Chain tensioner housing

Hello to all............

Had a question I thought I would throw out to the ones who may have done this before. Can the chain tensioner housing be removed (gasket replacement, inspection) with the engine in place? Looks close due to the vert frame rail which it may encounter as it is withdrawn from the studs. On mine, the hex adjusting screw is all the way in. The car is a 78 400A.

Thanks!


Godspeed!
Dave

 

it's not possible for the front cover to be removed with the engine in place because the oil sump has to be off.
there is the slightest possibility that it could ultimately be done but it would taking tons of time and farting around to make it happen.

 

Get ready for a timing chain R&R

 

Chain tensioner assy can be removed. If it still has the phenolic spring seat/tensioning piece it should be replaced with the newer steel one.

 

Yep, you are on target, want to inspect for the phenolic spacer, not remove the front cover. May end up removing cams, re-painting cam covers and rolling in a new chain.

Which brings up another interesting point. Ordered a replacement chain which was a complete chain not a length. Will now have to search for the proper pin extractor. Have one for the bicycle, but not the duplex chain!

Godspeed!
Dave

 

Hi Dave,

you are going to change the timing chain ? Be carefully ! I did it on my 365 gtc/4. And as I opened the chain on the master link, the tensioner spring sprung out and turned the left outlet camshaft, so that one valve was bent...
First of all turn the engine to so, that all marks on the camshafts and the 1/6 PM mark on the flywheel are ok. then remove the tensioner housing and fix back the tensioner so that the spring can not push to the chain. Then open the chain, remove the left outlet camshaft, fix the new chain to the old with the master pin and insert the new by turning the crankshaft and pulling the old one out.
Then you can reinstall the camshaft and close the new chain. In the following you can reed, what I wrote in the C/4 forum.


with the advices of many users of the forum I have now successfully changed the timing gear chain of my c4. Let me tell my experiences : You can get the chain from your local "Renold" dealer. The Renold part number is S114038 or ISO No. 06B-2 and it is a 3/8" x 7/32" Duplex roller chain. I payed about CHF 130.00 for it.
Now it becomes difficult : in the owners manual and the Wallace translation of the repair manual the chain is shown with the self-adjusting tensioner by "Renold" and has 180 pins; (master link included). From #15259 (Euro-cars) and #14839 (US-cars) on , there was installed the manual adjustment tensioner, which I have on my car too (#16273). I think, it is because of the manual adjustment, why my chain has only 178 links, also master link included. So, when you have to replace your timing gear chain, please first of all, count the links/pins on your engine!

And I am the air filter man...

Regards, Jacques

 

Jacques- Very interesting. Brian related to us in the 456/550/575 forum how something very similar could happen on the belt driven engines during assembly and bend a valve.

Taz
Terry Phillips

 

Thats different.

In this case spring pressure on a ramp spins the cam and a valve whacks a piston. In any of the 12s when you are at TDC where the cams are initially timed on installation both #1 and #6 piston are at top. In this position the cam does not want to lay in the head in such a way that you can install the caps to start drawing it down. You have to turn it out of time to do that and when you start tightening it down it wants to turn further out of time. At that point you have to be paying attention and keep correcting the cam position as you are adding caps and drawing the cam down. The cam lobes for #1 are so far from pushing a valve open that will never happen but at TDC the #6 valves are partially open and not very far from the piston. When the cam is turned to a position where it can be installed it will push the valves far enough open to bend the hell out of them. It takes constant correction during the drawing down process to keep that from happening. That is why the valves get bent and it happens to rookies all the time. Myself, I turn the crank out of position a little to get that #6 piston out of the way and ony after the cams are installed and tight do I reposition the motor to TDC.

 

Brian- Got it. Thanks. You keep instructing and I will keep learning.

Taz
Terry Phillips

 

I got a good idea yesterday : for fixing the camshaft in position until the chain, sprockets and central pins are installed, lay a bit of double folded paper under one of the bearing shells and do not tight too much the nuts. This will “brake” the cam and avoid turning it out of the marks.
Regards, Jacques.

 

This will only work when the bearing caps are all tightened down.

Rifledriver was referring to the procedure for reinstalling the cams when the caps are loose.

 

I agree, that's right. I didn't say, it works for tightenig down the bearing shells. Jq.

 

Please help! does any body know where I can get one of these newsteel tensioning part? Thanks in advance, Fritz

 

Fritz- Is this it? From Ricambi.

http://www.ricambiamerica.com/product_info.php?products_id=194255

Taz
Terry Phillips

 

Looks to be it, rather pricey little devil.

 

Terry, Thanks for the link. Ii is called a "guide shoe" in the exploded view in the link you gave. I did not follow the part you show, was that what you found? "guide shoe" for cam timing chain? Fritz

 

Fritz- The 400i and 412 use the same part, but the 412 parts catalog is in English and calls it a spring seat. Scroll further down and you will get to #31. I think that is the part to which they were referring.

Taz
Terry Phillips

 

Thanks, I see it now, Fritz