running SU's without spacers?

[Healey Z]

Has anyone run SU's without the spacers between the carb and the manifold?

[Travel'n Man]

I'm a little confused - IMO the spacers are really insulators to help reduce the heat transfer from the manifold directly to the carb..........not sure why you would want to remove the insulator....... I would be concerned about additional heat buildup and poor performance.

[Patcon]

I assume space is the problem and you want to remove the spacers for better clearance? I am pretty sure Travel n Man is right and they are to reduce heat transfer. Bruce Palmer is probably the resident expert on this.

Charles

[SteveJ]

They are definitely to reduce heat transfer to the carburetors. It's bad enough that they have to sit over the exhaust manifold. Why have them get heated up from the intake manifold, too?

[Healey Z]

I picked up this project last year; 1963 Austin Healey with a Z motor. It had a custom built manifold with two 32/36 down draft webers. I wanted to go back to SU's, but my measurements were off and I have two choices. Cut into the footbox of the car, which I really want to avoid, run without spacers or go back to the webers. Running without spacers certainly isn't a preference, but wondering if this is even a possibility.

[zKars]

Before you give up, reduce the spacer thickness to whatever the minimum is that you need and try them for a while. I'm sure you can do with a least half their current thickness without affecting their thermal properties much. You could even shave some off of the head side of the manifold to gain some more room.

[Bruce Palmer]

How much distance do you need to gain back?

What are you doing for an aircleaner? Is it conflicting space wise or are the carbs as mounted out of room?

Anything you do thickness of insulator wise will require you taking a look at linkage geometry as well.

[Travel'n Man]

If the geometry of the linkage throws off your linkage plaecment you could go to a LOKAR throttle cable (there's a thread on that install). Honestly I would not reduce the insulator depth - I would re-arrange the air cleaner to a different style (several filters on the market than the typical Datsun original air cleaner). The built in air horns of the original air filter housing (if you loose them) will decrease some of your power though. Those air horns have a purpose and a lot of folks don't use them for some crazy reason??

[Powderkeg]

Are the insulators in the photo too thick?

You might try an insulator from a 260Z. I converted my 280 to 240Z SU's and used the thinner 260Z insulator to give more room to get the 24OZ air cleaner past the strut tower.

Dave Ruiz

[Arne]

Ahhh. Now we know why the manifolds for those Webers were custom - there wasn't enough room for the off-the-shelf manifolds.

[jwtaylor]

Another possible option would be to shift the engine slightly to the right if you have the room. Better than cutting the footbox but still some work modifying the engine mounts, etc.

[Healey Z]

Guys, all great responses! I think everyone touched on some element of what I think will be a solution.

I went to an all British car show today and was able to look at some Healeys. As soon as I took a look at the motor, I thought yes, there may be a solution to use the SU's, with spacers, without hacking up the car.

Their motors sits higher and further foward in the engine bay than mine does. The intake on the Healey is also slanted, which gives it clearance in the one trouble spot.

I disconnected the motor/trans mounts and jacked it up pretty high (1 1/2 inches) and that helped a bunch, still not good enough, but it helped. It looks like I can also pull the motor forward a half inch. Of course this messes up other things like the exhaust, radiator hoses, engine mounts, trans mounts etc, but all doable.

I figured I can mill a 10 degree angle on the intake and still have half the width at the top flange. I have some other things to figure out, but that might give the the space I need where the SU hits the foot box. If not, the smaller spacer (thanks PK) or some creative things on the bottom of the float bowl of the SU (or a strategic ballpeen hammer blow to the foot box) may get me there.

I took a bunch of pictures of linkages, as I know that challenge is coming.