Mechanical Clutch Pivot Issue
Thread Starter
Intermediate
Joined: May 2016
Posts: 36
Likes: 2
Mechanical Clutch Pivot Issue
Ok, so I've got the new engine in and mounted, and as I was hooking everything up I made a discovery: The pivot on the block for the clutch is too far back by 4-6". There is a blank on the block where the old pivot hole was on the last block and it looks like it could be tapped to take the pivot. Dumb of me for not even considering this as a possible problem, but here I am.
I am considering 2 courses of action (the only ones I'm even aware of).
First: Tap the blank to receive the pivot. I've never needed to tap a block before, so if anyone has needed to do this in this particular spot, if you could give me some tips/recommendations please.
Second: Just do a conversion to hydraulic. I've never had any issues with mechanical, and @ $600 for a conversion kit, I'm finding it hard to be convinced to shift over. This issue with the block is making me consider it though.
On a related note, I'm looking at swapping to some hooked headers and side pipe in the near future. Does anyone have any experience with whether or not the mechanical clutch interferes with these?
I am considering 2 courses of action (the only ones I'm even aware of).
First: Tap the blank to receive the pivot. I've never needed to tap a block before, so if anyone has needed to do this in this particular spot, if you could give me some tips/recommendations please.
Second: Just do a conversion to hydraulic. I've never had any issues with mechanical, and @ $600 for a conversion kit, I'm finding it hard to be convinced to shift over. This issue with the block is making me consider it though.
On a related note, I'm looking at swapping to some hooked headers and side pipe in the near future. Does anyone have any experience with whether or not the mechanical clutch interferes with these?
Last edited by Aztroth; Apr 27, 2018 at 02:25 PM.
Melting Slicks
Joined: Dec 2009
Posts: 3,229
Likes: 656
From: Thunder Bay
I have tried to drill and tap a cast iron block with less than resounding success. That stuff is hard! Plus I'm not sure where you end up if you drill too deep, but I'm pretty sure that would ruin your whole day. Doing it with the block in the car is going to be an even bigger challenge. If it were me, I'd go with the hydraulic clutch. I don't have one in my car, but the guys that do rave about them.
Thread Starter
Intermediate
Joined: May 2016
Posts: 36
Likes: 2
I have tried to drill and tap a cast iron block with less than resounding success. That stuff is hard! Plus I'm not sure where you end up if you drill too deep, but I'm pretty sure that would ruin your whole day. Doing it with the block in the car is going to be an even bigger challenge. If it were me, I'd go with the hydraulic clutch. I don't have one in my car, but the guys that do rave about them.
Racer
Joined: Oct 2017
Posts: 312
Likes: 64
From: Henry county ohio
I haven' t had to tap a boss in a block, but it can be done, but you have to make sure you don't drill your hole too deep obviously. If I were doing it, I'd drill the hole, begin tapping with a taper tap and finish it with a bottoming tap to get the last couple threads cut. Hardest part is drilling the hole square to the block. Check the depth of your existing hole that is too far back and don't drill any deeper than that and you should be OK. I have no experience with the hydraulic conversion, but have heard of firewall flex from the master cylinder, but like I said, I know nothing of hydraulic conversions. Good luck, Jeff
Thread Starter
Intermediate
Joined: May 2016
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Ok, so I am trying to research options right now and I'm seeing quite a few results for brackets for the pivot to mount to the bell housing instead of using the block. This intrigues me. I might see if I can fab something.
Drifting
Joined: Aug 2005
Posts: 1,443
Likes: 65
From: Wauconda IL
I don't see a bell housing pivot bracket being as stable as a stud threaded in the block but that's me.
I would attempt to drill the boss in the block since the engine is out.
Use the proper bits and cutting lube- With a little patience, you should be able to get it done.
Worst case, you end up back with the bell housing bracket.
I would attempt to drill the boss in the block since the engine is out.
Use the proper bits and cutting lube- With a little patience, you should be able to get it done.
Worst case, you end up back with the bell housing bracket.
Thread Starter
Intermediate
Joined: May 2016
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Thread Starter
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Instructor
Joined: Jul 2007
Posts: 199
Likes: 83
From: College Station Texas
Gen V & VI big blocks didn't come with the provision for the mechanical clutch pivot either. There are brackets out there to convert for that. Not sure on forum rules for positing a vendor link, but a quick search found one at a popular dealer here in Texas. Looks like it's bellhousing mounted, so it shouldn't matter if you have a big block, small block, etc. For $60 it seems like an easy choice vs. hydraulic.
Thread Starter
Intermediate
Joined: May 2016
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Ok, well, this is the solution I've come to. Mostly because it was free, since I already had the drill and tap. I had to do it with a basic power drill, but its in. I'm gonna try to get it in another thread or 2, but its not a big deal if I can't. Its pretty solid right now.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
Ok, well, this is the solution I've come to. Mostly because it was free, since I already had the drill and tap. I had to do it with a basic power drill, but its in. I'm gonna try to get it in another thread or 2, but its not a big deal if I can't. Its pretty solid right now.
Glad to see you did it!!!
DUB
Thread Starter
Intermediate
Joined: May 2016
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Ok, well I managed to tap an additional thread without needing to drill deeper, and the engine is back the car, clutch is all connected up and working good. Bell housing and motor mounts are all bolted up, and I'm gonna call it a day. Maybe I'll have it up and running here in a week or so! (Probably wishful thinking)
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
Likes: 1,213
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
I have the Hookers and I didn't have any problems. To install, I removed the 'Z' bar but no problems with any part of the clutch linkage.
Safety Car
Joined: Sep 2005
Posts: 4,213
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From: Orange County Ca
FYI when my Hooker side mount headers rusted out last year, I replaced them with Doug"s. Cheaper, thicker tubes, thicker flanges, fit MUCH better on my 69 BB. The plug boots haven't melted either.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
Ok, well I managed to tap an additional thread without needing to drill deeper, and the engine is back the car, clutch is all connected up and working good. Bell housing and motor mounts are all bolted up, and I'm gonna call it a day. Maybe I'll have it up and running here in a week or so! (Probably wishful thinking)
Keep an eye on this...due to this pivot stud can back themselves out of the block...unless you use some removable threadlocker.
DUB