Torquing intake manifold bolts question
 

I am trying to rule out vac leaks. I want to re torque the intake. It is aluminum and was going to tighten to 25 ft lbs.
The first couple were looser than I expected, so I changed the wrench setting to 20, so I could bring them up more evenly. There are 2 bolts I can't get the socket on. They are the ones the fuel log mounts to. The one near the Diz is tough too. I used a universal on a wicked angle. i do not like to do this when I am torquing. I left them all at 20 lbs until I can figure out how to torque those 2 impossible bolts. I did not want to much of a difference
All my heads are 3/8 6 points and the two for the fuel log are 3/8 12 point. These two are on the Pass side right next to the biggest intake runners

Any ideas?
Thanks...Dave

Dave - you need to calibrate your hand. Seriously - unless something is really off the intake isn't going to notice +/- 3-4 lb ft difference in torque on the fasteners. I usually just use a ratchet or box wrench and tighten them without leaning on them very hard. As long as they are snug tight with some resistance they should be OK.

You can calibrate your feel a little by torqueing a bolt to 25 lb ft and then put the wrench or ratchet of your choice on it, pay attention to how and where you are holding it and twist until you pick up the slightest movement of the bolt. Then just try to duplicate that same approach and effort on the hard-to-get bolts.

Also - are you sure about the 25 lb ft value on the intake. I thought it was 35 lb ft but maybe my foggy brain cells are remembering a GM BB value. Even with aluminum heads and intake I think I would want around 30 lb ft minimum. :confused:

Just use a wrench and tighten them up. I can't recall ever using a torque wrench on an external fastener.

Just redid mine a few months ago and used a crows foot on a short extension on the bolts that I couldn't get a socket on.
DonC

Hi Dave,

If you are anything like me, you won't be happy until you know that you have properly torqued those manifold bolts. I ran into the same problem with my intake so I went out and purchased a couple of Snap-On extensions, recalculated the torque setting I would need on my torque wrench as the "arm" was now longer and torqued those last few hard to reach bolts down.

Good Luck.

Curious as to how exactly you recalibrated your wrench to the new lever length?

At the time I did a Google search and found several articles on the subject. Here are a few examples:

Torque Wrench Adapter - Extension Indicated Torque Calculator | Engineers Edge | www.engineersedge.com

Torque Conversions Charts

Dan,
Yes I tried that but it is to awkward positioning wise and the wrenches are all different. also no leverage. I tried matching the 20 lbs. You would be shocked on what 20lbs feels like on smaller wrenches. That fuel log is really a PITA but I love the way it looks.
I believe the 35 lbs might be for steel manifold and heads. if somebody could chime in on the Torque for Aluminum parts that would be great. I may even contact Edelbrock for the correct figure. I have aluminum for the manifold and the heads

Brent,
That is because you are seasoned mechanic and you have that feel from doing these jobs a million times!

DonC
I tried the crows foot, no way.

Mongoose,
Yes, I am just like you, I torque everything, and I mean everything unless it is impossible like all the rear caliper hardware. That pic of the dog-bone is what I will try next. i will have to go buy one. I have every size but 3/8. I must have misplaced it because I know I had one. I teach torque so I do know how to do the calculation formula.
i just went and simulated it using a 7/16 dog-bone, no way that is going to work, that fuel log is in the way. I think my only chance is with a 12 pt short crows foot with the carb removed. That sucks because I just put the freshened up carb on last week

Thanks everyone for the input so far...that is what makes the forum community so great!
Dave

The second link is basically what we teach for no angle on the extension/adapter.

If there is and angle due to obstructions, we just set it up, then lay it on a table, make a mark at the the center of the torque wrench sq drive and another at the center of the adapter end. Now measure the distance between the 2 marks. Then just use that new figure in your equation instead of the overall length of the adapter as you would do with no angle.
All that cosign stuff I do not understand...to old

