That's not supposed to do that is it? (SBC timing chain content)

Long and short of it. Soon to be brother in law brings his truck over to my parents place saying his truck is puking coolant. a bit of diagnosing later he's loosing it out of the rear freeze plug. 1 pulled motor later, he leaves town for work and it's sitting in pieces in my parents shop. Due to it being a roughly 30x30 steel building most of my tools live there as well. 5 months later I need to get in and pull the motor on the SVX due to some bearing noise. I'm not going to pull anything else apart with his motor/truck being spread over the bay we work on vehicles in, so I needed to wrap his motor up and get it out of the way. I say BERK it, and decide to put it back together again for him for him as a wedding present/get it the berk out of my way gift. While it's apart dad wanted to do all the gaskets/seals. He's paying for it, no problem. YEah..... Every time I pull something off something else needs to be fixed on this damn thing.

Yesterday was this... (sorry for the crappy cell photos, it's what I had at the moment)

Now it's been awhile, but I don't think it's supposed to be that damn loose. It would explain why his truck runs like a dog. Put the pedal to the floor and I think SWMBO 4cyl/auto S10 will outrun it. Waiting on Rock Auto now, good news on it is that I can return the other gaskets and seals I haven't used yet and even with the addition of the timing set, I'm saving money.

I'm no SBC expert, but that looks about right to me. There should be a spec you can measure and compare it to.

Spend the extra $ on a Cloyes set.

Does that cam gear still have nylon teeth? If so replace it for sure, those are junk.

Nah, it's got metal teeth, but they're WELL worn. Truck is an 88 that has 330k on it, but it supposedly had been rebuilt twice. It was purchased from the original owner, dude hauled a small horse trailer with it and a food stand around to fair's and festivals with it. only rust is in the bed around the 5th wheel setup, Decent paint. interior needs springs/foam on the drivers area of the bench but it's been a decent truck for him. I'm thinking the second rebuild didn't happen or they just "refreshed it" reusing what they could.

Depending on budget, a new aftermarket cam will help wake it up. 330k is a lot of wear on those lobes.

Careful shopping should let you find one that won't make the ecu complain, and keep cost reasonable.

Looks a little loose to me also. Since you have it exposed, I'd replace it for sure.

That thing is wore slap out. Is it still in time?

In reply to moparman76_69:

I don't think so. going to check later this evening.

Everyone else:

If it was mine, it would be getting a 383 with a TPI setup, Probably just go with a squirt for ease of tuning. Not having to deal with the whole prom burning would be nice. BUT it's not mine, and I don't like the guy that much. It's actually pissed me off quite a bit, he comes home from the road and talks about working on it, but never touches it. Oh well... I just want it out of the way at this point.

That's about normal for a small Chev. I've seen them so slack the chain wears a groove through the bottom of the timing cover...My first 283 had 4 of the plastic teeth left on the cam gear.Yet they hardly ever jump.

I had a J20 jeep with a 360, and it jumped the chain when I shut it off one day, bent all the intake pushrods. I remember thinking, when I pulled the cover, "Wow, that chain is tighter than a new small block Chev."

last i checked, a new cheap stock replacement timing set is about $30.. but i've seen a lot worse in engines that were running good.. you can also get a new Sealed Power cam and lifter set for under $100.. you know, while you are in there..

the lack of power was probably from having the ignition timing set at the factory spec of 0.. pull it ahead to 10btdc or so and the TBI motors really wake up.

Cloyes set from Rock auto was 18ish +shipping. Worked for me.

$19 buys a new timing set. Do that and be done. Seriously. Not worth the hassle.

That's the plan bob.

i had one worn enough that it was slapping the block and sounded just like a bad bearing through the stethoscope.

Played with it a bit tonight. I think it's pretty far off. With #1 @TDC the timing marks were lined up but the distributor was past the #1 point on the cap, I think someone may have screwed up the distributor install or tried to advance it and pushed it to the point the computer wasn't happy. would explain the abysmal mileage and power. Like low teens mpg for a 2wd 1500 with a 700r4 trans and a 350.

SBC timing chains are incredibly forgiving. 1/2" slack is not unheard of on a high-mileage engine that still runs fine. I have had a few that were so loose they rubbed the timing cover. That is when you need to replace them. Ok, I let one of them rub a hole in the timing cover, but seriously... that amount of slack accounts for very small amounts of cam timing, especially because the cam is always being driven by the crank. The slack has more effect at lower RPMs where it tends to dance around with opening and closing ramps. At higher RPM the pull from the crankshaft is much faster than the drag on the cam and it makes little difference.

SBC timing chain sets are also butt-fck cheap. A complete timing set (both gears and a chain) can be had from Cloyes (top notch stuff) for $12. You can also step up to include the gaskets (water pump, front main, oil pan, and timing cover) for a whopping $30.

Replace it. If you don't spend the $12 on a timing chain set while its already apart, you are a doofus. IIRC, its a cloyes 300188k part number, but double check. Rock Auto lists it for $12.88 including both gears and chain.

New chain came in last Thursday night. Had a scenario paintball event over the weekend that I had pledged to be at back in April.... Nevermind the fact that it rained so hard last weekend the frogs were looking for high ground. SOOOO

Monday night I got over to the shop and pulled the old one, tap, tap, tapped the new crank gear on, got it lined up and installed on the first try. Dad comes out and looks at it... "I think you have it on backwards..." bit of back and forth from there, I pointed out the timing marks on the front, etc. But in the end, I relented and pulled it back off. I was right, it was just fine.

Pics later, but the end result? A MUCH tighter chain.

While I've got you guys. another "disagreement" between my father and I came up.

I know they're hydraulic lifters and all, but isn't there supposed to be like zero lash on the valves, and if anything like a 1/4 turn of preload from zero lash?

With the valve closed, you run the rockers down to zero lash, then 1/4-1/2 turn beyond that. Which doesn't really matter, as you just want to make sure it has pre-load. But whichever you pick, do them all the same. Glad to hear the new chain did the trick.