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Author Topic: Mid- Engine Modified Sports  (Read 401496 times)

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Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1710 on: August 11, 2019, 08:52:21 PM »
Wednesday afternoon I fired the engine for the first time since I rebuilt it and it was LOUD. Fortunately we live in an area where lot sizes are >1 acre so the "next door" neighbors weren't irate. :rolleyes: The idle is much too high and can't be adjusted any lower. I think my carb has a serious problem so I ordered a new Proform black race series 850 cfm to replace the old Holley 850 "double-pumper".

Black Race Series Carburetor; 850 CFM, Mechanical Secondary, Black & Purple | #67303
www.proformparts.com

It should arrive by the end of next week so I'm working on other things right now.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1711 on: August 11, 2019, 09:15:45 PM »
Today I revised my shifter to make it a standard shift pattern instead of a reverse one. I had originally thought that it was easier to fabricate the linkage with the fore and aft position reversed and that I'd just get used to the "backwards" shift pattern. It turned out to be more of a bother than I thought it was going to be. Years ago I built a small Sabel sports racer with left hand shifting on the Porsche 914 transaxle and I found that it was not a difficult thing to learn- but the shift pattern was a "standard" one. I guess I'm just stuck with my old habits... 1st gear is supposed to be to the left and forward.  :-)


To reverse the fore and aft motion of the shift rod, I revised the shifter to pivot on a rod end bearing above the push-pull/rotate tubing instead of below. The link uses two high misalignment rod end bearings (made by Fabroid) with a threaded tube between them. This allows the link to rotate and swivel as the shifter moves through its pattern. In the photos the short yellow link will be replaced with a longer 7" swaged- end tube. The bracket is bolted to a transverse rectangular chassis tube with four 10-32 Phillips head titanium screws. The shifter rotates fore & aft on a 1/4" titanium bolt riding on a thin nylon insert bushing ( the top hole in the photo).
Regards, Neil  Tucson, AZ

Offline wheelrdealer

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Re: Mid- Engine Modified Sports
« Reply #1712 on: August 12, 2019, 08:56:39 AM »
Neil,

I am interested in seeing how the whole linkage works. I have been thinking about a setup like this for a while. I have a TREMEC 600, I believe I have seen the set up I am looking for in trans am style Mustangs and Camaros. Not been able to find any pictures of a linkage shifter system that gives me enough detail to copy one.

My seat is set back a lot. My shifter is too far forward. The problem was solved by building an extra long shifter. I can change gears fine but it does have a long throw which can lead to missed gears. I would like to build a linkage system and have a shifter moved back in a more natural position.

BR
ECTA    Maxton D/CGALT  Record Holder 167.522
ECTA    Maxton D/CBGALT Record Holder 166.715

WWW.WHEELRDEALER2100.COM

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1713 on: August 12, 2019, 11:18:45 AM »
BR;

My complete shift linkage is too convoluted to show in a photo. My car is a mid-engine layout so my transaxle is all the way to the rear. The shifter rotates and moves a 3/4" OD tube fore & aft. There are two Apex u-joints and intermediate tubes running in Thompson ball bushings.

Your setup is quite different and might benefit from a pantograph- type linkage to transmit the motion from your shifter to the transmission.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline wheelrdealer

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Re: Mid- Engine Modified Sports
« Reply #1714 on: August 12, 2019, 12:29:10 PM »
Rats!

I'll keep looking. It is one of those things I know I have seen somewhere but can't seem to find it.

