I'll be replacing a fiber cam gear, per advise from this forum. I've read several threads on the options for replacements, including the 7.5 degree advanced gears. The car is a 1919 Speedster. The engine has a Rajo head, and uses a period correct Delco distributor. Engine was rebuilt with new rings and aluminum pistons, new valves and valve guides, new babbit all around, new crank gear, new cam bushing, and the crank was ground. No magneto, just 6v battery. The cam itself is stock, and had not been ground. I'd like some advice on whether the advanced gear would be a benefit, or a detriment, given the car and engine it's to be installed in. Thanks for all input.
I really like what the advanced gear has done for three of our T's. I am not sure what effect it would have when using a RAJO head. But for our engines, I won't build another one without using the advanced gear.
And why are you not using a reground cam or a new 280? Seems to me that if you want the best performance possible with all the other stuff you are using, a good cam would be desired.
Dave, there is a lot of extra stress on the cam gears with the over head, the valve springs are stronger cause the valves are bigger, then you have the rocker shafts. I would not use any fiber or nylon gear, my self I chose the bronze gear and hardened lower for just the piece of mind nowing I would never have to worry about breaking a crank from jumping time. Just my two cents worth! Joe
Tom - The engine work was done in 1980, and the engine has been stored since then. I don't feel I have the knowledge and experience to tear it all apart and get it back together correctly, and I don't have the resources to have it done professionally. I want to do what I can at this point to correct any significant problems, and I've been told that the fiber gear needs to go. Another $400 for a new cam just isn't in the cards right now. I don't intend to push the car to it's limits, but I do want it to be safe and reliable.
Joe - That's what I was thinking as well; the extra stress of the OHV would necessitate a stronger gear. Given that, would an advanced gear be better that a standard gear? Since I am replacing it, I may as well get the best one I can for the situation.
Others may not agree but the advanced gear helps out a great deal on low end oomph. Like another poster has said, I wouldn't use anything else knowing you have a stock cam.
With the overhead there is a lot more variables and your advance gear would help but there is only two people that will make them, Bill Stipe has one that you can adjust what advance you want or Dan McChearn that will make a gear with the advance you want. My self I would spend the money on the bronze gear since the overhead is already going to give you enough bang for your buck!! The stock T"s steering and brakes get real iffy over 50 MPH !!
Actually, Jacque Smith makes them, non adjustable, made from some type of composite. Have had one for a little more than a year now with 1,000 miles or so with no problems, just more power.
I have two more on order now, for a couple of friends cars.
But again, I can't say much for the application on an overhead set up.
We run at 35 MPH most of the time and with 4 big folks in the car this weekend,(1,000# or so)and did a good job on some tough hills. Really makes a difference.
Thanks, guys. I plan to go with a bronze replacement. Perhaps I'll get brave and see if I can enlist some assistance to re-drill for the advance. I've read other threads that show/describe how it's done. Doesn't look too complex. That said, I'll be glad the fiber gear won't be in there anymore regardless.
Any hints on getting the old one off? I have the cover and retaining nut off, but it's still tight on the shaft. Gear puller?
Dave, Dan will drill what you want if you call a head for it, DMC gears.com
I am interested in the gear you are taking off. It apparently is unrun and my experience is the old fibre gears are just fine assuming that the line bore job is lined up right and it is used with new gears elsewhere (crank and generator).
Thanks Joe. Dave- my e-mail is dmcgearsatyahoodotcom if you want to contact me.
Les, You're correct; it was new when installed in 1980, and has never been run. From what I've read on the forum, the repro fiber gears are/were unreliable, especially with the added stress of the OHV. If I can get it off without breaking any teeth, I'll let you know.
Dan, I'll likely contact you via email when I'm ready for the replacement. I still need to figure out how much (if any) advance would be appropriate for the engine I'm putting it in. I think I read somewhere that no more than 3 degrees is necessary, but I've also read that 7.5 seems to be the norm for the nylon gears that are available. Any additional advice, given the OHV?
Is there a trick to getting the cam gear off? It doesn't seem like a gear puller (2 or 3 arm) would fit with the crank gear on. Does that need to be removed before the cam gear can be pulled? I'd rather not break it getting it off. The "bible" says to use a gear puller, but doesn't say that the crank gear needs to be removed first. Thanks.
