1996 SHO, Cam Sprocket Failure or not?

[Aaron88]

1996 SHO 143k Miles, was a 1 owner car that I bought with 136k on it, great condition inside and out, ran like a dream! then, there I was, in the taco bell drive thru and it was snowing (this actually happened this spring) and my car got a really rough Idle and was unable to start back up and I had to be towed home...

I thought it was a cam sprocket failure for sure, and maybe still? but I started it up today, while it is really loud and has a rough idle which requires a little bit of gas to keep from dying, it runs... (sounds almost like it has an intense exhaust leak right at the catalytic converter... now my question to you all...

Can your SHO Function even after cam sprocket failure? As I am looking everywhere for answers it seems to me like they say since it is an interference engine that it would be toast... well I can still get this guy to hit about 4,000rpms (didn't go too ******* this barely running beast or could have probably gotten higher) but the revs kind of lagged and it stayed at about 3k for a few seconds before hitting a wall and going back to barely running...

would you say that in theory that 8 of 32 (1 of 4 cams) is unfunctional and banging around while the other 6 cylinders are still running strong? or does it not work like that? I am able to put my car in reverse and drive and was able to drive it in my driveway but my gas light is on and that is some really old gas.. I am thinking about waiting until payday and getting some fresh gas in there and seeing if it is at all drive-able on the road/see how it actually acts

If anyone has any suggestions of what it could be, or why it would sound so loud right outside of the exhaust manifold, or if you know for sure it is the sprocket or whatever just post and let me know if you are familiar, I was 99.8% it was the sprockets when I couldn't get it restarted in the winter, but now that summer is here and it sat for awhile it appears to be at least runable...

thoughts?
Thank you

 

[jimtash]

No, it won't run because the valves will be bent. You have a check engine light on? Any codes? Sounds like either a coil or several coils are fried or the crank sensor is.

I replaced the coils on mine with a set from Ebay and the car ran like crap from cold. Missing, bogging down, and just didn't want to rev at all. That's how much of an impact coils have on these engines. The rear bank is especially susceptible due to the heat they endure. So definitely look at them even if you don't have a code because it sounds like after the engine cooled down, whatever quit started to work again. Another thing is to definitely pull the plugs and gauge their condition. Dark sooty plugs means the spark was weak which is indicative of a coil on the way out.

 

[Aaron88]

Thanks for your response!

Will definitely be doing some rooting around in there the next few days, if the cam sprocket failure would no longer let the engine run then I may be in LUCK! whew. that is definitely some good news to hear. I had a CEL on when it happened, but I took the brand new battery out that I had in there and had it on a slow charge so that it wouldn't go to shit, popped it back in there and while it was running for a short time 2-3 minutes with me messing with stuff and trying to get a feel for how it was running it didn't throw any codes/CEL's at all. hopefully I can get one so that I can diagnose it further..

is it possible that it only walked/slipped one tooth and that the valve timing didnt yet mess up enough to cause total failure and just banging and misfiring causing the power loss?

if anyone out there is real savvy with these engines their input is greatly appreciated, I will definitely look into the Coils/Crank Sensors.

Thanks!

 

[jimtash]

If the cam sprocket failed, the engine would run on the good bank but not on the other. You'd have a loud banging noise and backfiring. And by no means could you get it to 4000 RPM's.

 

[rubydist]

Guys, the cam sprocket failure is not always a total slipping of the cam sprocket, sometimes it slips a few degrees and sticks again for a while. So, I would say it is possible that has happened in this case, so that the valve timing is off on some valves but not enough to trash the valves.

OP - DO NOT ATTEMPT TO RUN THIS ENGINE! You need to pull the valve covers off to determine the issue - it still may be salvageable! But if the sprocket has moved some, it can fail completely at any time, which is why you need to stop running it until you know what is up.

 

[stephen newberg]

I think Rubydist just above is giving very good advice. You really need to look at the cam sprockets before running this motor again if you want to be sure that there is a chance to save the motor if one of the sprockets has started to slip.

The description you have given could be a so far small slip on the sprocket, it could be coil packs, or it could be the IAC sensor. All would produce about this sort of thing. If the car has not had its cam sprockets welded yet, that is certainly the first thing that needs to be checked before the motor is started again.

pax, smn

 

[mrecoolgar]

My 96 had cam failure just shy of 160,000 miles.
It ran rough, no banging or backfires.
The front bank intake sprocket slipped.
It's easier now to check and correct and eventually it will slip... guaranteed.
I repaired mine myself and it was a pain finding parts, the cost of said parts and the time and effort involved.

 

[Aaron88]

Thanks for your suggestions!
I took off the V8 SHO panel and that ignition box? and pulled out the 4 coils there on top and the 4 spark plugs beneath, they are older looking but appear to be in good working order, I noticed I had 3 Motorcraft coils and the one under the ignition box appeared to be OEM, also in that slot was a motorcraft Platinum plug, the other 3 spark plugs were autolite Iridium XPs.. in the hole with the OEM coil there was probably 2 1/2 to 3 inches of Oil standing over/inside the spark plug hole, (not sure what this is about) while the other 3 were clean, using a flash light it appears that all of my pistons on the front side of the engine are still a nice shiny chrome finish.

is there anyway to test the coils for workability? like putting alligator clips on the power outlets of the coil while it is holding the spark plug and tapping the other ends on the battery posts to see if it arcs? or would that be a bad Idea?

