Camshaft binding in head - Page 2

Wayne 962 · Wayne 962's Garage

Quote:

Originally posted by alchole
Now what the hell do I do? Where whould you get a machinists straight edge? Will that tell me anything I don't already know? Should I remove the heads, pull off the pistons and cylinders, clean the loctite from the copper gaskets, and then reassemble dry. Is there a way to deffinitively measure what's wrong? Is it possible to send the parts off to someone to measure and correct, since I don't trust myself to measure it with any precision.

Swap left and right cam towers before you do anything else, and let us know how that works...

-Wayne

Henry Schmidt · Henry Schmidt's Garage

Quote:

Originally posted by Eagledriver
As others have said you should remove the 574 from the base gaskets. If it hardened before you finished torquing the heads it will be different thicknesses under the cylinders. Also with the shifting around and pounding this area takes it may crack and start to leak. A non hardening sealant is what to use here. ..........
-Andy

I would also check the cylinder to cam tower joint for uneven drying. If you applied 574 here a thick coat can also dry unevenly causing the loads on the cam tower to be inconsistent.

Waynes advise also seems spot on.

alchole · 10-24-2005, 09:43 AM

So, first off, thanks everyone for all the advice.

Here's what I'm going to do. I've already pulled off the right hand pistons and cylinders. The loctite did appear to be unevenly distributed around the base of the cylinders, but maybe this is just me hoping.

I plan to clean all that stuff off, measure the shims and cylinders as best as I can. Then I'm going to dry fit everything and see what happens. If everything is ok then I can only assume the loctite hardened before I could torque everything down. For the rebuild I'll probably use Curil-T instead for the base gaskets.

I'll let you know how things go.

BTW, I don't think I'm going to swap left and right cam carriers because the left side of the engine bolted together fine and the cam spins smoothly on that side. I don't really want to mess with something that seems to be ok.

Also, how do you measure the head surfaces and distances between them with only a vernier caliper and dial indcator?

Wayne 962 · Wayne 962's Garage

Quote:

Originally posted by alchole
BTW, I don't think I'm going to swap left and right cam carriers because the left side of the engine bolted together fine and the cam spins smoothly on that side. I don't really want to mess with something that seems to be ok.

Okay, I can understand that. Then, I would maybe borrow a cam tower from someone and see if it fits and the camshaft spins freely - I'd hate to see something wrong with your cam tower, and you have to tweak it to get it to work properly. Don't forget that everything changes when these engines heat up, so you want to make sure that things are perfect when they are cold. On that thought too - the camshaft may spin freely when the engine is hot - you'll never really be able to tell. Still, I would personally feel more comfortable trying out another housing...

-Wayne

camgrinder · 10-24-2005, 10:02 AM

Does the cam spin free in the housing when its off the engine?

911pcars · 10-24-2005, 10:37 AM

Is the cam straight? I don't see a confirmation of this or did we just move along to step 6?

Sherwood

alchole · 10-24-2005, 11:24 AM

To answer some of the outstanding questions...

Yes the cam spins freely when off the engine.
On a side note off the engine, I was spinning the cam by hand and if I listened very closely you could hear the faintest (and I mean very faint) sound of drag when spinning the cam happening at the same position it did when torqued down. Whatever this is may be exaserbated when it gets torqued down unevenly. Again this was extreamly faint and couldn't be felt with the hand when rotating it. So it may have a certain amount of runout but shouldn't be a problem in a normal situation (meaning the carrier not being tweaked after torquing).

I haven't measured the cam. I don't have a shop and so thought of making some v-blocks out of hard wood and measuring that way. I would assume that would work. Actually I just recalled that Elgin(the cam maker is 5 min from my house). They might be kind enough to measure the runout on the cam for me.

It would be nice to have access to a know straight carrier that I could bolt on, but alas I haven't seen any lying around my house.

I'll have to see if anyone local can measure the flatness of my cam carrier. I'd like to be able to eliminate that once and for all.

Thanks again for everyone's help on this.....

911pcars · 10-24-2005, 01:01 PM

The V-blocks must be machined metal for trueness. Pay Elgin a visit and ask them to check the cams, then you can move forward.

Sherwood

alchole · 10-31-2005, 08:02 PM

Got the cam measured at Elgin.

