Worzey
|
 posted on 20/4/09 at 09:14 AM |
|
|
Cam change question
Just about to get the cams changed on my 4AGE 20v.
When I purchased the cams I was advised all I needed to do was get new valve springs - by a 4AGE specialist.
Just been advised I should also replace the followers. Was told by the garage who is porting the head that they have never heard of anyone changing
the cams without new followers. Is this right?
I already feel like I'm being screwed on the porting as the costs have gone through the roof.
Caterham R400
|
|
|
|
|
omega0684
|
| posted on 20/4/09 at 09:20 AM |
|
|
ideally when replacing the cam you should replace the follwoers and springs, it all normally comes as part of a kit.
you see when you have a new cam the lobes need to bed in onto new followers so they match as it were.
|
|
|
tomprescott
|
| posted on 20/4/09 at 09:25 AM |
|
|
Yep, What omega said, they normally come in a kit, I think its worth doing while you're in there, considering how little new followers and
springs cost compared with a new head.
|
|
|
02GF74
|
| posted on 20/4/09 at 09:42 AM |
|
|
my 2 p worth.
IMO, and I may be alone in thinking this, replacing the followers is necessary if they have worn down to match the cam.
look at the sruface, once they are visible marks, then too late.
in most cases, cam changes are done after many many 1000s of miles so what the shop says is correct as almost certainly they will have worn.
but as ^^^ say, cost of followers is cheap cmpared to replacing cams.
... and yes, the costs soon start to mount!!!
|
|
|
Mr Whippy
|
| posted on 20/4/09 at 09:52 AM |
|
|
depends on the mileage and the condition of the followers. If it’s due to wear of the original cam then you should replace them, but if the engines in
good nick and showing little in the way of wear I'd personally not bother as most aftermarket cams have a roughish finish that needs final
polishing while running, so the followers will also bed into the new cam. Just take it easy for the first 500 miles till the cam beds in and then
change the engine oil.
[Edited on 20/4/09 by Mr Whippy]
|
|
|
Worzey
|
| posted on 20/4/09 at 11:08 AM |
|
|
Thanks for the replies. Followers are expensive - approx £17 each for a 20v head. Gulp.
Wish I'd known this before embarking on the swap 
The cost of porting increased from £350 to over £800 overnight!!!!!
I know things cost what they cost, and you get what you pay for.....but to be quoted £350 then told £800 when it's in pieces is not very
professional.
Another machine shop is getting my business now.
Caterham R400
|
|
|
Mr Whippy
|
| posted on 20/4/09 at 12:22 PM |
|
|
pity as porting is dead easy and quite a lot of fun to do
|
|
|
MikeRJ
|
| posted on 20/4/09 at 05:10 PM |
|
|
quote:
Originally posted by Mr Whippy
pity as porting is dead easy and quite a lot of fun to do
It's fairly easy to remove obvious restrictions (rough casting, machining steps around the valve seat etc) with a die grinder, but it's
not always obvious how the port should be shaped to get really good flow without crucifying gas speed.
|
|
|
