Shurshot

While the gas millage that goes with a 5 speed with overdrive makes things far more livable the .6 series overdrive gear ratios are a death prescription for solid roller valve-trains.

This is due to the reduced oil pressure incurred with the extended low rpm cruising that goes hand in hand with a .6 overdrive ratio.

Solid roller motors run great at medium and high RPM but it is the low RPM at idle or stop and go traffic that have always been the problem for solid roller lifter longevity........ Consequently extended low rpm cruising with an overdrive can be a death sentence for an expensive custom motor all for the sake of getting better gas millage....

Doug

Plasticman

Thanks Doug, I needed that (that was what I was going to say)!

Plasticman

Frankie the Fink

Did I ever say the driveshaft wasn't turning ? I'm a little smarter than that folks. As I said that is a custom, balanced driveshaft and even so I would still expect vibrations to be exaggerated under load and they were not.

I have about 35lbs oil pressure at idle (850 RPM)....at 1600 RPM I prob have 45lb+ (I have a dyno sheet to back these numbers up). I doubt my engine's top end is going to be 'oil-starved' at low RPM cruising...
(Oh, and I have solid lifters but not roller lifters -- original motor).

I also am not concerned about gas mileage (why does this keep coming up?)....I wanted lower RPM cruising to keep from thrashing my motor to death at 75MPH...

ANYWAY....turns out I had a severely bent right front rim. I mean 1/2"-3/4" wobble on the tire balancing machine. All the d@mn construction around here I guess I nailed something and never knew it.
I swapped the bent rim with the spare tire rim and with all newly balanced wheels/tires my vibration is gone!

However I am now in the market for an original, straight rim with the 3 'nubs' to hold a hubcap...if anybody wants to unload one!

Plasticman

Frank,

Shurshot was talking about a solid ROLLER cam.........

Glad you found your problem (and easy to fix.....not necessarily cheap, but still easy).

John

macs65

Anything is possible, I sent the wheels out and had any dings or kniks repaired and had them checked for correct rotation, also intalled new tires at that time. Didn't help.

wmf62

Frank
there is no way on God's green earth that you could have bent a wheel that badly and not known what you hit..
Bill

midyearvette

i am a self proclaimed expert on the tko's as i have installed 5 of them on my car and others for friends and my view on the tranny is they are excellent up grades.....however there are many things to consider on the installations that will induce a vibration in 5 th gear...growing up in southern west virginia, we had an expression known as a "BLEVY" ..a blevy occurs when one tries to fit 10 lbs. of s@it in a 5 lb. bag....this happens when installing a tko in a c2 vette...the c1's im not familiar with but it all comes down to tunnel clearance with the top of the tranny and the resulting drive shaft angle...when it is off by even a slight amount, it will cause an un comfortable condition in od, when installed by keisler specs, even after using body shims, the rear of the tranny sags considerably that one can see with the naked eye!....we solved this issue by grinding the top cover ridges off the tranny and shimming the rear mount...also the taller .64 ratio's that some choose to run will amplify this situation because the mill could be running below it's 'sweet spot' or torque curve....the fault is not internal and when properly lined up, these cars run smoothly in all gears with the tko...jmo....

Frankie the Fink

I only did a short high speed run (coming home from the tire shop) and there was no more problem...I may get out some today for a longer check out.

I am amazed that nobody has brought up bellhousing run out as a source of vibrations....the TKO vendors stress this over any other issue and you have to show that the initial installation reading was within specs if you get warranty work done in most cases.

BILL - I don't know what to tell you. I saw how badly the rim was bent with my own eyeballs and I am a very attentive driver. I don't remember what I hit and worse yet, it had to be pretty recently or I would have been dealing with it sooner...

I might have run over one of those pokey Solstices that really old people drive around here and never thought any more about it.

toms silver 60

Frank, just drive over to Lakeland, I have a FOUR nub rim for you. Try not to run over any Solstices, VW convertibles or other chick cars on the way over.....

Frankie the Fink

About time for you to come North for a while...bring the rim & join me at this on Saturday:

Haiti Relief Benefit Open Show
4:00 PM - 9:00 PM
Hosted by the Lord's House, and held at the AutoZone store, 1726 South Highway 27. 100% of the proceeds from this show will benefit Haiti Relief. All cars and trucks welcome, judging begins at 7:00 PM. There's games, raffles, and food and beverage will be available. Registration fee is $15. For more info, call Debbie at (352) 217-9149.

and dinner will be on me!

Frankie the Fink

Problem was definitely the bent right front rim...took a hike this morning on the turnpike and from 60-85 MPH the car is actually 'glassy' riding....very pleased that it turned out to be a simple fix... Also the steering is decent now...I was drifting all over before but didn't know if it was the high winds or the car!

Stewart Allison

I was correct the vibration was from the wheels. Kiss principle always think basics before getting scientific. Stewy

drivette

I've been looking into a 5spd, but not just for fuel economy but for the lower the R.P.M.'s the engine will be turning. Making it easier on my drive-line parts!

Old Blazer

I agree, to bend a steel rim that much would be hard to miss. Perhaps the shop that did the install test drove it into a curb.

Frankie the Fink

The thought did occur to me but who knows.....
Its hard to buy that tho...this shop took better car of the car than anywhere else I've been....and I have a habit of showing up unexpectedly to check on progress and see how my car is cared for.

On the flip side, I can't accept the wheel was that way for any length of time because I'm too **** about the car not to have noticed the deterioration of the ride quality.

Picked up an angle gauge yesterday at Home Depot and will measure the driveshaft angle just to be persnickety ... not out of any real need to solve a problem.

StingU2

Frankie

We are glad everything is smooooooth...



se ya out on the turnpike

OLDED

FWIW, One thing not mentioned is the very solid front engine and trans. mounting system in the C1's. That tight mounting method doesn't allow for much engine movement absorption like the C2's and up can. The low RPM's below the "sweet spots" of the various engine set-ups can cause any slight engine roughness to be transmitted into the entire car at each engine's given rough spot - as it transitions from basically an idle speed in 5th. gear at 60 mph., ie. lugging, to a useable power level at it revs further. Just a thought.

Frankie the Fink

More than a thought....I suspect this is exactly what I still have (VERY slightly) at certain RPMs. Most folks I know with Tremecs in C1s have an aftermarket frame (Corvette Corrections, etc.) with an LS-? in it and its an entirely different beast than an original car.

ALSO - now that I drive at higher speeds routinely I'm running more air pressure in my skinny radials and I'm sure that contributes to how the car feels screaming down the interstate.

Frankie the Fink

Well I measured three different times and its like this:

(A) Very end of Tailhousing: 2-1/2*
(B) Driveshaft: 3-1/2*
(C) Pinion Yoke (measured with socket on it): 2-1/2*

A-B = 1*
B-C = 1*

As far as I can determine with my old eyes and a $9 angle gauge the driveshaft is perfectly aligned...