Dale760

Hi Guys

I finally got my 1980 resto mod running with my new Richmond 6 speed installed. Taking it easy it shifts hard into 2nd and 4th and wont down shift into those gears. 1 to 3 & 5th are all fine, also reverse.

My car is a original 4 speed car with the S T10 that shifted like butter.

I bought he car with brand new HO350 GM crate engine in it that I went through and detailed, and for now that's what I'm going to run. I could tell it had a brand new flywheel , pressure plate and clutch disc, and original bell housing clutch fork & pivot ball. I left the clutch alone, and did not unbolt it from the flywheel.

Though I know I should have, I did not dial in the bell housing but the trans slide right in very smooth. I could be wrong but really think its not an alignment issue. I'm really leaning towards that I'm not getting full clutch disengagement.

I spent 4 hours adjusting the shift linkage for the 2nd time, removing the cross member to get in there and getting it spot on, with the pin sliding in and out freeing. ...... No improvement.

The car will also row through the gears very smooth with the engine off or at idle.

Today I removed the dust boot on the clutch fork and realized I have zero clearance from the throw out bearing to the pressure plate fingers with the linkage rod removed. I installed a new Timken bearing that is a stock 80 replacement 1.25" to 1.28 " tall.

FINALLY ???

After all this my question >> Is the HO 350 GM one piece rear main block/ crank the same on the back as far as flywheel location. Will my 80 bell housing, clutch fork and stock parts be correct ?

I'm going to lengthen the fork rod and tighten up the clutch more just as a test before I pull the trans back out to see if it shifts better.

I have a feeling the shop that installed the new engine put the wrong pressure plate in it, but I will need to remove it, measure and compare everything with a new clutch kit.

Once I pull the trans back out I will also cut a hold on the bell housing so I can check the clutch air gap with the clutch pushed in.

Also what is the best low cost clutch that will hold about 400 hp

Thank you for any input on part compatibility with this engine.

Dale in NV

MCMLXIX

If the picture of the bell housing, clutch fork, and bearing is showing how it was installed this might be the problem.
The clutch fork spring clips should be in the groove of the throw out bearing not outside of it like in your picture.
The pivot ball spring should be behind the ball head.

Dale760

I hear yah MCM, but nope that's only in this picture, its all installed correctly in the wide groove of the bearing and the spring clip to the ball is cherry. I also have zero clearance from the front of the throw out bearing to the fingers on the pressure plate with the fork rod disconnected.

Ive built many Chevys' in the past, mostly big blocks, but never this exact combo.

It also looks like a pretty short pivot ball which I think is original and correct. I bought the car from the original owner and it only had one motor change.

Once I pull the trans back out it will be interested to compare a couple other pressure plate finger heights with it laying flat on a table.

Something is just wrong and I intend to find out

Thanks Dale

cagotzmann

Before removing the transmission you could test if you re getting proper release

You will need a assistant.

Remove the drive shaft and rotate the slip yoke by hand and compare when it starts to lock and release by pressing in and releasing the clutch.

With the clutch fully pressed in you will be able to easily rotate the the slip yoke by hand

When release you will not be able to rotate the yoke at all

Make sure you have the transmission in gear

gkull

Does your clutch pedal Z-Bar have multiple attachment points? If not you can drill a hole lower. This moves the throw out bearing farther for the movement of the clutch pedal.

Why didn't you make the tranny cross mount removable

Dale760

Good idea and I intend on doing that. I do have the old slip yoke. Its disengaging somewhat since it does go in every gear at idle, but I'm pretty sure not enough to make it shift smooth when the car is loaded out on the road.

I talked to Paul at 5 speed.com, and though very busy is always willing to help with his expert advice. He let me know the easy way to be sure the bell housing alignment is not the problem.

Remove the clutch and pressure plate and put the trans back in and lightly snug. Put it in any gear and rotate it with a slip yoke, just like you mentioned above. If it spins freely your fine on the bell housing location. He also says its not normally gear selective if it was out of spec, and does not sound like that's the problem. The tech at Richmond that called me back also agreed, and also said down shift block out 9 times out of 10 is because of the clutch not having the .070 air gap with the pedal pushed in.

It does act like its not full disengagement. Im testing a 1" longer rod either tonight or tomorrow just to see what it acts like.

Why the throw out bearing is already against the fingers of the pressure plate is the big question ? That's why I asked about the HO 350 engine being compatible with my other stock 1980 parts.

I still think the dealer that installed the engine in the car may have put the wrong clutch in it, but I will need to verify that.

Thanks Dale

Dale760

Hi George

Your speaking my language ............ LOL >> I was going to try just that next, but the trans has to come back out anyway now to figure out my throw out bearing to the pressure plate clearance problem anyway.

I still have about 1 1/4 " pedal play from it being against the rubber pedal stop under the dash, so with the 1" longer fork rod and tightening up the clutch a bit more just for a test, that should do the same thing, or least help.

The 80-82 cross member does bolt in and out at the frame rails, which is so nice compared to the older cars. I do need to go buy a transmission jack, this 6 speed is heavy, and Im not 25 anymore ..........

