Slow down the 915

[Nick Triesch]

My 85 is old like many and I do all the tricks to get it in first gear. But I also just noticed that if I put the box in neutral about a 100 yards before a stop sign or a light , it slides right into first. My question is would a thicker gear box oil help slow the gears down faster? So my 911, when the engine and trans are both moving slow, it pops right into gear. If you have a higher mileage car like mine, try it.

[BE911SC]

Peter Zimmerman* recommends a similar technique in that you snick it into 1st just before the car comes to a stop. Worked great when my '84 synchros were worn. With new synchros (April) it goes right in even nicer. The 915 must be fully understood and respected in what it can and cannot do in order for one to appreciate and enjoy it.

*The Used 911 Story

[DRACO A5OG]

To insure it will pop in "slow/stop" the gear by touching 2nd before plopping into 1st.

As far as thicker oil, it will not do much IMHO. Just practice the touching of a higher gear before dropping into 1st at LOW SPEEDS, like under 10MPH or even less or you will lose couple or several dog teeth.

BTW, do you have 75W90 or 80W90 in her now?

[Trackrash]

Thicker weight oil will likely make it worse.

The 915s really don't want to go into 1st if you are moving at more than 5-10mph. If you want to extend the life of your 1st gear synchro you can wait till stopped or almost stopped, double clutch, or touch 2nd before going to 1st.

[RetroSC]

Touching 2nd has always worked wonders for me, but I never understood exactly why. Is the mainshaft still spinning a bit, even with the clutch depressed, then touching 2nd synchros spins the cluster a bit to match the mainshaft rotation??

Short of that, I can't figure out what exactly touching 2nd does.

[porwolf]

Best way to go into a lower gear is double clutching. If done right synchros would not be needed.

[BE911SC]

Originally Posted by Trackrash

Thicker weight oil will likely make it worse.

The 915s really don't want to go into 1st if you are moving at more than 5-10mph. If you want to extend the life of your 1st gear synchro you can wait till stopped or almost stopped, double clutch, or touch 2nd before going to 1st.

Funny thing, now that you mention it, is that with new synchros I think I have almost money-shifted into first from second a few times. I'll come out of second and I swear it felt like I could have greased it right into first if my muscle memory hadn't felt the mistake and corrected it. And that's just normal 2-3 shifts, not boy-racer driving. Car has a short-shifter and I plan to put the stock unit back in.

[BE911SC]

Originally Posted by porwolf

Best way to go into a lower gear is double clutching. If done right synchros would not be needed.

Yep, pop taught me that in the Austin-Healey. Prolongs the life of the synchros too.

[chrismorse]

Originally Posted by BE911SC

Yep, pop taught me that in the Austin-Healey. Prolongs the life of the synchros too.

My first car was an MGA, non synchro first.

Double clutch into first.

chris

[Trackrash]

Originally Posted by BE911SC

Yep, pop taught me that in the Austin-Healey. Prolongs the life of the synchros too.

Your Austin Healey had synchros? I had to double clutch my 3000 in every gear.

[BE911SC]

Originally Posted by Trackrash

Your Austin Healey had synchros? I had to double clutch my 3000 in every gear.

Worn synchros were undoubtedly an epidemic on British stuff back then the same way worn 915s are today. My dad's '67 Healey didn't have a synchro on 1st. It would go into 1st at a very slow roll without any protest, however. 915 reminds me a lot of the Healey box.

[Trackrash]

Originally Posted by BE911SC

Worn synchros were undoubtedly an epidemic on British stuff back then the same way worn 915s are today. My dad's '67 Healey didn't have a synchro on 1st. It would go into 1st at a very slow roll without any protest, however. 915 reminds me a lot of the Healey box.

Yes. A couple of differences between the Healey and Porsche. When I replaced the synchros in my Healey's box all was great for awhile. Soon however, the new synchros wore out and I was back to double clutching.

A properly rebuilt 915 should last a long time.

The advantage of the Healey trans was the shifter came directly out of the trans. No shifter bushings or couplings like the 915.

Back to our normally scheduled program.......

[911pcars]

Originally Posted by Trackrash

......A properly rebuilt 915 should last a long time........

A properly driven (shifted) 915 should last a long time.

Sherwood

[Nick Triesch]

Jim, I have Swepco 212 in the 915 now. Recommended on this site years ago. By Early S man.