Valve Clearance other CAMS

[miked]

I have CPL2 cams in My Plus 2 motor from when I bought it. I always set them to Lotus settings. However when reviewing the Kent cam book for the twincam setting for the CPL2 it gives 10 thou inlet and exhaust. I am now on with getting them bang on these settings. I phoned them and they say it is correct. I have L14's on the other car (which they ground) and they are set at 8 inlet and exhaust which I queried at the time but are not so much adrift from standard.

I am now going to have to retime the CPL2. I was just wondering about this and can anybody comment. I am an electrical type of guy so limited in my mech' knowldege.

Also is it possible to take a thou off a shim with an oilstone (carefully) or will I make a balls of it (round the edges). I have a rake of shims but as usual struggle around either side of my settings on few and end up buying or taking to the engine guy to fashion.


Mike

[Lyn7]

Hi Mike, I cannot answer the questions regarding the cam/shim settings, but I have successfully ground the shims in the past. Without repercussions I might add.
Cheers Lyn...

[promotor]

Hi Mike,

I wouldn't have thought you would need to re-time your cams (as long as your cams are currently set for maximum lift at the correct point) if you set them using the maximum opening point method? The valve clearance won't affect where the cam is at its highest lift.

As for valve shims you could thin one down on an oil stone (might take a while), and as long as you put the face of the shim that you have whittled down facing the bucket you won't need to worry about the valve stem going into the shim - shims are normally hardened so the hard face needs to sit on top of the valve stem. The bucket follower can spread the load over the whole area of the shim face you are intending to modify.

If you need some shims I can look in my stock for you and see what I've got.

[69S4]

I've been using reground shims in my engine for the last 25yrs without any issues. Just make sure you grind the faces parallel.

[john.p.clegg]

it helps if you make a little holder for them...mine is a piece of ali. bar relieved to hold them with a little magnet in the middle..

John

[miked]

Thanks guys for the replies so far. It is good to know what you guys are up to and what you do.

As regards the timing; I do use the MOP method (per Miles Wilkins book). I had not really thought about it before but I think see what you are saying. The cam peak (dead/dwell spot) at the same position is still going to be the MOP. So it does not move the MOP of the timing but must alter the duration a little. Interesting. Well you live and learn.

Mike

[miked]

Some Top end cam Noise now.

Having finished getting the motor back in etc I ran it today with the 10 thou Inlet and Exhaust valve clearances (as shown in the Kent Cam book for these). Always had standard setting before with no problems.

Since the Dizzy had been out I timed it up at cranking speed with the plugs out. Was 10 degrees from fitting? The motor started and ran OK and I then checked the timing with it running. 10 degrees at tick over. The engine was quiet as usual. Ran for about 3 -4 minutes. Since the Aldon Dizzy 103 tends to walk in early with advance curve I retarded the timing a little. Whilst doing this I notice tappet type noise (could be coincidence ). I know there is none but this is the best description of the sound. Engine not at temperature yet but not happy with this noise. I put this down to the over large inlet clearance and the oil warming and beginning to thin.

I packed up and came in as I was a bit fed up after resetting to this, so called, manufactures instructions.

Upon reflection I am wondering if the retardation had any effect? Sorry if this is stupid.

I will reset to 10 degrees and run it up again in the next few days. At the moment my inclination is to reset the inlet clearances back to normal twincam spec. I will ring Kent again. I asked once and they stood by this setting for CPL2.

Should I wait for it to warm up by taking it out for run. Any thought or ideas welcome.

Mike

[types26/36]

While I realise you are using Kent Cams spec are the cams actually from Kent as I have an old Burtons spec sheet listing the CPL2 cams with the lower settings.

[miked]

Brian,

Thanks for that, it seems more like what you would expect. I can see me going back.

I dont actually know about the cams. When I bought the car there were recent receipts for the head from Kelvedon. I have just looked for the long receipt with some ?1600 worth of head work. I can't lay my hands on it at the moment. As I recall it gave an internal code number (mean't nothing) saying they had been reprofiled. I phoned and got no joy. Less said.

