freeze plugs

[mom'sZ]

I have replaced a couple of the freeze plugs on the passenger side of the block on my 78 280Z L6. I noticed the one on the back of the cylinder head appears to have a very slow leak as well. I searched and found this thread http://forums.hybridz.org/showthread.php?t=108857&highlight=freeze+plugs where Brycey states there are 4 in one side, 5 in the other, one in back and one behind the timing cover. I also found this thread http://forums.hybridz.org/showthread.php?t=89475&highlight=freeze+plugs where changing them is disscussed. Judging from the condition of the ones I've already pulled, I'm sure the rest are in bad shape. How many freeze plugs are in the entire engine total? I can see four on the pass. side of the block, am I to assume there are more hiding under the manifolds on the driver's side? Is there one (or more) in the back of the block? inside the bellhousing? The one inside the timing cover, if it leaks, can coolant go into the crankcase? Is there just that one in the cylinder head? And does anybody know where to get a kit that contains them all?

[zeiss150]

If I remember right there is one on the back of the block under the flywheel. Its been years since I rebuilt my engine though. good luck!

[Silent]

i can check my short block and let ya know. i know there is one behind the timing cover, and one behind the flywheel

[skipzoomie]

I replaced all of them in my 78. They were available at the local parts store. I found that it was easier to take the engine out of the car rather than trying to do it with the engine in place. Not a big deal. Out on Saturday and back in on Sunday.

[mom'sZ]

yeah, pulling the engine seems like SOP (standard operating procedure) for changing them. So... if nobody knows where a kit with all of them is available, and I'm going to have to get them locally through the parts store I need:

4 for pass side block 35 mm

5 for driver's side block ? 35mm?

1 for back of cylinder head size? just one?

1 for under timing chain cover size?

1 for inside bellhousing size?

Is there only one inside the bellhousing and only one on the whole cylinder head? I know the parts store can look up the sizes but availability is hit and miss so I want to order the correct number of plugs.

thanks andy

[mom'sZ]

here's a link to a thread that JaysZ gives a source for freeze plugs

 

http://forums.hybridz.org/showthread.php?t=112724&highlight=freeze+plugs

 

and here's a link to them

 

http://www.rockauto.com/catalog/x,ca...IengineID,2789

[BRAAP]

OUCH!!! You guys are KILLING ME HERE!!!!

 

Sorry, but as an engine builder/machinist, I must voice my $.02 here.

 

Ok, those plugs you guys are referring to are actually called, “CORE PLUGS!” They are NOT “freeze plugs”… They got the misnomer of freeze plugs way back in the early 1900’s totally by accident, and by chance, that name stuck!! We engine builders get a full body chill every time we here a customer refer to them as “freeze plugs”….. OUCH! Please call them “core plugs”, please?....

 

Those plugs are there for the sole purpose of evacuating the sand from the sand casting process when these blocks are manufactured. It just so happens that approx 1-5% of the time, if the coolant freezes in an engine block, those plugs sometimes will pop out of the block, and that is how the term “freeze plug” wrongly came about. Then the myth started that these so called “freeze plugs” would protect an engine block from cracking if the water/coolant froze by virtue of those plugs popping out! Total and complete BS! Engine blocks crack ALL the time if the water/coolant freezes, even with today’s ultra modern casting technology, and those “CORE PLUGS, do not save the block from cracking!!!! PERIOD! In short, they are NOT freeze plugs!

 

Now back to the L-series “CORE PLUGS”.

Yes, there is one behind the bell housing, there is also one under the front cover, and one in the rear of the cylinder head as well as one in the rear of the EFI intake manifolds. On the L-28 blocks, there are nine 35mm “core” plugs on both sides of the block, one 40mm core plug under the front cover, and one 50mm core plug at the rear under the bellhousing. The back of the cylinder head uses a 35mm core plug as well.

 

Core plug installation…

When we install “core” plugs, we use a flapper sanding drum in a die grinder to remove all rust and sealant from the machined core plug orifice. We then use Permatex gasket sealer, (part 1A, comes in small tube), lightly smeared around the core plug itself and on the prepped core plug orifice in the block, and then tap the core plug into the block so that it is “just” beyond flush with the core plug hole, (flush to the countersink of the core plug hole). We have not had any leaks ever, using this technique.

 

We, Rusch Motorsports, can get you the complete engine block core plug set in either Zinc plated steel or brass, or individual core plugs as well as the Permatex part 1A. E-mail us at ruschmotorsports@hotmail.com for current price and availability.

 

For those interested, here are a few pics of the core plugs in a L-28 block, casting F-54. I also included a pic of the driver side of a VERY early, (serial number 2800), L-24 block, (bottom right), with its three “core” plugs.

 

[wardie]

We here in Oz call these items "Welch Plugs" and it is derigueur to use only brass plugs as the steel ones will corrode relatively quickly.

 

Wardie

[mom'sZ]

sorry Paul, didn't mean to give you a full body chill...

I ordered my 'core' plugs from Rock auto yesterday. Used the online interface and it worked real well and I got a ship notification from fed-ex a few hours later. Had to buy bags of ten of each size but at .40 cents a piece, no big deal.

When we were kids (a long time ago) we used the brass ones. But awhile back I read some reason why they weren't so good, to soft I think, can't remember. But whatever it was, it was good enough to make me use the steel ones. I've seen where guys pin the brass ones in. I do like Paul says and smear a little silli on the back of em' before I put them in.

Rock has a kit with brass ones... 12 bucks I think.