So new motor build almost complete and go to install spark plugs and #2 just falls in and spins. Wtf?

Looking it is closely you can see its definitely larger than others and has threads. So I imagine that at one time before it was mine it blew out a spark plug and got either hellicoil or time Sert and who ever removed the plugs last time before the rebuild pulled said hellicoil or time Sert out with the plug. Question is what was it and now what?

Really hate to have to tear this motor down again after just putting it together.

What options do I have? And would you trust any of the options to a 350-400 HP efr build.

1) Pull head and use as boat anchor find new head. Probably hard to find another msm head.

2)Get tap used for helicoil and screw it in there by hand and If it fits good install new helicoil and let it eat.

3) Same as 2 but with tap for time sert

4)Stop bitching and pull the head back off and bring to machine shop.

5) what am I missing?


Another thought. I read now that time Serts are stronger than helicoils and if it had a helicoil originally can I now use a time Sert or is it already drilled to much? That make sense?

#pissed

 

Buy new 00-99 head. Transfer MSM cam.

IIRC the intake cam is the only thing different.

 

In aluminium a timecert is normally considered stronger than the original threads. Even sometimes helicoils are considered stronger (we have factory aluminium parts we intentional helicoil because they will be regularly threaded and unthreaded and the helicoils wear better). I really wouldnt put a 2nd thought into doing a timecert in the head.

 

I have see timecerts crack on certain things but it comes down to what you are fixing. in this case timecert will be just fine.

 

Anyone ever use these? Looks like it might fit bill. "repairs failed helicoils"

 

I would certainly consider replacing the head rather than just using a bandaid helicoil to remedy the issue.

 

It's a simple threaded screw in a chuck of aluminum, it doesn't support any load, just needs to stick in place -- no reason to replace the head over it.

 

Here is a really good priced 99 head.

 

They're probably tapped it out and put a larger format spark plug in the hole. There are two different sizes.

 

how's he going to fit that on his 1.6L? and why is spending $250 on a unusable head preferable than spending $20 at a machine shop to fix his threads?

 

Keensert? ?? I like those, just because no glue.

 

You missed the part where it is his built 1.8L MSM motor. :P

 

that i did.

 

No load? Since when does a spark plug not have to resist combustion pressure?

 

Well that's only like 37, 000 psi.

 

I'd be ok with a helicoil or similar solution on a road car (A personal opinion... I've no direct experience in the area of stripped spark plug thread repair).
Mechanically (ability to keep the plug in place against combustion pressures), a helicoil or timesert or similar product will likely be fully acceptable.

However, the use of any sort of helicoil or timesert is going to increase the thermal path resistance from the tip of the plug to the water coolant. So, that plug tip will likely run hotter than the other 3 plugs. IF you get the appearance of pre-ignition on that cylinder's spark plug, one option is to use a colder heat range plug in that cylinder only. Will you get pre-ignition? Will this lead to a melted piston? Do you want to risk this in your expensive rebuild? Your choice...

Ideally, a replacement head as suggested earlier is likely the best though more costly solution.

 

While that may be a concern, I'd honestly give serious thought to timeserting all the spark plugs on a true race engine. If you're worried about the force of combustion or just taking the spark plugs in and out a lot (more of a drag racer issue than a road race issue) I'd rather have the steel timesert threads experience all the thread loading from changing plugs and have larger stronger threads into the aluminum head that only get torqued once.

 

I timecerted one of mine, while the head was on the car nonetheless. There was lots of grease involved, similar to drilling/tapping an oil pan. Then as much cleanup as possible, red loctited in, and it had a tool to spread the top of it to mechanically fasten it. It's lived up to 10,000 miles of boost and a few track days.

 

I'd pull the head and have a machine shop (some who knows what they're doing) do the repair. Several ways to fix it as you mentioned. If you botch the repair, then you're better off buying a new core to build up again.

-Have purchased a used head that I later found had a poorly-repaired timesert. Ended up throwing it away as the repair job was so bad it ruined the head.