L-series engine gaskets

Engine, Transmission and related drivetrain.
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abisel
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Re: L-series engine gaskets

Postby abisel » 11 Apr 2016 17:12

Yesterday I ran a regular tap into the bolt head holes and there was a couple that were a bit gunked up at the bottom. Even though I had done it before I installed the head in the first place. But I will get a bottom tap to get the threads cleaned all the way down the hole.

Interesting thought about the front cover. So I checked to make sure it doesn't sit higher than the block, and it doesnn't. It is very slightly below the deck surface so the front cover isn't elevating the head during assembly.

So far, the only things that I find suspect is a couple bolt holes (center 2 on the spark plug side) a bit gunked at the bottom, suspect dowels (one doesn't look like the other) and old head bolts. Once I get the new dowels, I'll check to make sure they don't bottom out in the head when installed on the block. That would do it for sure but that area isn't where the water leak occurred. I'm thinking the bolts didn't torque down properly in the first place.

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Re: L-series engine gaskets

Postby Chickenman » 11 Apr 2016 17:50

Checking that the bolts don't bottom out is a very good idea. I always pre-fit the bolts and run them down hand tight without the head bolt washers installed, just to make sure that they go down all the way and don't bottom out. If the head bolts snug up against the head without the washers installed, you know you're good when you fit the washers for the final fitting.

I've had some heads that I've had shaved a fair bit that I've had to install double head bolt washers.

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abisel
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Re: L-series engine gaskets

Postby abisel » 19 Apr 2016 09:46

So I have 3 gaskets to choose from.
Left is the Fel-Pro, center is the DNJ, right is the ITM.
The Fel-Pro and ITM have what seems to be a silicon coating to the entire gasket. The DNJ does not and the grey beads are only on the head side.
The Fel-Pro is 1.15mm thick, and the DNJ and ITM 1.65mm thick.
Does the ITM look like the factory gaskets (no longer available)? It does have compression rings around the two water passages between cylinders 2 and 3 whereas the others do not.

Thoughts?
datsun gaskets-2.jpg
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Chickenman
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Re: L-series engine gaskets

Postby Chickenman » 19 Apr 2016 12:01

FelPro only 1.15mm thick? That answers why they don't compress enough.

Both the DNJ and the ITM look good. The ITM looks to be a graphite ML composition which is good. The water passage compression rings between #2 and #3 is also a plus for the ITM. I'd think I'd go with the ITM.

With a graphite face gasket I would not use any type of sealant on the surface.

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abisel
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Re: L-series engine gaskets

Postby abisel » 21 Apr 2016 11:51

Yep, the FelPro measured 1.15mm thick.

I'm liking the ITM as well being graphite composite on a metal core. But what would it hurt to put a thin layer if Hi-Tack on it? Will it compromise the sealing/compression, or help?

What with new bolts, cleaned out bolt holes and using ARP bolt assembly lube, it may be that a dry gasket will seal just fine and will be that way for who knows how long.

Comments/thoughts?

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Re: L-series engine gaskets

Postby Chickenman » 21 Apr 2016 12:08

From my understanding, never put any sealants on a Graphite composition head gasket. They are purposely designed to allow a specific amount of sliding action between the aluminium head and the Iron block to allow for different expansion rates. Putting any significant amount of sealing compound on the surface of the head gasket will defeat that purpose. A small bead of silicone around the water passages without compression rings probably wouldn't hurt... but it's really not necessary on a properly designed head gasket. Personally, I would not coat a Graphite gasket in Copper Spray or Hi-Tack.

Most OEM engine manufacturers now use Graphite composition head gaskets for engines with Aluminium heads and blocks made of either Iron or Aluminium.

Other's may have a different opinion, but I've never had a Graphite composition head gasket fail when put on dry. I always clean both head and block with Lacquer Thinner ( Not regular Paint Thinner!! That leaves an oily film ) or Acetone before installing head gaskets.

