Cam Gear Locking Tool for quick belt changes

The woodruff keys are only on the two belt drive gears. The gears that go on the ends of the cams have 5 holes, and there are 3 holes in the cams. A pin is inserted to select a particular pair gear & cam flange holes & lock the flange & gear together.

The various combinations of gear & cam holes permit fine adjustment of cam timing relative to the belt teeth. The belt teeth position is solely determined by the cam drive gears.

You can see the edges of the cam gear holes & part of the pin in the photo JWise posted earlier in this thread.

 

Been there, done that, that's exactly the problem I"m going after w/the tool.

Yup, that cam wasn't timed properly, a different combination of holes in the cam gear & cam flange needed to be selected. That's what I've found on at least 1 cam on every engine I've timed. I'm sure the engine had been running just fine that way also.

Once you're into fine tuning the cam-sprocket timing, you'll discover you can't leave the belt on. Unless you're incredibly lucky, the combination of holes you need will require rotating the cam gear relative to the cam which will requrie removing the belt anyway.

Here's a trick:
Glue a strip of belt to a strip of 1" wide x 1/8" thick steel long enough to go across the tops of the two cam gears with a bit extra sticking past. Now you can lay it across the top of the cam gears to align them relative to each other as if a belt were going across the top. Using this plus locking the cam into position once it's lined up will help ensure you've selected the right combination of holes. It can be held in place with 3" binder clips while inserting the alignment pin.

Once you've got them pinned, you can use the tool I'm developing to preserve the relationship while installing the belt.

As to vice grips or pliars leaving marks, you can always put strips of innertube inside the jaws. However, those cams are very very hard, I doubt the teeth would mark them. BTW, allegedly the Ferrari WSM actually recommends using vice grips to move/align the cams for one of the newer models.

 

Any answers?

 

PeterS,
See Sean F.'s post of 11/30 & my response. It's a real PITA if the gears move out of alignment while trying to get a belt on. Helps to have a helper to try to hold them in place from above, otherwise you can end up spending an hour or more /bank fighting with them (been there).

RF128706,
The SEALY tool is what Baum, SnapOn et al are selling. Very good prices over there: £66.23, & £65.95 w/VAT about $128 USD. Hmm, for a US buyer, w/o VAT Gets it down into the range I'm thinking about, but shipping probably wipes out the VAT savings & then some.

I think my tool will be easier to use for a 308/328 (less fiddling), I can sell it for less, and I think it'll be able to be used to lock the cam gears while torquing/breaking loose the cam gear bolt.

mcguy,
I have one of those. The tool won't work on a 308 for 3 reasons:
1) The flange on the front of one of the cam gears won't let the tool's pins engage the gears.
2) The spacing between the tool's arms can't be adjusted close enough for a 308's cam gears
3) The pins on the tools arms are about 3mm long. That's too short to reach past the ridge on the end of the gear w/o a flange & grab the teeth.

Reader, please see my earlier questions that started this thread:
Still looking for cam-cam dimension & pricing input (see my earlier threads).
Spider348's pricing suggestion is pretty close to what I've been thinking I can do. Maybe a few $ less on the single tool, & a tad more for a pair. What do you think?

 

Attached are photos of the first production 2V cam gear locking tools.

Altho at this time I haven't been able to verify it, the black marks thru the hole centerlines should be accurate enough for a quick check of cam alignment. I've asked my first customer to report on his experience with these tools. At this time, I do not recommend trying to use the marks to perform cam alignment, to do that you still must pull the cam covers & either use the cam cap & cam marks, or else use a timing wheel & dial indicator.

I do NOT recommend using these to hold the cams while you break the cam gear retaining bolts loose. I suspect that if you try to clamp them down that tight, you'll risk breaking them.

Price is $75 each, $135/pair.
If you need a one or a pair, send eMAIL to:
[email protected]
SUBJ: 2V Cam Gear Locking Tool

Altho they look simple, These turned out to be surprisingly hard to build. I analyzed the cam's imprints on the one Birdman & I put together, turns out we were only clamping onto about a 5 or 10 degree arc of the cam's surface!

Turns out you have to hold the hole spacing & dimensions to a tolerence of a few tenths of a mm or you wont be able to fit onto the cams & clamp onto more than a small arc of the cam's surface.

