Datsun Roadster Forum-311s.org

Bad news,
Took roadster out to drop off sleep over kid and stopped at the car wash. Spray degreaser most of the cake on and tried to find the source of oil on the block. Bingo look what I found.
This is posterior passenger side. And to top it off I recently had the head checked because of water leak. Tried the thicker gasket from Dean it was just too thick. Could not thread rockers. Regular head gasket installed w/in 600 miles. Could it be just head studs not tight enough? Maybe just have to check torque this week.

Did you have the head checked for flatness? It is not supposed to be needed but I use a thin coat of spray copper coat gasket sealer on head gaskets. There is an oil gallery that feeds the rockers. if all else fails you can use a 1/2 inch long piece of brass tube that press fits into the gallery with a dab of Permatex ultra blue to make an insert going from the block to the head through the head gasket.

First of course check the head bolt/stud torque. Are you using the ARP studs? What torque are you using?

keith0alan wrote:Did you have the head checked for flatness? It is not supposed to be needed but I use a thin coat of spray copper coat gasket sealer on head gaskets. There is an oil gallery that feeds the rockers. if all else fails you can use a 1/2 inch long piece of brass tube that press fits into the gallery with a dab of Permatex ultra blue to make an insert going from the block to the head through the head gasket.

First of course check the head bolt/stud torque. Are you using the ARP studs? What torque are you using?

I have this exact same oil leak. The brass galley insert sounds like a great idea. Any idea of the diameter of this piece? Is there an existing part that I can use for this or, is it something I can source at NAPA? Also, what should the torque be on ARP studs. I have em on my iron head '66 1600.

Thanks,

Dean

If the head and block are machined flat, the gasket will seal without tubes or special efforts at the normal torque setting. The key is flat, flat, flat and proper torque technique.

For gaskets that don't have a metal ring at the oil passage, there is a little o-ring part with a tube from Nissan, but you really should not need it.

Be sure it isn't the valve cover leaking at the rear. If you wipe the back of the head with your fingers, is it perfectly dry and clean? J

I agree that extra measures should not be needed. I measured the oil passages and picked up a piece of brass tube from a hobby store. The torque value for the ARP studs used on the R16 is 50-55 ft/lbs re ARP web site.

JT68 wrote:If the head and block are machined flat, the gasket will seal without tubes or special efforts at the normal torque setting. The key is flat, flat, flat and proper torque technique.

For gaskets that don't have a metal ring at the oil passage, there is a little o-ring part with a tube from Nissan, but you really should not need it.

Be sure it isn't the valve cover leaking at the rear. If you wipe the back of the head with your fingers, is it perfectly dry and clean? J

Back of the head is perfectly clean and dry, oil is definetely coming from between the head and the block. Would you happen to know the Nissan part number for the o-ring with tube? The head was rebuilt and machined flat 1000 miles ago by a reputable shop.

keith0alan wrote:I agree that extra measures should not be needed. I measured the oil passages and picked up a piece of brass tube from a hobby store. The torque value for the ARP studs used on the R16 is 50-55 ft/lbs re ARP web site.

Thanks Keith!

Studs have been noted by vendors as allowing a higher torque, 80 ft/lb, has there been a change?
Linda

Many people have that exact same leak at that location

My advice would be to do an Italian tune-up and get the engine really hot. Then let it cool.

Then back off each head bolt and replace with a APR stud, grease w/ Moli grease and torque to spec.

Then heat up the engine again and retorque after a few spirited runs.

If that doesn't stop the leak (total cost around $100) then the head has to come off and get milled flat.

HTH
James

I think I’ll try the heat up cool and re-torque. I have the studs in already, when I had the head checked the mechanic said the machinist said it was straight. I was concerned as to overheating 210/240 degrees issue. I replaced the radiator and the cooling issue improved to 190 on the money. Perhaps these has been some shift loosening.
What is the torque on head studs 1600? And the sequence?

I think I’ll try the heat up cool and re-torque. I have the studs in already, when I had the head checked the mechanic said the machinist said it was straight. I was concerned as to overheating 210/240 degrees issue. I replaced the radiator and the cooling issue improved to 190 on the money. Perhaps these has been some shift loosening.
What is the torque on head studs 1600? And the sequence?. I will check the torque and post my findings . If you reverse the torque rod to lefty/loosely when it breaks loose should give you a good estimate huh?

You start with both center bolts then move diagonally to the opposite bolts working your way out from the center, so the bolts at the front and rear will be last. There are several bolt patterns that will work equally well.

Do not loosen all the bolts.

You can loosen each one by 1/4 turn then increase in 5-10 lb increments. There is no need to go to 80 pounds cold and several good reasons not to. It should seal at 50lbs. 60-65 is not a problem. Remember AL expands far more than steel so 60-65 cold is way more at temp and significantly more than should be required.

If all this fails, you can add 3-5 lbs to the rear right bolt. You wouldn't do this with a U20, but the R head is far more forgiving.

If you have a cheap click type wrench you might borrow a beam type. If you are careful, one can be quite accurate with a beam. Cheap clickers are notorious for variance and mis-cal.

Did you put any sealants on the gasket? These often create failures.

Best of luck.
J

So on datsunparts.com, part #2285, stud kit lists 8o ft/lbs with moly lube.
ARP is not listed that I saw, as the manufacturer of these studs, so that could be a question for Dean.
So looks like a difference of opinion amongst the gurus.
On the ARP website it shows the A12 and A14 engine at 60 lbs, then other engines but I did not see the R16 or U20.
Linda

80 with super special moly lube is way up there. The ARP studs aren't going to stretch/yield as much as the headbolts with temp cycles, so personally I'd be more inclined to stay in the 60's max. With lube, that is a lot.

Plus, there really should be no reason to NEED to go that high and several reasons not to//

If you dig through the ARP sight they have the torque specs for various studs. According to the ARP chart this diameter stud should be torqued to 50-55 ft/lbs. The next size up uses 80 ft/lbs. Having said that, many people have torqued to 80 ft/lbs without any problems. These studs are stout. These studs with their fine threads will provide much more clamping force at 50-55 ft/lbs that stock bolts at the same torque. I am not saying Dean is wrong just that I do not know why he differs from the ARP site torque value.