RE: IML: Unleaded gas effects

Yes, I would do a “leak down test” in addition to the compression check, to establish the source of the compression leak, if that is the result of the compression check. Very likely, you’ll find out that you have a leaking exhaust valve, but don’t assume that – there might be some other cause, and you’d be wasting your money without fixing the problem.

I still feel that you don’t need to spend the extra money to have hardened valve seats installed UNLESS you are going to be driving the car a long ways at high speeds, in hot weather, especially with a heavy load. If you are going to be just going to shows and the like, and the occasional short freeway blast, I still feel this is not necessary (and there are hazards to installing hardened seats, as someone has already pointed out here, if it isn’t done by a skilled machinist.)

As for your transmission not kicking down, you don’t say what speed you tried to kick it down, but the problem is not likely to be band adjustment. Of course, if you haven’t adjusted the bands in the last 50,000 miles or so, it might make other things work better, but the kickdown problem is almost always a linkage adjustment problem. Perhaps you have a bent part in the kickdown or accelerator linkage which is preventing proper operation. I’m not an transmission expert on these cars; I’ve only done normal service and adjustment on the 727s, I don’t’ know a lot about them that isn’t in the manuals.

Good luck with it – I love the Crown Coupes!

Dick (too many cars, not enough time) Benjamin

From: mailing-list-owner@xxxxxxxxxxxxxxxx [mailto:mailing-list-owner@xxxxxxxxxxxxxxxx] On Behalf Of Carl F.
Sent: Sunday, November 20, 2005 8:11 AM
To: mailing-list@xxxxxxxxxxxxxxxx
Subject: RE: IML: Unleaded gas effects

Good advice, Dick.

My '67 CC has 125k original on it & I'll now bet that a compression check will reveal the cause of that slight, truly out-of-character 'miss' at idle. I've already replaced the plugs, wires & cap to no avail. A valve job, new timing chain & new hardened valve guides should do the trick!

Also, a quick question. The transmission upshifts smoothly, & downshifts to 1st at a stop, however I cannot get into "passing gear" automatically. I've re-adjusted the linkage to factory specs; still no auto-downshift. Band adjustment?

Thanks, Dick.