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Bugeye HIF6 Dashpot Cap

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erstearns

Jedi Trainee
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In the process of installing single HIF6 and not surprisingly have clearance issue with bonnet. Found low profile cap and noticed that the top of the piston stem needs the room in the standard cap to fully raise (i.e., when fully raised the piston stem sticks out about 3/8" above dashpot top).

To achieve full opening the top of the piston stem would have to be cut off. I have not noticed this mentioned anywhere regarding discussion of low profile dashpot cap to help with clearance issues.

Anyone dealt with this issue?
 
The most common problem with this is you might have a intake manifold for a Mini rather than a Spridget, they have two different angles and the Mini intakes are too steep of angle for the Spridgets. Since this is way more popular application for a Mini over a Spridget, this is my bet for what you are dealing with.
 
I am sending the manifold back. It must have been labeled incorrectly from the manufacturer but when you look at it, it is clearly not 20 degrees. The location of the intake flange must also be moved down as just rotating the flange more upright will result in a "taller" installation.

I was curious what folks did when installing a low profile cap as it will not let the piston go all the way up.

Oh well, hopefully get the correct manifold and see how it fits.
 
erstearns said:
I am sending the manifold back. It must have been labeled incorrectly from the manufacturer but when you look at it, it is clearly not 20 degrees. The location of the intake flange must also be moved down as just rotating the flange more upright will result in a "taller" installation.

I was curious what folks did when installing a low profile cap as it will not let the piston go all the way up.

Oh well, hopefully get the correct manifold and see how it fits.
Click to expand...


I'm betting intake too. My HIF6 had the correct intake
angle and had no clearance problems. It has the low profile cap
but the piston still went all the way up.
 

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Off Topic:

David, I was thinking about you yesterday. I was at the track with my father-in-law for some practice sessions. Your old tachometer is still working very well. Thanks again.
 
dklawson said:
Off Topic:

David, I was thinking about you yesterday. I was at the track with my father-in-law for some practice sessions. Your old tachometer is still working very well. Thanks again.
Click to expand...

Glad to hear it!
Back to the HIF6 deals. If these HS4s don't start humming a hit tune soon AND gas prices stay the way they are... that HIF6 preformed flawlessly and gave good gas mileage.
Just saying....
:devilgrin:
 
Whitephrog said:
As I recall there's about 10 degrees difference in the two.
Click to expand...

Thats right, 20 degrees for the inline motors and 30 degrees for the FWD motors, and the Mini 30 degree intakes often times interferes with the bottom of the inline engine cars.

Eric, if you still have a stock Spridget intake, you can stick both intakes on flat service and be able to see if they are the same angle, this will tell you what you have.
 
I have sent the manifold back to the supplier, I think I have a 30 degree but not exactly sure (didn't have a protractor and my sketch measurements resulted in a calculated 25 degree so don't know if its right or not). Don't have an original manifold, engine came out of a Mini delivery truck with a HS4.

Here is the pic of the carb top with the piston fully raised. I assume that I can cut off the stem so that it is flush with the top and use the low profile cap I purchased if necessary? Also, doesn't look like the snap ring serves any useful purpose.....


5522752344_15cdfdd002.jpg
 
Here's a pic of a "minispares.com" intake manifold that I sold on ebay a few months back for reference. The table saw is level and the angle finder shows 15*. I checked and rechecked because everyone told me it should be 20* but it came out at 15*. Anyways, I just happened to have this pic so I thought I would share.

JACK
 

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Eric, if you are using a HS6 pistons in a HIF6 shorter dashpot, then yes the damping tube will have to be shortened to get the cap on, and if you just install the cap, you will limit full throttle piston postion, so it will have to be shortened. Make sure you are getting good drop rate and fit between the non original combination of your piston and dashpot, they are matched for fit at the SU factory and normaly thought off as match pairs, not that you can't get oddballs to work, just make sure you don't have sticking pistons.
 
First heard of this matched pair stuff a few years back. Makes sense but also makes you wonder why they are not marked as such. The Brits seem to be so good at that kind of stuff. In any case I have never seen a mark.
 
I purchased the carb recently from some folks in California and was not aware that the piston was "mismatched" to the carb body. Will inquire as to what they know about it. It was not a problem with the normal cap as it is recessed at the top enough to allow the piston to fully rise.

In any event I guess will have a machine shop do the work and should be ok at that point.
 
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