88 duke timing gear replacement (Page 1/2)
sdgdf NOV 07, 11:28 PM
I bought a 88 duke coupe non-runner and from talking to the previous owner it may have a bad timing gear? These were made from plastic or fiberglass or something? I remember vaguely from years ago reading threads that this goes bad regularly on the duke and you can just change this and it’s fine?

What are the symptoms of this being bad? Is the engine interference? Is it safe to try spinning it or starting it?

I read in threads that the hard part of changing this is pressing the gear on for the camshaft?

What about changing this without dropping the engine completely?

Can I just buy https://www.fierostore.com/...%20%208588&d=184&p=1 and https://www.fierostore.com/...20%20STEEL&d=184&p=1 , get the gear pressed on by a shop, and drop the cradle a little and swap cams out through the wheel well or something?
skywurz NOV 07, 11:32 PM
Non interference engine

Pull oil cap and see if you can see a valve spring. Have someone crank it and watch and see if the valve train is moving

Cam has to be pulled and new gear pressed on

You can get away with slightly dropping the cradle until the cam gear clears. Just the 2 rear cradle bolts let it pivot on the front 2.
theogre NOV 08, 09:58 AM
A lot of problems make engine not starting &or running...

Example: "Dead" ECM &or ICM makes car no start. ECM may seem to work & MIL/CEL & Scanner perform as normal but just crack solder in the "wrong" joint means not turn on Injector etc. If have console out for any reason... see https://web.archive.org/web...ierocave/ecmheat.htm

Yes open oil fill & watch the rockers move or not.
If not... see https://web.archive.org/web...~fierocave/l4cam.htm

88 w/ fiber gear only runs the cam & should last longer. Not like older versions that cam runs the oil pump, worse oil pump & distributor & problems w/ them "blows" the cam gear like an electric fuse or "shear pins/keys" lawn mowers, snow blowers, etc.
is/was metal gear but maybe hard to find now.

⚠️ Warning: 88 Dukes have other problems like the balancer in oil pan likes to break & wreck the whole engine. If/when that happens then "easiest" is to find 87 Duke that have most 88 Duke features but uses normal oil filter & pump setup.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

sdgdf NOV 08, 07:04 PM
Yup the valvetrain doesn’t move.
buddycraigg NOV 09, 12:03 AM

quote
Originally posted by skywurz:
Cam has to be pulled and new gear pressed on
.



no it doesn't

You can replace the gear with the cam in the engine.
skywurz NOV 09, 10:33 AM

quote
Originally posted by buddycraigg:


no it doesn't

You can replace the gear with the cam in the engine.



Oh really. Could you please elaborate on the process?
82-T/A [At Work] NOV 09, 10:57 AM

quote
Originally posted by skywurz:

Oh really. Could you please elaborate on the process?




Realistically, you're going to have to remove everything off the front of the motor (passenger side)... or essentially get everything out of the way.

Then remove the harmonic balancer, remove the timing cover, and you'll have access to the gears and can replace it then. Then just work in reverse. It's only complicated in remembering where everything is supposed to go after you've taken it all off... and making sure you clean everything well and use new gaskets, etc.

It's definitely not impossible... but the L4 is a long engine and doesn't give you a whole heck of a lot of room in there to work.


EDIT: I'll say this... as far as parts go, it's a CHEAP job if you do everything yourself. You're just looking at new gears and gaskets. But it is time consuming.

[This message has been edited by 82-T/A [At Work] (edited 11-09-2023).]

skywurz NOV 09, 01:41 PM

quote
Originally posted by 82-T/A [At Work]:
Realistically, you're going to have to remove everything off the front of the motor (passenger side)... or essentially get everything out of the way.

Then remove the harmonic balancer, remove the timing cover, and you'll have access to the gears and can replace it then. Then just work in reverse. It's only complicated in remembering where everything is supposed to go after you've taken it all off... and making sure you clean everything well and use new gaskets, etc.

It's definitely not impossible... but the L4 is a long engine and doesn't give you a whole heck of a lot of room in there to work.


EDIT: I'll say this... as far as parts go, it's a CHEAP job if you do everything yourself. You're just looking at new gears and gaskets. But it is time consuming.




I was thinking more how you get the pressed on gear off of the cam and the new one pressed on without removing the cam.

Also another trick worth mentioning is not to tighten down the timing cover until you get the harmonic balancer seated otherwise you could be off center and you will never get the front seal to seal.
theogre NOV 09, 05:30 PM
Read the Cave Page that tells you how to remove & press on new.
There's more ways to remove but can cause other problems if done wrong & ignored.

The cam gets threaded so the press doesn't allow the cam to push in when installing new gear because push in can blow out cam's "freeze plug" requiring to pull the engine to fix that.

Carefully heat the cam gear to 200+°F w/ water or more heat w/ cooking oil (~ 250°F max) & gear needs little effort to put on.
But don't put on too far or will break the bearing that bolts to engine under the gear.

If can find a metal cam gear that same type as OE one, those can last if installed right.
Do Not use "performance" set w/ straight teeth if still around. This won't work w/o other mods & parts & even then not made for street use as daily ride.

Helical teeth & bearing under that keep cam in place the long way + is "quieter" as 2 teeth are loaded at any giving time.

If you really want to pull the cam...
Can remove the lifters w/o yanking the intake but do this before lowering the engine.
Need OP sender & DIS brick off to get lifter cover off.
Fix 10mm Ratchet end wrench helps too to save work pulling the Alt.
sdgdf NOV 09, 10:54 PM

quote
Originally posted by theogre:

Read the Cave Page that tells you how to remove & press on new.
There's more ways to remove but can cause other problems if done wrong & ignored.

The cam gets threaded so the press doesn't allow the cam to push in when installing new gear because push in can blow out cam's "freeze plug" requiring to pull the engine to fix that.

Carefully heat the cam gear to 200+°F w/ water or more heat w/ cooking oil (~ 250°F max) & gear needs little effort to put on.
But don't put on too far or will break the bearing that bolts to engine under the gear.

If can find a metal cam gear that same type as OE one, those can last if installed right.
Do Not use "performance" set w/ straight teeth if still around. This won't work w/o other mods & parts & even then not made for street use as daily ride.

Helical teeth & bearing under that keep cam in place the long way + is "quieter" as 2 teeth are loaded at any giving time.

If you really want to pull the cam...
Can remove the lifters w/o yanking the intake but do this before lowering the engine.
Need OP sender & DIS brick off to get lifter cover off.
Fix 10mm Ratchet end wrench helps too to save work pulling the Alt.



Sounds good, I started reading the cave earlier today and you have a link to an old thread with pictures that looks like it helps.

How do you line up the cam and time it? I would think there’d be a mark on the gear for TDC but can’t the gear just go on the cam any old way?