Air Cleaner Clearance

VaCat33

VaCat33

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CAT Member
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Hi All

As the title denotes, I am having trouble with air cleaner clearance on my MkI. It is, however, not the usual problem. It is not the top of the stud that is hitting the underside of the hood but rather the front edge of the air cleaner. On the trip to a show last week, it rubbed the paint right off. Not sure if it had been doing this for a while since I only noticed it last week. I put a level on the air cleaner and it is definitely higher in the front.

As background, I have the LAT 1 set up with a ¼ inch phenolic spacer which I installed last year. Everything was fine but about a month ago I switched out the Holley 4160 carb (List # 1848-1) for a newer model (same model and list number) rather than rebuild it for a 3rd time. It now appears that the front underside of the air cleaner is hitting the needle seat adjustment screw, causing the front of the air cleaner to sit a bit higher. It did not do that with the older model Holley in place. For some help visualizing things I attached a couple of photos of my set up. I was only using the fuel gauge to monitor fuel pressure for a while...it is now gone.

I know of course I can remove the spacer which would lower the entire air cleaner and might resolve the issue but the spacer has really helped with heat soak issues. I am also considering just getting the old Holley rebuilt for the 3rd time. That would be a shame because the new carb was really running great.

Can you use multiple gaskets as sort of a pseudo spacer but not the full ¼ inch?

I know many will say go with a different carb…but stock appearance is important to me.

Any ideas for a remedy? Any thoughts are welcome. Thanks.
 
the edelbrock and other Ramflo etc style filters all sit higher than the stock setup. The tiger setup with a standard filter is about as low as they come.
 
Second look

When first reading the original I did not understand the problem correctly? I think discussion of removing spacers had confused me.

If correct now the problem is:? That the base of the AC housing is not compatible with that carb. The housing does not have clearance in the front to set down level?

If so the solution is not messing with a spacer below the carb but changing or modifying the filter housing (shudder) or going to another carb.

Did a P.O. cut material from the base of housing to lower the filter for hood clearance? If so then it could be spaced up? As long as there is hood clearance?

Rick
 
TigerBlue said:
When first reading the original I did not understand the problem correctly? I think discussion of removing spacers had confused me.

If correct now the problem is:? That the base of the AC housing is not compatible with that carb. The housing does not have clearance in the front to set down level?

If so the solution is not messing with a spacer below the carb but changing or modifying the filter housing (shudder) or going to another carb.

Did a P.O. cut material from the base of housing to lower the filter for hood clearance? If so then it could be spaced up? As long as there is hood clearance?

Rick
Click to expand...
That is also what I see. The front fuel inlet on the new Holley carburetor has been changed in such a way that the Tiger air filter will not clear it.
Removing the carb spacer will not solve your problem and neither will machining down the intake manifold. I would NOT try to modify the very high dollar Tiger air cleaner!
Why not just dispense with Holley. Purchase an Edelbrock Performer (Carter AFB) carburetor and be done with it (and be done with the Holley rebuilds). After constantly messing around with a Holley, that is what I did and I have not regretted the decision.
 
Jim,

Since you still have the old carb, take a look at how high the adjuster screw sits compared to the new carb. If it sits lower, there may be a problem with a bent float arm in the new bowl. If the arm is bent, setting the float to shut off at the proper fill level may result in the needle valve assembly sticking out higher than it should be. It would be fairly easy to take off the primary bowls on both carbs and compare things.

As I recall the initial dry setting procedure, you hold the bowl upside down and set the needle valve assembly such that the float's flat side is parallel with the bowl top (which now would be on the bottom as you are holding and looking at it held upside down).

Gene

BTW, you probably could also just swap your old bowl over to the new carb if the casting is somehow different between the two. As long as the pump leverage and etc. on the bottom line up.
 
Problem Update

Hi All

Just a short update. I acquired a 1/2 spacer and some additional gaskets from JEGs. I used a variety of combinations to raise the bottom of the air cleaner so it clears the float adjustment screw. I got it to clear but the entire cleaner was now too high. I used about a 1/2 inch ball of modeling clay along the left front edge of the cleaner and when I closed the hood it squished it flat. I put a level on the top of the cleaner and it is still definitely higher in the front despite sitting clear of the adjustment screw.

At this point, I am back to the idea of removing the phenolic spacer to lower the entire carb and air cleaner in the process. Having some room to play with I might be able to use the gaskets/spacer to clear the adjustment screw. At that point the entire assembly will be slightly lower and the problem resolved.

Man, it's these little things that drive you crazy.

