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Discussion Starter · #1 ·
I just finished swaping a 3800 s/c motor into my cavalier.
The only problem i have is strength to the radiator support.
How much force is put on to the dogbone supports?
The cavalier rad support is much thiner and skinnyer than on a grandprix.
I have already twisted the support once with a peice of angle iron 1/8" thick accross the width of the support. I added 2 bars from the strut towers to the dogbone mounts on the motor. Will this be sufficiant to hold the torque.
Mods that I have are acustom pcm, 3.25 MPS, intense stage1X cam, and slp headers. I plan on doing more mods so this needs to be supported good.
This car will eventualy run in the 10s. Any ideas will help. :confused:
 

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agreed on the support of the rad mount

Hello all, I too am doing a 3800 swap... long story short, bought a GA for $500 needing intake gaskets and then found bottom end was trashed... pulled this 3100 and instead of doing a 3400 swap figured a 3800 was better, but as cavailer said im not sure about how strong the radiator frame is... so what im going to do is go to junk yard and cut out a rad support and then i can cut as necesssary to make a cap to go from side to side and also use strut tower braces...

jim
http://home.comcast.neta/~jimbutterfield/Grandamprojectcar.htm
 

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3000 cavalier said:
I just finished swaping a 3800 s/c motor into my cavalier.
The only problem i have is strength to the radiator support.
How much force is put on to the dogbone supports?
The cavalier rad support is much thiner and skinnyer than on a grandprix.
I have already twisted the support once with a peice of angle iron 1/8" thick accross the width of the support. I added 2 bars from the strut towers to the dogbone mounts on the motor. Will this be sufficiant to hold the torque.
Mods that I have are acustom pcm, 3.25 MPS, intense stage1X cam, and slp headers. I plan on doing more mods so this needs to be supported good.
This car will eventualy run in the 10s. Any ideas will help. :confused:
Are you Raven from www.L67swap.com? If not then look at this thread:
3800 SC cavalier
 

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Discussion Starter · #5 ·
No im not raven and i have seen his car. Its done fairly well. My setup is different. I intregraded the factory gtp mounts to fit my setup. Pluss his car is not a show car so it doesnt have to look perfectly clean. With Performance comes sacrifices...Looks!!!
 

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jimraelee said:
well I cant say im in favor of that hack job, Id prefer something a little nicer and factory looking for that radiator mount... just my opinion...
Hack job??? Are you serious? Everyone who has seen my car in person (including every GM tech around here) says it looks like factory....hack job lets see you do better.
:mad:

BTW here is an updated pic of the install...looks pretty damn clean to me


Anyway back to the original post...don't use the rad support at all, it's no where near strong enough. I found that out the hard way, everything now is mounted from below and it works great.
 

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raven said:
Hack job??? Are you serious? Everyone who has seen my car in person (including every GM tech around here) says it looks like factory....hack job lets see you do better.
:mad:

BTW here is an updated pic of the install...looks pretty damn clean to me


Anyway back to the original post...don't use the rad support at all, it's no where near strong enough. I found that out the hard way, everything now is mounted from below and it works great.
not sure what I was thinking about the "hack job"... from your pic seems alot nicer than my swap... great job
 

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from the way that it was described it did sound like a hack job...
so what im going to do is go to junk yard and cut out a rad support and then i can cut as necesssary to make a cap to go from side to side and also use strut tower braces
either way thats a niec engine bay
 

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Wow, that really does look VERY nice.
 

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smooth said:
from the way that it was described it did sound like a hack job...


either way thats a niec engine bay

Oh **** My bad, I thought he was talking to me about a hack job. That wasen't me that said I would cut out another rad support, I would never do that. Everything on my car was custom fabricated including the sub-frame and all mounts.

Now I just have to find some room for that nice big T61 :)
 

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what are you talking about hack job.!!!! It looks nicer than factory I think!!!!! Found out the gp has a reinforced fram accross the top ofd the rad so the dog bones dont twist it. Cavalier is much thinner. So I welded in a gp frame across the top and remover the cavalier one. Than i used the stock dog bones slightly cut shorter. And i added 2 bars to the strut towers they ar chrome by the way. Also added the factory mount for the 4t65-e to the trany and to the frame. It supports the motor more up top because its just below the throtle body height wise. this should be enough to support a good 400 whp. I think.
 

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Do you have any pics of your swap? I know a few people in Ontario that are in the process of doing the swap but no one has finnised it yet. I'm still not sure if that will hold the torque, mine not only twisted the rad support but also the sides of the unibody that it attaches to. Putting some braces from the strut towers to the rad support should help some though. Are you going to be going to the JCO bash this summer? I'll be there with the other 98 cavy that we did this swap in. Frank should be there too with his turbo'd 3800 and it should hit 10's this summer.
 