I ended up using my lathe's tool post grinder to cut a Forstner bit down to the necessary non-standard size. Once I realized how tight I had to hold the dimensions, It dawned that the dimensions should be tight enough to verify alignment using the marks on the cam's cam gear mounting flange.
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Steve,
How precise is that meas't?

I measured 140.50 mm for the 2V cam-cam spacing & that's what I'm building against. If I'm off by a half-mm on my nominal hole center-center dimension, I need to know it ASAP as am about to ship these parts.

If possible could you measure to nearest 0.01 mm/0.0005", or at least 0.05mm? The calipers I used only measured the nearest 0.1 mm.

Also, would appreciate your double-checking my cam diameter meas't: 28.0 mm. It's a rough surface, so will probably vary by a few tenths of a mm.

It's hard for me to repeat meas'ts & test the tools as the closest 2V engine is Birdman's & it's a 45 minuite drive away, & then I have to get access to the cams...

Yes, Steve, I'd very much appreciate your 4V making cam center-center & cam gear diameter meas'ts to check against mine. If you have access to some metal 4V cam gears, could use the OD of the teeth.

Tillman,
Yes I am working on the design for a 4V tool.

Unlike the 2V engine, the 4V engine doesn't have enough space between the cam seals & cam gear mounting flanges to grab with a clamp. Thus the tool must directly clamp onto the cam gear surfaces. See the pix in the 1st post in this thread for a crude prototype that JWise & I hacked out while re-doing his timing drive.

I just need the time to do a detailed mechanical design. Probably will have them in production this fall. Of course, a couple of orders would raise this project's priority.
l^)

 

Actually it was Nylon, & was a bit too slippery for a good grab w/o more force than I like to put on plastic cam gears. I glued the innertube pieces to it & solved the problem, however, as you can see, the glue gave some.

I may just cast the production clamp pieces out of my fibreglass/polyurethane compoosit, or else a softer poly like that used for bushings.

 

That's std with all the 3x8 engines. The back of the holed flange that the cam gears mount to has a small flat area with a vertical groove in it. On 2V cars, that groove is intended to let you check cam alignment by dropping a factory tool shaped like the long piece of my 2V clamp. (See pix very early in this thread). Like my clamp, the factory tool tool has marks that should line up with the marks on the cam gear mounting flange.

The intent is not for you to use the cam clamp marks to adjust your timing, just to check to see that it's where it shold be & that both cams are set up the same way. If both cams have their marks are in the same position relative to the tool's lines, and the marks are very close to or spot on the lines, then the cam timing should be correct. Same function as the little metal arrow tips on the fibreglass back of the 4V cam covers, but hopefully more accurate & easier to use. S/b good enough to detect a major problem such as a skipped belt tooth or significant miss-alignment.

If you're doing non-standard cam timing, you're going to be using a degree wheel/dial indicator anyway.

The wooden tool pictured is designed to clamp down on the 2V cams just as you described. Even our crude prototype worked quite well for a belt change. I just need to make sure I've got the cam center-center dimension right on as someone else posted a slightly different dimension.

Two flat knurled bars will let the cam gears rotate (been there), & people don't like the idea of metal teeth clamped onto their cams.

I'm trying to do a very cost-effective solution for the 308 engines.

Most other makes have either off-the shelf, or mfg. supplied tools, or (best of all) have a couple of holes in the head that match up with holes in the cam gears. You just put in a couple of bolts with a spacer or stack of washers behind them & the back of the cam gears, then snug the bolts down. The Dodge v6 used in the Stealth is that way. Didn't have to worry about the cams moving while I changed the belt in my son's Stealth.

 

It wasn't the looks, it was the dimensional precision. Center-Center was off by a couple of mm at least. Hole diameter was oversize by a similar amount. Btw, you left off the words 'left over scrap' before 'maple'.
;^P

Considering that it was all of 17F in your newly finished, uninsulated & unheated garage, that we'd been at it for several hours, & were trying to get done before our legs froze up to our cajones, they didn't come out too bad. More importantly, the 1st ones we made did the job (LOL). The belts went on that night.

 

BUMP: Don't have a definitive answer yet. Any chance someone could measure their 2V's cam-cam spacing & diameter of the camshaft in the gap between the back of the cam gears & the cam seal?