Timing Chain Housing & JB Weld

[smestas]

As noted in the rebuild book I'm replacing the original material covering the inserts on the outsides of the chain housings with JB Weld. As I was doing this I noticed that the factory used their material on the inside of the housings to cover the two studs that go all the way through. Is it recomended to use JB Weld on the inside of the housings or is there another alternative to use? As popular as it is I've had no experiance with the JB product untill now.

[Wayne 962]

By inside, you really mean outside, though? Inside would be inside the engine - I have never seen that...

-Wayne

[smestas]

Yup there is some on the inside. Here are a few pictures. It's the same material as whats on the outside. At least it looks that way to me.

Left Side Cover


Left Side Cover


Right Side Cover

[smestas]

Any suggestions on what to use for the inside?

[avi8torny]

While you're on this topic, I have noticed that the post that supports the chain tensioner on the left housing has crept back a bit out of the rear housing, and now is blocked in place by the cooling fins of cyl # 1. It has only moved about a 1/4 inch out of the housing and can't move any further. Without opening up the front cover, would the tensioner still be supported adequately or is this a ticking time bomb?

[smestas]

Originally posted by avi8torny
Without opening up the front cover, would the tensioner still be supported adequately or is this a ticking time bomb?

Does your car have the newer hydraulic chain tensioners? I’m not sure what year they started in. Either way I have read that any binding of the chain tensioners can cause catastrophic engine failure. This was already a common problem with the older chain tensioners let alone the stud coming out of the case.

To answer your question I'd say ticking "time bomb" but I’m not an expert and that’s my 2 cents worth. You might want to wait till some others chime in.

By the way... does anyone have a recommendation for re-sealing the exposed internal studs?

[mb911]

That stuff looks to me like the loctite 574 porsche used to assemble the engines at the factory. Just thinking out loud
Ben

[smestas]

Originally posted by mb911
That stuff looks to me like the loctite 574 porsche used to assemble the engines at the factory. Just thinking out loud
Ben

Is that whats on the outside of the covers? It seems to me that it is the same material or somthing similar. Anyone else? 180+ views someone must have something to say regarding this.

[Wayne 962]

Nope, 574 is a case sealant - not an epoxy. Just place a dab of the JB weld on each of those external spots (after cleaning them off), and you should be fine.

I'm not 100% sure about the inside spots - I'll have to check a pair of chain housings and take a look - I can't remember off the top of my head.

-Wayne

[mb911]

Wayne,

You are correct in saying that 574 is a case sealant quite similar to 515, and 518. It is only set by squeeze or "pressure "as the loctite Rep always tells me. It can though set up over time a long time to look some what like the picture.

A side note is to be very carful when choosing epoxies as not all are designed for heat. I have found that Honda-bond or yama-bond work well for this type of application as they do not require pressure to set and it can take a good amount of heat.

Best regards

Ben
77 911 3.0
75 914-6 2.7