graph is at the wheels, the higher one at the flywheel. the higher one is what we are interested in.
Apart from being a little smokey at high revs, Your car put some of the healthiest figures I've seen on a standard 500 for a long time, the curves are exactly as i would expect (bar it being a tad lean at the top end)
At the mileage I would say it must have had a new car at some point.
The lower number graph is at the wheels, the higher one at the flywheel. the higher one is what we are interested in.
Apart from being a little smokey at high revs, Your car put some of the healthiest figures I've seen on a standard 500 for a long time, the curves are exactly as i would expect (bar it being a tad lean at the top end)
At the mileage I would say it must have had a new car at some point.
Thanks Charlie to be honest you've saved me lots of money and also saved me from thinking which cam to get. Now I just need to figure out what’s making the taping sound and I’ll be sorted, well apart of course for getting a new chassis fitted, roof fixed, wheels tidied up, engine painted, ACT induction kits ect…………
Gassing Station | General TVR Stuff & Gossip | Top of Page | What's New | My Stuff