Loose timing chain replacement

[dec322]

I'm in the middle of a water pump replacement on my stock 305 for my 84 k10. This led to a timing cover gasket change to fix an oil leak which revealed slack in my timing chain (passenger side). I've never gone this deep before and never changed a timing chain set. All the videos I've seen are on engines that have been removed or being rebuilt. I've watched stuff about matching the marks on the camshaft sprocket and the crankshaft sprocket. Then stuff about turning 180 degrees. Etc. My question: Can I just remove the old stuff and put the new stuff on with the marks exactly where the old marks were at?

I am not upgrading or rebuilding anything. It's a simple remove and replace.

 

[Matt69olds]

Rotate the engine until the dots are lined up, remove the old chain WITHOUT moving the cam or crank. As long as you install the chain exactly as it was removed you should be good. Be sure to check and reset the ignition timing, and it wouldn’t be a bad idea to verify the ring on the balancer hasn’t slipped. If it has, the timing marks will be useless.

 

[Edelbrock]

The chain will always have "some" slack. How much is too much?

 

[edgephoto]

I am about to replace my timing chain too. Mine is on a 7.4L but it is the same design.

As was said above, turn the engine until the two dots line up. Then remove the cam gear bolts and cam gear and chain. Remove the crank pulley. Install new parts in reverse order. Finger tighten bolts then torque to spec.

You may need a gear puller to get the crank gear off.

Cloyes sets are made in the USA and are dirt cheap. My set was $20.77 delivered in 2 days from Amazon. Go to Cloyes website get the correct part number for a kit and search around.

 

[fast 99]

Hardest part will be reinstalling front cover.

Will need to be modified for installation unless oil pan is removed. Corners of inner edge for front pan seal need to be ground down diagonally. Use a little RTV where the cover meets the block and pan.

I generally use blue Locktite on cam bolts, torque to spec.

 

[75gmck25]

Also, if you get the idea to upgrade to a double roller chain, be ready for some more work. In most cases the extra width of the double chain hits the oil gallery bosses on the upper front of the block before the timing set is fully seated. It’s relatively easy to grind the bosses down for clearance, but you also have to catch all the metal filings to keep them out of the engine.

 

[edgephoto]

It is a 305 not a race motor. Stick with standard chain type. It was good for all these years, why go through the work and cost for no benefit?

 

[HotWheelsBurban]

This is tangentially related.... friend at work has a 2012 F150 with Ecoboost V6 twin turbo. His truck is throwing codes related to " camshafts out of sync" and other timing issues. Phord uses multiple long chains on these engines, with cam phasers and PLASTIC chain guides and keepers.
I tease him that his first problem is, it's a Phord. And he knows about how my Chevy has been making me spend $$$ on it, and miss days of work fixing it. I told him today," see this is another reason I like my Chevy: one timing chain, big gear on cam, small gear on crank, most decent mechanics can fix without issues, and it's a proven design since 1955".....
Actually there are several reasons in this statement, but y'all get the idea....

 

[dec322]

Thanks guys. I am not looking to upgrade the chain. This truck is for cruising and I'm happy with what it was doing before I pulled it apart. I'll go with the cloyes set up.
Regarding how loose is too loose, one side of my chain barely moves in towards the sprockets. The other side has at least an inch of movement (maybe more).

 

[dec322]

Hardest part will be reinstalling front cover.

Will need to be modified for installation unless oil pan is removed. Corners of inner edge for front pan seal need to be ground down diagonally. Use a little RTV where the cover meets the block and pan.

I generally use blue Locktite on cam bolts, torque to spec.

I read about this in the book but didn't notice any issues removing the cover without dropping the pan. The book made it sound like it does not apply to every engine but didn't clarify. I'll do a dry run before I apply any rtv and gaskets.
Maybe I'll just order a new oil pan gasket and change it while I'm doing everything else.

 

[fast 99]

If I had a cover laying around I would take a picture to show the modification. Easy to do. Front cover will be very hard / impossible to re-install without the modification or removing pan.

 

[edgephoto]

Here is a video of my timing chain. 1987 7.4L engine. This is way too loose. One side will always be tight. Rotation put all the slack on one side.

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[YakkoWarner]

Do these engines not have some sort of timing chain tensioner? I have the same engine and I would have just assumed there was a chain tensioner in there somewhere....

 

[edgephoto]

No there is no chain tensioner.

I installed my new chain and gears today. You need a puller to get the crank gear off.

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[Ricko1966]

Do these engines not have some sort of timing chain tensioner? I have the same engine and I would have just assumed there was a chain tensioner in there somewhere....

No tensioner. If you are worried about timing chain wear,it's actually a fairly easy check. Pop the distributor cap rotate the engine to the TDC mark on the timing tab,do not overshoot the mark and do not rotate the engine counter clockwise. Now you are on zero,rotate the engine counter clockwise while watching the distributor rotor AS SOON as it budges,stop, look at your timing tab did you go counter clockwise more or less than 10 degrees. 10 or more do a timing chain.