Actually, come to think of it... I've never had any Head gaskets on any car fail on me. Must be doing something right.

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abisel
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Re: L-series engine gaskets

Postby abisel » 01 May 2016 19:07

Update:
I went with the ITM graphite composite gasket and ARP head studs. I just finished installing the head and torquing to 40, 50 then 60 ft-lbs. Assembly of the other components will take place later this week. We shall see if the ITM gasket does the trick. I suspect so. And with the ARP studs, nuts and washers with the ARP supplied assembly lube, the torque values should be spot on.

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abisel
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Re: L-series engine gaskets

Postby abisel » 10 May 2016 07:07

Update:
The ITM gasket got torn during installation of the front cover. The oil pan gasket too.

So... off with the head and off with the oil pan. I didn't like the FelPro oil pan gasket anyway and I have a Nissan oil pan gasket to use.

Now I am thinking of the FelPro with copper coat as I discovered the ITM did not register properly on the dowel pins. It slid around too much to my liking. The DNJ gasket doesn't cover the block/head completely and I am just not convinced about it. I have a Nismo gasket but it is for a larger bore and it would leave a side gap to fill up with carbon deposits.

Thoughts?

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Re: L-series engine gaskets

Postby Chickenman » 10 May 2016 09:17

Wait..., if I'm reading this correct by the time frames, you installed the head and torqued it down before installing the TC? That's not gonna work.

Normally you always attach the front cover before you drop the head on. Just align the bottom link to crank pulley with #1 Piston at TDC , make sure the chain tensioner is compressed all the way and use a proper chain stopper. Install the TC, then drop the head back on. Always tighten the TC before torquing the head down.

If you like to check the alignment of things with the head on and the front cover off, loosen the oil pan bolts to allow it a bit of movement. ( Since you have the oil pan removed and replacing the gasket, just put it on last ) Only use two head bolts finger tight at the back of the head. That way you can lift the front head enough to slip the timing cover back in. Two people definitely helps. One lifts head while the other slips the TC back on. Or you can use a " Cherry picker " to lift front of head if you have one. But you never EVER torque the head down before the TC is in place.

Head studs can make things a bit more difficult. I'd highly recommend assembling it with the TC in place before installing the head if you're using studs... which you are. Regardless, if you drop the head in place before installing the TC ( Some people like to do it this way just to be sure, ) make sure that you can lift the front of the head a bit with the studs in place ( No nuts on the studs obviously ) . You'll need two people or the Cherry Picker to do it right.

I would NOT use the Felpro gasket unless you want to do this all over again. It's too thin IMHO. Order up another ITM gasket ( or two...they're cheap enough ) and do it right..... ONCE. Don't worry about the dowel holes being a bit large. A couple of small dabs of Contact Cement on the gasket to block interface will lock the head gasket in place. The head studs should also help align the gasket.

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Re: L-series engine gaskets

Postby okayfine » 11 May 2016 06:22

People R&R the timing chain by pulling just the cover all the time. Same with using FelPro HGs. Probably just one of those cursed builds:) I had one of those.
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Chickenman
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Re: L-series engine gaskets

Postby Chickenman » 11 May 2016 09:02

okayfine wrote:People R&R the timing chain by pulling just the cover all the time. Same with using FelPro HGs. Probably just one of those cursed builds:) I had one of those.


Read his timeline again. He did things in the wrong order. He torqued the Head gasket down fully before he re-installed the TC. That is not the recommended method, either by FSM or experienced builders. It is also the reason he tore both the front of the HG and the front of the oil pan gasket. Nothing to do with " cursed builds". All to do with incorrect procedures.

Yes, lots of people do use FelPro head gaskets on Datsuns. And from research and witnessing it myself, more than what could be considered normal, have had failures with water oil passage leakage. Most times they seal, but there are too many times they don't.

