Springs, et al.

[ribbert]

.....Springs get sacked after 30 years, esp. oem Japanese steel springs........... but new (modern steel) springs will help keep valve float away in the 8k-10k rpm kookaloo zone.

Just my opinion.   Cheers.  Pat

WTF??  Where did these ideas come from?

Noel

[Pat Conlon]

WTF do you mean?

Take your pick and please elaborate:
1) the fact that weak valve springs cause high rpm valve float?...or
2) the fact that over time and use, springs lose their strength?....or
3) the fact that high performance spring steel manufactured today is better than the oem Japanese spring steel made in the '80's?

Noel, so as not to co mingle discussion, as you see, I've started a new thread.....

[TexasDave]

I think this discussion will result in the metal fatigue failure of old springs and mental fatigue failure of old participants.      
Just my opinion but if you are replacing valve stem seals might as well replace springs too.

Dave

[Pat Conlon]

I hear ya Dave, it will be interesting to read Noel's response. Even though we argue, I really enjoy Noel.
He's a smart fellow with years of experience, and 'thou we may not always agree, I respect his opinion.

Could Old Rider get away with re-using his old valve springs? Sure, probably.....maybe.

[ribbert]

WTF do you mean?

Take your pick and please elaborate:
1) the fact that weak valve springs cause high rpm valve float?...or
2) the fact that over time and use, springs lose their strength?....or
3) the fact that high performance spring steel manufactured today is better than the oem Japanese spring steel made in the '80's?

Noel, so as not to co mingle discussion, as you see, I've started a new thread.....

Pat, I was just interested in where these ideas came from, not looking for a discussion. These sort generalizations get passed around and are often re posted without much thought given to them, but, as you're expecting a response I couldn't be rude and ignore you........

1) What you say is technically true, if a valve spring is too weak to do the job it was designed for the valve will float/bounce at high rpm but what's that it got to do with FJ's?
A small capacity, twin cam, 4 valve motor has very little inertia in the valve. Have you ever experienced yourself or heard first hand of anyone else having a problem with valve bounce on an FJ motor up to redline (and still mounted in a motorbike?) In fact the whole notion of valve bounce on road vehicles revving within design limits is something I don't ever recall afflicting any particular vehicle nor did it become an issue as mileage increased.

2) Technically, once again this is true, but by such an insignificant amount as to have zero effect on the running of an engine. It weakens by a mere fraction of the the buffer the spring has to do the job. Once again, as FJ's are unaffected by this I fail to see the connection? You had also originally attributed this wear to the passage of time only (30 years)

3) I have never heard this claim before. Japanese engines from the 80's were amongst the most reliable, high mileage achieving, low maintenance and technologically advanced engines ever. Probably why we never checked valve springs for fatigue, they never needed to come apart.
I can remember bits and pieces of thousands of engine jobs from the 60's through to only a few weeks back but I can't recall a solitary thing about valve springs being a problem on any engine, other than the odd broken one on non Jap motors.

Pat, everything you say is technically true (except IMO the FJ valve bounce above 8K) but has nothing to do with FJ's.






"I think this discussion will result in the metal fatigue failure of old springs and mental fatigue failure of old participants.   biggrin "

Dave, that's very clever and very funny (and all too often, true) but it's been a while.


Noel