Struts instead of trunnions
Printed From: TheAMCForum.com
Category: The Garage
Forum Name: Suspension, Steering, Brakes & Wheels
Forum Description: What makes it stop, turn, and smooths the ride
URL: https://theamcforum.com/forum/forum_posts.asp?TID=113317
Printed Date: Apr/19/2024 at 5:42pm
Software Version: Web Wiz Forums 12.03 - http://www.webwizforums.com
Topic: Struts instead of trunnions
Posted By: wayne_m
Subject: Struts instead of trunnions
Date Posted: Nov/24/2021 at 8:25pm
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A trunnion setup is similar to a Macpherson strut. Is there a strut assembly with the right geometry that can adapt to a trunnion? ------------- 1969 AMX 390 |
Replies:
Posted By: mixed up
Date Posted: Nov/25/2021 at 6:16am
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dairy land makes a nice set up he has a write up some were on the site and sells his set up or control freak ------------- 69 amx 290 auto 65 220 290 4spd 80 ford fairmont |
Posted By: 304-dude
Date Posted: Nov/25/2021 at 6:44am
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I think he really wants to use struts not a custom kit. IMO if anyone really knew what would bolt in with minor mods, they would have done it in their drag setups, by now. UnclJohn posted pictures of his AMC 70s suspension hump swap on a pre 70s big body, in my thread, which upgraded away from trunion. But tyat requires cutting and welding. The only reason to use struts is to allow header clearance. No mechanical gains for street driving are worth the trouble of conversion. It would be the option for non amc big engine swaps with headers in a small body racer. ProStreetTom was looking into grafting late model frames to use double wishbone in a small body drag car. Maybe he has found something and may give some insight. ------------- 71 Javelin SST body 390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker |
Posted By: Mopar_guy
Date Posted: Nov/25/2021 at 7:34am
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There are a couple of companies that make them for Mustangs and Torino's. When I was talking to Fatman Fabrications for a front end for my car, we talked about possibly doing a strut style but I didn't have the lead time for him to design it. Since both Fords and AMC's have a similar architecture he said it looked feasible and he offers one for Fords. You might look into those and see what you can make work. Unfortunately, Brent sold the company to retire so I don't know if they would be interested in designing one for an AMC. He was really good about supporting less popular cars but so many companies now only care about volume. -------------  " http://theamcforum.com/forum/hemilina_topic95889.html" rel="nofollow - Hemilina " My 1973, 5.7 Hemi swapped Javelin |
Posted By: Trader
Date Posted: Nov/25/2021 at 8:32am
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I modified the trunnion with a greaseable bronze bushing and better thrust bearing. Basically moving the "strut" bearing from the top to the bottom. The rubber bushings in the control arms take the shock loads so the bearings in the trunnion have not shown any signs of wear in 12+ years. Original trunnion bushings and even the urethane have too much friction, twisting the front suspension, and not enough road feel feedback in my opinion. On comparison to my modern vehicles with struts, the modified trunnions are very similar. After truing and polishing the steering knuckle pin, made my own bushings. This was not a lot of work, but a major improvement over the factory design. Again, my opinion. |
Posted By: sweatlock
Date Posted: Nov/25/2021 at 9:18am
Can you please provide some details, photos, part numbers/mfr.’s, etc.? Thanks
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Trader wrote:Posted By: Trader
Date Posted: Nov/25/2021 at 9:55am
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Details: Turned the slightly worn steering knuckle pins true and polished with 400/800 grit paper. Ensure you leave a good fillet at the bottom of the pin. Bored the trunnions true and the same. Turned hard bronze bushings for a 0.003" press fit into the trunnion. Drilled and tapped a hole in the trunnion for a 45 degree grease zerk. Reamed the bushing for 0.0015" clearance. Bought SKF thrust bearings from there catalogue. Milled a shallow channel in the bushing from the grease zerk hole to supply grease to the thrust bearing. Assembled with a fiber washer as a bearing on top of the bushing, with a ground washer and double nut to lock in place with a very slight preload. Didn't take pictures and all that you see different is a grease zerk on the inside of the lower trunnion on the car. |
Posted By: sweatlock
Date Posted: Nov/25/2021 at 10:17am
| Okay, great thank you. So you left the trunnion’s horizontal rubber bushings alone for the control arms, you just modified the trunnions for the vertical bushing for the steering knuckle pins, correct? |
Posted By: Trader
Date Posted: Nov/25/2021 at 10:33am
| Correct! |
Posted By: tomj
Date Posted: Nov/25/2021 at 2:43pm
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Wayn_m, what problem are you trying to solve? Or improvement you hope to gain? There's nothing wrong inherently with the trunnion setup, otherw than often worn out. Unless you plan to strip it out for some reason standard advice of make it all like-new before modifying is good advise. Stock will cost less, no matter what.
------------- 1960 Rambler Super two-door wagon, OHV auto 1961 Roadster American, 195.6 OHV, T5 http://www.ramblerLore.com |
Posted By: wayne_m
Date Posted: Nov/25/2021 at 9:04pm
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For my ‘69 AMX. As the parts become rarer and harder to find, a strut set up is so simple. If you fabricate a lower control arm and the connecting links, I’m curious if a strut assembly from a current gen Camar would work. The entire assembly with the strut, spindle, brakes etc… ------------- 1969 AMX 390 |
Posted By: Trader
Date Posted: Nov/25/2021 at 10:11pm
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A lot of math goes into designing a steering/suspension system. Big project if your going to do a ground up new design. That's why most will steel a system complete from a donor or buy aftermarket. Someone at a show this summer used a complete Corvette, 2004??? Anyhow, it was very little work to bolt in, they stated, and was "amazing". Did not see it myself.
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Posted By: tomj
Date Posted: Nov/26/2021 at 9:13pm
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Yes, the parts are getting more expensive, but it will still be far cheaper to buy new ones/rebuild than to replace. Thousands to replace, hundreds to fix. The parts are available still. Set up right they work fine unless you're competitively road racing or something. ------------- 1960 Rambler Super two-door wagon, OHV auto 1961 Roadster American, 195.6 OHV, T5 http://www.ramblerLore.com |
Posted By: Amx68
Date Posted: Nov/28/2021 at 5:21pm
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I had wondered if something like a Fox body Mustang or the 94+ era aftermarket coil overs with adjustable upper plate would work, while using the Mustang knuckle and even the brake setup. And then if could get away with making the AMC lower arm and strut rod stay the same. Then build a strut brace across the top in the engine bay. I have no comparison on measurements or anything specific more than just thought and seeing pictures of the Mustang setups. In my Amx I ended up just rebuilding the stock trunnion front end though, for the ease of knowing it works. ------------- 1968 Amx - Was 390/4spd, will have mild 360/5spd T5 (project) 1999 Jeep Cherokee Limited - 4.0L Auto, 3-link front, 6.5" lift, 36" Swampers, locked front/rear, 4.56 gears, doorless, etc. Wheeled & DD |