DIY timeserts

[SnM.Man]

So I'm looking at a 2000 deville with the N☆. Ad says it has a slight overheating issue. Right way I'm suspecting a headgasket and I'm looking for cheaper way of repairing.

I have full access to a machine shop and thinking about making my own timeserts.

Anybody try this?

[Bruce Nunnally]

A lot of work has bee done on this topic; I would hesitate to design my own solution. Tim Carroll at http://www.carrollcustomcadillac.com is where I would recommend you start.

[airmike]

Being a do it yourself kinda guy, I wouldn't even think about doing that. If you were to get it wrong somehow, you wouldn't want to pull that engine out again a few months later would you?

[Logan]

I think the time-sert kit needed is J-42385-2000. There are over a dozen different J-42385 kits...

At one time..used 2003 engines were a dime-a-dozen ($1000). I think the pistons had a anti-slap coating added that year...so it makes it a one year engine in the salvage yard books. They cannot sell it as a 'exact' replacement for a 2000.

I almost went the used 2003 engine route on my 2001....but ended up selling the car with a suspect head gasket issue.

[KHE]

You would spend way more money developing your own inserts vs. the cost of the Timesert kit. Why risk having to do the job twice?

[Cadillac Jim]

One of the "tricks" in a Timesert is that the inner and outer threads are "synchronized." The pitch on the inner threads, which is the same as the pitch of the production head bolts, is matched by the pitch of the outer threads, so that the thickness of the Timesert is constant over its entire length. If you cut one like a hot dog bun and look at the cross-section, you see a zig-zag shape where the thickness of one side is the same as the thickness of the other side. This gives the Timesert maximum strength.

The bottoms of the threads is radiused in both inner and outer threads to prevent cracking. This must match the peaks of the threads in the bolts, and the tapped threads in the block must have the peaks rounded to avoid binding.

Installing the Timesert involves drilling and tapping the block at the bottom of the head bolt wells. Both involve use of an alignment plate bolted on the block face that keeps the drill perfectly aligned so that the hole and threads are straight. The drill bit and alignment plate are designed so that the diameters of the bit and the hole match to keep alignment within specifications. A misaligned insert will cause unknown torque decrease on head bolt installation, and high stresses on the insert and bolt on heating and cooling.

The alloy of the Timesert is selected to match expansion with heat and cooling with the block, compatibility with the hard threadlock used between it and the block, and minimum galvanic reaction with the insert and the block alloy and the bolt alloy, while providing strength to make a permanent repair with high clamping force.

All this tells me that this is not a DIY job like pulling the manifold and changing the starter, or even overhauling an engine. It requires application of metallurgy, chemistry, and specialized machining skills just to get an insert that will work well for a permanent repair. The alignment plate is another design problem that requires specialized machining skills. At the minimum, a CNC precision lathe is needed for both the inserts and the alignment plate - which imply computer skills to feed the CNC.

[Bruce Nunnally]

So I'm looking at a 2000 deville with the N☆. Ad says it has a slight overheating issue. Right way I'm suspecting a headgasket and I'm looking for cheaper way of repairing.

I have full access to a machine shop and thinking about making my own timeserts.

Anybody try this?

Jim' post is insightful. Please keep us updated on your progress regardless of which path you choose for repair. I like to hear repair stories.