How do you Inspect chain rails

[Homeoboxter]

Originally Posted by JFP in PA

That only gives you a partial peek at two of the eight chain pads, you cannot even see the four large ones, or the two short ones on the short chain:

True, but the large ones last much longer, I don`t think those should be worn off at this mileage. You can`t see the lower small pad, I agree. This test is good to tell you if the upper is shot, and then you don`t have to hesitate to pull the cover off. I think you can have a vague idea about the condition of the large ones after removing the pump and the tensioners and looking down toward the crankcase with a camera or small mirror. The crank-to-IMS chain pad is partially visible after the RMS is removed, that also can give you a vague idea. In my engine at 100k the four long rails were in perfect condition, the crank-to-IMS pad was shot, and the four little pads were disintegrated and the chain was running on the tensioner, metal on metal.

[JFP in PA]

Originally Posted by Homeoboxter

True, but the large ones last much longer, I don`t think those should be worn off at this mileage. You can`t see the lower small pad, I agree. This test is good to tell you if the upper is shot, and then you don`t have to hesitate to pull the cover off. I think you can have a vague idea about the condition of the large ones after removing the pump and the tensioners and looking down toward the crankcase with a camera or small mirror. The crank-to-IMS chain pad is partially visible after the RMS is removed, that also can give you a vague idea. In my engine at 100k the four long rails were in perfect condition, the crank-to-IMS pad was shot, and the four little pads were disintegrated and the chain was running on the tensioner, metal on metal.

We have seen all of the rail pads go south at one time or another; the little ones between the cam fail most often due to their small surface area, but the larger ones are not immune. We have also seen the longer units break near their pivot points, which is why updated parts are now available.

[flmont]

Could I pull the spark plug tubes and then use a bore scope to get a good look..??

and would a Bore scope that connects to your phone work,.?? Thanks Frank

[JFP in PA]

Originally Posted by flmont

Could I pull the spark plug tubes and then use a bore scope to get a good look..??

and would a Bore scope that connects to your phone work,.?? Thanks Frank

You would still only be able to see the chain rail pads on the little rails between the cams; you will not be able to see the other units as they are too deep in the engine to realistically get a bore scope down there without getting it stuck.

[Homeoboxter]

Originally Posted by flmont

Could I pull the spark plug tubes and then use a bore scope to get a good look..??

and would a Bore scope that connects to your phone work,.?? Thanks Frank

I`m not sure if you could take a better look at anything through the spark plug hole than just using the green plug, but here`s a picture I took recently of the variocam, may give you an idea.



For reference, here is a picture for the size of the camera I used for inspecting the actuators, it`s a cheap Depstech camera from Amazon and it works with a smartphone.



And yes, this is only good for inspecting one of the small chain pads, the upper one, but this is the most likely to fail out of all the pads. For inspecting the long side rails I would lock the camshafts and crankshaft, pull the tensioners (to free up the rails) and the scavanging pumps and look into there with a camera. Wear is not likely on these at this mileage, but if one is broken at the pivots probably you will see it.

My bet is you`ll find the small pads worn down, did you see yellowish or brown plastic debris in the oil filter?

[flmont]

Great Thanks..Since I'am doing the tensioners anyway this will be the easy to look at the rail pads..Thanks a lot really saves me on the how to do it the right way !..Ill be doing this next weekend hopefully camera is available thru Amazon !

[flmont]

I did my tensioners yesterday could not see the rails I Still have the start up rattle,but I only changed the IMS tensioner the other one was plenty strong enough didn't bother with the top one Yet,the good news NO notable pieces of anything in my oil canister,..I will inspect filter today..But nothing obvious in the filter at first glance looked at about half of the filter seemed very clean.