[bottlefedgt]

Theres no reason you should have to grind anything to fit the clutch. Something is wrong in there

 

[d347643]

Actually, there are numerous threads about having to do this with the chinese King Cobra wannabe clutches. I'm not saying it's ok, I'm just stating that I'm definitely not the first.

 

[kim]

you found your problem, the cheap off shore knock off part............ try it two or three more times...

 

[FiveLiterFox]

Why in the world would you risk running a clutch like that?

 

[d347643]

Hey, don't need to be harsh. Believe it or not, Astro performance sold me that clutch and it worked fine on my previous build. It's only when I built this new engine and used a stock replacement flywheel that I even had to mess with the bell housing area. To elaborate, there were three high spots on the pressure plate causing the issue and I felt better about grinding the bell housing a little than the pressure plate. Rumor has it that they include disclaimers about this in the kits as there is an apparent difference between t5 bell housing depending on the location they were cast.

Ok, you guys are trashing me about the clutch. If I clearanced the bell housing and the pressure plate didn't make contact then how did the clutch cause this? Not saying you all are wrong but give me some info to go on here....

thanks,

Drew

 

[408foureye]

The king cobra spec pressure plate he's talking about is likely the Korean made hd valeo. It's taller than the original version previously sold by ford racing and requires clearancing some t5 bell housings. I've used them before without issues but they're not as durable as the originals.

I doubt the problem is the clutch. I once had a bad pilot bearing take out a thrust bearing. When I pulled the engine I happen to notice some of the needles dislodged in the back of the pilot bearing causing the trans input shaft to bottom out early and push on the crank. The only symptom it had was the trans being hard to shift into 1st from a complete stop.

 

[FiveLiterFox]

Well I guess just the way you were describing it made me wonder why you would have run it...


.

 

[d347643]

Wow, sad to say the thrust has gone out again on my rebuild. It was .0045 and now its almost .013 when I put dial indicator on the crank. Clutch pedal lightly clunks when pushing in and there is copper in the filter. Really at a loss here guys. I'm definitely no pro but I've prob assembled a dozen small block fords and never seen this issue. Could there be anything wrong with the crank or block? I'm open to any ideas here...

I know folks are saying it's from the bell housing side since it's wearing on the back side of the thrust bearing. When I mated the engine and transmission I still had .0045 endplay on the crank so I don't think anything was binding. I even chamfered the rear half of the thrust bearing as per Clevite's article to allow more oiling.

Changes since last time:

- Had flywheel milled to match the thickness of the previous flywheel used with this block.

- Had rear thrust surface on crank polished

- Chamfered rear half of thrust bearing to help with more oiling

- Swapped from adjustable clutch pivot ball to stock replacement

- Tried better quality oil

- Bypassed the clutch switch for starting

In the process of tearing down....will update with findings.

thanks,

Drew

 

[Old School EFI]

Sorry to hear its being torn down again. Trevor told me the other day via text.

 

[willyt]

It's not the block, it's something with the trans and/or clutch.

Different types of oil won't make a difference if the thrust flange on the crank is in constant contact with the thrust bearing. Polishing will not help this problem (though it's good to do).

Not sure if you're running a cable or hydraulic set up. I'd maybe be sniffing around in that area.

 

[d347643]

Thanks guys. What about the crank itself? What about the crank thrust surface not making even contact with the thrust bearing? This wouldnt allow the clutch pressure to be evenly distributed over the thrust, no?

Willyt - I am running a cable clutch and have a firewall adjuster. I do not preload the pressure plate and the have the adjsuter set so there is 1/8" or more free play.

thanks,

Drew

 

[willyt]

It's possible that the crank thrust flange is un-even (wavy), but unlikely. That's something that can be checked with the crank on rollers and a dial indicator.

Hell, it's possible that the crank itself is bent, though you'd probably notice that during assembly.

 

[d347643]

The bearings looked good last tear down. Just the thrust was shot. I really want to blame the clutch but I used the same clutch in a previous build with this same block with no thrust issues. I'm almost tempted to chaulk it up to block voodoo andbuild up another shortblock I have

 

[d347643]

Tore it down and thrust is same as last time but not as bad since I caught it even earlier. I did notice something about the center main cap though. With the bearing in the cap, it can move in the thrust direction back and forth about .002. I chucked the main cap in the vice and put a dial indicator on the bearing to check this. Maybe there is ~.002 play in bearing plus ~.002 actual thrust endplay which wasn't enough???

 

[88coupelx]

Wow. Subscribing.

 

[willyt]

There should be zero play in the bearing when it sits in the cap.

Do the faces on the main cap look worn, or the back of the bearing?

That could cause a problem, albeit an unusual one.

 

[d347643]

They dont look worn, no. Only talking a few thou here. When this block was originally machined, I was using king bearings. I pulled the clevite out and put a new king in the thrust cap and there is no movement whatsoever.

I'll post some pics later but I also noticed that the thrust surface of the crank has very very small pitting. It appears the machine shop polished over everything instead of cutting the thrust surface back. The only reason I noticed the pitting is because I tried to wipe the copper off the crank thrust surface but found that copper was embedded.

thanks,

Drew

 

[88coupelx]

They dont look worn, no. Only talking a few thou here. When this block was originally machined, I was using king bearings. I pulled the clevite out and put a new king in the thrust cap and there is no movement whatsoever.

I'll post some pics later but I also noticed that the thrust surface of the crank has very very small pitting. It appears the machine shop polished over everything instead of cutting the thrust surface back. The only reason I noticed the pitting is because I tried to wipe the copper off the crank thrust surface but found that copper was embedded.

thanks,

Drew

I imagine a pitted crank surface is the reason for the failure no?

 

[willyt]

Pitting. I wonder if they tried to weld the thrust face?

 

[d347643]

I should prob clarify. The pitting I'm talking about is like the size of grains of salt or sand. When I first saw the thrust surface on the crank there was a bunch of fine copper pieces. Tried to wipe it off but it wouldnt clean up. It's only when I shined a light at an angle that I could see there was pitting and the copper was lodged in these pits. I'll try and use the macro setting on my camera to show what I'm talking about.

Here's my plan of attack

- Get another crank and have it turned and balanced.

- Get another clutch. Prob a stock replacement Napa unit.

- Have this Pagan High Priestess gal my friend knows bless the block and dispel all remaining bad energy.

- Rebuild