Cam Repair Needed For 97 SHO

[stephen newberg]

Ah, I see. Sorry. Obviously not enough coffee in yet that morning. Thank you for catching it.

pax, smn

 

[outatyme357]

I took the front valve cover off to see if i could get the spark plug well vacuum leaks sealed up and noticed no scoring where the sprockets meet the cams on the front bank - curiously, I do have these numbers scribed into the cams that i have not noticed before - not sure what is going on here - car runs well aside from that periodic ticking and leaking oil like a seive from the oil cooler. even having these vacuum leaks in the valve cover found with a smoke machine it still runs well though i am attempting to address those now. I will have to get some sprocket pics tomorrow

 

[gamefanatic]

Definitely need a better picture of the sprocket and CAM. From what I can see there is no movement. Also see no weld or pin? Yikes!

 

[outatyme357]

what do the pins look like? (what i mean is how would i spot them if i had them - i'd assume they are drilled through the sprockets.)

 

[stephen newberg]

I do not see anything either. When pinned, you are correct, there is a hole drilled through and a pin pressed in and then its ends flattened to prevent it from coming out. Its a far less common way of handling the problem, but back in the day when this was a newly found thing, it was tried by some and worked fine, but was a lot more hassle than just welding if you could find a decent welder to do the job.

pax, smn

 

[E1]

Hi Stephen -
So you and all else know, the pinning was found to be a temporary fix.

The problem was with the hardness characteristics of the sprocket material vs the shaft material.

The powder-cast sprockets were almost ceramic in hardness vs the tool steel hardness of the shaft.

A pin was caught in the middle in a high vibration environment.

Hard enough to not be damaged by the sprocket = the pin chewed up the shaft.
Soft enough to spare the shaft and the sprocket ate the pin.

It was a no-win situation in the long run.

Many folks with pins ended up getting the cams welded once the pins started wearing. I have welded my share of pinned cams which were found to be chattering.

 

[stephen newberg]

Makes sense to me. Back forever ago when all this was happening, I remember briefly considering doing pinning for mine, but instead figured welding was likely a better idea and went with that.

pax, smn

 

[GEN 3 SHO FAN]

Like others said, there is no pinning, no welding and also no grinding marks on the cams (2 photos only : xxx242 and xxx248).

To see them correctly, you have to take photo of the junction of the secondaries sprockets with the cam, from the "driver side" of the sprockets. Its more complexe to see between the sprocket and the octogon but its doable with a small flashlight at least.

For the welding, the octogonal part has to be weld to the cam too (2 step for them : sprocket to octogon and octogon to cam).

By the way your oil leak in oil filter area is really bad, that let me remember my leak which I first tought it was coming from the cooler but it was the cam seal which let going out a large quantity of oil... (Once they leak, they leak a lot.) Watch if you have oil under you vanity cover at extreme driver side. If its the case, you will have a straight line of oil in the same axe of the waterpump pulley.

 

[gamefanatic]

By the way your oil leak in oil filter area is really bad, that let me remember my leak which I first tought it was coming from the cooler but it was the cam seal which let going out a large quantity of oil... (Once they leak, they leak a lot.) Watch if you have oil under you vanity cover at extreme driver side. If its the case, you will have a straight line of oil in the same axe of the waterpump pulley.

I think the motto that I heard about leaks works well: "Fix leaks from the top down"

 

[outatyme357]

i appreciate all the kind advice! - I did ultimately find rotted out oil cooler coolant hoses, a leaking water pump side camshaft seal and a leaking oil cooler (oil leaking from the oil cooler o-ring) i am in the final stages of dealing with all this. I snapped a valve cover bolt off in one of the heads. figure if it is not sealed correctly i can always get a welder and weld a nut to the broken bolt and turn the remains of it out - gates 21832 and 20605 are excellent replacements for the oil cooler coolant hoses along with trimmed down 5/8 stainless steel hose clamps. you have to measure and trim the hoses some but they work nicely.

 

[GEN 3 SHO FAN]

I snapped a valve cover bolt off in one of the heads. figure if it is not sealed correctly i can always get a welder and weld a nut to the broken bolt and turn the remains of it out .

Welcome to the club !

Another owner said to me what he did. He grinded out all the remnant of the bolt and made a new hole. Mine isn't corrected but isn't leaking.