L20 cam tower alignment.

[HRH]

Okay, so I'm trying to get this gd motor together and I'm fighting the piss out of the cam towers. I have the head bare, tried the original cam towers, couldn't get it very well, so figured maybe something was amiss. Swapped in a known set of L16 cam towers that were in order when pulled off the head. Can't get the fuckers to align!!!

 

I can rotate it just fine when all the cam towers are loose, been back and forth loosening and tightening, tweaking with a plastic hammer, etc. Once I get to final torque, I can turn the cam, but not nicely. Takes a good amount of grunt. Does it warm up then move, or is there some trick here I don't know? Head has been resurfaced, but not on the valve cover side.

[banzai510(hainz)]

what i did is loosely put the towers on with lots of oil. and then gently spec them down to about 10pounds torq.I had the cam already in the towers when bolting them down

 

if you can torn the cam by hand with the cam sprocket .call it good. i try the machine shp not to take the towers off but soemtimes they do. all my heads I can turn them with just my fingers.but the last motor It was tighter. If a used my hand on the cam sproket it turned. I havent had any proplems with it in 50k miles. It will wear in. This head was milled from the top also. just head one rear mismatch tower as thats the one that went bad as the head was warped.

[HRH]

Yeah, I just really don't want to have a cam snap. I may swap the other set back on. I got them a little better than the other set here. Frickin' A, talk about annoying though. Been dicking with the head for two hours.

[banzai510(hainz)]

I forgot to tell yea since my head was milled .030 I had 2 shims installed on cam towers. But soem how there was a 3rd shim stack up on already 2 other shims. and when I torqd it down that fucker wouldnt move. I couldnt figure it out . then finally notice that there was 2 shims but one tower had 3 shims and that all it took to lock up the cam when it was torqd down

[ggzilla]

Use the original ones. They are line-honed AFTER assembly, so ones from another head won't always line up correctly. Hopefully they are marked so as to go back in the same spots.

[HRH]

Yeah, but this motor had someone previously working on it who was not the best mechanic shall we say. Hopefully those caps are original to the head. I don't know. I'll try the others again and try and get it better. I'd prefer if it turned like butter after torqued.

[RedBanner]

How to hotrod datsun says, intsall the towers snug, tap with mallet. Tighten them down, if it doesnt turn try again.

[HRH]

Yep, I got my bible out too. :D Going another round here in a second.

[Sealik]

Assuming the bottom of the caps/top of head are clean, no 'burs', etc.....

5-10-12 lbs

[datzenmike]

This is why they should never be removed.

 

When a head warps, imagine a banana, and is then milled, you are only making it flat on the engine side.... the head is still bent every where else including being high in the middle. When torqued down the cam must be bent like a banana also.

 

Try a paper thin shims on the two outside towers. Keep adding until it turns when torqued down. Remove and measure the 'shims' and make them out of brass stock. Seems like this will eventually fix it.

 

 

Try another cam ... maybe the cam is bent.

[HRH]

Whaaaaaattt? No no no, there is no reason they shouldn't be removed. If they weren't meant to be removed they would be integrated into the head like newer heads. If it can't be fucked with, why would I play with it? ;) Besides, this head wasn't warped.

 

Anyway, finally got the little shit turning and torqued. Guess the second try and some Datsun luck with multiple fiddlings did the trick! I tried another cam initially. Same issue. Went back to the original caps. Cleaning off head bolts and getting this motor built!

[ggzilla]

So with that logic, if the main bearing caps weren't meant to be removed they should be able to be put back in any position mix and match? Yet it doesn't work that way.

 

Glad to hear you got it working.

[Boaty]

I had a similar issue, but it went away after torquing the head down. Apparently did the trick.

 

I broke my first camshaft, because I used head shims. Which is fine and all, except one of the shims ended up being two instead of one, and it broke the cam. It rotated just fine by hand. Apparently .030" on #3 tower isn't a good thing with 1/2/4 being at .015" ..... DOH!

 

One more L back on the road. This pleases Boaty.

[Xnke]

The cam towers can be removed and replaced just fine, as long as they are kept in order and replaced as a SET. DO NOT mix and match towers...doesn't usually work.

 

If you have a datsun head decked, it needs to be done top and bottom. If the head was warped at all, then milled on the bottom side only, then the top surface will not be straight and the cam towers will NOT align, no matter what you do shim-wise.

 

Datto L-series heads need to be straightened, then milled top and bottom. Straight out of the FSM, How To Modify, How to Rebuild, ect...

[HRH]

Yes, I know all this. And my point was Datzenmike said they shouldn't be removed period. Ideally no, but c'mon, they're bolted in, and you have to remove them for certain operations. Anyway, it's a moot point because I have now decided that I should be fucked today.

 

Consequently I was tightening down the head on this project for a fellow that I'm already losing my ass on. My old race block was plenty robust, but wouldn't you know it. Tightening, tightening, tightening......still tightening, a little release, then tightening, then a release. Somehow, even though it held together for three fucking years, somehow one of the center head bolts stripped the threads.

 

So now I need to got get a 10x1.5 helicoil kit, which of course I don't have. Only a 6mm helicoil kit. Unfuckingbelievable. Here I thought I was going to get the head on and then finish assembly tonight. Bah.

[ggzilla]

yes, removed for certain operations. But almost never need to be removed.

 

It is fair to charge extra to fix the thread. It's not included in the price of replacing a head or head gasket.

[HRH]

No, but I'm building a motor for this guy and already quoted a price. I may be tacking on a few things. Hopefully he won't be upset by it. I just went for an hour bike ride, was thinking about it, there was one head stud that had loctite on it when I disassembled the motor. Considering Jones (S&S) put the head stud kit in when I had them do the block way back when, I'll bet they're the ones who fucked it up partially. Probably good enough for one tighten, after I got the red loctite out, all over for the second go 'round.

 

Anyway, f cars for today. I'm eating dinner and watching Super Troopers. Take that crappy karma! :)

[RedBanner]

you ARE freakin out.... man.

[HRH]

Well, got the helicoil in, everything is hunky dory, except torquing to final specs, the bolt has a little bit of spring. I actually tightened that one to 64 ft-lbs instead of 61, just to account for a little bit of it. I'm sure it will be fine, just somewhat annoying.

[Boaty]

I helicoiled my block as well. Also, stripped the threads out.

I tightened it down to 80 ft/lbs as a test - held fine, backed it out and re-torqued all the bolts as normal. Haven't had a problem since.

 

You wouldn't believe the flame wars that erupted when I asked if it was safe to heli-coil a block. My simple question back then turned into 40 people posting different arguments all of which contradicted one another.

 

Woosah, man. Woosah.

I've said I'm done with cars a dozen times. But once it all starts working out, you're rewarded with awesome feels. And awesome feels are awesome.

[HRH]

Yeah I'm not too worried, should work fine. I've helicoiled lots of stuff. Got the head and chain on last night, getting close. Need to clean the timing cover now.

[wayno]

I also have put a helicoil in my LZ23 block, I also used the ARP stud kit, and have had no issues since, I didn't notice anything differant when torquing the head, well nothing except that the the headbolt torqued down this time, that was differant. :)

I am very happy with the results of the helicoil, I have not had to replace a headgasket since.

BTW HRH, thanks for pointing me in the right direction on that stud kit, I'm so happy, I have not had to make another headgasket since. :D

[HRH]

No problem there Wayno! I dig the stud kit too.