Healey Hints For The Weekend Mechanic
Originally published in Healey Highlights, Vol. 7-6
Austin Healey Smoking
What gives? I consider myself a fair mechanic but I have a real puzzler. I am restoring a 1966 Austin-Healey 3000. The back three cylinders were oil fouling the spark plugs and emitting smoke when I got the car. A valve job with new guides didn’t help much. So I bored 0.020 in. over size and put in new pistons, rings and bearings. The engine now develops full power but still emits too much smoke. The compression is normal at 160 psi. The only thing I can think of is a hairline crack in the block but no water is being lost. It’s not carburetion, as I have tried
everything from lean to full rich.
Our expert on Austin-Healeys, David Ramstad of Austin-Healey Club Pacific Centre, thinks you’ve tried just about everything. The only suggestion he offered was that perhaps you might need to replace the head. It could be cracked or warped and thus causing the oiling condition.
AUSTIN HEALEY STILL SMOKING?
I don’t believe the advice given to Tom Mason in “Technical Correspondence” titled “Austin-Healey Smoking” (January 1976) is correct. The symptoms he describes are probably those of a worn-out rockershaft and bushing and not that of a sick engine, cracked head or any such major failure. If the rockershaft bushings are worn beyond 0.004 in., the shaft will emit small geysers of oil which increase at higher RPM. Vacuum created within the engine will pull this excess oil thorough the hose leading to the rear air cleaner and introduce engine oil into the intake manifold. This would foul the sparkplugs and create smoking at the tailpipe. A simple check for the home mechanic is to remove the rocker assembly cover. Oil should just barely ooze out of the hole in the top of each rocker. Steady stream or spouting of oil indicates wear.
It would appear Mr. Mason has unfortunately spent his money on an engine overhaul and is about to replace his engine’s cylinder head. Incidentally, the rockershaft and bushings are among the very few parts still carried by British Leyland for the Healey. Approximate cost of the shaft is $40 and the set of bushings isa bout $12.
I am enclosing copies of our October 1971 issue of “Healey Highlights” in which we discussed this problem.
Past Pres.AH Club,
San Jose, CA
Hank, thank you for the information. We have forwarded a copy of the club newsletter to Tom Mason.
The following is the text of a letter sent to Thomas L. Bryant of Road & Track magazine in March of 1976. Mr. Bryant is the magazine’s associate editor and he is involved with the Technical Correspondence feature. A quick reference to R&T’s Technical Correspondence columns of January and April 1976 will make the paragraphs to follow self-explanatory.
I have some additional, and I pray final, light, to shed on the by now notorious “Smoking Healey” controversy which was discussed in the Technical Correspondence of the January and April 1976 issues. Feeling some embarrassment personally at not having recalled the worn rocker shaft possibility suggested by Hank Leach (April R&T, p. 151), and not totally satisfied with his insistence on that one possibility alone, I was moved to contact Tom Mason of Minneapolis, writer of the original request for aid. I felt that apologies to Mr. Mason might be in order had my suggestion of a cracked or warped cylinder head forced him to replace it needlessly.
Tom Mason is evidently a mechanic of some ability and well versed in the quirks of certain English sports car powerplants. He stated that in addition to work described in his letter to R&T (January 1976), further attentions included both a thorough Magnaflux of the head for flaws, and a careful scrutiny of the infamous rocker shaft’s tolerances. Mason routinely considered both areas as quite easily conceivable sources for oil-fouling in the Healey’s aft three cylinders. Neither possibility panned out as the culprit, however. Further labor brought to light the fact that quantities of brake fluid had entered forbidden areas of the car’s power brake servo system, probably via a seal failure. This vacuum servo system was an optional extra on Austin-Healey 3000 BJ7 series cars, and a standard feature of the final BJ8 series. Since this servo system is dependent upon intake vacuum supplied through a rubber hose which is attached to the aft end of the intake manifold, Mason finally concluded that cylinders 4, 5 and 6 were consuming and burning brake fluid, not engine oil. A real long shot in anyone’s book, I’d say, but apparently the true cause of the problem.
I feel certain that this situation, but involving another marque, was covered in Technical Correspondence in the past, but have been unsuccessful in locating the article. Owners of cars other than the Healey which feature a similar type of vacuum brake servo should keep Mr. Mason’s problem and cause in mind.
We would all do well to recognize the obvious lesson in Mason’s smoking Healey. Technical problem solving requires the utmost patience and a firm resolve to maintain an open mind at all times. The simplest, or even the most logical solution is not always the correct one.
Austin-Healey Club, Pacific Centre
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