Engine Mounts (3/4" Stud)

Part Number: 800-020

Determining Engine Mount Capacity
Determining Engine Mount Weight Capacity

Below are the formulas to use to determine the required pounds per engine mount.


Formulas

Front Engine Mount

(W x 0.4) x 0.5 = lbs per mount

Back Engine Mount

(W x 0.6) x 0.5 = lbs per mount

W = weight of engine and gearbox

Example:

Total weight of engine and gearbox = 1,200 lbs.

Front Engine Mount

(1,200 x 0.4) x 0.5 = 240 lbs per mount

Back Engine Mount

(1,200 x 0.6) x 0.5 = 360 lbs per mount



General Weight Distribution
R&D Marine Engine Mount weight distribution

  1. Find the center of gravity by balancing on a roller (If possible)
  2. If the center of gravity cannot be found, assume a weight distribution of 60% on the rear engine mounts, with 40% on the front engine mounts (if the rear engine mount is in line with the flywheel)

Note: Make sure your measurements match your application.



  • Description

    • Designed for marine use, accepts propeller and engine thrust in both directions.
    • Offers a fail-safe design.
    • Are height adjustable.
    • Pre-loaded to reduce movement.
    • Slotted holes in the base to assist in alignment.
    • Mount types to fit all applications.

    The R&D Marine Engine Mounts are designed specifically for the rigors of marine applications. The mounts are stiff enough to absorb forward and reverse propeller thrust, yet soft enough to isolate drivetrain vibrations from the hull.

    To help increase the longevity of the mounts, all steel parts are zinc plated and passivated to limit corrosion. The rubber component is covered by an oil shield to protect it from petroleum-based products.

    R&D Marine mounts are preloaded based on the combined engine and transmission weight to limit engine movement. To facilitate the ease of installation the mounts are height adjusting and the mounting holes in the base of the mount are slotted to assist in the alignment of the drivetrain.

    Available for most brands such as Yanmar, Perkins, Universal, Westerbeke, and many more.

  • Determining Engine Mount Weight Capacity


    Below are the formulas to use to determine the required pounds per engine mount.

    Formulas

    Front Engine Mount

    (W x 0.4) x 0.5 = lbs per mount

    Back Engine Mount

    (W x 0.6) x 0.5 = lbs per mount

    W = weight of engine and gearbox

    Example:

    Total weight of engine and gearbox = 1,200 lbs.

    Front Engine Mount

    (1,200 x 0.4) x 0.5 = 240 lbs per mount

    Back Engine Mount

    (1,200 x 0.6) x 0.5 = 360 lbs per mount



    General Weight Distribution
    R&D Marine Engine Mount weight distribution
    1. Find the center of gravity by balancing on a roller (If possible)
    2. If the center of gravity cannot be found, assume a weight distribution of 60% on the rear engine mounts, with 40% on the front engine mounts (if the rear engine mount is in line with the flywheel)
  • Technical Specifications


    Part # Stud Size Capacity Per Mount Foot Print Mount Pre-Loaded Deflection Minimum Height Maximum Height
    800-020 3/4 UNF 80-231 lbs 4" 0.09" 0.09"-0.21" 3.05" 5.38"
    800-021 3/4 UNF 120-411 lbs 4" 0.09" 0.09"-0.21" 3.05" 5.38"
    800-022 3/4 UNF 250-561 lbs 4" 0.09" 0.09"-0.21" 3.05" 5.38"
    800-023 3/4 UNF 300-681 lbs 4" 0.09" 0.09"-0.21" 3.05" 5.38"
    800-035 3/4 UNF 340-761 lbs 4" 0.09" 0.09"-0.19" 2.81" 6"
    800-051 3/4 UNF 80-235 lbs 4" 0.09" 0.09"-0.21" 3.47" 5.45"
    800-052 3/4 UNF 120-415 lbs 4" 0.09" 0.09"-0.21" 3.47" 5.45"
    800-053 3/4 UNF 250-565 lbs 4" 0.09" 0.09"-0.21" 3.47" 5.45"
    800-054 3/4 UNF 300-685 lbs 4" 0.09" 0.09"-0.21" 3.47" 5.45"
    800-042 3/4 UNF 160-671 lbs 4"-5.5" 0.19" 0.19"-0.30" 3.39" 6"
    800-028 3/4 UNF 80-233 lbs 5"-5.5" 0.09" 0.09"-0.21" 2.93" 6.5"
    800-029 3/4 UNF 120-413 lbs 5"-5.5" 0.09" 0.09"-0.21" 2.93" 6.5"
    800-030 3/4 UNF 250-563 lbs 5"-5.5" 0.09" 0.09"-0.21" 2.93" 6.5"
    800-031 3/4 UNF 300-683 lbs 5"-5.5" 0.09" 0.09"-0.21" 2.93" 6.5"
    800-063 3/4 UNF 500-1,300 lbs 5.5" 0.12" 0.12"-0.25" 3.97" 7.16"
    800-064 3/4 UNF 650-1,700 lbs 5.5" 0.12" 0.12"-0.25" 3.97" 7.16"
    800-065 3/4 UNF 1,100-2,101 lbs 5.5" 0.12" 0.12"-0.25" 3.97" 7.16"
    800-015 3/4 UNF 500-1,200 lbs 5.5" 0.12" 0.12"-0.25" 4.04" 7.22"
    800-016 3/4 UNF 650-1,500 lbs 5.5" 0.12" 0.12"-0.25" 4.04" 7.22"
    800-017 3/4 UNF 880-2,00 lbs 5.5" 0.12" 0.12"-0.25" 4.04" 7.22"

Customer Reviews

Based on 14 reviews
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P
Paul Bailey
Engine Mounts

Not knowing which type of mounts that were your required, your technical support person went over the various types which was extremely helpful since there were no information available from the engine manufacturer.

N
N Haggard
Yanmar replacement mounts

Fits and works great!

R
Ron Ricci
Happy Camper

Great pre-sale customer support!! The mounts were a perfect fit.

I picked these because of the stainless steel shield over the rubber parts. This, along with the coating on the base is a much better design than the Vetus mounts that were replaced. The bolts that hold the mount into the stringers were also replaced since the base is thicker than the old mounts.

N
Norman Facey
Good work!

1) I chatted online with Eric Young who was excellent in helping me to identify my old mounts & provide order number for new
2) a couple days later, once I’d confirmed the old mounts were toast (threads rusted so bad they were unlikely to be adjustable for realignment) I was able to go online & easily order the correct replacements
3) AND specify rapid shipment vis UPS that actually worked across the border and up into rural Canada.
Shipment worked, mounts bolted directly in place, and alignment was easy. Lots o’ stars for PYI.

P
Percy Roberts
5 star all the way

great product and service, set arrived with one mount wrong weight raqnge replacement was overnighted along with prepaid return lable for wrong mount. The R&D mounts are high quality, comparing the original Yanmar mounts to the R&D mounts I'll just say is like comparing a ford pinto to ferrari

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