Thanks
 
VaCat33 said:
Hi All



Man, it's these little things that drive you crazy.
Click to expand...

Don't I know it !!
For me, it's trying to get those crappy offshore 'o' ringed water necks to seal to the manifold !! This last install lasted about 200 miles :confused:


Jim
B382000446
 
VaCat33 said:
Hi All

Just a short update. I acquired a 1/2 spacer and some additional gaskets from JEGs. I used a variety of combinations to raise the bottom of the air cleaner so it clears the float adjustment screw. I got it to clear but the entire cleaner was now too high. I used about a 1/2 inch ball of modeling clay along the left front edge of the cleaner and when I closed the hood it squished it flat. I put a level on the top of the cleaner and it is still definitely higher in the front despite sitting clear of the adjustment screw.

At this point, I am back to the idea of removing the phenolic spacer to lower the entire carb and air cleaner in the process. Having some room to play with I might be able to use the gaskets/spacer to clear the adjustment screw. At that point the entire assembly will be slightly lower and the problem resolved.

Man, it's these little things that drive you crazy.

Thanks
Click to expand...

I'm curious, you said the front of the air cleaner is higher than the rear, you must have quite a lot of driveline angle considering the F4B manifold carb mounting surface is higher in the back than the front. Do you have a T5 in the car or possibly a bad trans mount?

Tigerracer
 
something else to try?

I used a stack of carb plates and gaskets to attain maximum height without hitting the hood. I have an Edelbrock Performer RPM and a Carter AFB Competition Carb. This was a pretty tall combination already, so I didn't know how much higher I could go. I didn't have any heat transfer issues- I just wanted as much 'ram air' effect as I could get away with, although I'm sure the stack of plates with rubber gaskets in between each one does insulate the carb from heat. I was surprised that I got just about a half inch raise with the plates and gaskets before I needed to stop. Maybe you could start with a plate or two and go from there- instead of your spacer- and you still might gain some needed insulation from heat.

2ynp21k.jpg
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Think I Found the Answer

Hi All

Based upon some advice from Cadreamin, I put a straight edge across of the top of the air cleaner with only the bottom part and filter element in place to see if any of the body of the carb or vent tube protruded above the top line of the filter element. Everything cleared but only by a smidge. I then inspected the top part of the air cleaner and noticed the top surface was notched down inside the groove for the filter element. So it was even lower than the top edge of the filter element. Further inspection of the underside of the top part of the cleaner revealed damage where the front vent tube had been rubbing.

As I contemplated solutions, I compared the old carb to the new one. See Photos. The vent tube on the new carb (Photo 2) is higher (5/16") than the one on the old carb (Photo 1).

My questions are:

Are these tubes interchangeable? I have not been able to find any at any of the usual sites.

If not, can they be tapped down so they sit lower?

Or do I need to trim the top of the tube?

I have a call into Holley Tech but they have not returned my call from a few hours ago and now their tech phones are down.

Thanks,
 
Whack It

VaCat33 said:
Hi All

Based upon some advice from Cadreamin, I put a straight edge across of the top of the air cleaner with only the bottom part and filter element in place to see if any of the body of the carb or vent tube protruded above the top line of the filter element. Everything cleared but only by a smidge. I then inspected the top part of the air cleaner and noticed the top surface was notched down inside the groove for the filter element. So it was even lower than the top edge of the filter element. Further inspection of the underside of the top part of the cleaner revealed damage where the front vent tube had been rubbing.

As I contemplated solutions, I compared the old carb to the new one. See Photos. The vent tube on the new carb (Photo 2) is higher (5/16") than the one on the old carb (Photo 1).

My questions are:

Are these tubes interchangeable? I have not been able to find any at any of the usual sites.

If not, can they be tapped down so they sit lower?

Or do I need to trim the top of the tube?

I have a call into Holley Tech but they have not returned my call from a few hours ago and now their tech phones are down.

Thanks,
Click to expand...

FYI: Any hardware store will have a mini tubing cutter for cheap. Use it to gently lop 5/16" ish off the vent tube (height isn't that critical). Done . . .:D
 
Done

Hi All

Well I shortened the vent tubes using the mini tube cutter recommended by Oneoffive. It worked great but at the end of the day the entire assembly was still too high.

In the end I had to remove the phenolic spacer. Now everything fits fine. As I see how the new carb handles the heat I might be able to squeeze in a heat resistant layer per hottigr's recommendation. For now though I'm done. Time now to repair the underside of the hood.

Thanks to all for the input.
 
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