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Hydraulic engine mounts compression

tomasss

former PRVert
Joined
Oct 13, 2008
Location
Sydney, Australia
I ordered a PU engine mounts as a replacement of my old leaky hydraulic engine mounts.
What is surprising for me is that the hydraulic engine mount height is 10.4cm while the PU mount is 86mm only.
That is almost 2cm difference.
The only thing I can think of is that the hydraulic mount will collapse a bit when the engine weight is pressing it down...but can it make those 2cm's?

<a href="https://imgur.com/PKbOMfj"><img src="https://i.imgur.com/PKbOMfjl.jpg" title="source: imgur.com" /></a>
 
Any experience with these classicswede?

Actually I think that the theory with the pneumatic mounts compressing under engine load is not valid.

The reason why I think so: there are these steel wires going around the mount, securing the top part of the mount to the bottom of the mount even if the mount has already degraded completely.

I remember how loose those wires were when the engine was still in the car. And now those wires are almost as loose as before. There is no way that the mount extended it's length by 18mm...
 
Ok, after some more checks it really seems that the PU mounts height is correct...weird to me but confirmed from several independent suppliers.
 
Well..unfortunately it seems that the PU mounts from retro turbo are really too low.

This is what I found when I crawled under the car today to check the oilpan to crossmember clearance :-( the paint on the oil pan is even slightly wrinkled from the engine weight pressing it against the crossmember.

<a href="https://imgur.com/NDyw0ae"><img src="https://i.imgur.com/NDyw0ael.jpg" title="source: imgur.com" /></a>
 
I did this to use 240 solid mounts onto 940 brackets. A similar idea might work for you.

1431300.jpg

2v2dzer.jpg
 
Yup. I am not missing that much height as you, so I am thinking of adding like 5mm shims on three places: between the crossmember and the solid mount, between the solid mount and PU mount and then between the PU mount and the engine. That would give me around 15mm gap.
But yeah...the idea was that it will be plug&play...:roll:
 
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I think I see the issue.
Their website says their mounts are a direct replacement for Volvo OE part number 3514485 and to ensure that this product matches your existing mounts.

Your photo shows a mount with part number 3514487. I found only one reference to 3514485 which shows LH (left hand?) so see if that number is on your left side mount. Obviously if the left mount is 3514485 then they have screwed up their design but if it's different they might be unaware of some different mounts that B204GT came with.
 
Well, they call their product "Volvo 740 940, 16V Pro Engine Mounts for B204GT (PRT)" so it should be compatible with B204GT right :)
The engine mount numbers I have already checked before, one had 3514487 stamped on it and the other one had 3514485. Seems that the first one has been replaced at some point as it looks less rusty, but other than that they look exactly the same, and also on the Volvo web they look exactly the same:

https://www.volvopartswebstore.com/products/1134046/3514485.html
https://www.volvopartswebstore.com/products/1132443/3514487.html
 
Well, they call their product "Volvo 740 940, 16V Pro Engine Mounts for B204GT (PRT)" so it should be compatible with B204GT right :)
The engine mount numbers I have already checked before, one had 3514487 stamped on it and the other one had 3514485. Seems that the first one has been replaced at some point as it looks less rusty, but other than that they look exactly the same, and also on the Volvo web they look exactly the same:

https://www.volvopartswebstore.com/products/1134046/3514485.html
https://www.volvopartswebstore.com/products/1132443/3514487.html
Sounds like they sold you a bill of goods then, obviously your mounts are the ones these are supposed to replace but something went wrong in the production process or something. The bracket previously posted would do the job although I'd explore the idea of making new shackle-type engine mounts as they will control engine movement much more completely.
 
The 16v part explains it. The length is about right for 8v, the either sent you the wrong ones or just make them wrong

I can do one off mounts to the length you want
 
Well, I am not sure about the height. The guy from retroturbo is stating that the height should be perfectly correct for 16v turbo 740, but apparently it is not. He said it was perfectly fine on his 940 with the same engine but as far as I know 940 never received this engine (960 did)...

Anyway...I really needed to solve this, so today I tried to play with some shims. Using some big flat washers I was able to lift the engine mount holder and also sandwich the shims on both sides of the PU mount so the engine is in exactly the stock position now :cool:

<a href="https://imgur.com/uzL8k0L"><img src="https://i.imgur.com/uzL8k0Ll.jpg" title="source: imgur.com" /></a>

<a href="https://imgur.com/WwsxKe9"><img src="https://i.imgur.com/WwsxKe9l.jpg" title="source: imgur.com" /></a>

<a href="https://imgur.com/jbu3bGE"><img src="https://i.imgur.com/jbu3bGEl.jpg" title="source: imgur.com" /></a>
 
Complaints

Hi Tomasss,
About these pu engine mounts from Retro Turbo you installed: have read so many complaints about pu mounts concerning rattles, noisy idling, humms at certain rev areas, that I ask myself if the benefits (less engine movements) weigh up to those disadvantages. Curious about your experiences.
On the RT website there was talk of a completely redesigned 16V engine mount as a correction of the older version. Did you follow that?
 
To be honest, it felt completely fine for a fun car. Probably little bit too stiff for a daily driver but it is very subjective to one's liking. Also depends if you keep the balance shafts; I didn't and it was better than I expected. With the balance shafts connected I would say it's more than acceptable for average turbobricker :)
Indeed it seems that there is some >upgraded version< of the mounts now.
I've got the round ones (actually the RT pics with the black ones are from my build :) ) and these were created based on this thread and my subsequent communication with Pete from RT. It's a longer version of >these< that I've received originally and that were too short.
 
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Can get pretty annoying

Thanks for the info Thomasss, no balance shafts here. Replaced the B204FT 2-ltr short block for a 230FK. What I am really interested in is the noise they generate. It is not a daily driver though but occasionally I will make 2500 km trips inside Europe. Drone noises while in certain rpm ranges can get pretty annoying in the long run.
 
Ok, that means no extra harmonics for your engine either.
It's really difficult to quantify the feeling though; the perception of such thing is very subjective. Also the PU mounts are now 3rd generation, so your setup will be very different from mine and so will be the experience. But I really liked the immediate response when you hit the gas.
There were no noises or droning but the car felt more tight as a whole. But that's not a surprise considering the state of the old hydraulic mounts.
If I were you I would give it a try. Btw are the OEM hydraulic mounts even available? When I was looking for it some time ago it was n/a from the dealer already...
 
Thanks Tomass. The hydraulic mounts for my Volvo 960 (height 104 mm, pn #3514487) are no longer available. I think I will try the 3rd generation ones from RT. Ask myself if together with stiffer engine mounts, the M90 box also needs stiffer mounts. Did you replace those?
 
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