Nice to hear from you

Dale

gkull

Would you like to work on it tomorrow or Friday I can drive over

Bell house alignment is easy with the Allen locking offset down pins

I don't have a tranny jack. Just aluminum 1.5 ton

gkull

When I installed my 5 speed. It ground reverse trying to get it out of the garage for the first test drive.

My problem was too short of pivot ball I went from a stock short to a stock long

Dale760

Thanks for the offer G, but I'm going to wait to pull the trans until after the car show here in Yerington on the 18th. I'm going to order a tall trans jack so I can still have the car up on my lift. It will take a couple weeks to get in, and I'm also always busy with my bike projects.

I will make it disengage more a bit for now and worst comes to worse I can drive it down town to the car show in 1-3 & 5th.

First I need to check the pressure plate finger height to see what the heck is going on with the throw out bearing having zero free play to the fingers, and go from there.

I added a inch to the rod as a test only for now, and I have another new stock one on the way.

I'm also dealing with a PS pump leak and also a new bad hose end, so it will be a day or so before a short test drive.

Thanks again and if you want to come down for a visit to my shop, and the car show, that would be great.

Dale

bmans vette

Just a quick note....
There was an article in the back of Hot Rod a month or so back.
Turned out the guys pressure plate fingers were the problem.
They were not all at the same height, Making the disc hang up.
They pulled the pressure plate and used two pry bars to make them all level again.
Worked fine after that.
It was a Centerforce clutch and it was $800 to replace it.

Be interested to see how this one plays out.

Good luck

Dale760

Thanks bmans


BUT IM FIRED ! LOL

Well I hate to admit it guys since I've been doing this stuff for many years, but after looking close I may have made a dumb mistake. I'm not positive since it hard to see in there with it together, but I may in fact have the fork spring clips on the back of the throw out bearing. I think I can see the top one, which is not good. I do know I would have not put one in front and the other on the back.

Just getting senile I guess at 59 ......... ha ha

So this does explain not getting fill clutch release without more push, but it does not explain why when relaxed the fork will not pivot enough to get the bearing off the pressure plate fingers.

I did not measure them or anything like that, but did not notice anything strange when I had it in front of me and it worked flawless with the 4 speed. But the throw out bearing was starting to be dried out and worn with very low miles on it, so it was most likely touching the fingers, and the clutch pedal had plenty of free play.


I'm looking at clutch kits in this price range, keep in mind this is not a real high horsepower application and at the most even with a cam swap will be at best 400 hp. I wont power shift or beat the crap out of it, but will get on it and go through the gears. I want it to be a good street clutch with smooth engagement.


Have any of you used any of these clutches, I know opinions can vary

http://www.summitracing.com/parts/mc...model/corvette


http://www.summitracing.com/parts/ra...model/corvette


http://www.summitracing.com/parts/ra...model/corvette


http://www.summitracing.com/parts/mc...model/corvette

Thanks Dale

bmans vette

No matter what....its always great when a mystery gets solved.
Then its just a matter of correcting it.
Good luck with finishing it up.
I have a LONG way to go before mine will see the road.

Dennis (Bman)

Dale760

Hi Dennis, I fire myself every couple weeks, but then I run out of money and have to get back to work........... LOL

I make some pretty bitchin motor cycle parts, do all my own dyno work, exhaust , jetting and fuel injection ..... blah blah blah.

Its been quite a few years since I built my last hot rod so maybe that's why I spaced on this one and made the rookie mistake.

Thanks Dale

gkull

I posted the parts numbers for my Sachs 11 inch 168 tooth 26 spline for TKO 600 years ago.

it has to be the best clutch/PP I've ever used. Very light pedal, very little ware, Just lasts for years. I've had behind 3 different roller motors of mine 383, 427, and 434 SBC's.

My only other clutch in my Vette was the Centerforce DFX

MCMLXIX

Take a good look at your picture of the bell housing with the throw out bearing and fork.
If the fork is not installed in the bearing properly it moves the bearing forward using up the slack at rest and keeps the bearing in contact with the pressure plate.
It also shortens the travel of the bearing to get full clutch release.

Dale760

I will have to check out the Sachs clutch as an option GK, they do make good stuff. I think another very good stock replacement may be a LUK.

DW

Dale760

Hi MCM

I've never installed a throw out bearing wrong I until now thank god, I did not think it would push it forward, but I understand what your talking about how you explained it. Once I pull the trans back out and install it on the fork properly, I can check it right in front of me even with the trans out of the car. What I mean is at least the free play to the pressure plate fingers, with linkage connected and not to the fork.

Thanks Dale

gkull

How i came about Sachs clutch and pp was from Keisler back when they were still alive.

I bought the tko 600 kit with block saver plate, blow proof bell housing, sfi rated 22 pound steel 11 inch 168 tooth. I had told them that I had a 650 hp 427 sbc motown block SR doing 7500 rpm.

The nearly $5000 dollar kit came with the Sachs ....... I was skeptical and bought the 1000 hp handling DFX or what ever rating,,,,,, It uses weights and rpm to increase clamping force. I was out road racing and it never seemed right. It was more of a pro street idea.

So I broke my Bill Mitchel motown 427 crank shaft and
had it bored to 434 because of damage. i went to a custom cam of my design with a 4/7 swap firing order and put in the Sachs clutch/ pp. years of road racing and drag strip runs



i have been very happy

Dale760

Nice