QuestionI have a 1975 Spitfire 1500 and I recently drove around town for approximately 90 miles. During that time (on the highway) I couldn't get the top speed over 60mph. A few months ago it went 70mph. It didn't rattle, struggle or feel any different.
Secondly, after this trip and a few days in the garage I noticed a large oil leak from the rear end.
Are they related? Any suggestions?
Thanks!!
AnswerTodd,
It's possible that if a bearing is failing in the differential it could put enough drag on the engine to limit the top speed.
It's more likely that in the past several months you've either a) developed a vacuum leak to the distributor, b) have built up deposits in the carb that are keeping the dashpot piston from moving through it's full travel, c) the float needle is not set properly or is sticking and sufficient fuel isn't in the float chamber, d) the distributor mechanical advance weights are gummed up or e) some combination of problems.
A Spitfire 1500 in good shape should be able to provide much more than 60 or 70 mph on a flat straight piece of highway. I'm not advocating breaking traffic laws, just a statement of fact.
As to the differential, it sounds like one of the 3 seals (pinion and 2 stub axle) has failed. The original pinion seal was made from leather and on cars not used on a consistent basis the leather eventually fails.
Unless you're blessed with a good local shop that understands the Spitfire differential setup it's almost impossible to replace the stub axle seals without removing and/or destroying the stub axle bearings. They're not expensive but it adds up.
Cheers,
Jim
