View Full Version : TR4/4A TR4a engine mounts - round vs rectangular & vendor

12-10-2009, 10:33 AM
Hi guys - the Moss catalog lists the round & rectangular mounts are interchangeable which has me wondering if one is better than the other.

I'm also wondering if the TRF mounts, which Charles makes a big deal about being better than what else us available, are in fact better.

Any experiences to pass along?


12-10-2009, 11:28 AM
There has been quite a bit of discussion in past threads so make sure you do a search, too.

From what I recall, TRF does not make the rectangular 4A engine mounts, but you can buy the 4 round.

BPNW sells the uprated round mounts. I think these are the same offered by Revington TR.

I bought the 4A rectangular from Moss and the round from BPNW and ended up going with the rectangular. I guess they are better. I have no point of reference because the rectangular mounts that came on the car were put in sideways.

I'll let you know how it works when I sort out my water pump housing issue.

12-10-2009, 11:32 AM
I have the round ones (that's what it had originally on my '66 4A). My replacements are made by Powertune (England).

12-10-2009, 11:41 AM
tdskip, It's been awhile sense I did mounts, but here's what was going on last time I did one. The round ones all seemed to be NOS, which was real rubber and if your engine (God forbid) did leak they tended to squash down. The rectangular ones were made of synthetic rubber and were much harder, thus the engine was in place better. The Roadster used the round ones and there seemed to be a slight difference in height once installed. I will go with the synthetic if I ever replace them again, (hope I live that long).


12-10-2009, 12:08 PM
I replaced the (stock?) rectangular ones in my 4A with rectangular replacements. The replacements were not thick enough (fan pulley rubbing on the steering column), even with the existing shims, so I re-replaced them with the round mounts from the 4. YMMV.

Marvin Gruber
12-10-2009, 12:16 PM
Early TR4s had the rectangular mounts, they were left over from the TR3s. TR4a's had the round ones.


Marvin Gruber
12-10-2009, 01:19 PM
Early TR4s had the rectangular mounts, they were left over from the TR3s. TR4a's had the round ones.


12-10-2009, 03:30 PM
Howdy Folks,

I have`nt had the pleasure of changing either one as of yet but soon plan on it in the TR3 project.

A "Round" pcs of whatever typ. spreads any forces, stress etc. in a more equal direction as opposed to square or rectangular items. It applies very well in severe metal cutting (Turning & Milling). How it would apply here?? I would think the same principal would apply.

Just my $.02.


12-10-2009, 05:53 PM
The attachment to the frame is different between TR3 & TR4; I'd be surprised if any TR4s actually came with TR3 mounts. The TR3 style uses two bolts (and theoretically, two plates to limit mount deflection) while the TR4 uses a single stud and no plates.

12-10-2009, 06:16 PM

My 66 TR4A had round mounts. I replaced them sometime last year as they were finally fried. I went with the round TriumphTune "uprated" mounts sourced from BPNW. They totally do the job and I have two main comments:

1. I have to admit, I was AMAZED at the difference in the feel of the whole car with new motor mounts. The reduction in buzzes, vibrations and harmonics was amazing. I never noticed it as an issue until AFTER I installed the new mounts. The car literally drives down the road so much better. Who'da thunk?

2. I never measured the clearance between the fan hub and steering rack before the motor mount replacement but, I can tell you now it is EXTREMELY close. It doesn't rub but, the clearance is so tight I can't even slip a credit card b/t the two. As I said, they don't rub but, I may eventually install a diff mount washer under each motor mount (this is the recommended solution for tight fan hub/steering rack clearance. Each washer provides ~4mm extra clearance).


12-11-2009, 12:11 AM
Thnanks guys. Round it is.

12-11-2009, 12:10 PM
Just my story on my TR4A:

I bought both the round and the square from BPNW. Measured them with calipers, compared them, etc.

With the help of folks here, I decided on the square ones (OK, rectangular), and used large washers for extra space on the upper bolt end of each mount.

They are quite, and great so far.

In addition, I have about 1/4 inch space between the fan extension and the frame brace.

12-11-2009, 12:51 PM
ISTR that the non-round mounts were used on later TR4A's. Both of mine (66&67) had the rectangular mounts when I got them. And that's what I am using on my 4A.

12-11-2009, 01:01 PM
Oh sure, confuse me with more data....LOL.

Thanks guys.