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Healey 3000 Camshafts

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Morris56

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Hey everyone - I just joined the sight but have been paging through posts for the past couple weeks. There's a wealth a very appreciated info here that I have just scratched the surface of.

I almost hate to post this (cause I am sure it is buried in these 186 pages) - but I need some help on a camshaft. I've got a 62 tri-carb and I want to regrind to MKIII spec. I know the lift and duration for a MKIII, but these are the only two spec numbers I was able to come up with. I want to make sure I have all the info needed before sending this off for re-grind. Also - I am seeing a huge price range in terms of re-grinds. Anyone that has had good luck with a machine shop - please let me know.

Unfortunately - it's back to work... only 161 pages of info left to go. Thanks for the help.
 
I have a BJ7 and wanted it profiled to BJ8 specs.
I sent these guys a letter saying just that. I'm told that they've done many. $125. A word of caution about shipping back and forth to Canada. The part went through a broker, who wanted to charge me hundreds. They finally waived the charges. I'd speak with CCPC about the shipping before sending your part.
Canadian Chrome Plating & Crankshaft Inc
416-249-7495
55 Torbarrie Road, 
North York, ON M3L 1G5
 
Morris, I also have a tricarb and live in NC. I had my camshaft reground to a chevy spec at Holman Moody Racing in Charlotte NC. I can look on the cam card for the specs if you are intrested. Holman Moody was recomended to me by Vaughns Austin Healey restorations in Pinevlle NC. They have a pretty impressive racing History at Holman Moody dating way back. Where are you located in the State. I live near Hickory. Our car is a 62 Bn7 actually built eary in 61.
Bob G
 
Thanks everyone for the help. So many places... so many prices. CCPC seems to be the way to go - based on price, delivery time, and knowledge but there are two more people I want to call first.

Thanks Ed - I'll give them a call and find out their recommendation.

Bob G... I sure would like the cam info before I make my final decision. I'm over on the east coast in Wilson, NC. It's not much of a British car area but we do have a few running around town. Be sure to look me up if you ever make it over this way.

Now that the cam question is coming to an end... time to find some lifters. I found a good post on this here but these appear tougher to find than I thought. I don't think mine are worth re-finishing... but I worry about the hardness of some of the big parts suppliers.
 
What ever you end up with, have a good independent machine shop check all cam lobes & lifters for a hardness of 55 MINIMUM on the Rockwell C scale. Don't take anyones word for it.

Re-profiling a cam results in a smaller base circle diameter which places more strain on the cam & lifters. Some very good cam grinders will build up the lobes before re-grinding so that the base circle is not reduced. Costs a lot more though.

If it's not too late, I would trust Dema Elgin most of all to do the best job on a cam.
https://www.elgincams.com/navigation.html
D
 
Morris, The card reads as follows
Top Center exhaust closes 28 exhaust opens 67
bottem center intake closes 64 intake opens 31
lobe centers 108
intake lift 425
exhaust lift 425
lash on intake and exhaust is .018
rocker ratio is 1.42 on exhaust and intake.
It has a nice sound but I haven't had the chance to put more than a couple miles on it so far.
Cam model HA 406.8
Part number Austin HA 6250 Healey
I don't know what most of this info means but maybe Dave R can explain it to us. Bob
 
Bob,
Your "numbers" mean:
The exhaust valve starts to open 67 degrees before BDC as the piston is traveling downward on the power stroke.

The exhaust valve closes 28 degrees after the piston has reached TDC on the exhaust stroke & has started the intake stroke.

Total exhaust valve open time is 67 degrees plus 180 degrees plus 28 degrees for a total of 275 degrees which is the exhaust duration.

The intake valve opens 31 degrees before TDC while the piston is still traveling up on the exhaust stroke.

The intake valve closes 64 degrees after BDC when the piston is traveling upward on the compression stroke.

Total intake valve open time is 31 degrees plus 180 degrees plus 64 degrees for a total of 275 degrees which is the intake duration.

The time when both intake & exhaust valves are open at the top of the exhaust stroke is 31 degrees plus 28 degrees for a total of 59 degrees, which is the overlap.
Note that the IO of 31 degrees & the EC of 28 degrees means that the cam is advanced 1.5 degrees from "split overlap". This will normally give a bit more low rpm torque.

108 degree lobe centers is the actual angle between intake & exhaust lobes as measured on the cam itself. All of the other numbers are on crankshaft degrees. This is a fairly standard number. Wider lobe centers would give less TDC overlap & narrower LC's would give more TDC overlap. Lobe centers is not the same as the sometimes used "lobe center line angle" which refers to the point on the engine rotation where the cam lobe has reached maximum lift.

