Valve spring broke
Discussion
My pre 1930's engine has broken a valve spring, I am planning to replace the entire set on the basis that if one has broken the remainder are likely to be weak.
Unfortunately I do not have a specification for the valve springs, owing to the age of the car, is it reasonable to expect a bespoke manufacturer to be able to assess/measure the springs (they are double springs) for correct performance based upon the old springs as a guide?
Any recommendations please as to whom can do the job of manufacture. Thanks.
Unfortunately I do not have a specification for the valve springs, owing to the age of the car, is it reasonable to expect a bespoke manufacturer to be able to assess/measure the springs (they are double springs) for correct performance based upon the old springs as a guide?
Any recommendations please as to whom can do the job of manufacture. Thanks.
Why not try the owners club first,they often have such spares available or can advise on a suitable alternative.
As for getting them made ,it may be worth the effort of having a few more sets made for other owners consumption.One set is expensive to set up for, amortizing the set up/tooling costs would make sense.
As for getting them made ,it may be worth the effort of having a few more sets made for other owners consumption.One set is expensive to set up for, amortizing the set up/tooling costs would make sense.
Thanks for input Auntiroll, I've approached the club and the mentor for the car model is asking around and will publish the query in the next club newsletter. Agree if other owners come forward then setting up a 'group purchase' makes sense. However, I need the car on the road as soon as possible, although I can still use the car as the inner spring is still OK on the particular valve. Having said that I am wary of that spring breaking.
You must absolutely not use the car like that. The inner spring alone will only sustain very limited rpm anyway and the broken outer may well also break the inner leading to a dropped valve and a written off piston and cylinder head.
I can do the spring force calculations with the requisite data to see if an existing spring from a modern car will fit or for the manufacture of OE replacements. It will require you to measure quite a lot of stuff accurately though.
Better reposting this in engine and drivetrain though as it's a tad technical for a home mechanics forum.
I can do the spring force calculations with the requisite data to see if an existing spring from a modern car will fit or for the manufacture of OE replacements. It will require you to measure quite a lot of stuff accurately though.
Better reposting this in engine and drivetrain though as it's a tad technical for a home mechanics forum.
Pumaracing said:
You must absolutely not use the car like that. The inner spring alone will only sustain very limited rpm anyway and the broken outer may well also break the inner leading to a dropped valve and a written off piston and cylinder head.
I can do the spring force calculations with the requisite data to see if an existing spring from a modern car will fit or for the manufacture of OE replacements. It will require you to measure quite a lot of stuff accurately though.
Better reposting this in engine and drivetrain though as it's a tad technical for a home mechanics forum.
Thanks Pumaracing, sounds like good advise. A fellow club member is sending me a spare valve spring and I will have it fitted next week. At least I can keep on the road that way and concentrate on replacements. I can do the spring force calculations with the requisite data to see if an existing spring from a modern car will fit or for the manufacture of OE replacements. It will require you to measure quite a lot of stuff accurately though.
Better reposting this in engine and drivetrain though as it's a tad technical for a home mechanics forum.
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