A friend was kind enough to gift me his original 400 motor from his 69 GS for my 67 Skylark. The motor ran when pulled but sat in his garage for maybe 10 years. I decided to refresh some gaskets and inspect a few things. Turns out it’s never been apart...all the nylon on the cam timing gear long ago made its way to the pan and the timing chain was riding on aluminum teeth with about an inch of chain slop! Anyway I can see many of the cam lobes from the underside and several of them have rust spots. Looks like they could actually be pitted. Is there any saving this or is it time to spring for new cam and lifters? Another option...I’ve got a pristine cam out of a stock 455 Electra that had low miles on a rebuild. Any reason I couldn’t use that cam with some new lifters? Follow the normal break in process? My goal here is just to have a driver.
I'd go with a new cam and lifters. If you used the cam from the 455, it may not be in the exact same position in your block as it was in the 455 block, and or the lifter bores may not be in the same spot over the lobes, which will wipe it out.
The cylinder walls should be checked for rust as well. If present, a little tlc now could avoid much greater expense later.
Not sure I'd be too eager to use that IMO. AT least a new cam and lifters, and from there a general inspection of everything else would be in order. Could be lucky and end up as a re-gasket and a cam kit.
Cam, I am afraid the GS 400 cam is kaput.. it's likey worn out anyway, even without the rust. As far as the Electra cam, rule of thumb is that if the peak of the lobe is worn all the way across (no black left on it from the parkerizing), then all the taper is gone, and it's likely to fail if put into service again. If it looks like the peak of the lobe only partially was in contact with the lifters, then it should be fine, that is the situation your after. The lobes are tapered to promote lifter rotation, and if the lifter rotates, it typically will survive. You can get away with a lot with stock type valve spring pressures, so I would be tempted to say that if the Electra motor had the cam replaced at rebuild, and has low miles, odds are that it would be fine in the 400. Call TA and get a small container of their cam prelube, if you chose to use the 455 cam, goo it up real well and make sure it has a break-in oil in it, from Gibbs or Penn.. JW
Ok, new cam and lifters it is. Looking at a pic of the Electra cam it looks like all the parkerizing is gone off the lobe peaks but still a little left on the ramps (yes I know, it’s filthy!) I think I’ll go with the TA_112.
Actually the cam is probably ok. While it does show rust, the lifter actually only rides on a certain part of the lobe. If you will notice the wear pattern, the distance from the edge is proportionally related to the lifter velocity. What that means is that during high tappet velocity, the wear pattern (on the lobe flanks) will be close to the edge of the lobe. At periods of zero velocity (across the nose and base circle), the wear pattern will migrate away from the edge and towards the middle, as can be seen in the pics. Where is transitions from zero velocity to high and back, it will migrate across the surface. It will not contact the cam in any other places, if things are working ok.
The front and #3 cam bearings are trashed. Will have to buy a cam bearing tool and replace all those. I decided to go with Federal-Mogul CS586 stock replacement cam. Lower lift than the aftermarket TA_112, which the stock valve springs should like. Paired with the matching timing gear set it’s not supposed to need degreeing. Some TA_1406 lifters to finish it off and hopefully it’ll be a runner. Should I be alright using the old pushrods in this scenario? The tips all look fine and they’re straight.