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I do plan to be at the bash. Dont know if I can for sure though. I depends on work. Sorry I dont have any pics yet!!!! All i have are photos from my 35mm camera, and I dont have a scanner. I now have a digital camera and plan to take picks of it when it comes out of storsge. I had no problem with the subframe at all, just the rad support. Looking at your swap pics all I can suggest is that you dont have enough rubber inbetween your mounts. Rubber helps alot to absorbe the movement of the motor. Also i used the 4t65-e stock on the 3800. I used the stock mounts on both the tranny and motor. Bottom line Rubber is your best friend.
 

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I look forward to seeing the pics. You know that you can have your 35mm film developed and digitized and put onto a disc right? Anyway back to your statment on rubber. Yes you are right to say that rubber absorbes movement and vibration from the engine so that it is not transferred to the chassis of the car but it doesn't do anything for strength. If your support is not strong enough the engine will still twist it no matter how much rubber you use. Also the more rubber you use the more power you will lose to the ground, thats why people replace their factory rubber mounts with poly ones. My car was built to race, that is why there is only a small amount of rubber used, so I can get as much power to the ground as possible. I do sacrafice some comfort on the road with the added vibration in the car but it doesn't really bother me and I'm happy with the performance of it. From the way you describe your setup it sounds like it should hold just fine.

You said that you used the stock auto tranny with it. I'm curious to know what you used for axles?

Pluss his car is not a show car so it doesnt have to look perfectly clean. With Performance comes sacrifices...Looks!!!
I have to disagree with you on that statement. I have won awards with it at every show I have been in, including Sport Compact Nights where I beat out over 200 cars to win Best Performance in the Crazzy 8 catagory including a tri-turbo'd VW golf. I have the performance and I don't think we sacrificed looks at all, you just need to take your time and plan it out well. Here's a pic of the tri-turbo'd golf, pretty sweet car.




Good luck with your car and I hope to see ya at the bash this summer. It's on June 11th, plenty of time to get the day off work and come out. It should be a great time.
 

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3800cavalier said:
Rubber helps alot to absorbe the movement of the motor. Also i used the 4t65-e stock on the 3800. I used the stock mounts on both the tranny and motor. Bottom line Rubber is your best friend.
I ended up cutting the stock dogbones in 1/2 and welding them to the radiator to strut tower supports I installed... Engine has little movment. BUT, I'm still not sold on my tranny mount. The 4t65 stock trans mount is only in with the bottom 2 of the 4 bolts. There simply isnt enough room between the trans and the bolt heads to fit the top two bolts in... Im looking at alternatives like, using different mount alltogther from the bottom 4 of the 6 holes that are on the case and fab a L shape bracket to mount to the subframe.... Still kind of undecided.... Jim
 

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jimraelee said:
I ended up cutting the stock dogbones in 1/2 and welding them to the radiator to strut tower supports I installed... Engine has little movment. BUT, I'm still not sold on my tranny mount. The 4t65 stock trans mount is only in with the bottom 2 of the 4 bolts. There simply isnt enough room between the trans and the bolt heads to fit the top two bolts in... Im looking at alternatives like, using different mount alltogther from the bottom 4 of the 6 holes that are on the case and fab a L shape bracket to mount to the subframe.... Still kind of undecided.... Jim
We are currently doing a 3.4l quad cam swap into a 98 convertable cavalier with an auto tranny and we ended up using some mounts from a dodge. They are really small and work great in tight spots. I'll get you the part number for them tomorrow and post it up, they are cheap too. :)

Here's a few pics of that swap...


We did have to make up a new rad support for it to allow the oil dip stick tube to clear.
 

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Holy C#$%, I think you have less space than I do in there with that DOHC engine, I was in the junk yard and saw one still in a Z34 lumina and it was crowded.... no way of putting that in a J or N body for me.... right now I worry about the day I need to change a water pump and out comes the engine... :(
 

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lol...there is not much room in there for it for sure. It's about the same size wize between the frame rails but front to back it is much thicker than the 3800. Everyone said it couldn't be done and that's the reason we did it, always up for a challange. Here is another pic of the rear corner of the rear head, as you can see it's quite tight.

 

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well when I put mine in I had to modify the throttle body of the L67 so that it would not hit the brake cylinder... and will have to get a LS1 TB to have my cruise control back installed.... Great work and Its funny how someone says "You cant do that," will make you want to do it even more...
 

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You had to modify the TB? Really I didn't have to modify mine at all, I have about an inch from the braket that holds the throtle cables to the brakes. I did have an issue with it though when the engine was "squatting" back before we fixed that porblem. The bracket came back and hit the brakes and bent it but I haven't had any of those issues since we fixed the "spuatting" problems.

Here's a pic of the bracket after the rad support broke, the engine is actually sitting about 1/2 an inch back from where it is now.




...and yeah when people say that it can't be done it makes you want to do it more :)
 
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