Motor mount problem......which ones are they?

[Lee R]

Ordered some fresh motor mounts from RockAuto for my 1974 620.  Before ordering, I didn't get in there to take a good look before ordering but after I recieved them, I knew straight out of the box they were not right. 

 

Part number 105-2404

 

 

Driver side mount that I removed for comparison

 

 

side by side

 

 

Called up RockAuto and the guy was adamant it was the right part for a 74 620.  He said they sold "dozens" in the past and none of them were returned for not fitting properly or being the wrong part.  Looking at them side by side ,I don't know how that could be?!?!?Eeven in the Haynes manual it shows 2 bolts not 3.   Anyway, put the old mount back in and here I am doing research. 

 

Could the PO have used some other mounts?  Nothing looks hacked up or fabbed in there.  Here is a shot looking down from the from drivers side where the original mount was removed.  Looks all stock to me.

 

[Sealik]

You sure your 620 is a 74????

Looks like the 75 MM from Rockauto is similar to your old one

[ggzilla]

You got 1973-1974 triple stud type.

 

Look at the build date on your door jamb, if it is September 1974 that is the 1975 model year. 1975-1979 used the other type (RH & LH type).

[Lee R]

You got 1973-1974 triple stud type.

 

Look at the build date on your door jamb, if it is September 1974 that is the 1975 model year. 1975-1979 used the other type (RH & LH type).

 

Thanks so much....I never knew late model 74's did that.  I looked up the 1975 mounts and they look just like the one I took off in the above photo.  I'm going to see if RockAuto can add that info to their listing for these since the operator I spoke too wasn't too much help.  Sending em' back today for the correct ones.

 

thanks again!

[ggzilla]

ALL cars do that. The USA model year traditionally starts in September/October of the previous year, but can start even earlier if the manufacturer wants it to.

[datsunaholic]

Actually it still could really be a '74.  The front mounts changed the same time the REAR (Transmission) mount changed, which was when they switched to the longtail transmission.  Which was for the '74 Model year.  But, some folks have claimed to have '74 with the short 63-series trans (could be).  My '74 is a terrible one to try and compare, as the transmission is KNOWN to be non-stock, as is the engine (both are from a '78 200SX).  A TRUE '74 is pretty damn easy to identify if the engine room tag is present- it's the ONLY year the 620 had an L18 stock.  '73 was an L16, '75 lots of things changed- the core support, the VIN prefix, the engine...  '75s have HL620 as the VIN.  '74s and earlier are PL620s.

 

 

HOWEVER... I'm not so sure about those triple-stud mounts.  My Mom's 73 has specifically different right/left mounts.  Maybe.  Haven't changed them (and they NEED to be changed).  Suppose I could look tonight if I can get the door open (probably frozen shut like all of mine were this morning).

[datsunaholic]

OK, I just looked at my Mom's '73.  It does NOT use those 3-stud mounts.  It uses the same kind as came off Lee's truck. 

My Mom bought a set of mounts 6 years ago and they are those 3-bolt ones, so they won't work.

 

The 2404 motor mount is actually a 75-77 Datsun 710 motor mount.  The Master parts catalog is screwed up.

[ggzilla]

Good to know.

 

Datsun 710 L20B motor mount

[datsunaholic]

Did some research.  Still convinced that Rockauto (and everyone else) is screwed up in the master parts catalog as EVERYONE shows that the 710 mount and the early 620 mount are the same, when they are clearly not even close.

 

The 620 mounts FACTOR part numbers:

 

TO September 1973 (which is all 72-73 model year trucks):  11220-B2000  (both right and left).  This is the SAME part number as a 70-72 PL521.

 

From  Sept 1973-Aug 1974  (which are 1974 model year)   11220-B7900

 

However, in looking at my Mom's '73  and my '74 (Mar 74) the mounts look identical (except that the ones in my Mom's truck are totally shot).  It looks like it's POSSIBLE that a 70-73 510 mount will fit, though the 510 mount has some differences in that they have a overload hook (which later 620 ones have as well).

 

Aug 74-1979 620s use very different mounts, which are different right to left.  11220-B8000 (right) and 11221-B8000 (left).  I compared the new factory one of these (the left one) I have to a new 510 mount and the newer 620 mount is 1/4" thicker than the 510 mount, but the holes all line up.  It would have issues lining up due to being taller. 

 

 

I cannot find the 521 mounts anywhere aftermarket.  It may be because the parts suppliers all superseded them with the wrong part number.  Unfortunately all parts suppliers that list the 73-74 mount also are showing the incorrect 710 3-stud mount, so they're useless.  Many of the Nissan parts suppliers list both the 11220-B2000 and 11220-B7900 mounts (for over $50 EACH) but I'm not entirely sure they can actually get them.

 

So, the only option I can think of is get a pair of mount brackets for a 75-79 620, and use the 75-79 mounts (which are different right to left).  The steel brackets on the later trucks are slightly different to accommodate the revised taller mounts.  But the frame pads (where the rubber mount bolts on) appears to be exactly the same.

[datsun 160J SSS]

Hi all . Ok I now have this problem 1973 620 I can't find the mounts .I did the same thing ordered mount's form Rock Auto and these will not work from 710 .I just recived 75 L20B mounts and will just remove 1/4 from engine plate mounts I hope this works I will post my results