Valve + timing chain Q

[Andreas]

I'm posting this Q for nr94 on the forum
On 2:nd startup the brand new timing chain broke!
I found this post http://www.syty.net/forums/showthread.php?t=51947&highlight=chain
He had an Edelbrock timing chain.

Now over to the Q:

"Does the valves hit the pistons if the motor is cranking and timing chain broken. Pistons are JE's and stock stroke crank, 1.6 rockers. Motor is turning easy now but could the valves be damaged?"

 

[NecroWolf]

Re: Valve + timing chain Q

i doubt it

 

[Don W.]

Re: Valve + timing chain Q

Well if one valve ended up at its full lift position I wouldn't bet against it. It won't hurt to replace the chain, re-time it and do a test crank. DON'T start it. you should be able to tell if one or more cyls crank through with no compression. If it cranks evenly then you're prolly OK. Compression check to confirm maybe?

 

[turbodig]

Re: Valve + timing chain Q

I'm posting this Q for nr94 on the forum
On 2:nd startup the brand new timing chain broke!
I found this post http://www.syty.net/forums/showthread.php?t=51947&highlight=chain
He had an Edelbrock timing chain.

Now over to the Q:

"Does the valves hit the pistons if the motor is cranking and timing chain broken. Pistons are JE's and stock stroke crank, 1.6 rockers. Motor is turning easy now but could the valves be damaged?"

I'm afraid it's quite possible, especially with a higher-lift cam than stock.
I'd put the chain on, and do a quick compression check before going any further.

 

[Andreas]

Re: Valve + timing chain Q

Thanks all.
Very good help in all answers.

Yes, quite jaw dropping that the chain broke.
Sprockets were lined up and block material were grinded of so the sprocket wouldn't hit (as in the link in the first post)

I'm sure he's gone go to the bottom with why it broke.

 

[Don W.]

Re: Valve + timing chain Q

Was the crank sprocket not installed all the way?

 

[Andreas]

Re: Valve + timing chain Q

He found out what happened.
The freeze/oil plug at approx 1 o'clock had came out!!!
From what I was told when we spoke over the phone it was just shreds left of the plug.
Maybe somehow it got in between the gears and the chain and stretched it until it broke, or just got grinded between chain and the block.

And unfortunally valves were damaged. No comprossion in cylinders 1, 2 and 3.

 

[Quickstop [UK]]

Re: Valve + timing chain Q

jeez - bad luck for him hope you can get it fixed without too much headache

 

[Don W.]

Re: Valve + timing chain Q

When reinstalling these plugs be sure to "stake" them.

 

[Try Me]

Re: Valve + timing chain Q

Wow if it ate it up that bad id be pulling that motor back out and making dam sure its clean inside. Otherwise you put it all back together and spin a couple bearings.

 

[Don W.]

Re: Valve + timing chain Q

Difficult with engine assembled because of the debris but you can tap the hole and screw in a plug. I've got the info somewhere. LMK and I'll look for it.

 

[Andreas]

Re: Valve + timing chain Q

Absolutly that was the first thought, tap it and screw in a plug but as you said there would be debris.
The topend will be coming of so it might be a option.

However he's talked about making "marks" infront of the plug in the block with a chisel so the plug will not be pushed out again. Could that be what "stake" means?

 

[Don W.]

Re: Valve + timing chain Q

Absolutly that was the first thought, tap it and screw in a plug but as you said there would be debris.
The topend will be coming of so it might be a option.

However he's talked about making "marks" infront of the plug in the block with a chisel so the plug will not be pushed out again. Could that be what "stake" means?

Yes, the after the plug is inserted the edge of the hole is deformed slightly, with a punch, so the plug can't come back out.

 

[Andreas]

Re: Valve + timing chain Q

Just came home from the garage were nr94(jim) and I put a ridiculous amounth of time and money into our trucks, like everyone else here *lol*

New plug is in and punches in the block are made infront of the plug, we even talked about make a small tackweld lip as a stop for the plug, dont wanne have that happening again.

3 new valves and a chain is on its way from U.S tommorow, so for now the waiting game is on.

Thanks for all the advice and good input.

 

[Don W.]

Re: Valve + timing chain Q

The other thing you can do is drill and tap a small hole through the side of the plug and insert a small screw to secure the plug.