I've used Felpro on many, many different cars. Most of their products are very good, but some of their designs, particularly their Permatorque Blue gasket line for intake gaskets ( Chevy and Ford ) and water pumps are just utter failures. I'm just speaking from my own ( and some other close racing friends ) experiences. YMMV.

For GM I use Felpro ML head gaskets ( Racing version) and oil pan gaskets. GM, Cometic or Detroit or FelPro Printoseal Racing Intake gaskets ( The regular Blue Felpro's do not seal well with aluminium manifolds. Too hard of a material ). ROL or Felpro graphite composition all the time for header flanges. GM or Detroit Water Pump gaskets. I had 3 failures in a row with Felpro blue water pump gaskets on my SBC engines. The gaskets would slowly dissolve and crumble till it was like flakey cardboard. Took about 2 years for the gaskets to fail. But they failed like clockwork. Some sort of weird electrolysis action between the iron block and Aluminium water pumps I was using is all I could attribute this to. GM and Detroit gaskets never did this.... only Felpro.

Just some of the things I've experienced with different gaskets on different cars over many decades. FWIW. Image

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abisel
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Re: L-series engine gaskets

Postby abisel » 12 May 2016 07:52

I appreciate all the comments on this R&R of the head gasket.

In my original R&R for a head rebuild because of a dropped intake valve seat, I had the oil pan removed 'cause it was leaking. For assembly, the order of installation was first the head and torqued to 62 ft-lbs, then installed the timing chain components, installed the front cover, and finally install the oil pan. That seems to be the order as outlined in the Haynes and other Datsun books. I just thought I could do the FC with the oil pan still installed. Wrong! That don't work very well. If I had dropped the oil pan, I would not have had any damage to the head gasket. Lesson learned.

I will give the ITM gasket another try instead of the FelPro, but I will apply a thin coat of K&N Copper Coat to the block side of the gasket as there are minor factory machining marks and minor pitting around a couple water passage holes. The head had just been machined so the head side of the gasket will not get any copper coat. Also, the front cover part of the head gasket will get some High Tack or Permatex #2.

Thoughts?

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Re: L-series engine gaskets

Postby Chickenman » 12 May 2016 09:37

That should work well.

The reason I prefer to install the TC first and then Torque the TC is that the TC is dowelled ( 11046-73402 ) to align it flush with the top of the block. When you torque the head gasket the front overhang of the Head Gasket gets compressed over the TC area. It's can be really hard to compress the gasket enough to fit the TC in place over the dowels... if you torque the head down first.

A lot of guys remove the dowels to make it easier to fit the TC with the head torqued in place. This allows the TC to move a bit and fit easier. The idea being that oil pan gasket can take up the extra gasket compression on it's end. That doesn't always work. Depends on oil pan gasket thickness and composition.

What also gets forgotten about, if the TC dowels are removed, is that the crank seal may not be perfectly centered on the crank shaft. The TC usually gets pushed down .005" to .010 from flush with the top of the block. This can cause leaks at the crank seal.

I always checked that the TC was perfectly flush with the top of the block before installing the head. Less aggravation and oil leaks that way for me. Just my .02c...

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Re: L-series engine gaskets

Postby abisel » 12 May 2016 15:25

^^^^
What you say makes since about the TC and the block and head all mating together before torquing the head. I do have a chain block but really like to see the chain in place with the tensioner fully compressed. You can't see that if you install the chain to the cam after the TC is installed. Even with a chain block, the tensioner can slip out a little and if it does, it makes it difficult to do any chain rail adjustments to get the tensioner compressed. I plan to install the head, torque to 20 or so, install the chain components, install the TC, final torque the head to 60, install the oil pan. This should work ok as it did when I first R&R'd after the head was rebuilt.

Thanks again for everyone's comments.
Last edited by abisel on 13 May 2016 08:24, edited 1 time in total.

Chickenman
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Re: L-series engine gaskets

Postby Chickenman » 12 May 2016 20:52

You're welcome and good luck with the repair. What ever works for you...


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