4 Cam engine tool pictures

Discussion of 4-Cam Type 547 engines (and all the Fuhrmann racing variants) and cars that powered them.
Message
Author
User avatar
Jacques Lefriant
356 Fan
Posts: 4037
Joined: Mon Dec 06, 2010 1:50 pm
Location: National City Ca

Re: 4 Cam engine tool pictures

#16 Post by Jacques Lefriant » Tue Mar 23, 2021 9:42 pm

Hi Jeff
it's an easy way to tell if it lobes have the same profile and if the keyway is in the same place. you can put the mandrel in a lathe and run an indicator over all the lobes or just feel with your finger. i will make a better one if i have a need .
j
 

User avatar
Mike Smith
356 Fan
Posts: 1156
Joined: Wed Mar 26, 2008 10:55 am
Tag: Its Only for Fun
Location: Ramsden Heath, Essex, CM11 1HS, UK
Contact:

Re: 4 Cam engine tool pictures

#17 Post by Mike Smith » Wed Mar 24, 2021 4:03 am

What are you checking??
To Not Check - is to assume
Mike Smith (Essex - UK)

User avatar
Martin Benade
356 Fan
Posts: 8742
Joined: Wed Nov 23, 2011 10:52 am
Location: Cleveland, Ohio

Re: 4 Cam engine tool pictures

#18 Post by Martin Benade » Wed Mar 24, 2021 8:56 am

So this won’t check if they are correct but it will check if it is a matched set.
Cleveland Ohio
62 Cabriolet
56 VW
02 IS 300
04 Sienna

User avatar
Ibrahim Kuzu
356 Fan
Posts: 746
Joined: Wed Mar 26, 2008 8:15 am

Re: 4 Cam engine tool pictures

#19 Post by Ibrahim Kuzu » Wed Mar 24, 2021 9:43 am

Jacques,
Very simple but effective Cam lobe inspection tool ..Smart....with this no assumption if the keyways or any lobe profile is off or not
so all 8 lobes are perfectly in precession alignment profile ...
Than comes to drag levers profile to check all 8 is perfectly in same radius of polished area were cam lobes rides ,this way all 8 valves lifts are synchronized perfectly....
I have learned one more thing today.....
Thank you all.
IK

User avatar
Jacques Lefriant
356 Fan
Posts: 4037
Joined: Mon Dec 06, 2010 1:50 pm
Location: National City Ca

Re: 4 Cam engine tool pictures

#20 Post by Jacques Lefriant » Wed Mar 24, 2021 11:15 am

Hi Martin
since there were at least 5 different cam profiles that were available from the factory and a few custom ones finding a matched pair was obligatory when replacing a lobe on one of the shafts since you assumed the shaft keyways were orthogonal. i have tooling to check that and to check the actual profiles but rarely do i use them. I was particularly happy with my keyway checker and it saved a lot of time correcting a custom shaft that allowed moving the gear to incrementally change the position on the shaft. the keyways were not correct and when assembling the engine the varience in the lobe centers side to side was greater than normal.(the factory had anticipated such problems and used the quick and dirty solution of changing the lash cap to correct) Sorry no pictures will be posted. Ibrahm when you get to see it you can make it more complicated.
j
 

User avatar
Harlan Halsey
356 Fan
Posts: 1600
Joined: Fri Mar 02, 2012 2:05 pm
Location: No Cal SF Peninsula

