cam lobe wear measurements taken!
Discussion
hi guys,
I tried measureing the cam lift at the rockers unsuccessfully. Now ive got my inlet manifold off etc, it was a great oppertunity to do it properly directly onto the cam lobes.
heres the readings from front of the engine to back:
1) 7.86
2) 7.36
3) 5.69 ***
4) 7.33
5) 6.10 ***
6) 7.72
7) 5.52 ***
8) 7.00
9) 4.93 ***
10) 7.35
11) 7.57
12) 7.60
13) 7.60
14) 7.33
15) 7.80
16) 7.55
wheres the cheapest supplier? its a 1993 430 by the way.
what should lift be when its brand new and whats the tolerance out of interest?
thanks
chris
I tried measureing the cam lift at the rockers unsuccessfully. Now ive got my inlet manifold off etc, it was a great oppertunity to do it properly directly onto the cam lobes.
heres the readings from front of the engine to back:
1) 7.86
2) 7.36
3) 5.69 ***
4) 7.33
5) 6.10 ***
6) 7.72
7) 5.52 ***
8) 7.00
9) 4.93 ***
10) 7.35
11) 7.57
12) 7.60
13) 7.60
14) 7.33
15) 7.80
16) 7.55
- All the low ones were rechecked.
wheres the cheapest supplier? its a 1993 430 by the way.
what should lift be when its brand new and whats the tolerance out of interest?
thanks
chris
Yes, Real Steel offer some good cams as Peter says.
The 430 uses a Kent 214. If you want to stick to that as i did i found TVR Power to be as good a price as anyone. Dom will try and talk you into a 218 which will give you a smoother bottom end and better tick over. Its up to you though what you go for, theres loads out there to choose from. Personally i stuck to the 214 and find it fine.
The 430 uses a Kent 214. If you want to stick to that as i did i found TVR Power to be as good a price as anyone. Dom will try and talk you into a 218 which will give you a smoother bottom end and better tick over. Its up to you though what you go for, theres loads out there to choose from. Personally i stuck to the 214 and find it fine.
EGB said:
Stealth cam has a good all round reputation.
I've been very happy with my Stealth from Rob @ V8 Developments.I measured my lift at the rockers, & while I appreciate doing it this way with hydraulic lifters is not ideal, once the cam was extracted the measurements did follow the true wear on each lobe very closely.
Proving this method is actually more reliable than you would expect but I would still only consider it an indicator, clearly getting a DTI directly on the lobe would be more accurate.
Mine definitely needed replacing but it wasn't the worse cam wear I have ever seen, however the Stealth & fresh timing set gave a very noticeable & immediate improvement to performance with no loss in drivability.
OP's figures seem to indicate a much worse situation than mine, so I would say a new cam will transform his car.
http://www.pistonheads.com/gassing/topic.asp?h=8&a...
chrisdurham said:
im still trying to get a reliable reference for the cam lift measurements when new - plenty on valve lift, is it a 1.51:1 ratio?
If you are doing a quick measure at the rockers don't worry about the rocker ratio.Take your measurement at the push rod end of the rocker, it's your most direct contact with the cam lobes without resorting to removing the inlet manifold.
When measuring mine I was expecting to see a minimum of 11.00mm of lift, what I got was an average an average of 10.52mm.
So I asked the question if this was normal, Rob Robertson responded by saying 10.50mm is about right for a mild cam, the HC engines and 500 ran around 11.50mm.
So over 30,000 miles my cam had gone from a highish lift fast road cam to a very mild Range Rover profile.
However my 10.52mm figure was just an average the thirteen more healthy lobes, things got even worse from there.
The remaining three lobes were clearly more worn, including cylinder 3 Exhaust lobe at a shocking 6.99mm.
I would say look for 11.00mm or more, any less than 11.00mm and it's time for a new cam.
As I've said before you really should remove the inlet manifold and put your DTI directly on the lobes to get an accurate reading.
I was too lazy to do this, but I did end up proving a quick check at the push rod end of the rocker (even accepting the RV8 runs hydraulic followers) will give you a pretty good indication of your cam wear situation.
It's worth pointing out not all the wear is in the cam lobe itself, my followers were badly dished too, adding to the reduction in lift.
With a properly dialled in Stealth cam, fresh quality followers and a tight timing chain set the difference was very very noticeable.
http://www.pistonheads.com/gassing/topic.asp?h=8&a...
http://www.pistonheads.com/gassing/topic.asp?h=1&a...
Edited by ChimpofDarkness on Monday 23 July 10:12
chrisdurham said:
hello,
yeah, I took my measurements above directly on the cam lobes, so should be quite accurate.
If we are looking for 10-11mm new - then mine are all horrendous! LOL
Seems that way Chris, but don't be disheartened.yeah, I took my measurements above directly on the cam lobes, so should be quite accurate.
If we are looking for 10-11mm new - then mine are all horrendous! LOL
I would see it as a perfect opportunity to get one of the newer profiles in there.
Then just take a moment to think about what your new cam will give you over your very worn original, the difference will be huge!!!
Absolutely no question, it'll feel like a new engine
Get it done.
chrisdurham said:
OK so now onto the serious bit! how much ££ am I looking at?
I would most definitely be talking with Rob Robertson.I looked at buying a cam kit and fitting it myself, then compared it with the drive in drive out fitted price from Rob.
For a number of reasons I decided to outsource the work to Rob.
Here's what he & Ray did while I sat back, watched and made tea
- Steam clean inlet manifold
- Remove & refit all eight injectors that were badly seated (engine running on 7 cylinders when I arrived in the morning, that's another story)
- Steam clean timing cover
- Remove seized bolt from timing cover (required a lot of heat to free it)
- Replace various corroded bolts, free of charge
- Check oil pump for wear (all good)
- Uprate oil pressure, double relief spring fitted
- Clean, polish & deburr oil pressure relief valve plunger & seat
- Oil pressure increased from 35 psi to 40psi on the TVR gauge (now more like a true 50 - 60lbs with a decent sender)
- Rockers stripped from rocker shafts, rocker end faces deburred, flatted & polished on a surface plate
- Rocker shafts deburred & polished
- Fit missing cam retaining plate £15.00 (TVR had not fitted one to my car from new)
- Steam clean rocker covers & secure lose oil trap plate screws
- Drill out old snapped off stainless screw in rocker cover (hard as hell) & fit new dip stick retaining bracket
- Engine oil & filter change
- Antifreeze replaced with new
- Lots of other bits I didn't see because I was on tea duty (best not to get in the way of the experts)
How about that for attention to detail, and the whole thing came in at more than £600.00 cheaper than my local very well respected TVR specialist.
It sounds like you're halfway into the job already, so if you plan to finish the work yourself it's still worth buying the cam kit from Rob as the components are top quality and his prices are very realistic too
Edited by ChimpofDarkness on Monday 23 July 11:54
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