Engine Mounts
Thread Starter
Drifting
Joined: Oct 2005
Posts: 1,527
Likes: 148
From: East London/SW Essex UK
Engine Mounts
Any thoughts/comments guys on the following problem. I replaced the engine mounts on my '68 with new stock big block interlock type engine mounts when installing new 528hp/565 ft/lb 489 cu in. Gearbox is Muncie 4 speed. The additional torque (compared with stock L36) is causing what appears to be excessive torque reaction and engine movement on acceleration and deccelleration - so much so that the viscous coupled fan is taking chunks out of the top of the fibre fan shroud, the left hand 'Tall' rocker cover is hitting firewall (even though I cut away firewall for extra clearance) and air filter nut is rubbing against underside of L88 hood. Q; Are the aftermarket 'Poly' mounts suitable for big blocks (I seem to remember they were only listed for small blocks?) I am weary about using 'solid' mounts on what is a street driven car.
Drifting
Joined: Jul 2003
Posts: 1,253
Likes: 1
From: East China MI
I have solid mounts on mine and yes, there is some vibration transmitted via the mounts. To me it's worth it for the extra stability (I also have a solid trans mount).
But if you are leary, Morosso makes a very nice poly mount that is much stiffer than stock but still dampens some vibration.
But if you are leary, Morosso makes a very nice poly mount that is much stiffer than stock but still dampens some vibration.
Thread Starter
Drifting
Joined: Oct 2005
Posts: 1,527
Likes: 148
From: East London/SW Essex UK
I have solid mounts on mine and yes, there is some vibration transmitted via the mounts. To me it's worth it for the extra stability (I also have a solid trans mount).
But if you are leary, Morosso makes a very nice poly mount that is much stiffer than stock but still dampens some vibration.
But if you are leary, Morosso makes a very nice poly mount that is much stiffer than stock but still dampens some vibration.
Drifting
Joined: Jul 2003
Posts: 1,253
Likes: 1
From: East China MI
I have had no issues with it but I'm the type who gets rid of the radio because all I want to hear is the engine. I like the vibration (it's a little intimidating to some ricers) and I just have to check nuts and bolts once a year; which is something everybody should do. I have never had any components fail because of the vibration.
I should also mention that the solid mounts cured a problem for me; the stock mounts could not take the torque and kept breaking. From what you describe, you may be headed for that situation; if you have that much movement. The Morosso's are a good choice and yes they have whaterver application you need.
Another low tech cure for movement is an engine chain. Very simply, a chain attached from the engine to the frame. It's an old drag racers trick that is cheep and it works.
I should also mention that the solid mounts cured a problem for me; the stock mounts could not take the torque and kept breaking. From what you describe, you may be headed for that situation; if you have that much movement. The Morosso's are a good choice and yes they have whaterver application you need.
Another low tech cure for movement is an engine chain. Very simply, a chain attached from the engine to the frame. It's an old drag racers trick that is cheep and it works.
Thread Starter
Drifting
Joined: Oct 2005
Posts: 1,527
Likes: 148
From: East London/SW Essex UK
I have had no issues with it but I'm the type who gets rid of the radio because all I want to hear is the engine. I like the vibration (it's a little intimidating to some ricers) and I just have to check nuts and bolts once a year; which is something everybody should do. I have never had any components fail because of the vibration.
I should also mention that the solid mounts cured a problem for me; the stock mounts could not take the torque and kept breaking. From what you describe, you may be headed for that situation; if you have that much movement. The Morosso's are a good choice and yes they have whaterver application you need.
Another low tech cure for movement is an engine chain. Very simply, a chain attached from the engine to the frame. It's an old drag racers trick that is cheep and it works.
I should also mention that the solid mounts cured a problem for me; the stock mounts could not take the torque and kept breaking. From what you describe, you may be headed for that situation; if you have that much movement. The Morosso's are a good choice and yes they have whaterver application you need.
Another low tech cure for movement is an engine chain. Very simply, a chain attached from the engine to the frame. It's an old drag racers trick that is cheep and it works.
(the clutch WAS on its way out, but just worn out) I have just found a supplier here in UK (Real Steel) listing Energy Suspension HD Poly engine mounts with safety interlock - so I guess I'm sorted
(if they have in stock)
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
I had a similar issue with left engine mount after installing my stroker...
