Hi I am trying to get some measurements so I can check my scattershield out before I order the new trans. My picot ball without block plate is 4.770 is this wright? I had an older link to his website but it is no longer valid. any help would be greatly apprecitated. It is a 69z28 with 350/330ho motor and a lake wood scattershield.

Dave,

Your number sounds good, 4.75 is the number your .020 high which shouldn't be a problem. More important is to check the fork geometry, depending on the flywheel and clutch you choose hopefully the standard fork ball height will work for you, sometimes doesn't work out that way. Also the lakewood bells are usually not so concentric with the pilot, I would dial indicate the retainer bore to insure good reliability with shifting and bearing wear on your new gear box. I have found the mcleod scattershields to be spot on.

Good luck Rich

Dave69Z
The section of your clutch fork between the tip of the ball stud and the point of contact (the front edge of the wide groove of the throwout brg.) where the fork pushes the throwout bearing, should be at about 5* to 7* from parallel. With the throwout bearing more toward the transmission.
http://classicchevy5speed.com/files/Clutch_Fork_TO_Bearing_instr.pdf
Jim

Thanks Guys, every little bit helps. Jim was that you I spoke to on the phone thursday about dialing in a bell housing? 5-7 degrees is hard to see, any easy way to do it? The old trans blew up so I can't really put it all together to measure it. Does the Mcleod bolt up without dialing in and is the clutch geometry usually better? I really can't stand the lakewood setup, and the ihra frowns on a scattershield without a block plate. I am considering going back to a stock bell housing or reproduction 621 housing just to get the geometry correct. My motor is only about 375 hp.

Hi I am trying to get some measurements so I can check my scattershield out before I order the new trans. My picot ball without block plate is 4.770 is this wright? I had an older link to his website but it is no longer valid. any help would be greatly apprecitated. It is a 69z28 with 350/330ho motor and a lake wood scattershield.

You must include the block saver plate if you are using one with the overall height measurement of 4.750". Also the pivot ball height of 4.750" is for a flywheel that measures .950"

Dave69Z
The section of your clutch fork between the tip of the ball stud and the point of contact (the front edge of the wide groove of the throwout brg.) where the fork pushes the throwout bearing, should be at about 5* to 7* from parallel. With the throwout bearing more toward the transmission.
http://classicchevy5speed.com/files/Clutch_Fork_TO_Bearing_instr.pdf
Jim

Hey Jim,

I like your .pdf file on this subject.

Dave
Sorry I can't remember if I spoke to you or not. The last week was a blur. Yes the McLeod will bolt in without dialing it in but the block must have never been align bored & honed. If it has, the McLeod will have to be checked and possibly aligned. The geometry will still have to be adjusted for the clutch fork though. It's relatively easy to do. You don't have the transmission in when you do it and you just eyeball it to be about 5* to 7*. Your stock bell should be checked too. It may be off due to years of stress and heat.
Jim

Jody
Thanks on the pdf.

I t appears I need to get the clutch and have the flywheel surfaced. If the block plate measures .110 does this mean I need to subtract .110 from 4.750? And if the fly wheel measures .920 due to surfacing do I again -.030 from the previous total?

Dave ,
I'm using a McLeod on my SBC w/out the block saver, the block was only align honed. I did have to use a pivot ball from a later model chev truck to get the right pivot action without hitting the firewall...Anyway, I didn't indicate my housing in and have had no problems. ( about 400 miles on new combo so far )

Is the pivot ball from an 80's error 1/2 ton? If so I may already have one. I bleieve the truck one is significantly longer, which may help.

Mid 80's sounds about right..I was still able to get it at my local Chev dealer, so it couldn't have been too old.. And it is indeed longer. When I put the assembly together , I was out to the last thread on the stock pivot ball trying to acheive proper articulation. Needess to say if that sucker fell off I'd be in deep doo doo. I searched this section and was able to solve the problem, all the way down to a part # for the pivot. This place is amazing!!

Thanks for your input. Hopefully I will begin mocking up everything next week. I will probably use my old clutch etc just to see how far off I am.

I t appears I need to get the clutch and have the flywheel surfaced. If the block plate measures .110 does this mean I need to subtract .110 from 4.750? And if the fly wheel measures .920 due to surfacing do I again -.030 from the previous total?

