oinojo Posted March 2, 2006 Share Posted March 2, 2006 i was finishing up my engine build when i noticed my rear (6 cylinder) cam tower had a shim on it. I didnt notice it until i started on the exhaust valve of the 6th cylinder. The pivot point for the rocker arm was way higher than the others. I also noticed the lash pad was different color than the others. As of now i have the valve lash on that one valve correct but im worried that if i ran the car i would have BIG issues. Now if i were to remove the shim, would adjusting the lash pad be back to normal like the others. And also would i ruin my headgasket by taking out that one head bolt in the rear in order to remove the cam tower shim? *edit* the head was bought on ebay from ur-gelis through another z owner. Its freshly restored but this has me worried. Quote Link to comment Share on other sites More sharing options...
katman Posted March 2, 2006 Share Posted March 2, 2006 Take all the rockers out, take the cam sprocket off, and see if the cam turns freely (duh, don't forget to do something about the chain if you have the front timing cover on already). If it does, then you at least have something you can work with. My guess is the head was "freshly restored" by a hack and it's worthless, but let's hope for the best. Removing one head bolt won't hurt your gasket. Let us know if the cam turns with two fingers. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 2, 2006 Share Posted March 2, 2006 I'm thinking there is no way in hell one cam tower would be shimmed without totally binding the cam, unless the towers were inserted and line-bored. Look closer, are you SURE the rest of the towers are not shimmed? Quote Link to comment Share on other sites More sharing options...
oinojo Posted March 2, 2006 Author Share Posted March 2, 2006 I'm thinking there is no way in hell one cam tower would be shimmed without totally binding the cam' date=' unless the towers were inserted and line-bored. Look closer, are you SURE the rest of the towers are not shimmed?[/quote'] yes, im positive that there is only on shim on that cam tower. Its baffling me as well because i have been able to rotate my assembly no problem... Quote Link to comment Share on other sites More sharing options...
oinojo Posted March 2, 2006 Author Share Posted March 2, 2006 Given what you've just written, I would guess that the head is a "bitza" made up from at least 2 heads. As long as the cam rotates freely and the wipe pattern on the cam lobe is even, then the head is usable. This was from zedrally on classiczcars.com... he said it could possibly be a "bitza" - rebuilt from 2 or more heads... well that would explain why my cam rotates freely, now i have to address one of the lash pads... it appears the (6) exhaust lash pad is stock instead of the pad correlating to the cam. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 2, 2006 Share Posted March 2, 2006 Normally those shims are 0.015" thick, and I can't see it rotating with that much of a bind in there! It shouldn't affect the lash pads, as it would have to actually deflect the cam from the tower preceeding it---I don't see that happening! Quote Link to comment Share on other sites More sharing options...
oinojo Posted March 2, 2006 Author Share Posted March 2, 2006 Normally those shims are 0.015" thick' date=' and I can't see it rotating with that much of a bind in there!It shouldn't affect the lash pads, as it would have to actually deflect the cam from the tower preceeding it---I don't see that happening![/quote'] visually, i can see that one lash pad obviously not being the proper pad for this cam. But it does strike me why the cam can rotate freely with that shim on the cam tower. ive never heard of ppl shaving the ends of the actual towers seeing as the head was completely level. Quote Link to comment Share on other sites More sharing options...
Sam280Z Posted March 2, 2006 Share Posted March 2, 2006 What type of head is it? My best guess is that the back of the cam lost oil which wiped the old cam and tower. Replacements were sourced from another engine and it had to be shimmed to align the cam bore. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted March 2, 2006 Share Posted March 2, 2006 If it turns freely in the cam tower when everything is tightened down, that is what is important. I agree, someone probably replaced that tower and it didn't line up properly. No reason not to use it if everything aligns properly. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 2, 2006 Share Posted March 2, 2006 If it turns freely in the cam tower when everything is tightened down, that is what is important. I agree, someone probably replaced that tower and it didn't line up properly. No reason not to use it if everything aligns properly. Ya know, I've swapped countless cam towers from head to head. Hell, I've evne had them in a "Big Grab Box 'o Cam Towers" at one time. The MOST that I EVER had to do was follow the Tome Monroe "Knock and Turn" method to get the cam towers to free up on the head. The towers tied together with the spray bar were from the same head, but who knows where the rest came from??? I could never see why ONE cam tower would need shimming---then again I am assuming it's a .015" shim---information or a photo hasn't exactly been forthcoming, so going further beyond "I Say-You Say-Anybody Got a Guess?" kind of discussion is to take the next step and do measurements and maybe snap a photo of the mutant. I know I'm curious as to what it looks like! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 2, 2006 Share Posted March 2, 2006 Ya know' date=' I've swapped countless cam towers from head to head.Hell, I've evne had them in a "Big Grab Box 'o Cam Towers" at one time. The MOST that I EVER had to do was follow the Tome Monroe "Knock and Turn" method to get the cam towers to free up on the head. The towers tied together with the spray bar were from the same head, but who knows where the rest came from???[/quote'] Agreed. Cam towers are not head specific, regardless of the internet horror stories. Quote Link to comment Share on other sites More sharing options...
oinojo Posted March 2, 2006 Author Share Posted March 2, 2006 thanks for the help guys, ill try to get a hold of a digicam as soon as i can and take snaps of it. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted March 2, 2006 Share Posted March 2, 2006 Agreed. Cam towers are not head specific, regardless of the internet horror stories. I have swapped a number of cam towers from head to head also, and the tap the tower method to align has always worked, unless for some strange reason the tower has been shaved...I've never heard of it being done, but that doesn't mean someone hasn't tried to 'cheat' and shave a tower to make up for a warped head on top... without a known history of the head, well, you know... Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 6, 2006 Share Posted March 6, 2006 I actually know of someone who had cam towers shaved, but it was for rocker train geometry---basically so they didn't have to run some lash pad .280" think, or run non-standard length valves. Again, that was for ALL SIX towers. I can see no reason only one would have a shim! I would call the seller and see what his explanation was--besides this needed the "bump"! LOL Photos! I want PHO-TOS! LOL Quote Link to comment Share on other sites More sharing options...
oinojo Posted March 6, 2006 Author Share Posted March 6, 2006 I actually know of someone who had cam towers shaved' date=' but it was for rocker train geometry---basically so they didn't have to run some lash pad .280" think, or run non-standard length valves. Again, that was for ALL SIX towers. I can see no reason only one would have a shim! I would call the seller and see what his explanation was--besides this needed the "bump"! LOL Photos! I want PHO-TOS! LOL[/quote'] hahah yeah im trying to get hold a digicam, i should be able to take pics tonight and post them. Quote Link to comment Share on other sites More sharing options...
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