Author Topic: HIF Manifolds  (Read 465 times)

Offline tmsmini

HIF Manifolds
« on: November 09, 2019, 10:08:11 AM »
While sorting through some manifolds, I saw a difference in the current MS C-AHT770 compared to the older CAM6618.

https://www.7ent.com/products/intake-manifold-single-su-hif-used-cam6618-used.html

If anyone is running into clearance issues, the older manifold might work. The new versions flow better, but if they don't fit, they don't work either.
I just reinstalled the newer manifold and I did not measure the difference before hand, so I am not sure of the exact difference.

It looks like most CAM6618 are pretty well used from looking on EBAY. Someone had cut the heater hose pipes off of mine.
Is there any way to repair those? Can you thread in an NPT hose barb?

Offline Jimini II

Re: HIF Manifolds
« Reply #1 on: November 09, 2019, 10:20:57 AM »
I have heard that the MG Metro intakes also have no clearance issues.

Offline MiniDave

Re: HIF Manifolds
« Reply #2 on: November 09, 2019, 10:30:14 AM »
Wow, that's a significant difference!

I'd think Metro intakes would be fairly the on the ground in the US since they ever imported them here.....

I'm pretty sure those hose ends are just pressed into the manifold - but I don't know this for a fact. I would see if you can knock one out from the other side with a long drift. If you can then either press in a new one or as you said, thread it for a hose barb.
« Last Edit: November 09, 2019, 10:32:36 AM by MiniDave »
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline 94touring

Re: HIF Manifolds
« Reply #3 on: November 09, 2019, 11:13:21 AM »
Any idea what the size of the ports are on each?  Minus the centering ring part on the old. 
« Last Edit: November 09, 2019, 11:46:31 AM by 94touring »

Offline tmsmini

Re: HIF Manifolds
« Reply #4 on: November 09, 2019, 11:44:08 AM »
I will get some measurements after I get things back together.

Offline 94touring

Re: HIF Manifolds
« Reply #5 on: November 09, 2019, 11:53:12 AM »
Cool thanks.  Also my understanding was the new manifolds have the spacer built in. 

Offline tmsmini

Re: HIF Manifolds
« Reply #6 on: November 09, 2019, 12:41:45 PM »
Looks like 32 mm on the old version and 35 mm on the new which would account for the lack of the locator rings on the new.
Now I need to measure my heads to see what matched up...

Offline tmsmini

Re: HIF Manifolds
« Reply #7 on: November 09, 2019, 01:08:55 PM »
Cool thanks.  Also my understanding was the new manifolds have the spacer built in.

That would make sense, but I never put 2+2 together.
Now I need to check the other car with the HIF on it to see which manifold it is as I am pretty sure I a have a spacer on it.

Offline 94touring

Re: HIF Manifolds
« Reply #8 on: November 09, 2019, 02:14:36 PM »
Spares use to make one of these with even bigger ports.  Though unless you have some monster race build, the velocity of the ports become an issue.  I've been thinking of testing a hif44 on my engine or going to a standard twin hs4 manifold to see if port sizing fixes some issues I have.

Offline bikewiz

Re: HIF Manifolds
« Reply #9 on: November 09, 2019, 04:13:22 PM »
It looks like most CAM6618 are pretty well used from looking on EBAY. Someone had cut the heater hose pipes off of mine.
Is there any way to repair those? Can you thread in an NPT hose barb?
I cut mine off and threaded it with 3/8 NPT I think, I don't plumb the heated manifold and wanted to just plug the ends to clean thing up.

Offline 94touring

Re: HIF Manifolds
« Reply #10 on: November 09, 2019, 07:00:11 PM »
Used a flow calculator on those port sizes.  Plugging in a generic volume of fluid through a 1.75" carb feeding into two 1.26" (32mm) and two 1.37" (35mm) ports, the two 1.26" equals nearly the same volume as the 1.75" carb can supply.  The 1.37" ports would require nearly a 2 inch carb mouth to equal their volumes.  How much that effects power in a real world environment I'd need to see dyno comparisons.   Maybe vizardizing the carbs would work better on the larger manifold.  Shaving the lower edges of the carb piston and reducing the butterfly shaft diameter/cleaning up screws.
« Last Edit: November 09, 2019, 07:09:20 PM by 94touring »

Offline tmsmini

Re: HIF Manifolds
« Reply #11 on: November 09, 2019, 07:53:54 PM »
I tried a 3/8 NPT tap on mine and the internal rust just crumbled. I think if the pipes were in good shape then 3/8 might work.
There is a small freeze plug that prevents getting a decent sized drift on the end. I suppose they could be drilled as well.
Someone on the Miniforum has shown how to replace the pipes on an SPi inlet manifold. As SPi inlet are NLA.

Offline tmsmini

Re: HIF Manifolds
« Reply #12 on: November 18, 2019, 10:10:12 PM »
I spoke to Jack at Seven when I picked up our engine. He said at one time Mini Spares did make a manifold that had longer runners. It was developed for 1380 and the use of the HIF44.
Now I need to go back and check the dimensions of the assorted manifolds I have.

