Why no washers on 2x4 manifolds?

[Steven B.]

Why weren't washers used on the al. 2X4 intakes?

[Joe L.]

Re: Why no washers on 2x4 manifolds?

Why weren't washers used on the al. 2X4 intakes?

Steve----

Washers were not used on any small block or big block intakes. Big blocks used flanged head bolts which were essentially as good as using a flatwasher. Why weren't washers or flanged head bolts used on small blocks? Who knows? I'm sure the "engineering reasons" are lost in antiquity now. However, I've said for years it was a VERY dumb thing to do for EITHER cast iron or aluminum manifolds.

Washers or flanged head bolts were not used on an head bolts for small blocks or big blocks (except aluminum head big blocks). That was another dumb thing to do. But, they did it for YEARS. Finally, in the 90's they started using flanged head bolts.

[John D.]

Re: Why no washers on 2x4 manifolds?

Joe is 100% correct on saying it was a dumb thing to eliminate washers on manifold bolts,etc.
If you are having your car judged you will get dinged if you use washers under the intake bolts. If you look hard enough you can find some cheater washers that are not seen when installed to help prevent tearing up the aluminum. I used to buy them from a local gunsmith. Very thin and small OD.
Rule of thumb on our Corvettes. Aluminum: No washers. JD

[Tom P.]

Re: Why no washers on 2x4 manifolds?

Yes, this is true, no washers on intake manifold bolts.
But for a non-judged driver, my philosophy is screw correct. Steel bolts will chew up aluminum, plus, for the holes that go through the heads into the lifter area, oil can eventually weep up around the threads and deposit onto the surface of the manifold.
I buy THICK stainless washers from Paragon that are about the size of the steel washers which are used on exhaust manifold bolts. I buy them 100 at a time and use them on FI base plates as well as on the studs for FI plenums.
These washers serve two purposes. First, it keeps the bolt head from chewing up the alum and second it serves to seal between the bolt head and the hole in the manifold.
No, it IS NOT correct, but it is certainly more functional and more practical.

[Jerry J.]

Re: Why no washers on 2x4 manifolds?



I'll probably get yelled at for this one...

I owned a '57 FI in '58. I removed the dog-house for some un-known reason, and there were washers on the studs, eight of 'em.....
As I was buttoning it back up, I ended up with eight nuts and seven washers. I thought - No it couldn't be... When I started it up I heard a God awful noise, like a washer getting smashed between the top of the piston and the head..

After dis-assembleing, there they were, 3 washer marks in the piston.
Won't ever forget.... I'm sure the dog-house had never been off before....
Everyone says NO washers.... I say YES washers.....

[Tom P.]

Re: Why no washers on 2x4 manifolds?

Oh ya, something else that I do, I use stainless bolts on all intake manifolds (alum and iron). It's especially nice on the end holes where steel bolts have a greater tendency to rust because of their close proximity to the water source.

[Steven B.]

Re: Why no washers on 2x4 manifolds?

I have never been able to figure out why no washers. I thought possibly cost but the washers don't, or didn't, cost that much. Years ago when I put my 2X4 engine back together I used washers because I did not want to cause any more wear on the manifold. I still have thoughts about breaking it at one of the bolt holes.

[Stuart F.]

Re: Why no washers on 2x4 manifolds?

One thing that could be mentioned that might have some bearing on whether GM/Chevrolet used washers under the manifold mounting bolts is the minimal torque specified of 25 to 35 ft-lbs.

On my 63, I replaced the bolts about 25 years ago for appearance sake one at a time and did not use washers. Being as how, even with the carb off, it is hard to torque all the bolts with the engine in the car, I'm sure many backyard mechanics do it by the: ugh! that's tight enough method using a box end wrench. I admit I used that method a number of times back in the day, and I paid the price by breaking off the right front ear (flange) of a dual quad manifold. It was on a friends car as we were trading my dual quads for his single 4gc and cast manifold. He was there, saw it happen, but being as how I used a lot of sealer around the water ports, it didn't leak. I knocked off another $10.. It was in the middle of a cold winter day and we weren't about to take them back off again then.

Stu Fox