ConcoursMustang Forums

Restoring - General discussions that span across many different groups of years and models => Drivetrain => Topic started by: lightwtjet on February 24, 2025, 12:41:40 AM

Title: Engine Mount Tuning
Post by: lightwtjet on February 24, 2025, 12:41:40 AM

At Ford Vehicle Development, the engine mount was often used to fine tune the vehicle. Especially prone was the convertible that often had mid car shake.
Per SAE International - Engine mount tuning is a multi-disciplinary exercise since it affects Idle-shake, Road-shake and powertrain noise response. Engine inertia is often used as a tuned absorber for controlling suspension resonance related road-shake issues. Last but not least, vehicle ride and handling may also be affected by mount tuning.
    My question - Since members here want the vehicles to be production representative, do you find that the convertible engine mounts are different from the sedan?  And are special mounts available in the after market?       

Title: Re: Engine Mount Tuning
Post by: ruppstang on February 24, 2025, 09:38:11 AM

Thanks, I always wondered why they were different. In 67 all body's got the different mount.

Title: Re: Engine Mount Tuning
Post by: Bob Gaines on February 24, 2025, 10:37:57 AM

I am aware of of the 69 70 convertibles to have a different rubber  motor mounts. I think that there were other years too requiring a different mount for convertible . In all of the cases that I am aware of the convertible mount (engine rubber mount) allowed the engine to sit slightly lower. In the case of 69/70 351 windsor in a convertible Shelby with air conditioning for example it was enough of a difference to keep the hood from making contact with the upper air compressor bracket or not. With that said apparently it was not that critical enough that after normal Ford inventory was used up the later service and aftermarket replacements were meant to be used or all applications regardless of if convertible or not.

Title: Re: Engine Mount Tuning
Post by: ruppstang on February 24, 2025, 02:14:42 PM

The standard insulator will not work with the steel motor mount without modification. I do not think anyone reproduces the special insulators.

Title: Re: Engine Mount Tuning
Post by: krelboyne on February 24, 2025, 10:28:04 PM

I have had this email from a customer for a while now. Have been wanting to share it, for discussion.
Wondering if it has merit.

We talked earlier on the phone about 1967 motor mounts.
Heres the story.
After 2 long months researching why 1967 289 and 68 to 70 convertible mounts are so hard to find or why they are not reproduced took me on a nice journey of Ford history. Also found out why the big change.
After hitting brick walls with online searches about 1967 289 motor mounts. I finally asked my great uncle Johnny that worked for Ford motor headquarters in the 60s and 70s. He was part of product development team for ford. So, I asked. If he knew anything about the reason why 1967 289 motor mounts are a one year item but still used in 69- 70 convertibles. My Uncle Johnny said 1968 happened to be a big shake up year with federal auto safety standards. Longer hood latch, collapsible steering columns, side reflectors. And motor mounts were also included into this shake up. Seems the 67 289 motor mounts now required a safety cage. To stop motors from falling out during mont failures. An exception was made for 68- 70 302 convertible models since they didnt expect high sales numbers on convertibles for those years.. In 1970 Ford wanted to stuff a Boss 302 motor in the cars, but the standard 302 caused hood clearance issues. So the took the 1967 289 motor mount out of stock and redesigned it to comply with federal standards. The new Boss 302 motor mount now has the the safety cage and much stronger than the original 67 289 motor mount. The 1970 Boss 302 motor mount number 9n the part is D0ZA-6038-E. Which now has the original dimensions and geometry of the 1967 289 or 68-70 302 convertibles. But stronger with a safety cage. So Ford actually stopped all production on al 67 289 old mounts and the 70 Boss 302 mount became the service replacement part. Which explains why my 67 had one D0ZA-6038-E motor mount. The reason aftermarket companies cant reproduce the 67 289 motor mount is because it wasn't federal safety compliant. The big shake up in 67-68 cause the aftermarket to get confused of what mount actually belongs on the 67 289. I can imagine 50 years of people getting wrong motor mounts. Very frustrating. Now my in depth research unvieled the truth. All 67 289 or 68- 70 302 convertible or Boss 302 and I believe the cougar eliminator. With the boss 302 will now and forever take the D0ZA-6038-E motor mount.
Sincerely ,
James S

Title: Re: Engine Mount Tuning
Post by: lightwtjet on February 24, 2025, 11:55:51 PM

Related to the effect of mount tuning, the new 1974 Mustang at Job#1 had unacceptable levels of mid car shake. The structure of the car apparently was different compared to the development cars and not compatible with the mount. No cars were shipped while our team of 40 engineers drove every car for a week to determine the shake level and try new mount designs. 51 years ago-doesn't seem like it. 

Title: Re: Engine Mount Tuning
Post by: ruppstang on February 25, 2025, 08:35:47 PM

I found this some time ago and found it helpful.

Title: Re: Engine Mount Tuning
Post by: 70cj428 on March 04, 2025, 03:01:01 PM

H Lightwtjet, a good example of this are 67/70 big block mounts, There's at least 4 mounts with different engineering numbers moulded in the rubber of the insulators, all are dimensionally the same as far as I can tell. The handful of 1970 CJ/SCJ convertibles got a unique motor mount than the rest of the CJ's in 70... If I'm not mistaken, they were all replaced with the 1971 429CJ part.

Title: Re: Engine Mount Tuning
Post by: james70 on April 17, 2025, 01:28:50 PM

The 1970 insulators were all "caged" and the 1970 boss 302 used the same insulator as regular 302 and 351W/351C - it is MPC # D0OZ-6038-G and embossed D0OA-6038-F,G or J, and used the same small block (non-convertible) frame mount brackets. For 1970 302/351 convertibles, the insulator was embossed D0ZA-6038-E and is MPC # D0ZZ-6038-B, and was also the service replacement for all 1967 289 cars and 1968/1969 302/351 convertibles. For correct fitment (bolt hole alignment), the convertible D0ZA-6038-E insulators require the big block 390GT/428CJ frame mount brackets

Title: Re: Engine Mount Tuning
Post by: cocomusti on April 18, 2025, 04:43:20 PM

Very good question! I have always found that the convertible requires more attention on the vibration side.
It seems to me that the engine mounts were sometimes different, precisely to compensate for the lack of rigidity.
But on the competition side, we often try to remain "visually" consistent with the production.
There are some options in the aftermarket, but not all visible once installed.
I would be curious to see what others have tested or observed!

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