I have this 351W that I rebuilt and I had water get into the oil soon after I started the motor so I had to take out the motor to get it cleaned. I got everything back today and we noticed a problem with my cam gear. It is worn on one side in sort of a strange way. I am not sure how it would do this.

It's a roller cam and I had a steel cam gear installed on to my distributor.

I figured the best way for me to describe it was to draw a picture.

Any thoughts as to what caused this (could it have been the water?) and how to prevent?

 

You say"soon after start up".Did you drive it?If not how long did it run?Minutes,hours?An engine running without proper lubrication will start"eating itself up"within minutes after start up.It appears from your drawing that it was making "steps"in the gear.How quickly it begins to wear can depend upon RPM and many other factors.Did it get up to operating temp or overheat?Either way,you're going to have to inspect every part of that engine for signs of scoring or wear.Have any actual photos?That would help.

 

Did you find the cause?Head gasket?Improper cylinder head or intake torque?Cracked engine component?Timing cover,cracked head.Could be one of many reasons.Is this the engine in your sig.Adding boost could easily cause a head to lift.Water/antifreeze and oil are a bad combo.Oil looses its viscosity when mixed with water.

 

Once I finally got the timing right and started the motor, it ran for ~10 min. I did not drive it, only had it at 2000 RPM for that long.

As for the head gasket, yes I found the issue. There were some instructions for the heads to cut out certain holes on the gasket if I had a certain setup. When I cut the holes I read it wrong, realized now I shouldn't have done that.

I just got the block and everything back from the block shop. They inspected the cylinders, journals, etc and everything else is fine.

Oh...one more thing I found out when I got the block...the middle bearing for the cam was shot so they replaced it. I am wondering if maybe that caused things to get a little loose with the water in there and cause this?

I'll try to take a pic but the reason why I drew the pic is because I am not sure I will be able to capture the detail in the damaged gears in a picture.

 

by contrast, the distributor gear looks great, I mean really good. Over the entire gear surface, the wear spot only covers about 1/3 of the area.

Well I am going to get a new cam and probably a new distributor as well. I used an old distributor that came out of a working motor, just changed it to a steel gear. I'll also check for cam play after I install it to see if it is moving. Not really sure what else to do except try again fixing the known mistakes.

 

So far everything has been going together really well. The crank end play is perfectly within its limits and so is the cam end play. All the pistons are in but one because when I was putting the sleeve on piston #3 to put it in, I broke the second piston ring so I need to try and find a new one.

The timing is set and the crank turns very smooth. I put the heads on one side and will set the rockers today. I should be able to complete one side today.

 

What did the crank gear look like?

 

no problems, using the same one.

 

roller cams require a brass distributor gear.

 

...Or steel

 

Probably a DAQ, but are either of the gears or chain new? Old and new parts don't get along very well in these situations.

 

DAQ??

The steel gear on the distributor is new but not the distributor itself. That distributor came out of the original motor in my 92 F150 which I had for years. I took the distributor and had them put on the gear.

This time around I already have a new MSD distributor with steel gear.

 

before you started the engine did you prime the oil pump !

 

I certainly did, I felt the pump start to pull in the oil and I heard the oil coming back down into the pan. However, a friend of mine did notice on the cam gear there is some discoloration (like you see on chrome exhaust pipes) in a small area next to the gear. The next one will get more than enough lube - each time I take out the distributor to reposition it.

 

another thing , you said that one of the cam bearings was shot and with what looks like no oil on the timing chain i was wondering if the oil passages were clogged with some thing !
might want to pull the plugs and run a brush down them !