For what it is worth I ran a 8 valve Roof using a fibre gear from that era with no problems. That car has toured many miles. In MY opinion fibre gears get a unfair rap!! I agree that they will not put up with poor gear mesh or being run against worn gears or a improperly set up generator installation.
OK on removal now. Given as how this is a OH engine removing the camshaft is a pretty much a breeze.
Lift off the rocker arms as assemblies.
Remove the pushrods and stick them in numbered holes in a piece of cardboard
Get 8 clothes pins and lift up the lifters and clip on the clothes pins to hold them up.
Remove the two hex head set screws that hold the cam bearings.
Pull the whole camshaft out the front.
Now you can inspect the camshaft AND bearings.
If this is all good (now would be a good time to buy a fancy cam), and slide the cam back in.
Yes you want to make sure the set screw holes in the cam bearings are pointing in the right direction as you slide the cam in AND make sure that you have the cam rotated to the right position to mesh with the timing mark of the cam gear.
With a bright light and a awl you can get the cam bearings into the right position to install the set screws
The rest is easy and if you kept track of everything them all you will need to do is verify the valve lash.
The way I have done it I use a pinch bar that
has a slight curve on it at the end I pry one side of it the rotate the cam one half turn and pry again and kept doing this untill the gear came off No need to remove the crank gear.
The way I have done it I use a pinch bar that
has a slight curve on it at the end I pry one side of it then rotate the cam one half turn and pry again and kept doing this until the gear came off No need to remove the crank gear.
I have a fiber gear on the coupe, it has been there since 1978 with no problems for the past 35 years. Lee suggests that they fail due to the generator gear not running true and biting into the gear teeth. I have carried a spare since the so-called problems came up in the 1980's, lets hope it stays in the box!
Tried to remove the camshaft today. Engine on the stand, upside down (lifters are dropped). No pushrods installed. Crank gear and shaft are in. Removed the two bearing hex bolts and tried to pull it out. No dice. Tighter than ever. Rapped on the stub end a few times, and it moved, but it seems pretty tight, and I'm not sure if I'd be able to drive the shaft out through the rear bearing without damaging something. Well, unless I can get the camshaft out and the old gear off, I guess I may be leaving the fiber gear in!
Any other suggestions? I'd rather not take the crank gear and shaft off if I don't need to. Thanks.
Use a brass drift on the end of the camshaft - just drive it out.
Maybe I'm missing something here but, you don't have to remove the camshaft just to change the cam gear.
Jerry, I don't have room between the gear and the housing to get a puller in. I don't see any other way to get the gear off; maybe I'm missing something?
Steve Jelf made this one to fit. Some pullers have flat narrow grabs on them that fit.
Is this picture recent? Not trying to insult your intelligence but the cam gear will definitely pop off if not almost fall off once you get that nut off the front of the camshaft.
Just use an adjustable wrench and take that nut off of the front before you try to do anything else.
Seth - good one. I've had the nut off, and actually whacked the back of the gear to see if would pop off. No dice. I think I'd break it that way. Just trying to get it off in one piece. Thought it might be easier to fit the gear to the shaft with the shaft out anyway, but maybe not. Guess I'll try to fabricate a puller like Steve's. Thanks.
Have you tried rotatating the crankshaft and camshaft and tapping on the back side in various places around the gear? Once it is started to come off, it should come off easy. It is the two dowel pins holding the gear, so try to get it in position where your tap will be opposite one of the pins, and then rotate and tap the other side
Dave -- Do it the Arkie way and use a Stanley Wonderbar and a big screwdriver to pry it off. If you mess up the fiber gear, you haven't lost anything.
Well, finally got the fiber gear off - not without a bit of damage to a few teeth, and to one of the pin holes (sorry, Les). That thing was tighter than all get out (possibly oversized?).
Drove the shaft out of the rear bushing just enough for it to disengage with the crank gear, then gave it a few whacks to pop it off. Installing the new one was easy compared with getting the old one off! Thanks for all the advice, it's greatly appreciated.
I have two comments for those who may face the task of replacing a fiber timing gear.
1 The puller arms in the picture Ed posted above worked very well.
2 Don't worry about damaging the fiber gear while removing it. It shouldn't be used again anyway.
A good solution to removing the cam gear is to drill and tap two small jacking screw holes Before you install the gear. That way it's easy to get to gear off later if needed.