IMS Chain tenionser thread pitch size? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

spdrcr21 · 07-13-2021, 06:01 PM

Hi All,

I just installed my new IMS Retrofit IMS bearing and was installing the IMS tensioner (996-105-180-58-M100) and the first thread in the engine case for the tensioner cracked. Anyone know the size of the bolt? I'm going to have to get a tap and die to chase the threads. Beyond frustrating!

Thank you

blue62 · 07-14-2021, 05:21 AM

[QUOTE=spdrcr21;638723]Hi All,

I just installed my new IMS Retrofit IMS bearing and was installing the IMS tensioner (996-105-180-58-M100) and the first thread in the engine case for the tensioner cracked. Anyone know the size of the bolt? I'm going to have to get a tap and die to chase the threads. Beyond frustrating!
Thank you[/QUOTE

You do not want to use a standard thread cutting tap to do this.
If you use a a standard tap to chase the threads your going to remove metal.
Then the bolt will work loose over time.
Not what you want.

If you are going to just "chase" the threads.
You want to use a thread correcting tap they do not remove metal.

spdrcr21 · 07-14-2021, 07:50 AM

Hi blue62,

Thank you for the info. I appreciate it! Definitely just want chase the threads. I'm going to head down to a few hardware stores to see if I can find the size I need for the tap.

Have a wonderful day!

JFP in PA · 07-14-2021, 07:59 AM

You are going to have a problem trying to find a thread chaser that large at a hardware; you need something like McMaster-Carr or an industrial machine shop supplier, and it ain't going to be cheap...

blue62 · 07-14-2021, 08:21 AM

Quote:

Originally Posted by spdrcr21

Hi blue62,

Thank you for the info. I appreciate it! Definitely just want chase the threads. I'm going to head down to a few hardware stores to see if I can find the size I need for the tap.

Have a wonderful day!

Let me know the size of the bolt you need the tap for.
I may be able to point you in the right direction.
Also if you google "thread restorer tap and die"
You will see the type of tap and dies I am talking about.

911monty · 07-14-2021, 09:13 AM

Quote:

Originally Posted by spdrcr21

Hi All,

I just installed my new IMS Retrofit IMS bearing and was installing the IMS tensioner (996-105-180-58-M100) and the first thread in the engine case for the tensioner cracked. Anyone know the size of the bolt? I'm going to have to get a tap and die to chase the threads. Beyond frustrating!

Thank you

Are we missing some detail here? That tensioner should screw in easily by finger if the chain is slack. How did the threads crack? That is highly unusual.

Homeoboxter · 07-14-2021, 09:31 AM

Assuming you forced the tensioner in the bore in an angle and you just broke the first thread you can easily fix it with a tap, it will remove aluminum only from the beginning of the bore since the rest is fine. You can measure the pitch size with a simple caliper by measuring multiple threads at once then by calculating the width of a single thread. Taps like this can be easily found on ebay or amazon, in the $50-ish range. If you damage multiple threads, before you do the tapping, make sure you put a rag in the bore and/or a hose connected to a vacuum cleaner from the other side if possible to prevent aluminum chips getting into the engine.

Eric-986 · 07-14-2021, 02:02 PM

If I remember correctly the bottom tensioner was a pain in the ass to get started, it definitely had some tension pushing back.......

-Eric

99 986
09 987.2 CS

spdrcr21 · 07-14-2021, 03:13 PM

Hi All, thank you for the advice. I do believe it was because I had the tensioner in at an angle. It was difficult to get it pushed in and started into the block. I just completed the IMS install so both cams in banks 1-3 are locked and so is one cam on the 4-6 side. Looks like its M27 x 2.0. I will head to McMaster-Carr tomorrow. Thanks!

blue62 · 07-14-2021, 04:05 PM

Quote:

Originally Posted by spdrcr21

Hi All, thanks you for the advice. I do believe it was because I had the tensioner in at an angle. It was difficult to get it pushed in and started into the block. I just completed the IMS install so both cams in banks 1-3 are locked and so is one cam on the 4-6 side. Looks like its M27 x 2.0. I will head to McMaster-Carr tomorrow. Thanks!

Much bigger than I imagined.
A thread restorer that size will be difficult to find.
Looks like your going to have to use a standard tap.
There are three basic types of tap.
they are:
Taper
plug
and bottoming.
You may want to look at the different types to see which one fits your needs the best.
Basically the taper has the first 5-8 cutting edges slightly tapered.
The plug tap has the first 3-5 cutting edges tapered.
Bottoming tap has no taper on the first cutting edges.

spdrcr21 · 07-15-2021, 09:49 AM

I'm going to pick up a plug tap from McMaster-Carr today. Thanks all!

flmont · 07-15-2021, 05:57 PM

Sorry to Hi-jack..would chain rattle have anything to do with the front ( by the A/C unit ) Tensioner,.that's the only one I have not changed out yet ?? Thanks Frank

spdrcr21 · 07-15-2021, 08:29 PM

I bought a plug tap (M27x2.0) from McMaster-Carr as blue62/JFP in PA suggested and chased the threads in the block. It quite some time clean up the threads, clean out metal residue, and use a diagnostic camera to make sure everything was clean. After doing this I was able to thread in and torque the IMS tensioner to spec (59 ft-lbs). Thank you all for your assistance. I am grateful!

blue62 · 07-16-2021, 09:59 AM

Quote:

Originally Posted by spdrcr21

I bought a plug tap (M27x2.0) from McMaster-Carr as blue62/JFP in PA suggested and chased the threads in the block. It quite some time clean up the threads, clean out metal residue, and use a diagnostic camera to make sure everything was clean. After doing this I was able to thread in and torque the IMS tensioner to spec (59 ft-lbs). Thank you all for your assistance. I am grateful!

Glad to hear you got it sorted

spdrcr21 · 07-16-2021, 12:29 PM

Thank you Sir!

Gilles · 07-16-2021, 04:01 PM

Quote:

Originally Posted by blue62

Glad to hear you got it sorted

+ 1

I am glad that it worked out for you, this is Not one of the threads you want to mess up..

spdrcr21 · 07-24-2021, 05:39 PM

Quote:

Originally Posted by Gilles

+ 1

I am glad that it worked out for you, this is Not one of the threads you want to mess up..

Thank you. I've put around 500 miles after fixing the threads (and replacing the IMS, Rear Main Seal, Clutch, Flywheel, Slave Cylinder, AOS, Sparkplugs, Waterpump and Thermostat) the car is running great!