They said it was in spec. One of the journals was just slightly out (still in spec) and they cleaned it up, but I don't think the cam was the problem.

So, off come the pistons and cylinders. I've scrapped off most of the loctite. Let me tell, that's not been fun. Once that's done, I'm going to put everything together dry and see what happens.

One interesting thing I found out. It looks like John Dougherty(camginder) worked for Elgin for 15 years and they didn't seem to happy to see me bringing in that cam. They measured it for free though, so that was nice.

camgrinder · 10-31-2005, 08:17 PM

Thats too cool.

Jeff Alton · 11-01-2005, 01:39 PM

He He.............

Cheers

alchole · 11-06-2005, 07:12 PM

Status Update....

Assembled the right side of the engine dry and ......

Still having a little binding with the cam. Loosened the 4 cylinder head bolts from the middle cylinder (#5) and the binding went away. So, either my cam carrier is warped/not flat or my cylinder+head height is wrong. Anyone know of a place in the bay area (San Francisco) that can measure my carrier for straightness?

Any one have any other suggestions?

jimbauman · 11-06-2005, 07:24 PM

I'm pretty sure Ted from German Precision in Sunnyvale can narrow down the problem for you...

JB

ChrisBennet · ChrisBennet's Garage

You can get a piece of ground stock and use that for a straight edge.
I use something like this http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1750523&PMT4NO=2509883 from MSC.
You can use it when you measure your sprocket parallelism too.
-Chris

cstreit · cstreit's Garage

As others mentioned uneven cylinder heights will do this.

Did you measure your base gaskets? Are you SURE your cylinders are the same heights?

You could have have mixed a single cyinder from left to right and one side group was shorter or taller. WHen you torqued the head down, you warped the cam carrier. Every time you retorque it, it'll get a bit worse.

Did you have your heads or cylinders machined?

88911coupe · 09-15-2008, 06:09 AM

Searched and only found 2 threads on this problem but I'm in the same boat. On the driver's side if I loosen the head studs on #2 the cam spins fine (spins when just put in the cam free as well, right side seems fine) The only thing I've had done was send the heads to Walt at CE for rebuilding. I marked all of them, along with the cylinders, so everything would go back in the same spot but when I got the heads back the marks were gone on all but 2 heads, and it's not very clear on those two. I know cylinders have height groups but can't find anything in Wayne's book or Bentley to indicate that heads are grouped in size. Nothing was indicated in the paperwork with regard to cutting of the heads but i emailed Walt and he said he'd cut .25 off so I went with 2 .25 gaskets. This all tells me the #2 head/cylinder assembly is just a bit "shorter" than 1 and 3...correct? I plan to remove the heads and try to measure how much shorter then add another shim...does this sound like the right solution? Not sure I really have any other choice. I did try retorquing but the heads bind up even with the 1st low level torque, regardless of pattern. Pretty frustrating...

cgarr · cgarr's Garage

Can you swap the heads and try them on the other side? You have one good side right?

88911coupe · 09-15-2008, 07:50 AM

Yes, the "right" side spins fine. I'm reluctant to pull it since it's working fine but it may be that I have to mix n' match to get them both spinning smoothly. I do know that before I removed the cams they both spun fine in the cam towers and neither the towers or cams were altered since they look to be in perfect condition. I really wish I knew which heads came of which cylinders but that's a moot point now...the marks are gone. Do heads get grouped into sizes like cylinders? If I do end up with one head slightly shorter than the other 5 due to the cutting I can just add a spacer, correct?
Also, I assume torquing #2 at a lower level is not an option correct? I'm not even sure that would work. The only option is the torque SEQUENCE, right, not the torque value?
Starting to regret taking this on...really had no choice though.

cgarr · cgarr's Garage

The heads are not grouped, Sounds like the only thing that changed was cutting the sealing surface on the heads, if one is off it will make it bind, if you can get a 3-4 inch mic you can check the heads for sameness.

88911coupe · 09-15-2008, 08:16 AM

Thanks Craig, that looks like my best option, at least I'll know one way or the other. Dumb of me to assume they'd come back the same but I was thinking if they removed the same amount of material off all 6 then they'd be okay. I did do a dry test fit but did not torque the head studs all the way...looks like that was a mistake too. Nothing like going back a week in the process! LOL!
Thanks for the suggestions,