For Want of a Special Screw

59coupe · 12-23-2011, 02:49 PM

How important are the M6X1X25mm Set Screws if I have the LN kit with the cam locks? I cannot find these set screws anywhere and have spent 40 in fuel driving to different stores looking for them. It doesn't help that I am in a rural area.
Wayne discusses them in his tech article as being important to insure you don't jump time when releasing the tensioners but that is without the cam locks.
Later in the article he states the set screws keep the IMS shaft stable and locked in place. This seems important but having not arrived at that stage of the project, I am uncertain. I am still waiting on parts so there is no serious rush but once they arrive I may be dead in the water (again) for want of a screw.
Any sources for a M6X1X25MM set screw with cone tip would be appreciated.
Best Regards, Z

dad911 · 12-23-2011, 03:12 PM

McMaster-Carr

Item # 91390A135

JFP in PA · 12-23-2011, 03:19 PM

I really would not be doing an IMS upgrade without the proper tools; while some have been able to do it without locking the cams, others have not been as fortunate and have had the car flatbedded as the result. But I have also never heard of anyone that locked the cams down before pulling the tensioners having a problem.......

59coupe · 12-23-2011, 06:15 PM

Dad911, thank you. Screws ordered!!!

JFP, I concur, that is why I have not proceeded, instead asking questions of you good folks here on the board. Risk vs Reward, I would rather spend an extra week with the car in the air than risk jumping time.
Do it right the first time and drive the damn thing!

derfo · derfo's Garage

Any sources for a M6X1X25MM set screw with cone tip would be appreciated.
Best Regards, Z[/QUOTE]

I have spent my life improvising. You can try this if you want. Cut the heads off
the M6 set screws then file the ends nice and flat. You can now cut a neat slot in
the end of each one. Choose a screwdriver that you are going to use first to make sure the slot is the right size also the screwdriver wants to be little under the width of the threads on the screw. Its critical that you get the slot dead center in the end of the screw!

dmairspotter · 12-24-2011, 05:33 AM

Try McMaster Carr. Google them.

59coupe · 12-24-2011, 05:41 AM

Derfo, I understand improvising, in this case I don't think it wise. Losing a set screw in the engine case or having to remove by another means is more trouble than waiting for the correct screws.
Neither have really answered my question though.

How important are the set screws if you have the cams locked?

In Wayne's tech article he mentions two purposes for the set screws; one, to keep the timing chain from jumping and two to immobilize the IMS shaft. Immobilizing seems important yet you must set the engine to TDC to lock the cams. This doesn't necessarily coincide with insuring the sprocket of the IMS is visible through the cover bolt holes which clearly prohibits the use of set screws.

The LN engineering instructions that come with the installation tool do not mention set screws at all.

So, how important are the set screws if you have your cams locked?

Thanks, Z

JFP in PA · 12-24-2011, 07:29 AM

As mentioned elsewhere, the gear on the intermediate shaft is simple interference press fit, pushing on it with either bolts or set screws leaves me cold because if you get it wrong and push the gear too far, the engine will most likely have to come apart to correct it. Not fun.

For somewhere around $150 or so, you can purchase all the necessary special tools (cam and engine locking fixtures) that allow you to zip right through an IMS retrofit without any issues. I cannot emphasize how important it is to do this procedure correctly, which means using the correct tools. And if the cost of the tools concerns you, you can always resell them afterwards if you need to.

59coupe · 12-24-2011, 08:16 AM

JFP, you are a trusted poster. I already have engine and cam locks. Perhaps I am being a little anal. Studying the photos in the write up, it appears the IMS shaft is not perfectly centered while doing this retro fit and it does not appear necessary for it to be centered. Only that the bearing is pressed/knocked in straight.

So, just to be clear, with engine set at TDC and locked, cams locked there is no need for set screws? Further, you do not recommend the use of set screws to immobilize the IMS shaft because the sprocket is press fit and set screws may cause it to cant/ cock or even come off.

02 S, 5 chain engine as well. I will proceed with engine and cam locks even though I have set screws on the way.

Best Regards, Z

59coupe · 12-24-2011, 08:17 AM

JFP, you are a trusted poster. I already have engine and cam locks. Perhaps I am being a little anal. Studying the photos in the write up, it appears the IMS shaft is not perfectly centered while doing this retro fit and it does not appear necessary for it to be centered. Only that the bearing is pressed/knocked in straight.

So, just to be clear, with engine set at TDC and locked, cams locked there is no need for set screws? Further, you do not recommend the use of set screws to immobilize the IMS shaft because the sprocket is press fit and set screws may cause it to cant/ cock or even come off.

02 S, 5 chain engine as well. I will proceed with engine and cam locks even though I have set screws on the way.

Best Regards, Z

JFP in PA · 12-24-2011, 08:33 AM

I have never used the set screw approach for doing a retrofit, simply because of the way the rear shaft gear is mounted. With the engine at TDC and the cams locked, releasing the tensioners will sometimes leave the shaft slightly offset, but not enough to interfere with changing the bearing. If you encounter a problem pulling the bearing, usually it is because the bearing decides to come apart, not because of centering, and even that does not happen very often……..