broke timing belt on 05 Ezgo

Sand Man

Newbie here been lurking for a few years so here is my 1st post , I bought a Ezgo today with a broken timing belt started the tear down and discovered that the cam will turn even with a wrench on the cam bolt any ideas on why would be greatly appreciated , thanks Len

BGW

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my1423

I assume you are saying the cam will not turn?

If this is the case there are a few possibilities.
1. The engine could have been run out of oil and the cam bearings are seized up.
2. A valve could be broken or bent from over revving or bad adjustment.
3. Could have lost a rod and the piston destroyed the valves.
4. Could be you just are not turning hard enough, doubt it.

basically an internal issue and the valve cover needs to be removed and the cam and head inspected. Possibly even pulling the engine head.

Sand Man

the motor turns over no broken rod sounds , I put a wrench on the bolt that holds on the cam gear on and could not turn it , I started taking the cart apart today going to pull the motor off from the cart to work on it on the bench . Tomorrow I am going to back off the rockers to see if I can turn the cam , I removed the valve cover oil looks clean no shavings, just thought I would see if anyone else has come across this problem.

Maintenance 6

Yeah. The cam seized in the bearings on my son-in-law's cart and tore the teeth off of the timing belt.

Sand Man

Looks like that is what happened to mine valves move but cant turn the cam , not sure what route to go any suggestions

my1423

I have never pulled one of these apart so someone who knows needs to chime in.

That being said,
I am assuming that the cam rides directly in the head and the head is machined to accept it.
If this is the case, The right way would be to find a used head and cam.
A cheap used engine maybe easier to come by.
Sometimes a person on a budget with lots of time can get the bearings to free up and just run them but it takes a lot of work and time to clean out the metal from the oil galleys and free the bearings up without making them so loose that they are serviceable..

Or this could have a roller bearing. Take a look at the bearings and see.
If the roller bearing is shot just take the bearings out and take them to a good parts store and replace them.
There is a number on the race that can be cross referenced and order new ones.

I am also not sure if this is a clearance engine or not. I think it is.
If it is not you will also need new valves if they got bent from jumping time when the belt broke.

Either way you need to check oil level and the oil pump to make sure it is pumping oil before you start replacing parts.
Since You can turn the engine over do so with the valve cover off and see if oil is being pumped out in the head ect.

Sand Man

I removed the engine tonight , got the cam out seized up on the left side not sure if it can be polished out , if not has anyone tried to bore out the cam bore and put a sleeve in ? I have access to a complete machine shop so being able to do this is not an issue.

my1423

15 years ago i had a honda xr500 i bought dead.
The oil galley ended up being plugged up from rtv silicone chunks from a badly done clutch.
It had a seized cam in a similar fashion.
The dealer wanted 700$ for a head and 250$ for a cam.

The local machine shop line bored the head to a larger size and turned down the cam bearing journals and polished them. They then turned brass bushings to the correct size, grooved them for oil flow and drilled oil galley holes in them. Also pined them to prevent movement in the head. Out the door 200$
But i lucked out. They had bushings in a close size that was needed.

Sand Man

my1423 that is the plan I bought a bronze bushing from Fastenal for $5.00 going to set it up on the Jig Grinder this weekend to open up the head, then shrink fit the bushing in , now I need to find a used upper cam gear , thenks for all the replys

my1423

I am not positive but i did look at a few pictures of it.
Does oil pump through that bearing into the cam and oil the other bits or does it just end at that bearing?

If it ends there and since the cam is so long and the head does not have a split in it to insert a pin i suggest you shrink fit the bushing to the cam and leave the head as the bearing surface just like stock. This also leaves the oil galley hole alone so you dont have an issue with it turning and blocking up.

If it does pump oil you might consider grinding a dimple in the head and pounding a tang in to prevent turning.

Btw, No problem your welcome. Fun to help.