Re: 4 Cam engine tool pictures

#21 Post by Harlan Halsey » Sat Mar 27, 2021 4:26 am

In principle, with a new engine, the valve end depths below the cam center line would all be the same and the lash caps required to set the valve clearance would all be the same. (I recall Bill Doyle saying that the proxy was something like 27mm, valve end below the cam cover surface.) But I have never seen anything close to a new engine. With each valve job the valve end goes up and a thinner shim is needed. (In the old days they sometimes ground the end of the valve to compensate.) And in the real world of production tolerances, the valve motion varies. The factory solution was, and for me is, to sort of rotate the follower around the cam by changing the lash cap thickness and recovering the clearance by raising or lowering the other end of the follower with the adjusting ball pivot. This is not an exact rotation and it causes the cam to contact the follower curve at a slightly different place, which I suppose is the point of Jacques critique. The lift curve will be affected. I wonder how much?
I typically tried to get the lift centered, as measured close to the ends of the curve, say .060" lift to within 2 deg of target by playing with the shims. In principle you get within 4 deg with the gear engagement, but sometimes the differential between lobes on the same shaft makes a further adjustment necessary. So I did the best I could with the gears and then corrected with the shims. This works for an engine which is redlined at 6,500 RPM. I wonder If a more exact method, say an offset key, would show results which can be detected on a dyno?

The cam followers wear a divot in their curved surface. It took a while until I found a drawing of the follower which indicated the radius of the curve. Is there anyone out there who can accurately resurface followers? I've thought about how to make jig, but have never done it. (There is a machinist, Dean Lyon, who made a jig to resurface pushrod rockers correctly.)

User avatar
Jacques Lefriant
356 Fan
Posts: 4037
Joined: Mon Dec 06, 2010 1:50 pm
Location: National City Ca

Re: 4 Cam engine tool pictures

#22 Post by Jacques Lefriant » Sat Mar 27, 2021 2:45 pm

Hi Harlan
like this
DSC_8816.JPG
DSC_8816.JPG (1.95 MiB) Viewed 1662 times
 

User avatar
Jacques Lefriant
356 Fan
Posts: 4037
Joined: Mon Dec 06, 2010 1:50 pm
Location: National City Ca

Re: 4 Cam engine tool pictures

#23 Post by Jacques Lefriant » Sat Mar 27, 2021 3:11 pm

Hi Harlan
i like the approach that the factory race mechanics used for Count Corel de Beaufor. i can recalibrate my Dyno for any result you want.
j
 

User avatar
Harlan Halsey
356 Fan
Posts: 1600
Joined: Fri Mar 02, 2012 2:05 pm
Location: No Cal SF Peninsula

Re: 4 Cam engine tool pictures

#24 Post by Harlan Halsey » Sun Mar 28, 2021 3:52 am

Hello Jacques,
It isn't clear to me how that jig on the surface grinder reproduces the surface curve. As I recall the radius of that curve is about 12". My thought was to mount the follower on an arm of the radius length and swing it past the grinding wheel, swing and wheel in the same plane. Micrometer adjustment of the pivot point and the mount, indexing on the unworn portions. Just never got around to it. I'm hoping someone else has-there are a lot of worn followers out there.

What approach did they use? (Supposedly the car I have was driven by De Beaufort in the 1960 Sebring race, by the way.)
Last edited by Harlan Halsey on Sun Mar 28, 2021 4:28 am, edited 1 time in total.

User avatar
Harlan Halsey
356 Fan
Posts: 1600
Joined: Fri Mar 02, 2012 2:05 pm
Location: No Cal SF Peninsula

Re: 4 Cam engine tool pictures

#25 Post by Harlan Halsey » Sun Mar 28, 2021 4:21 am

Off the cam topic for a moment, the following picture shows the Carrera valve tool and my substitute.
IMG_0711 Carrera Valve Tool.jpg
IMG_0711 Carrera Valve Tool.jpg (1.65 MiB) Viewed 1643 times
This tool is useful for changing valve lash caps on an assembled engine as you can depress the spring sufficiently to remove the follower without further disassembly. ( I should mention that there's another 1/4" pin which passes the cam used to compress the spring.)

The tool on top is my substitute for installing valve springs. I think it started out as a piece of pipe. So far it has been used on Carrera, 356, BMW, MGA Twin Cam, Coventry Climax, Mercedes Benz, and VW. Modified a bit as needed for each engine. I don't think I have ever used that Sears valve spring compressor with out that adapter. I use a magnet to retrieve the keepers and long nose pliers to position them. Consequently, I have never used the wood hemispherical valve holder up.