These cam specs should give good performance over a broad rpm range. Assuming that the cam was Nitrided & the lifters are not soft, you should have a very good, long lasting combination.
----------------------
I note that your valve lift is specified at 0.425". Normally, any valve lift over 0.370" requires cutting valve relief pockets in the block under the exhaust valves. This is because the exhaust valves overhang the cylinder bores & the valves will come dangerously close to hitting the block.

You could check this by rotating the engine until an exhaust valve is fully open & then pushing the exhaust valve further down to see how much additional travel there is before the valve hits the block. There should be about 0.080" of margin.

Also, the valve top collar must have this same clearance to the valve guide & the valve spring the same margin before it reaches coil bind.

If any one of these three clearances is too small there is danger of breaking or wearing something. Especially if you are using high rpm.

If you or the shop has verified these clearances disregard.
D
 
Hello BlueRidge1.

The cam figures you showed are quite similar to the one I have in my 1960 BN7 and along with the HD8's they really make a difference.

I noticed in your figures you quoted the figure for the rocker arm ratio that is shown in the workshop manual. I used to use that figure also until I did some homework for myself.

I have a spare set of late BJ8 rockers and so I mounted them in the vyce and with 2 dial indicators measured the movements of both ends of the rocker arm at the same time.

After zeroing both dial indicators I moved the pushrod end through the range from 0.010" lift through to 0.260" lift at intervals of 0.010" increments and recorded the movements of both ends. At 0.260" lift the dial indicators were ready to come off the ends of the arms which is why I stopped there.

The rocker arm ratio varies as you move the rocker through the range because both ends move through different arcs.

The ratio varied from 1.03:1 to 1.49:1 which is a difference from what the factory states. It will however give you an idea about the valve lift and any clearance problems that may be waiting to happen.

Regards

bundyrum
 
Dave, Yikes, No one advised me of the relief pockets on the block. I have run the engine but probably not over about 3500 rpms just to run the cam and lifters in. I have an extra block ad head and some old valves that I am going to mock up to get a better visual of where the valves could contact the block. Thanks for the heads up. Is there a less complicated way of increasing the clearance? Could the lifters be ground shorter or would that not make a difference? Could the rocker ratio be changed to compensate this potential problem. Is that what Bundyrum was refering to in his post about rocker ratios? Thanks Bob
 
Hi Bob,
Here's a photo of where my block was relieved for the exhaust valves.
 

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I guess the mock up would be ok. Not nearly as good as checking the engine itself though.

It's really not so hard to get a valve at full lift & then push it further by hand to see how much overtravel room there is. The springs are stiff but with a little creative leverage they can be moved. All valves should be checked.

Ideally, you would also check valve retainer to top of guide clearance & spring compressed length before the springs & head are installed. At least, this overall check will tell if anything is wrong. It just wouldn't tell what is actually too tight, if anything. If you can get the .080" over travel, it means that block clearance, spring coil bind, & retainer to valve guide clearance are all ok.

Relieving the block also helps unblock exhaust flow. Greg has a beautiful pic of the relief notches.

Shortening the lifters or push rods would only increase the valve lash a whole lot & not solve the problem. Rocker arms with less lift would only defeat the lift that's built into the cam.

Now is the time to get it right even if you have to take something apart.
D
 
Bob, basically I was trying to explain what rocker ratio is and the fact that it differs as the rockers go through their motion.

Dave's idea is the easiest to measure the clearance. All you have to remove is the valve cover and lever the valve down further after you have turned the crank over to get maximum valve lift.

If you had a dial indicator on top of the spring and measured the extra movement as you lever the valve down you would be able to see how much clearance the valve has before it hits the top of the block.

A 6" scale could be used also to get an idea providing your eyesight is reasonable or your glasses very good, (if you have either).

Hope this helps.

bundyrum.
 
Wow, Geat visual! Thanks Greg for the picture and all ya all for the information. I will check the clearance as Dave recomends prior to cranking the engine up again. Greg what lift cam are you running and how deep is the deck before you get into the water jacket? Does the releif increase the likelyhood of blowing a head gasket? Bob
 
Hi Bob,
.430 on the lift. Not sure how much metal is there before you cut into anything bad. I don't think there is any problem with regard to the head gasket. Remember that the relieved area it right below the exhaust valve, so the block is still "inside" the combustion chamber.
 
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