Oil behind intake
- Thread starter str8stang036
- Start date
As far as the gaskets on the front and back of the intake go, I usually use the original equipment rubber ones. I wouldn't use the cork ones. Some people just use RTV, which is fine, but I've never had any luck with that method. Do not use a torque wrench on the intake. The factory torque spec can cause the heads to lift and blow the head gaskets. Just use the proper sequence and do it nice and hand tight with a 1/4" ratchet.
Kurt
Kurt
95Vert383AOD
15 Year Member
Not sure about the factory torque sequence. I use trickflows torque sequence. (It works) And you def. need to tighten them up to a specific foot pound (torque wrench). As you go threw the sequence the intake will start to settle in. You'll notice this when finishing the sequence and the first bole is not not as tight. Doing stuff by the book doesn't hurt. I personally don't like using just Gasket maker....use the gaskets too. I haven't seen rubber gaskets for the 351. Also the front and rear gaskets on a 351 are longer than the 302 because the oil valley is wider on a 351 block. I have seen guys not use torque wrenches on intakes and it work.....but why risk it not working??? $40 worth of gaskets and a few hours of labor i rather not repeat. If you have a torque wrench....use it! Thats what they're made for. I have never had a head lift. 351's use bigger head bolts and i went with ARP's....Good bolts help with getting a accurate torque. You cant expect a 10+ year old factory bolt or cheap replacement bolt to give you an accurate torque reading.
Stock torque is 24 ft lbs. I'm telling you, if you torque them down that far you run the risk of lifting the heads.
Kurt
Kurt
Well I removed the intake today and it was leaking from behind, I was watching it as the car idled. When I removed it, the whole driver side bolts seemed like they had lost some torque. I did torque them down to specs before, not sure why that happened.
I am torn as to this crankcase ventilation setup. There are many setup out there. Like 95Vert383AOD says, I prefer it to be sucked out instead of pushed out. I am consulting with a reputable NMRA competitor and car builder about my situation. So far he suggest a -12an line from each cover to a catch can on each side. This will push the excess pressure out. I was reading and it has helped many others a lot.
Also Gearhead- let me know if NAPA has the neoprene gaskets for the 351w.
I am torn as to this crankcase ventilation setup. There are many setup out there. Like 95Vert383AOD says, I prefer it to be sucked out instead of pushed out. I am consulting with a reputable NMRA competitor and car builder about my situation. So far he suggest a -12an line from each cover to a catch can on each side. This will push the excess pressure out. I was reading and it has helped many others a lot.
Also Gearhead- let me know if NAPA has the neoprene gaskets for the 351w.
I gotta say I think along the same lines about that much torque
Also ... I think that is too much torque on soft threads you find in
Aluminum heads
If you think about it
The torque spec was made up with iron heads in mind
I personally don't use a torque wrench for the lower intake
If I had to guess ... I'd say 16 to 18 lbs would be about what I use
I just kinda know what feels right with a 3/8" ratchet
What I think is really important is this :Word:
When you install a new lower ... You must run through the torque sequence
three, four, five times or more until you get even tightness on all bolts
You should go over them again after two heat cycles because it is a
given ... you will find some loose bolts
Grady
95Vert383AOD
15 Year Member
Wow only 16 to 18 lbs? I generally torque mine to 26lbs going threw the sequence more times than i care to admit. Ive done this with name brand trickflow heads as well as the generic Pro Comp heads im running now. Never a problem. Also i thought the stress from combustion was on the head bolts. Im trying to figure out how intake torquing can cause a head to lift. To get it right you may have to go threw the torque sequence at say 6lbs 4 times...i don't move onto the higher torque until im sure every bolt is at that correct setting...so i tend to do something like 6lbs, 10lbs, 14,lbs, 20lbs, 24lbs.....i know its excessive but its never let me down.....and i have never had a loose bolt. I don't know about you but my hand cant tell the difference between 20lbs and 24lbs....This is like when my Chevy loving friend told me he could accurately do the timing on his car by ear. I let him then grabbed my timing gun and noticed he was about 9-10 degrees off. But i digress....Tighten it by hand till where you think its right......then grab a torque wrench and see how accurate your hand is.....you may be superised.
The intake wedges down on the heads, pushing them apart if it's too tight. That's what causes them to lift away from the block. It sounds really weird, and I didn't believe it first time I heard it, but it's the truth.
Kurt
Kurt
95Vert383AOD
15 Year Member
Not trying to be a wise guy or anything like that
but
How do you think I got the ... feel ... for what is ... about right
Seriously ... did all that ... long time ago
But ... you bet ... I see you're reasoning as being ... Right On
Grady
Alright, I just installed new gaskets. I cleaned up the heads and the lower intake very well. I used sandpaper on the front and back ends of the block and intake to make the RTV stick much more. I also used the cork gaskets because I couldn't find the neoprene ones for the 351w. I used the tightening sequence 5 times to make sure everything is how it's supposed to be.
I am going to let it dry over night and then hopefully there will be no leaks tomorrow. I am also in the process of getting some bungs welded on to the covers to then attach to a breather tank for my crankcase ventilation.
I am going to let it dry over night and then hopefully there will be no leaks tomorrow. I am also in the process of getting some bungs welded on to the covers to then attach to a breather tank for my crankcase ventilation.
95Vert383AOD
15 Year Member
Similar threads