The following picture shows my way of finding the valve spring space. The aluminum cylinder is 1" high, replicating the spring. I assemble the valve around the cylinder on the bare head, set the keepers, and measure the valve free motion with the dial indicator mounted on the steel bar across the cam box.
IMG_0710 Spring Space.jpg
IMG_0710 Spring Space.jpg (992.45 KiB) Viewed 1643 times

Then I calculate the shims required and measure the seat force and the full open force by placing the stack in the valve spring tester:
IMG_0707 Spring Comp.jpg
IMG_0707 Spring Comp.jpg (1009.63 KiB) Viewed 1643 times
The digital caliper mounted to the compressor compensates for the table motion, and makes reading the distance easy.
This way I can easily compensate for a slightly weak or strong spring with a shim or two.

User avatar
Jacques Lefriant
356 Fan
Posts: 4037
Joined: Mon Dec 06, 2010 1:50 pm
Location: National City Ca

Re: 4 Cam engine tool pictures

#26 Post by Jacques Lefriant » Mon Mar 29, 2021 6:38 pm

Hi Harlan
if you rotate the handle you can create the arc
DSC_8817.JPG
DSC_8817.JPG (2 MiB) Viewed 1612 times
DSC_8818.JPG
DSC_8818.JPG (2.04 MiB) Viewed 1612 times
 

User avatar
Jacques Lefriant
356 Fan
Posts: 4037
Joined: Mon Dec 06, 2010 1:50 pm
Location: National City Ca

Re: 4 Cam engine tool pictures

#27 Post by Jacques Lefriant » Mon Mar 29, 2021 6:40 pm

tool of the day
using this tool and a grinder you can size the valve stem to fit the caps
DSC_8819.JPG
DSC_8819.JPG (2.15 MiB) Viewed 1612 times
j
 

User avatar
Jacques Lefriant
356 Fan
Posts: 4037
Joined: Mon Dec 06, 2010 1:50 pm
Location: National City Ca

Re: 4 Cam engine tool pictures

#28 Post by Jacques Lefriant » Mon Mar 29, 2021 8:52 pm

Hi Harlan
the manual recommends changing the seats or valves if the distance deviates from 25.7-26.4mm. To ensure a symmetrical valve lift profile you must install a lash cap with the dimension that produces an ideal installed distance to the top of the cap. using the small lifts like .060" is problematic since the cams are either pushed or pulled depending on what side of the engine. i check at those small lifts in addition to the recommended distance which is specified for the actual profile which ideally produce 200 digress of duration so you can get an idea of the lobe center quickly. If the lobe centers are different at different checking dimensions you have a problem also if you get excessive lift of not enough lift it is an indication that you are not getting the proper lift profile. Some of the old guy would ues thin lash caps to get extra lift that sometimes had the lobe hook the end of the finger follower pad arc. I attribute the "divot" if very distinct to coil bind.
j
 

User avatar
Jacques Lefriant
356 Fan
Posts: 4037
Joined: Mon Dec 06, 2010 1:50 pm
Location: National City Ca

Re: 4 Cam engine tool pictures

#29 Post by Jacques Lefriant » Mon Mar 29, 2021 9:35 pm

Hi Harlan the guys at the factory would get a reward from De Beaufort(beer?) if they got extra horsepower from his engines so sometimes they cheated.
j
 

User avatar
Martin Benade
356 Fan
Posts: 8742
Joined: Wed Nov 23, 2011 10:52 am
Location: Cleveland, Ohio

Re: 4 Cam engine tool pictures

#30 Post by Martin Benade » Mon Mar 29, 2021 9:42 pm

Wouldn’t that follower fixture make an arc of a rather small radius?
And don’t standard valve grinders have a provision for shortening the stem to make up for what is removed from the valve head? (Or seat)
Cleveland Ohio
62 Cabriolet
56 VW
02 IS 300
04 Sienna

Post Reply