What is best precaution to ensure no engine damage would result from "missed shift"

[BReyes]

What is best precaution to ensure no engine damage would result from "missed shift" 2nd instead of 4th. Engine is presently apart (heads are all cleaned [by machine shop] and are still disassembled) and machine shop has completed inspection, evaluation, cleaning, blasting, prep ($1K).

Thank you.

Regards,

[Bobboloo]

1. Racing valve springs (Aase, Jerry Woods, etc.) and titanium retainers to help prevent valve float.

2. Wevo, Rennshift, Seine Systems, etc. style gate shifters.

[CharlesJones]

This is the cheapest gate shift kit I've found, which seems to have been designed specifically to help prevent missed shifts;

http://www.seinesystems.com/GateShift-1.htm

They sell them at Pelican. I've bought one but haven't fitted it yet because I'm still rebuilding my top end after a missed shift. Once the engines back together again I won't drive the car until its fitted - I don't want to go and do it again!

[ChrisBennet]

Like Bobbolo said, stiffer valve springs. Pelican "Camgrinder" sells some reasonably priced "street" performance springs that are plug and play i.e. don't require machining the spring seats or changing the spring height like the AASCO ones.
I'd skip the Ti retainers unless you get a good deal.
-Chris

[BReyes]

As it relates to shifter:
I have a G-50 that shift wonderfully (my 915 [ on previous '83 SC]shifted alot different [e.g. harder to get into second with out a lil {grind}]). I have to read up the Seine system and the substitute products.

Tell me more guys. This seems reaaly important to me. I have been on Sebring Raceway with my 911 and I know a missed shift would be a problem.

As it relates to valve springs and retainers: My springs (and all my valve train components came out of the machine shop as "good"). The top end has been rebuilt once before.

I believe I will need better springs/retainers/keepers to keep her together should a problem occur.

I have always been careful about missing a shift. I did this once as a teen ager in my '67 SS 396 (I had muscle cars in the eighties , [Beemers in the '90s], and P cars since 2000! Going into first instead of third at speed is not fun to experience. I about jumped out of my skin that evening. I learned with the Beemers that in order to fix a problem, the best bet would be with a replacement part.

Regards,

[Bobboloo]

If you want the extra insurance you should consider the whole shift package. Gate shift, coupler, and stiffer motor mounts.

People rave over the Wevo products and never seem to regret the added expense.

I don't know if the factory G50 has the spring loaded lockout 1st to 2nd gear plane but the gate shift products do. You have to apply extra muscle to get into 1st or 2nd when coming from a higher gear.

If the coupler has fresh bushings it will have less slop. The Wevo coupler or the brass bushings reduce slop even more.

Stiffer motor mounts keep the drive train from twisting do to torque. When it twists the alignment between the tranny and shifter is compromised.

P.S. If you do any of these recommened upgrades you should post back your results. Most the info in the data base here relates to 901 and 915 trannies. It would be nice to get reports on G50 improvements.

[wevoid]

Originally posted by BReyes
What is best precaution to ensure no engine damage would result from "missed shift" 2nd instead of 4th.

Just so there is absolutley no confusion - none of the WEVO products mentioned are capable of preventing engine damage.

The fact that all gears are accessible allows a driver to select the wrong gear at the wrong time. Among other things, our products offer some warning that you execution and intention may be at odds.

We fully appreciate all the enthusiasm and solid support we receive from our customers. But - I always feel a little nervous when reading something that heads beyond what we are comfortable claiming about the technical aspects of our products.

Having said that, a miss-shift over-rev is less likely with our products installed, however - once that crankshaft speed goes above the safe valve clearence speed - it's an engine builder
question.

Regards

Hayden

[ChrisBennet]

Originally posted by wevoid
We fully appreciate all the enthusiasm and solid support we receive from our customers. But - I always feel a little nervous when reading something that heads beyond what we are comfortable claiming about the technical aspects of our products.

Hayden,
OK, so maybe it won't prevent a missed shift. It's still true that the Wevo shifter will make you more attractive to members of the opposite sex though right?
-Chris

[wevoid]

Chris,

As you are probably aware we undertake extensive testing with our products.

A test like that can take a considerable period of time to render useful results.

Since we were satisfied with the technical, operational and mechanical durability of the shifters - we launched the product (Jan '02) The sex appeal is part of an extended ongoing test.

We have engaged a test group of users who are participating in a blind control test. This group are contracted to secrecy, so even though many are board members, I would hope they will maintain confidentiality on this matter.

I expect we will have a breakthrough result sometime soon and will be pleased to announce this on the forum.

We also started testing a new knob design that has met with approval from both same and opposite sex.

Regards

Hayden

[john walker's workshop]

stiff valve springs and plenty of clearance between valve and piston is your best insurance. a missed shift is one thing, but a downshift into 2nd when you were going for 4th is another. it's gonna get way more wound up than with a missed shift, generally.

[camgrinder]

The camshaft choice can affect which spring you should use. If you have a stock profile (SC) a new set of factory springs are good, or my performance spring set.

[snowman]

I think Bobboloo is on the right track. Get the best valve springs you can find along with TI retainers and a very good shift gate.

This will most likely save your bacon in most cases. And if your quick on your clutch maybe more.

[mtelliott]

I never thought of it but my wife has trouble with mis-shifts. OK, so she did it once and I almost fainted. Is the gate shift really only an hour to install. I would think that if she had better feedback, she would feel more confident in the car; not to mention how much less I would worry.

I've installed a new shift bushing so I'm not intimidated with taking the assembly apart.

Michael

[wevoid]

Michael,

One aspect often overlooked when husband and wife, or any other partner combination are driving a car together is seat fit.
If there is a significant difference in size and weight between drivers, it is inevitable that the seat fit is likely to be less good for the smaller driver.
As a result, the smaller driver is often clinging to the wheel to hold themselves up in the seat. When that grip is then shared with the shift lever, the results can be disasterous.
One of the best investements to protect your engine from mis-shifts is to ensure that the seating position is adequate to drive the car with above normal lateral g's and not use the shift lever as a crutch to hold yourself in the seat.

Regards

Hayden