Durability of adjustable cam timing gears

[Tim]

I have seen a variety of adjustable cam timing gears / pulleys, and I don't like the design of most of them.

First, anything with less than 5 bolts is asking for it to slip.

Second, I saw an AEM gear for a Neon the other day, and on the back side, the metal around each bolt hole was less than 1/4" thick, which makes me think it could break or strip easily.

Third, most cam timing gear makers seem obsessed with taking as much metal out of the center of the gear as possible to make it lighter, never mind the fact that this lightness only weakens it, and does next to nothing for improved performance. I'll take a 3 ounce heavier timing gear any day that won't break!

Has anyone has a gear break or slip out of timing on them? If I were to put one on my 5 Neon with a cam and ported head, it needs to be as reliable and solid as the factory part. I'll be living in L.A. in 6 months and will not have the time or patience to dig into the motor and reset it every couple thousand miles!

In addition to 5 adjusting bolts, these timing gears should have additional threaded holes drilled and tapped at varying timing positions, so once you have it where you want it, you can Loctite in an additional bolt that locks it in place and it can't slip.

[DOHCRT]

So...did you have one slip or fail and that is driving the questions/rant? or are you just making observations. I have been running adjustable gears from FWD Performance on my 8 and 16 v cars for over 10 years without even a hint of them slipping. I can't recall anyone else having any real issues either.

[Gaboon]

I have seen a variety of adjustable cam timing gears / pulleys, and I don't like the design of most of them.

First, anything with less than 5 bolts is asking for it to slip.

Second, I saw an AEM gear for a Neon the other day, and on the back side, the metal around each bolt hole was less than 1/4" thick, which makes me think it could break or strip easily.

Third, most cam timing gear makers seem obsessed with taking as much metal out of the center of the gear as possible to make it lighter, never mind the fact that this lightness only weakens it, and does next to nothing for improved performance. I'll take a 3 ounce heavier timing gear any day that won't break!

Has anyone has a gear break or slip out of timing on them? If I were to put one on my 5 Neon with a cam and ported head, it needs to be as reliable and solid as the factory part. I'll be living in L.A. in 6 months and will not have the time or patience to dig into the motor and reset it every couple thousand miles!

In addition to 5 adjusting bolts, these timing gears should have additional threaded holes drilled and tapped at varying timing positions, so once you have it where you want it, you can Loctite in an additional bolt that locks it in place and it can't slip.

I've been running the cheap four bolt on my 8 valve engine for years, never had an issue. I must be lucky seeing they are so prone to failure due to poor engineering....*blink*

[shackwrrr]

Safety wire the bolts and it'll be good.

[turbovanman²]

TIII's have 4 bolts, NEVER had one come loose and they have some of the worst loading of any engine.

[zin]

I will say that I did have a Neon (SOHC) kill itself on the dyno due to this, well that and the fact we were running nitrous at the time. And no, it wasn't the nitrous itself that did it in, but a combo of the two.

Mike

[GLHNSLHT2]

I've heard about the neon one's breaking. The TD 8v and the Masi gears that Todd had made have more material around the holes than the neon ones and should hold up just fine.

[iTurbo]

Well I hate to be a pain in the ---, but I have had a TIII adjustable sprocket come apart. I can't say I blame the sprocket though...

A little over five years ago, my brother and I took a road trip from Wyoming to Iowa to get my white Spirit R/T. We drove my red Spirit R/T to go get it. Half way through Nebraska, the engine started making a ticking noise, which eventually turned into a clanking noise. Turns out the timing belt tensioner ---- the bed! I didn't have much choice but to keep driving, hoping I could at least make it to my Dad's house in Minnesota. Finally, just before I got to Des Moines the timing belt broke. When I got the car towed home and repaired it, I found that two of the exhaust cam sprocket's lock down screws were gone and the other two were about to fall out. The timing belt tensioner came out in 2-3 pieces it was so bad. I called FWDP and she sent me new replacement screws and the sprocket was just fine to reuse.

I ended up finding one of the screws in the oil pan during the repair. Turns out one of them fell down into the front seal retainer area, got wedged in between the belt and seal retainer and busted a hole right through it. No wonder I had oil all over the place!

[tryingbe]

There you go, heavy duty version made just for you.

http://www.modernperformance.com/product/MPx_Adjustable_Cam_Gear_03-05_Neon_SRT4_95-99_Neon_24L_DOHC/587

[Tim]

Yes, those Modern Performance gears do address some of my concerns. Although I think they could fit 8 bolts in there if they tried! :) Do they have one for a 5 SOHC 2.0 engine in a Neon?

I recently saw an AEM cam gear for a Neon, and was not at all impressed with its spindly and very weak looking hub section. Too much metal cut out for no good reason.

[shadow88]

While we're on the topic and I'm sure this plays a large role in longevity of the part. Anyone care to share the correct torque for the adjusting bolts?

[Gaboon]

While we're on the topic and I'm sure this plays a large role in longevity of the part. Anyone care to share the correct torque for the adjusting bolts?

Tighten each nut in a circular pattern. Torque each nut until it gets loose, then back it off half a turn...:nod:

[shadow88]

1/4 turn before it feels "mushy"

[Gaboon]

1/4 turn before it feels "mushy"

I stand corrected.

[tryingbe]

8 valves can use MP offset cam keys if owner wants factory reliability.

http://turbosunleashed.com/shop/images/Cam%20Keys.jpg

http://turbosunleashed.com/shop/offset-camshaft-p-250.html

Are there no offset cam keys available for neon?

[Tim]

The Neon cam uses a small 1/8" pin in the end of the cam. And nothing else. No key slot.

And that's something else I have a real problem with. A pin 1/8" in diameter is all there is keeping the cam turning? That can't be too hard to shear off! And even if it does somehow meet engineering specs, and even if it rarely shears off in any application, surely they could have put in 2-3 shear pins, or something a little more solid! Maybe 3 smaller bolts like a big block Mopar V8 cam.

I did recently see a photo of that shear pin slot in the cam pulley being machined out, and a square piece of metal put in with the hole for the shear pin offset drilled. That is a possibility.

[shadow88]

Joey, you crack me up!

Tim, the neon pin is only for alignment purposes and it's the torque of the cam bolt that holds the sprocket to the cam.

[turbovanman²]

Many use a small pin for alignment, and unless you don't tighten it correctly, you won't have issues.

[shadow88]

As a side note, the other day after reading this thread, I thought I would take a look at adjusting my sproket a little more advanced and I noticed the nuts were surprisingly loose.

Not loose, like falling off and slipping the alignment, but surely not as tight as I would have left them some time ago. I made my adjustment and retightened to about 150 inch pounds without a torque wrench. No loctite, just the factory fidanza fasteners.

So maybe these failures might be caused by improper initail torque and never checking them?