Hideous V8 engine noise

[agrid]

My brother's 59 Oldsmobile Rocket 88 371 V8 started making a horrible noise and running shithouse. I can only describe the noise as and intermittent crack. As soon as it starts making the noise the car misses and cuts out. Sounds ominous right?

I, optimistically, wondered if the crack noise could be detonation due to poor timing so I checked the points and timing. Points were ok but timing was no where near the mark which seemed odd. I wondered if a tooth had come off the distributor drive gear so pulled it out and it looked fine. I used my phone to take a photo down the distributor shaft hole and found the attached. Are you thinking what I'm thinking?

[Nero Diablo]

Depending on how the camshaft is timed you could have a timing chain or gears issue.

[agrid]

Have a look at those cam gears, am I reading to much into it?

[Desmo]

No you're not.
I take it the dizzy runs of the end of the cam?

[agrid]

Yep same as a Holden V8. I've just noticed over recent years that once I get and idea in my head of what something might be I tend to see what I think I'm seeing. Its cost me some money too and is a good thing I do double-blind experiments at work.

Can you see a missing tooth or is it just me?

My brother just wants to put another motor in it but he just doesn't realise whats involved and that it will halve the value of that gorgeous car. The engine was rebuilt a few thousand k's ago and, until he fucked it, sounded better than any V8 I've ever heard before.

I've put a cam in before without removing the engine, just removing the radiator and pulling it out the front like a shishkebab.

[Captain Starfish]

Hard to see initially in the photo but, now you've mentioned it, that does look awfully like a black hole about the width of the tooth either side of it.

[GSX IN SHED]

what is left on the end of distributor? looks a lot like busted dist shaft......
is there a carton for guessing right???????????

[agrid]

I was trying not to put too many ideas in people's heads but I reckon the red circled bit is a missing tooth and the yellow circled but is a mark caused by the impact on the next tooth.

[agrid]

This is the bit we are looking at if you are having trouble getting you bearings (pun intended).

[Desmo]

Sorry mate, I'm with you on this one.
How's the gear on the dizzy? Any wear characteristics on it?

[agrid]

The dizzy gears looked fine although there did seem to be the same shiny spot on all teeth. No need to feel bad, I'm just trying to help my brother out and preserve a lovely car [see attached]. He wants to just put a 350 in it but I'm tying to explain that if he does the value of the car will drop by about the same amount. It shouldn't be that big a deal to put a cam in.

[agrid]

Wow! This series of videos is excellent.

[Desmo]

If his solution is to drop a 350 in it, he doesn't deserve that car.

[agrid]

^ Tell me about it.

[Desmo]

What's the big circular piece at the bottom of the pic? It looks fatigued and broken.

[agrid]

Thats a sleeve that the dizzy slides through, I think damged appearance is just oil sitting on it.

Funny thing is that sliding the distributor shaft up and down seemed to make the same "crack" noise which make sme wonder if the damaged tooth on the cam is hitting the distributor gears and pushing it up.

The bit down the bottom is presumably the oil pump drive, it looks a bit knocked around.

[edit, second thoughts maybe its just a dob of grease on it, seems to be a hex drive, I thought it would be flat]

[ReCon]

Cam is borked. Dizzy drive gear looks like it will need to be replaced if it was part of that disaster when it happened. [Fatigued tooth end likely to let go]. Also where the hell is the missing piece of tooth now living?, sump or in the thick of the action near the big ends or mains. [crank].

The timing gears haven't lost any teeth have they? Was the chain rattling like all hell beforehand?

Tell him the Olds needs some TLC right now..

[agrid]

The engine was rebuilt only a few thousand miles ago and ran like a dream. One of the quietest V8s I've ever heard so I' thinking everything else is in good shape. The distributor gear looked fine but I suppose a smart person would replace it to be on the safe side. Hopefully the tooth made its way into the sump. I can't see on the parts catalogue if there is a filter on the oil pickup or not. I haven't seen inside one of these engine so don't know how large the openings are around that end of the cam. My other brother (the one that knows about engines) told me that the pin holding the dizzy gear on once dropped out and got caught between it and the cam in his 186 with fairly disastrous results. I'm thinking the dizzy shaft may have skipped a tooth because the timing mark didn't even show up when I checked the timing (although I did forget to remove the vacuum advance hose).

[Arwon]

who rebuilt it?
i would be talking to them before i changed anything. That cam doesn't look bad from the pics supplied.

[agrid]

Yeah, I thought the cam looked good too, unlike some of he cams I've seen in low-mileage Holden V8s. It the distributor drive gear I am worried about. I'll go back and take more photos when the oil has run off and there are less fumes.