Here's what I do:
- Use ARP thread lube on the threads and under the washers. I used ARP bolts and washers, no lock washers. 25 ft-lb.
- Put all the bolts in and torque them as tight as I can with a knurled finger wheel (something like this) [ame="http://www.amazon.com/SK-8-Inch-Professional-Thumbwheel-Ratchet/dp/B0002NYCWC"]SK 45172 3/8-Inch Drive 1-1/2-Inch Professional Thumbwheel Ratchet - Socket Wrenches - Amazon.com@@AMEPARAM@@http://ecx.images-amazon.com/images/I/51XQ71CWECL.@@AMEPARAM@@51XQ71CWECL[/ame]
- Torque in sequence bringing them up to maybe 15 or 18 ft-lb. Start with a couple I can get a torque wrench on and eyeball the travel of the wrench (for example, 180 degrees)
- On the ones I can't get a torque wrench on, use whatever wrench works (for me a box wrench) and swing the wrench the same amount of travel.
- Go back in sequence and tighten up again to 25 ft-lb.
- Check torque after a heat cycle, and again after a week or so. I found that with the hard Cometic gaskets I used I needed very little retorque.

My sbf aluminum Edelbrock intake instructions say 18-20 ft-lb. Don't know if an FE would be different.

Very interesting approach! Why lube on the threads? That is a quick way to over torque without even realizing it. Also, why no lock washers?
Do you know the proper sequence to tighten them? Are you sure about the 25 lbs, Dan has me wondering???

I borrowed a friends weird wrench. It is a open end on one end and a 3/8 12 point hinged socket on the other end. It is about 6" long. I can actually get on both of them with this! No freakin leverage though, even trying to move one the others that I went to 20 lbs was impossible, and I don't want to resort to the PIPE! I may have to though. I also do not have a set point because they are already tightened different amounts. I am definitely afraid to back off and start at zero as you suggest because I'm afraid of leaks etc etc

You wouldn't think so.
OK, I looked up your engine and you are right, 18-20.
Then I found this which states 25 ft lbs for Intake into Alum heads.
http://www.edelbrock.com/automotive/.../6000/6007.pdf

I have a Blue Thunder aluminum IM. The only part my builder specifically instructed me to retorque after a few hundred miles was the IM. The torque figure was 32 ft/lbs. I had to use a crow foot extension to get to a couple of them ... and that was going on ten years ago.

Patrick, I have no ID on my manifold. It just says DOVE on the breather adapter for the PCV valve. I am sure that was purchased separately or after the car was built.
I just went thru all the paperwork I got with the car including the engine build parts list. On that list it says "1 BT 1x4 Int". Could that BT mean Blue Thunder? Does your manifold say "blue thunder" on it?
So, 32 ft lbs? Do you have steel heads? I'm thinking that spec is for steel heads.
I have the Edelbrock aluminum "performer" heads and it calls out 25 ft lbs for the manifold bolts. I would think that would be pretty important since the threads are in the heads.

Pretty sure BT mean Blue Thunder. I agree the torque spec from the head manufacturer should take precedence over the intake spec. I would probably take into consideration the length of the bolts and the length of threaded engagement in the head is a key factor. Also, I assume these are a fine thread bolt but if a coarse thread then the spec would be a little lower. Considering all the comments above I would try to get to around 20 as you originally stated. If you have a vacuum leak at that spec another 5 lb ft torque probably wouldn't cure it for long anyway.

The difference between a small block and an FE is that a SBF uses 5/16" intake manifold bolts and an FE uses 3/8". They are all coarse thread.

If the bolt is going into an aluminum head, use a little lube on the threads.

20 lb-ft would be low to me. 25-28 would be closer.

Directly from the Edelbrock RPM FE Performer Head installation sheet:

Other Assembly Tips: Do not exceed a torque of 25 ft./lbs. on the intake manifold bolts and lubricate the bolt threads
prior to assembly.

I stripped the threads on one of my heads while installing my BT intake manifold and I don't ever want to do that again.

Well, what can I say.... Blue Thunder 4-V MR manifold, Edelbrock aluminum heads, all on top of an old school iron 428 FE block. 32 ft/lbs on the intake bolts.

Dan and Brent,
I will end up doing 25 as Brent and Edelbrock agree. I am assuming the lube is for dissimilar metal? What would you recommend, maybe nickel anti-sieze (very little).

Mongoose,
Yes, I see it, amazing that they don't say why or what to use! They also are not giving the pattern to tighten.

Patrick,
Is your manifold marked anywhere. If yes, what and where.

Thanks all...Dave