Offline 94touring

Re: HIF Manifolds
« Reply #13 on: December 01, 2019, 01:34:10 PM »
Just fitted one to my 1275.  I needed a 6mm spacer between the manifold and carb so the linkages didn't foul.  Otherwise had no clearance issues. 

Offline MiniDave

Re: HIF Manifolds
« Reply #14 on: December 01, 2019, 01:41:41 PM »
Air cleaner can be difficult on these, the pancake, cone style K&N seems to work the best - it's biased up wards on the base plate, so the cone doesn't hit the bulkhead.
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline 94touring

Re: HIF Manifolds
« Reply #15 on: December 01, 2019, 04:54:21 PM »
Going with the med stub stack and filter box.  Should fit just fine but the speedo cable may give it fits.  I wanted to go with a 45mm ram pipe but a filter won't fit without some major modifications.

Offline MiniDave

Re: HIF Manifolds
« Reply #16 on: December 01, 2019, 05:49:23 PM »
Heck, you don't need a speedo anyway!   77.gif

Best be careful tho, this time the cop radaring you at 90 mph might be right!  :D
1989 Cooper Racing Green
2009 Clubman S
2004 Audi Allroad 2.7 TT

Offline MPlayle

Re: HIF Manifolds
« Reply #17 on: December 02, 2019, 02:20:41 AM »
Depending upon the dash - one of the newer electronic speedometers?  Very accurate and no stiff, mechanical cable.


Offline 94touring

Re: HIF Manifolds
« Reply #18 on: December 02, 2019, 07:55:14 AM »
I think I'll be ok but what's the website for them?

Offline tmsmini

Re: HIF Manifolds
« Reply #19 on: December 02, 2019, 11:35:22 AM »
MiniSpares sell them, but I bought one from here:
https://www.digital-speedos.co.uk/gauges-c4/car-gauges-c28/smiths-m2/classic-british-mini-t40

There can be issues with the sensors as they modify them for the Mini. I am pretty sure Dean ended up buying a second sensor as the first did not fit well at all.
Being electronic, you need to pick your power source/supply care fully.

Offline MPlayle

Re: HIF Manifolds
« Reply #20 on: December 02, 2019, 01:31:23 PM »
I got the one for the Moke from the same place Dave linked.  I was first going to try with the sensor on the transmission, but the sender did not pulse correctly.  I could have received a free replacement, but I upgraded to the GPS based sender instead.  They credited me the cost of the old sender against the price of the GPS sender.

The GPS sender worked fine on the Moke.  I mounted it on the flat of the left front fender, up near the base of the firewall/bulkhead/windshield frame.

With the transmission mounted senders, you have to recalibrate them when changing tire sizes, but that is an easy process.  With the GPS sender, you set the calibration once and do not have to change it again.


Offline Jimini II

Re: HIF Manifolds
« Reply #21 on: December 02, 2019, 05:43:21 PM »
While sorting through some manifolds, I saw a difference in the current MS C-AHT770 compared to the older CAM6618.

https://www.7ent.com/products/intake-manifold-single-su-hif-used-cam6618-used.html

If anyone is running into clearance issues, the older manifold might work. The new versions flow better, but if they don't fit, they don't work either.
I just reinstalled the newer manifold and I did not measure the difference before hand, so I am not sure of the exact difference.

It looks like most CAM6618 are pretty well used from looking on EBAY. Someone had cut the heater hose pipes off of mine.
Is there any way to repair those? Can you thread in an NPT hose barb?

The last one I did I did not use the ports for water (no need in Florida) but I did put the crankcase breather line through it as it tidied things up.

Offline Jimini II

Re: HIF Manifolds
« Reply #22 on: December 02, 2019, 05:49:22 PM »
Just fitted one to my 1275.  I needed a 6mm spacer between the manifold and carb so the linkages didn't foul.  Otherwise had no clearance issues.

The later production 1275 HIF carbed Mini's had the engine moved forward about 3/4" to 1" by moving the engine mount holes, this along with a longer engine stabilizer bar is how the factory made it work in the early 90's before the SPI came out complete with a full size dog dish air cleaner on top.

Offline 94touring

Re: HIF Manifolds
« Reply #23 on: December 02, 2019, 05:59:24 PM »
Just fitted one to my 1275.  I needed a 6mm spacer between the manifold and carb so the linkages didn't foul.  Otherwise had no clearance issues.

The later production 1275 HIF carbed Mini's had the engine moved forward about 3/4" to 1" by moving the engine mount holes, this along with a longer engine stabilizer bar is how the factory made it work in the early 90's before the SPI came out complete with a full size dog dish air cleaner on top.

This is on a 74 that was originally fitted with a 998.  I do have the longer upper arm though.

Offline Jimini II

Re: HIF Manifolds
« Reply #24 on: December 03, 2019, 06:15:24 PM »
How did that affect the angle of the header?
I did one for a friend on a 1970 Clubman Estate who did not want to lift the engine to drill new engine mount holes.
I machined the spacer like yours and "tweaking" the throttle quadrant along with an adjustable stabilizer bar and shorter studs it worked fine but the lcb header which previously leaked sounded worse as it now faced further upward which the owner got sorted at the muffler shop and then traded for a VW Beetle convertible which is another story.