I cleaned the IAC out and started the car with no change in how it runs. (sorry to the fellas who said not to start the car until I check the cam sprockets) I'd want to **** around with a few other fixes first, and this car has pretty much been sitting in the garage taking up space being practically "dead" for awhile.

to check the sprockets I would need to take off all of the intake manifold/ those 8 metal tubes and get to it from the center of the engine correct? I found this page: http://v8sho.com/SHO/valvecovers.html on how to take them off, but I am not sure if I can handle the job, who has done it? is it something that
a novice mechanic should be able to do? I've done brakes, starters, fuel pumps, alternators, but never really anything this intense, it would be a lot of nuts and bolts to worry about!

Appreciate the help, if I can turn my horribly rough,hardly running car back into the reliable great runner it once was without spending a ton of money I'd be so happy I'd jump up and down!

Any comments/concerns with my recent findings? is there a way to check the coils?
Thanks!!
-Aaron

 

[Aaron88]

Oh... and I forgot to mention, when I purchased the car, it being a 1 owner, well taken care of car, and it having 136k on it, I kind of assumed they would have fixed the cam issue, but a week or two before it "died" on me I did notice it making a light ticking noise at idle that would go away at higher rpms. and from what I read that is pretty much the tell-tale signs of the sprocket failure... well, if nothing else, i'll have some more experience taking apart an engine.

 

[Aaron88]

front valve cover is off, at first glance everything appears fine, I am trying to locate some pictures so I better know what I am looking for. one of the cylinder valve head gaskets was broken on the one with the Oil in it.

 

[Aaron88]

Well.... not sure if that is normal or not... it does appear to have some kind of newer looking wear... what do you all think? one picture is the top cam, and the other is the bottom, both on the front side of the engine... is it F*%ked?

 

[rubydist]

you will have to check cam timing to confirm that all is well (on both front and rear banks.)

btw, oil in the plug well can cause the poor idle quality, lack of power, etc.

BUT, since these V8 SHO engines are known to fail the cam sprockets eventually, you need to get yours welded once you confirm that the sprocket orientation is correct (or fix the orientation if it is not.)

 

[Aaron88]

well then, maybe next week, (or this weekend if I get ambitious) I will have to tear open the rear bank... do you know of any diagrams/websites showing sprocket position? are there TDC/BDC markings on the sprockets and where they should line up? any info on where I can find this would be great, I know it is out there somewhere... once I get everything opened up, make sure the timing is adjusted back to spec, find a welder somewhere, put it back together and start it up and hope for the best... once I get stuff ripped apart I'll try to take/post more pics.

Thanks.

 

[stephen newberg]

If you go over to v8sho.com I think with a bit of searching about you will be able to find out everything you need to know about checking on the cam sprockets and getting them welded up to fix the problem permanently.

pax, smn

 

[GEN 3 SHO FAN]

When we look attentively, we can see on the first photo that the cam stay right in place, the only thing we see is the horizontal marks when the sprocket wheel is put on the cam in factory (pressed on it) but when we look at the second (enlarged), we can see between the sprocket and the octogonal part that the cam is heavily "sandblasted" (the golden color is gone all around the cam) because the wheel broke loose from the cam. This cam is not good anymore and have probably damaged valves (too much play), sorry. Here, a photo of one beginning to move, recoverable maybe (from V8SHO IIRC) :



And this a good one like your first photo :

I'm not a veteran mechanic but with the knowledge I have on this problem, don't waste time on the second cam, it will be better to change it and verify the valves, no ? The good new is the coils are probably good.

 

[mrecoolgar]

My cam was fine, however all the valves where bent.
Remember the cam lobes ride against the shims.
The pistons hit the valves when the valves are down in the chamber to low.
Caused by the sprocket to cam failure.
The sprocket moves more than the cam.
The cam doesn't keep up with the sprockets rotation due to excessive pressure from the valve train.
Head had to be pulled of course to replace the valves.

 

[Aaron88]

Idk how dumb of a question this is, but after you take off the throttle body, and all of the upper intake tubing, there is still that air chamber thing that would connect to the throttle body, How in the world does that come off? ha.

I read about jacking up the car and going in behind the engine to remove some stuff, at first I didn't think it seemed necessary, but now I am stuck. anyone have any pointers? or a picture of behind the engine so I know what I will be looking at?

Thanks in advance!

 

[GEN 3 SHO FAN]

I you give me a e-mail, I can send you the document I made to remind me how the remove it (word with photos).

 

[Aaron88]

awesome man, [email protected]

 

[Aaron88]

UPDATE:

Rear valve cover is off. both cams have great 'teeth' and do not appear to have slipped at all.


in rebuilding/repairing ideas, I came to a timing realization, when looking at the lobes on the camshaft that turn when the valves open/close you can find a correlation, the first 3 cams (from the rear to the front of the car) I have no question that they are GOOD. so looking at the lobes... the rear right lobe in the back is facing almost dead left, the next camshaft over, that lobe is facing straight up, the next one, straight right, sooo judging by that set of mechanical sequence, the last and final camshafts lobe in that same line of valves etc, should be facing straight downward...which is not the position it is in to say the least.

unfortunately, that is the camshaft in pic 2 with the stripped looking spot between the timing chain drive and the big wrench-nut? apperatus where it connects. meaning I did have some sort of slippage/camshaft failure... luckily? that is the cam with the wrench-like nut? where it attaches, I haven't tried YET. but if I can get that cam lined up in conjunction with the other 3 cams, get it welded up, and assuming internal damage isn't severe? (piston tops look great through the spark plug hole no valve bashing damage present atleast)

that maybe \I can put it back together and it should* run fairly well again! ....

best case scenario I know... but I have my hopes up, hopefully getting that cam turned to the correct position will be the hardest task I am faced with.
Any thoughts or concerns? is my thinking on lining up the 4th cam in sequence with the rest of them a good idea for how to time the shaft with the rest of the engine? or are there timing marks somewhere for me to look for?

Thanks for any and all responses, hopefully someone is familar with the situation.

-Aaron