I took the cams out and found CPL2 stamped into the ends. I only assumed Kent had done them as they seem to be the main ones.

Mike

[elanman999]

Mike,
I have had Kent CPL2 cams in my +2 for the last 20 odd years now and the official tappet clearances are 10 and 10. I now try to run the inlets at 8 or 9. Yes, there are not very quiet but they are a nice road cam with lots of torque. Can't really help with the ignition timing as I've run mapped ignition for a long time.
Cheers
John

[miked]

Thanks John,
Yes I agree they are a nice cam and the Plus 2 runs very well with them. Does the noise not go less when the engine is at working temperature? I am just worrying myself reading Miles book about excessive clearance.

Just found this on Burton Site.

PRODUCT DESCRIPTION
Gives smooth flexible power throughout the whole rev range. Should fit without any further modifications, but all clearances should be checked during assembly. 1500-6500rpm. Valve lift .350". Duration 270deg. Timing 25/65/65/25. Timing at full lift 110deg ATDC. Valve clearances .010"/.010". Lift at TDC inlet 0.071"/exhaust 0.068"
ADDITIONAL INFORMATION
Part No CPL2
Fits Engine Type Ford Lotus Twin Cam 1558cc 8v
Product Group Camshafts
Suggested Qty 2
Catalogue 2013 Page Click HERE to view this part on page 30 of our 2013 catalogue
Stock Status Available From Stock
Product Area Engine Components
Fits Engine Make Ford
Brand Logo Burton Power



Mike

[elanman999]

Mike

Does the noise not go less when the engine is at working temperature?
Mike

No, it is what I would call "tappety" and always has been.
I know mine are Kent regrinds set up to the Kent data. Well, except as above I now run the inlets on the tight side. As they have done at least 60K miles now I would say the data is correct.
Cheers
John

[rgh0]

Hi Mike
Resetting the cam timing and changing the clearance may mean the cams are now not coming into contact with the followers on the clearance take up ramp.

The cams have an initial gentle increase to take up the clearance and then a more rapid lift once the cam is in contact with the follower. Both cam timing and clearances need to be correct to the grinders specifications (and the cams ground correctly !!) for the follower to hit the cam in the right point in its rotation on the clearance take up ramp and not make "tappety" noises.

cheers
Rohan

[miked]

Thanks John,

I just took it out on a gentle run to get it a bit more temperature into the engine. It is tappety still with the stat' open and the gauge up to temp. It never was before when I ran old standard clearances

Thanks Rohan,
I rechecked my off set dowel cam timing (done by me about 8k miles ago - 4 Ex and 3 inlet to correct) when the motor was out when I went through the valve clearances. The cam timing was bob on to spec' using the MOP method. The pedigree of the cam regrind is a bit unknown as I could not get any info' apart from the CPL 2 stamping. I see what you mean about the gentle take up ramp. I have got to be hitting it with a slap then with too much clearance now. That noise does not sound right or normal. My limited mechanical knowledge says to re work the inlets down irrespective of the 10 thou inlet data. I ran at 6 on the inlet before with no problems.
I know I am asking really awkward questions but practically what do you think, should I go a bit more to say 7 as John still has noise at 8/9. Does that make sense. No come backs, my responsibility I knwo I was Ok at 6 before. It is also no use ringing Kent Cams (on Monday) as they will just say to spec' (as they did last time) and I don?t fancy sending the cams, off to be checked when the car runs great normally.

Thanks Guys appreciated

Ater thought. When I looked down the inlets they were clean as a whistle so had 6 thou been way too tight would I have been showing blackness due so leakage?

Mike

[rgh0]

A smaller clearance means you hit the take up ramp earlier in its slope. This should not present a problem and if you are missing it now may bring you back to contacting the take up ramp and not the higher acceleration section of the profile. You just need the clearance not so small that at operating temperature the clearance disappears totally and the valve is held open. Going back to the Lotus spec inlet clearance should not present a problem and since you have operated at this for many years worth trying to see if the noise goes away again.

cheers
Rohan