Timing chain slack.

[Speedbird]

Did a search. Didn't find anything.
So I'll be lazy and go with your experience rather than looking in a factory manual.
Better off anyway.
I'm thinking this is too much play.
Measures 1/2 to 5/8 inch deflection.
77 stock 440.
Thanks.

 

[69Bee]

The manual says that if there is more than 1/8" movement (backlash) between the cam and crank, you need to replace. I say; you have the cover off, there seems to be a lot of slack, now is the BEST time to do it.

 

[Funship32]

The manual says that if there is more than 1/8" movement (backlash) between the cam and crank, you need to replace. I say; you have the cover off, there seems to be a lot of slack, now is the BEST time to do it.

X2. Parts are cheap, labor is timely and expensive. Just pony up the coins and replace it, IMO.

 

[69a100]

Just remember to either cut a replacement gasket for that portion of the oil pan, or goop it up good with gasket sealer. I forgot to do that and now I hate myself for it! Good Luck

 

[lewtot184]

that timing set is shot.

 

[69a100]

I gotta admit thou. If the rest of the motor is as clean as that gear & chain, that motor's in super shape for a chain that trashed.

 

[barnfind]

already torn down R&R time

 

[440roadrunner]

For a stocker truck / motorhome, that would be just fine for a long time.

For a performance car, I'd change it just because it's apart and cam drives don't cost much. This would be an EXCELLENT time to degree the cam.

 

[Speedbird]

Thanks.
Now for my next stupid question.
And I feel a little sheepish for asking.
Can I get by with just a new chain?
I bought it from someone that was trustworthy.
Yes the whole engine is clean inside.
They told me low mileage and running when pulled.
I've already solved the transmission input shaft problem but I'm gambling that it is a good motor and spent money on a drilled cast flywheel.
Hope it doesn't bite me.

 

[cryplydog]

No, that could be worse yet. good luck

 

[Speedbird]

Oh, I checked different places.
My local stores are pretty high on a set.
But some online don't look so bad for a complete set.
Stupid question, sorry.

 

[gtxno1]

I would replace it but a quicker method would have been to just turn the crank back and forth by hand while looking at the rotor and measure the degrees on the crank timing marks

 

[bm02tj]

Soak the new chain in oil before install so you do not get the high start up wear that most people get
and spring for the good true roller not a cheap knock off

 

[Yatzee]

Romac timing set are about as good as they come. Check online for buying options. I believe they previously went under the name of Rollmaster. Should be about $120 a set.

 

[ckessel]

Don't just replace the chain. The chain wears/stretches, gears wear. Replace all or none. Cheap parts don't last so watch what you buy. Also, has the block been align bored or honed? It so, this changes the distance from the crank to the cam, closer together, which makes the chain seem loose. Your better companies have sets available to help compensate for the change. Stiff valve springs and fast cam profiles will shorten timing component life too.

 

[Speedbird]

I've ordered a Coyles set. It said "true roller" and made in USA.
Most because of that and I recognized the name.
So the engine is factory. I'm waiting to see if it is a new set is any tighter when it gets here.
I'm hoping that I'm not wasting money on parts. That's why I didn't buy a real expensive chain set because I've never heard this engine run myself.
Thanks.
I think it's time for a new avatar.

 

[69Bee]

...Also, has the block been align bored or honed? It so, this changes the distance from the crank to the cam, closer together, which makes the chain seem loose...

Done properly, the caps are ground (shortened) about 0.003" which will only move the cam centerline towards the crank by half, or 0.0015" when align honed. Align bored will/can move the cam more if desired because a larger amount can be removed at a time; installing HP steel main caps for example. Some companies do make a timing set with shorter chains to compensate for this. I have also seen special rear main seals for SBC motors that have been align honed up to 0.010".

All of this aside, grind the caps 0.003" and you just make a few passes to get the main bores round and straight, and you are good to go.

 

[Speedbird]

The new chain is tight. The old one was sloppy. Thanks.
Here’s were I am.
This is a stock 77 motor home engine so I’m thinking maybe the camshaft is different.
I lined the marks up on the original gears. And had equal slack on both sides of the chain. TCD on the correct stroke.
I want to just put a new set on and not mess with degreeing the cam or anything fancy.
When I try and put the new set on, the “advanced” keyway seems to work best.
It slips right on.
But if I try and use the middle keyway (the “0” one) the cam sprocket doesn’t even seem to want to go on the cam easily like it does if I used the “advance” keyway.
The next to the last picture is the "0" keyway with no chain just to show where the actual marks would be if I can get the cam sprocket on in that position.
The middle keyway ("0") also doesn’t line up the timing marks as well as the "advance" one does either.
And the "retard" doesn't look so good at all. (Last picture)
What I wondering is if this original set was set up different with an “advance” built into it since it was a motor home cam?
I'm wondering this because the original marks line up so good. But I have to use the "advance" keyway on the new set to get that close.
The paper work says that advancing it will give more lowend torque.
In other words maybe the motor home cam used a different timing set than a car engine.
Which one should I use without more work since this engine may need rebuilding once I get it running anyway?
I’ve got no problem with using the advanced keyway since this car is just street use.
I just want to get the motor running.
Thanks again for opinions.

 

[Speedbird]

AH HA!

I think I figured it out.
I compared the two crankshaft sprockets.
The relationship of the dot to keyway by teeth on the old crankshaft sprocket is the same as the keyway to dot by teeth on the "advanced" marking in the new sprocket.
The "o" and the "retard" marks teeth placement is different from the old sprocket.
(Or is the "tooth". Whatever)
So I use the "advance" keyway on the new sprocket.

 

[440roadrunner]

YES. Your last photo you have it set up 4 retard, which you normally do NOT want