Hello All:

1967 Volvo 122S Wagon. I hate to keep burning up the bandwidth with this, but to refresh - I have a mystery knock in my car. Details can be found here:

http://www.brickboard.com/RWD/index.htm?id=1097042

Talks offline with Jim (jiimboden in these parts) have yielded a neat bit of information. Jim suspects - and I suspect he is right - that "tooth flank clearance" as described in our manuals is nothing other than the English way of saying "backlash". Kind of like "bonnet", "boot" and "pissed." In fact, we looked at a diagram that showed measuring "tooth flank clearance" which looked exactly like measuring backlash. Also, there is no mention of backlash in the manual, so I think we have a winner. For those of you who indicated that no one seems to know how to measure tooth flank clearance, let me know and I will walk you through it.

In other magnanimous brickboarder news, I had my first face-to-face with a fellow Brickboarder this weekend and what a pleasant experience it was. New great friend Chris (cardog in these parts) brought down his 142 (B20B lump) so we could compare it to my B18D Type III lump and see if the knock is that trademark "vintage Singer sewing machine" sound or a genuine knock. Guess what?

It is a knock.

And, despite our best efforts with large screwdrivers, sections of hose and "Nurse Ratchet's Motor Motion Potion" we could not isolate the sound. Not at all. Not climbing under the car, not crawling over the top.

Chris was reporting some problems with his B20B which I will allow him to elaborate on if he chooses, but bottom line is I had a few suggestions about things to try and they worked. Feeling pretty emboldened by that, I am going to forego the professional mechanic route and solve my own illness. Followers of my malady might be aware that we have identified the following possible knocking sources:

1) Cam is pushed back just a tad, retained by the valve spring pressure from being brought forward during torquing of cam nut. This prevents a firm lock between the cam, spacing ring and timing gear. Oversized gap with respect to brand new thrust plate ensues.

2) Cam followers/lifters might have been chipped or otherwise disoriented when I reassembled the head. (Unlikely, but timing coincides nicely with when I believe I first heard the knock).

3) Cam itself has worn spot or chip.

4) Oil pump/distributor drive might by failing.

Yet again, I am draining and pulling my radiator and opening the front of this motor. Once I get the timing gear off I am going to remove the valve train and test my theory which is item 1) above. Although it might not seem like it, I would really prefer to not go through this routine again. Therefore, I would like to examine everything possible without removing the head. What are the best ways of tacking analysis of issues 2), 3) and 4) above without removing the head?

Thanks for your help and patience, folks. I know this will benefit other Brickboarders down the road.

Cheers,

Jeff Pucillo