Thanks,

BR
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WWW.WHEELRDEALER2100.COM

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1715 on: August 14, 2019, 08:19:47 PM »
The 7" long threaded aluminum tubing arrived this afternoon. This is how it looks; I will shorten it a bit by turning it further onto the threads of the rod-end bearings.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1716 on: August 14, 2019, 08:33:58 PM »
Having determined that my old "bargain" Holley DP 850 was shot, I ordered a new Proform 850 to replace it and it arrived yesterday evening by FedEx. It looks a lot nicer that the old cast zinc Holley and it has a four-corner idle adjustment which the Holley did not have. I can't say much in favor of its tarty black & purple tarty color scheme but I'll mount this on my engine and fire it up on Saturday.
The replacement ACDelco thermostat also arrived today and I checked it in a pot of boiling water. It opened about 1/4" so it is OK, unlike the one I just removed. It has a small air bleed hole to make expelling air when filling the cooling system easier.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline wobblywalrus

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Re: Mid- Engine Modified Sports
« Reply #1717 on: August 15, 2019, 08:02:36 PM »
Are the float bowls mounted OK?  It looks like the drain screws are on top.

Offline Peter Jack

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Re: Mid- Engine Modified Sports
« Reply #1718 on: August 15, 2019, 09:06:30 PM »
Are the float bowls mounted OK?  It looks like the drain screws are on top.

Those aren't drain screws Bo. Those are the adjusting mechanism for setting the float level.

Pete

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1719 on: August 16, 2019, 07:24:10 PM »
Pete is right. On a Holley, turning the hex nuts adjust the float level up & down.

I just did that on my new Proform 850. I installed it this morning in an almost "out of the box" condition; the only thing I did was torque the bowl screws to 50 in lbs per instructions and set the fuel level in the bowl a bit lower. This carb has glass sight windows to view the fuel level, a BIG improvement over the Holley "remove the brass plugs and let the fuel dribble out" system.

I put in a new "Robertshaw" high flow thermostat after I checked it in a pot of hot water. It opens much wider than even the new ACDelco one. The engine fired right up without any problems at all. I'll need to adjust the 4-corner idle screws when I find my vacuum gauge.

The shifter is now in and adjusted.
Regards, Neil  Tucson, AZ

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1720 on: August 16, 2019, 08:08:42 PM »
https://youtu.be/Ug6braYzEn0

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1721 on: August 21, 2019, 10:04:19 PM »
I was letting the rear of my car down from jack stands and inadvertently dropped it too fast and a pair of wood blocks that I was using as spacers to raise the jack travel higher slipped and the car fell about 6 inches. Wouldn't you know it- the jack stand hit the rearmost shift rod (actually a 3/4" OD tube) and bent it into a question mark. Arrggghhh.  :oops:

I had planned to replace it and one other part of my shift linkage anyway so that wasn't a complete disaster. I bought some Thompson Case 60 ground & polished rod a while ago for that purpose since the linkage runs in ball bushings. The problem started when I tried to drill the shaft for universal joint retaining bolts. A high speed drill would not touch it and neither would a cobalt drill. Not having a carbide drill, the hard surface of the shaft was resisting my attempts to drill a hole through the rod. Thompson says their surface hardness is 60 Rockwell C minimum and typically 62 RC.

The solution was to grind off the hard outer surface on both sides of the rod, exposing the softer inner core. I used a Dremel tool with an abrasive and it worked very well. I was finally able to drill the through hole with an ordinary high speed #10 drill. Cutting the rod to length with a hacksaw was impossible but an abrasive cut-off disc worked just fine.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1722 on: August 22, 2019, 10:42:01 AM »
I removed my main power relay to check the condition of its contacts. This relay is able to be easily disassembled, unlike most others. I was surprised to find that the contacts looked virtually new, no wear, arcing, or pitting. Not bad for a relay that probably dates from the 1940s.

I can't find any reference to its part number on the internet but it is a style that is still in production (but modernized somewhat) by Cutler-Hammer & Eaton. This style was predominately used as an aircraft engine start contactor... but what aircraft? Most military planes had 24V electrical systems by then but this relay is 12V. Any guesses?

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline wobblywalrus

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Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1724 on: August 24, 2019, 10:31:23 AM »
Amazing! You are a great detective to find that- thanks!

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