Yes, you subtract .110" and .030" from the stock 4.750" height. You will need a Mr. Gasket pivot ball #3855 to set the new pivot ball height of 4.610". You will have perfect fork travel geometry by the numbers. This will also put your fork in the position GMJim has shown in his .pdf file diagram.

Don't forget to dial indicate the bellhousing too.

Happy Shifting!

Thank You. that clears up alot of it. I'm going to mock it al lup next week and my magnetic base for the dial indicator just showed up last night.

I reinstalled my flywhwheel and scattershield everyhting looks and measures up fine. Howeve I can't get an accurate measurement on a stock gm flywheel. It is a late model one piece design and measures well in excess of .950 if I go from a clutch bolt hole to the face of the fly wheel? Am i missing something? I also dial indicatied the bell housing by using a magnetic base adn a dial indicator on the inside of the ridge wear the trans mounts to it. Either i got luck or I did something wrong. It measured 12 oclock .001 3 oclock .003 y6 0clock .002 9 oclock .001. so does this sound correct I measured it twice and it was the same. so from 12-6 is .003 and 3-9 is .004?

Anybody? Does this sound correct? I just zeroed the dial indicator on the lowest rading and then rotated 2 full revolutions. so I could double check everything.

I reinstalled my flywhwheel and scattershield everyhting looks and measures up fine. Howeve I can't get an accurate measurement on a stock gm flywheel. It is a late model one piece design and measures well in excess of .950 if I go from a clutch bolt hole to the face of the fly wheel? Am i missing something? I also dial indicatied the bell housing by using a magnetic base adn a dial indicator on the inside of the ridge wear the trans mounts to it. Either i got luck or I did something wrong. It measured 12 oclock .001 3 oclock .003 y6 0clock .002 9 oclock .001. so does this sound correct I measured it twice and it was the same. so from 12-6 is .003 and 3-9 is .004?

Place your flywheel on a flat and smooth table with the pressure plate surface side down. Measure through one of the crankshaft mounting bolt holes for the proper flywheel thickness.

I have measured many new GM flywheels in excess of .950", some have measured as much as .980". You will need to make adjustments to the pivotball height if you are over .950".

On your bellhousing measurement for concentric, you didn't state if you were + or - on your dial indicator numbers. You should also check that your bellhousing is parrallel to the crankshaft.

All measurements were +. I still need to check for paralellism. But I was trying to find out if I am doing this wright. I just tried that way on the concrete floor which is smooth and it mesures 1.005 to 1.0015 i am using a vernier so its not as accurate as I would like. since the measurements were all positive does it soundlike its dialed in? If so I will order a block plate and try to re-use this scattershield.

I am not trying to take over this thread, but I too am having the same simalar problems...I just looked at my setup with my lakewood scatter shield attached to the block and I definetly do not have the 5 to 7 degrees. Mine is probably straight or maybe even a negitive couple degrees. It sounds like I am going to have to adjust the ball height too...I have a new Hays flywheel (10-130) and using the centerforce clutch setup. I also have the lakewood scatter shield with the block plate. I guess my questions is how do I measure the 5 to 7 degrees and also is that 5 to 7 degrees more important than the recommendations of 4.750 from the block to the ball stud?

Is it possible, with the bell housing off the motor, lay a straight edge accross the housing and measure the height of the stud to the straight edge to get the ball height?

it's possible, but you'd lose the width of the block plate, and that makes a difference. That 5-7 isn't brain surgery, it's an eyeball measurement. If you purch the outer end of the fork back, pressing everything against the clutch plate, the fork should visibly tilt forward as it goes out away from the bell. Ajust your ball stud to get that and it may solve you firewall clearance problems.

I am not trying to take over this thread, but I too am having the same simalar problems...I just looked at my setup with my lakewood scatter shield attached to the block and I definetly do not have the 5 to 7 degrees. Mine is probably straight or maybe even a negitive couple degrees. It sounds like I am going to have to adjust the ball height too...I have a new Hays flywheel (10-130) and using the centerforce clutch setup. I also have the lakewood scatter shield with the block plate. I guess my questions is how do I measure the 5 to 7 degrees and also is that 5 to 7 degrees more important than the recommendations of 4.750 from the block to the ball stud?

Check out your original posting of "Clutch fork hitting firewall". Hopefully we can get you where you need to be on your pivotball height.