u20 head cam tower question

[dynaguy]

Are cam towers interchangeable on u20 heads? I have a very good condition head that is missing these. TIA Pat

[keith0alan]

Yes and no. They will bolt on however they will quite likely need line bored.

[david premo]

Yes it can be done, with the head off the engine it takes time and the removal of the alignment dowels. The factory put the towers on then line bored them for perfect alignment the dowels are there to maintain alignment side to side. When you remove the dowels from the head, leave in the ones at each end of the head and install the cam shaft and slowly torque them down. The towers need to be a matched set for height and by removing the dowels it lets them line up straight front to rear. At all times you need to be sure the cam turns Very freely, if not it will break the cam. Finally check is after installing the head on a block make sure the cam still turns freely.
Dave

[Solex68]

That's great information Dave. I have a set of towers and I am not sure I know which head they came off of.
Using this technique, I can probably figure it out. Sounds like a fun weekend project to remarry the two.

[redroadster]

I use the frozen Vasilene or trans assy lube in the / on the journals seems to keep it aligned better

[david premo]

Redroadster, you make no sense! Cam tower alignment is achieved by using the cam it self to find center on all of the towers and carefully torquing down the towers after you achieve alignment in both directions. Using a frozen product like petroleum jelly is of zero value, or transmission assembly lube does what???? Is this like putting sawdust in the crankcase to quite a rod that is knocking?
Dave

[redroadster]

No it isn't Dave it melts use a hair dryer turns to oil , machine shops used it , AT lube if your picky or 140 w , then it tends to keep it center / straight while tightening , also having a 2 or 3rd to spin The cam while tightening can help just curious how many you've done ?
Ours assy lubed almost every crank , cam ,jack shaft ,even cyls , if it's fleet stock it may sit up on a shelf in 90 plus heat and humidity for 1-2yrs before install

[DCroadster]

As I am now looking into the U20 head on my car, I am enjoying the tech banter among the community.

I am loving the commitment to the marque.

I also have a Sunbeam Tiger and both are on the same level. East Coast thinks of preservation (rust by salt), while West Coast thinks of perfection (points during concours).

Rob

[david premo]

I still I have no idea what you think you are trying to explain redroadster, maybe it’s that you have never done this before. What were you at the dealer the ASE certified detailer? I think you’re supposed to use the hairdryer to style your hair not the camshaft. Maybe you and your hairdryer can get a job at a styling salon. And answer your question looks like I’ve done this quite a few more times than you as don’t know what you are talking about!
Dave

[redroadster]

Let me walk you thru it , I bet most understand though. The thick Vaseline type grease will not nove out of the slim clearance as oil will and the cam isn't bending so you get it aligned easier it's a miniscule amount and turns mostly into oil
This isn't the big deal your trying to make it .
Try to get a dealership tech job one that keeps you and sends you to the factory training , try not to start teaching the class then , some do .

I ask you 1st of your expertise , and zero answer Im still waiting
Me , since you ask : 2 years auto mechanics votec in high school 3 hours a day, 1 or 2 in the book .
Working ( at a job , not a hobbiest )on cars or trucks since 16 see my posts at bottom forth rest

[S Allen]

I can attest to Dave's expertise. He helped me line up my cam and towers for my 67 2 liter and it is spot on. No grease involved what so ever. You do not need to question Dave's abilities when it comes to working on and building engines. He knows his stuff and I trust his knowledge thouroughly. You, however come up with some off the wall comments that make me scratch my head.

Steve

[devo]

I can attest to Dave's expertise. He helped me line up my cam and towers for my 67 2 liter and it is spot on. No grease involved what so ever. You do not need to question Dave's abilities when it comes to working on and building engines. He knows his stuff and I trust his knowledge thouroughly. You, however come up with some off the wall comments that make me scratch my head.

Steve

Agreed! +1

[DCroadster]

Where can I find torque values for the head. I received head off engine and somebody was fiddling with cam. Besides cam being rusty, cam retainers were out of order and loose as well as towers. Besides the "Roadster Book" is there an engine manual?

TIA Rob

[nismou20]

Max U20 torque at 65ft lbs in increments. With Datsun head bolts. APR can go higher

[david premo]

Be careful you might wreck your block, the fine thread ARP head studs can pull the threads out of the block. With I fine thread you get a much higher squeeze on the gasket and pull on the block threads. So the pulling force on the block is much higher than what a standard or corse thread can do.
Dave