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#1
10-31-2014, 01:13 PM
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Engine chained to frame?
As I posted in a recent thread, I broke the clutch ball stud on my 65. At first I thought it happened from jacking the car up, but the more I think about it I bet it was me pounding on the car that really caused it. While the motor mounts are fine, it seems like the engine can move a fair amount when I smack it and when that happens one side of the Z bar is bolted to the frame and the other side to the engine. So I think the relative movement between the engine and frame may be what actually caused the stud to break.
I was thinking about chaining the engine down to limit movement of the engine relative to the frame. Is that a bad idea? I was also wondering if there was any way I could leave some room for movement on the frame side of the Z bar, some way to use a rubber bushing or something? Anyway, I often find that when I post here you guys have way better ideas than I do, so let's hear 'em before I screw things up even worse 
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#2
10-31-2014, 01:21 PM
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A chain works quite well to control excessive engine movement, will post pics of my installation later.
Others like to use a turnbuckle, both methods will do the job just fine. |
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#3
10-31-2014, 01:58 PM
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Quote:
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#4
10-31-2014, 02:26 PM
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 Kinda fuzzy, but you get the idea. |
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#5
10-31-2014, 05:53 PM
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Quote:
I guess my other question is, does my theory make sense, that engine movement could screw up the clutch ball stud that bolts into the block? |
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#6
10-31-2014, 06:02 PM
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The '71-72 B-body guys do this a lot because their factory mounts are very prone to failure. If the engine is lifting it could theoretically screw up the ball stud, but I'd think it would have to lift up a pretty good amount to do that...
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#7
10-31-2014, 06:15 PM
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Mike slick bracket even!
__________________
Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
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#8
10-31-2014, 08:17 PM
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In the mid 70's GM had a problem with the motor mounts delaminating.
The recall fix was to use a length of cable around the exhaust manifold and the upper A frame shaft. Yes, Mike slick idea. Do you have a detail photo of the frame anchor.
__________________
Its ok to giggle and snicker, Dont laugh and point Last edited by Ollie; 10-31-2014 at 08:24 PM. |
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#9
10-31-2014, 08:21 PM
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Excuse the mess, this one was mid motor swap...and that is a long story in itself...
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#10
10-31-2014, 08:24 PM
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Yes, Mike slick idea. Do you have a detail photo of the frame anchor.
__________________
Its ok to giggle and snicker, Dont laugh and point |
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#11
10-31-2014, 08:37 PM
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I do not but it is simply two pieces of angle iron welded to the frame opposing each other.
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#12
10-31-2014, 08:52 PM
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Quote:
There is very little slack in the chain so the engine doesn't move much before the links are pulled tight, the chain doesn't rattle or make any noise.  The picture below shows the chain mounted to the outside of the frame rail using a short bracket when I was running the car without an inner fenders, I moved the mounting location to the inside after reinstalling the inner fenders (converted my bracket car back to a street car). 
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#13
10-31-2014, 09:58 PM
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Why don't you just put in a solid engine mount on the drivers side only.
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#14
10-31-2014, 11:46 PM
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I think a solid mount on one side would still transmit noticeable vibration. The chain approach makes sense to me and B-mans setup on the frame side is fdoanle in my 65. I will have to see where a good spot is in on the engine though, I have a later bracket setup but cant remember exactly which year.
I like the turnbuckle idea for adjustability, too though. |
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#15
11-01-2014, 01:02 AM
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You could always put a piece of rollbar foam or pipe foam over the short section of chain if it did rattle or to hide the chain....
__________________
Also Known As "Beebe" on other sites....... PZ , Pro-Touring , Lateral-G, TAC |
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#16
11-01-2014, 05:16 AM
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Double Nuts
I also used turnbuckles on my bracket racers. I found that I had to double nut the right hand thread end of it to keep it from backing off when it was hit hard on a launch.
Also, if you don't want to drill holes in your frame or weld brackets to it, you can just wrap a piece of small cable around the frame rail, thru one end of the turnbuckle. It seems that using chain almost always results in a small amount of slack. I suppose chain might work better if you use 2 pieces, a bit shorter than you need, joined together with a proper size bolt. The bolt can be used to remove all slack, then double nutted to secure it. Will probably work better with a good thick washer on both ends.
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#17
11-01-2014, 10:26 AM
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Although it's been covered before, I used turnbuckles on my 69 SJ 428 dirt car because new stock mounts would last about 2 weeks. I used them on both sides because of the quick deceleration on a dirt car and hard braking. The turnbuckles were used for 3 years and when I scrapped the car the mounts came out like new.
I liked the turnbuckles because of the adjustability (preloaded, or some clearance if you want some) factor and IMO they are a cleaner looking addition. If your using stock style head bolts the type with the 3/8" studs (negative battery cable, A/C mounting points) can be used for an attachment point on the engine making the ease of attachment simple. I used a 3/8" thick flat washer with a self locking nut on the stud an welded a bolt to the frame for the other attachment point also with a lock nut and washer.
__________________
Brad Yost 1973 T/A (SOLD) 2005 GTO 1984 Grand Prix 100% Pontiacs in my driveway!!! What's in your driveway? If you don't take some of the RACETRACK home with you, Ya got cheated    
Last edited by Sirrotica; 11-01-2014 at 10:33 AM. |
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#18
11-01-2014, 12:02 PM
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I used to have a 3/8 rod welded into the drivers side motor mount on my 71 GTO along with a turnbuckle when I was racing it years ago. Worked fine and never many issues with breakage after that. The advantage of the turnbuckle as stated before is you can determine how much preload you want on the engine and the drivetrain. I even had a hose clamp on the trans mount to lessen the chance of breakage there and the shifter bouncing around.
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1971 GTO,72 400, stock bottom end, 670 heads, Lunati BMII cam, headers, iron intake Q-jet, four speed. Best 60 ft 1.806in 2004. Best 1/8th mile e.t. 8.46 with 3.55 open rear 85 Grand Prix, 70 400, casting 62 heads stock rebuild, Turbo 350 trans 78 800 cfm Q-jet modified as per Cliff Ruggles book. 87 F350 6.9 4 speed dually A poor man has poor ways. |
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#19
11-01-2014, 04:01 PM
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I was kinda hoping that the engine mounts I built here http://forums.maxperformanceinc.com/...d.php?t=757075 would help in limiting engine movement.
What do you guys think? 
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No! Do not try! Do! Or do not. There is no try. - Yoda 1967 Firebird Restoration 2005 - 1/25/2017 
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#20
11-01-2014, 04:43 PM
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Quote:
Of course, in 75 they went to the clamshell mounts which don't have those problems.
__________________
Steve F. |
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