1967 starting problem..only when hot...

[russ]

my 67 convertible turns right over and starts when cold...and it runs great.  If I stop for gas..have it shut off for 5 minutes...when I go to start, it really hesitates, you turn the key and you think it's dead...then the starter will try to crank ...sometimes it catches..other times, you let it cool off for a few minutes and then it will start right up ? the starter and cables are have all been replaced in the last 4 years...could it be these ? or is this vapor lock ? only does this when it's hot...any insight / advice/ help would be appreciated.

[Otto Skorzeny]

When you say only when hot, do you mean hot engine or hot days or both?

Are your cables the correct diameter (gauge)? Not too thick, not too thin? Are connections , including grounds firm and clean? What condition is the battery in?

You say the starter hesitates and you think it's dead. Those are not symptoms of vapor lock.

When you say the starter will try to crank, does it crank slowly or spin fast and strong?

My inclination is that you have a problem with the starter. Did you buy new or rebuilt? Or did you have your original rebuilt?

[Philippe M. Ruel]

If the battery is new or like new, it may be a charging system trouble : battery is weak after driving, and "recovers" after a few minutes. Check it or have it checked promptly.

Is it the original exhaust system, or aftermarket ("4-in-1" or so) manifolds that get too close to the starter ?

[Roger Zimmermann]

It can be also the starter motor relay, located on top of the starter motor. They go bad with age and mileage.
Roger

[russ]

thanks for the replies...

it only does this when the engine is hot...after it cools off, all is fine...the battery is new...only a few months old...the exhaust system has been on there forever...

[russ]

when I say the starter hesitates...it doesn't want to spin at all....it acts like it is being driven by a dead battery ( which isn't the case, the battery is new) and doesn't want turn over...again when the car is cold, it turns right over no problem and starts right up...

[Roger Zimmermann]

when I say the starter hesitates...it doesn't want to spin at all....it acts like it is being driven by a dead battery

Exactly the syptom from a bad relay.

[jaxops]

It could also be the dreaded "vapor lock."  Check your carburetor settings and your timing.  A lot of my vapor locking was being caused by incorrect timing.  It may have been correct, but the car ran better after making some further adjustments.  Note that there is a pretty wide range for dwell as an example.  I don't remember my Dad having vapor lock problems with the mid-sixties cars.  Keep working the car through the issues.  It took me several months of adjustments and retightening to stop the leaks and the rough timing. 

[35-709]

Vapor lock has to do with the fuel in the fuel lines, not a hesitant starter.  Basically, all other things being equal, with vapor lock the engine will turn over normally but will not start because the fuel cannot get to the carburetor.  The problem as described by "russ" is not caused by vapor lock.  As has been suggested make sure all starter/battery/ground, connections are clean and tight.  A bad relay is certainly a distinct possibility ---- also, new or rebuilt components can fail anytime and should not be overlooked just because they are new or rebuilt.   

[mgbeda]

I used to have a similar problem with my '76.  The cause was that the positive battery cable to the starter just got too hot from the nearby exhaust manifold.  This increased resistance in the cable and left the car just barely able to crank when hot.  I solved the problem by getting oversized (about half inch diameter) battery cables, routing the positive one as far from the manifold as possible and fashioning a "heat shield" for the cable with shiny aluminum tape.  I've never had the problem since.

-mB

["Cadillac Kid" Greg Surfas 15364]

Russ,
Check your battery connections at the starter and at the battery as well as the ground cable  at the battery and at the frame where it connects.  You might just check to see that the battery posts are clean and the contact at the posts is good.
Also verify that the ground strap from the sarter to the frame (or engine) is good and the connections are firm.  As an added task while you are under there, check to see that all the screws holding the starter solonoid to the starter case are tight, and all the screws and small gage wiring connections are tigne on the end cap of the starter solonoid.
I think you will find this elusive gremlin soon. It doesn't sound too serious.
Greg

[russ]

I changed out the starter today...put another rebuilt one in..and it's fine now...the old one only lasted 5K miles...all the connections, cables, ground etc were fine.....I appreciate all the suggestions from everyone...I've learned more things to watch-out for...thanks again for your help.

Russ

[The Tassie Devil(le)]

Did you get the old Starter motor diagnosed as to what the problem was?

Bruce.