If you have problems with the poly mount, this is an option.
Drilling through standard mount and fitting a pair of bolts to limit extension under load.
I have done this mod with the stock rubber mount, and is holding up without problem. There is only a slight increase in transferred vibration from motor under full load.
http://forums.corvetteforum.com/c3-t...ne-mounts.html
If you have problems with the poly mount, this is an option.
Drilling through standard mount and fitting a pair of bolts to limit extension under load.
I have done this mod with the stock rubber mount, and is holding up without problem. There is only a slight increase in transferred vibration from motor under full load.
http://forums.corvetteforum.com/c3-t...ne-mounts.html
Thread Starter
Drifting
Joined: Oct 2005
Posts: 1,527
Likes: 148
From: East London/SW Essex UK
I had a similar issue with left engine mount after installing my stroker...
If you have problems with the poly mount, this is an option.
Drilling through standard mount and fitting a pair of bolts to limit extension under load.
I have done this mod with the stock rubber mount, and is holding up without problem. There is only a slight increase in transferred vibration from motor under full load.
http://forums.corvetteforum.com/c3-t...ne-mounts.html
If you have problems with the poly mount, this is an option.
Drilling through standard mount and fitting a pair of bolts to limit extension under load.
I have done this mod with the stock rubber mount, and is holding up without problem. There is only a slight increase in transferred vibration from motor under full load.
http://forums.corvetteforum.com/c3-t...ne-mounts.html
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Drifting
Joined: Jul 1999
Posts: 1,541
Likes: 43
From: Plano TX
I would get the stock mounts welded into one piece and use them as solid mounts. This will also stiffen up the chassis.
I went with solid mounts after breaking 3 over several years.
Good luck with it.
I went with solid mounts after breaking 3 over several years.
Good luck with it.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Oldest hot rodder trick on the net.
Just drilled a hole and installed a 1/4"x20 bolt in mine. Mount still has some squish and won't bust open. Used the thinnest 1/4x20 nut i could find at the hardware store then trimmed and ground down the bolt to clearance fit the frame mount.
That's it and it costs less than a buck, er i mean less than a pound to u.
cardo0
That's it and it costs less than a buck, er i mean less than a pound to u.
cardo0
Thread Starter
Drifting
Joined: Oct 2005
Posts: 1,527
Likes: 148
From: East London/SW Essex UK
Any thoughts/comments guys on the following problem. I replaced the engine mounts on my '68 with new stock big block interlock type engine mounts when installing new 528hp/565 ft/lb 489 cu in. Gearbox is Muncie 4 speed. The additional torque (compared with stock L36) is causing what appears to be excessive torque reaction and engine movement on acceleration and deccelleration - so much so that the viscous coupled fan is taking chunks out of the top of the fibre fan shroud, the left hand 'Tall' rocker cover is hitting firewall (even though I cut away firewall for extra clearance) and air filter nut is rubbing against underside of L88 hood. Q; Are the aftermarket 'Poly' mounts suitable for big blocks (I seem to remember they were only listed for small blocks?) I am weary about using 'solid' mounts on what is a street driven car.
Thread Starter
Drifting
Joined: Oct 2005
Posts: 1,527
Likes: 148
From: East London/SW Essex UK
Well - Iv'e tried the car out - what a transformation! the engine is now rock steady on the mounts and barely moves at all under heavy torque. What is most surprising is that the gear shift quality has improved and the whole car just seems to be sharper! there is a slight bit of vibration felt through the chassis at about 2500 rpm - but no real issue
Drifting
Joined: Jul 2003
Posts: 1,253
Likes: 1
From: East China MI
Well - Iv'e tried the car out - what a transformation! the engine is now rock steady on the mounts and barely moves at all under heavy torque. What is most surprising is that the gear shift quality has improved and the whole car just seems to be sharper! there is a slight bit of vibration felt through the chassis at about 2500 rpm - but no real issue
Tech Contributor
Joined: Jun 2004
Posts: 20,847
Likes: 959
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Torque always goes through the chassis. Otherwise the entire engine would just sit there and spin like the water pump fan.