Bolt-On vs Welding IFS

In general terms, can a bolt on subframe be as strong and reliable as a welded subframe? I really like the idea of being able to unbolt the whole front end to drop it out if need be. It seems to me like the Chevy truck clips post-60's were all bolted on I think?

 

They still recommend welding bolt in kits

 

what he said.

 

Unless, of course, you're installing an all-aluminum subframe, such as the post-2003 Crown Vic Police Interceptor front suspension...(26" left to right, bolts in with 4 blots and 2 trailing arms...72" front tread...Magic for the wider pickups...There's a thread...

 

I thought '60-87 Chevy trucks were all bolted in?

I know the aftermarket Porterbuilt dropmembers that the C10 guys love so much are also bolt in...

Just thinking.

 

There were a fair number of OEM's that used a bolted in X-member. Jag ,49-54 Chevy,53 -62 Vette. Just a matter of correct design to take a bolt in.

 

I just want to play the devil's advocate here and ask, " ever been on a bridge that was welded together? How about a pre composite airliner... I've installed both front ends, and have not got a complaint about either...I personally think the welded vs. bolted thing is not strength related, but that of cost and ease of assembly....

 

I've always used welded in crossmembers but I have a 40 Ford in the shop right now that the owner installed a Chassis Engineering Bolt in Mustang II kit. Got to admit, it looks preety good and I don't see any problem with it, stought enough I don't see it moving any. I think I'd rather see it then a weld on that was put in with substandard welding, something you see too often with "homebuilts".

 

I have seen the bolt in ones on some cars , but I really prefer to weld them in to get the most strength out of them , unless you just have them for show and no really heavy ground pounding from a high torque engine !
Just my 2 cents .

Retro Jim

 

Do you prefer mustard or ketchup on your hamburger? Same difference, if, as previously said, components are well designed.

Ray

 

I would think it depends on the rest of the frames strength. If it flexs a lot, weld it, if it is stiff and won't move much, bolt it in.

 

Most of the older Chevies had bolt in front suspensions and the chassis builders I talked to recommended bolt in conversions because the stock "top hat" frames are thin and were designed to flex. I bought a unit from Jim Meyer Racing and it is a thing of beauty. Handles good and very adjustable including ride height. And yes, it was about twice the price of the M2 setup from Fatman that I put under my '37 Terraplane.

 

In General terms - YES

 

Yes, How many vehicles where made between 1900 and the late 1950's (when industrial welding became cost effective) with frames that were just bolted and riveted together???

(All of them I think....)

If it is done correctly, bolted subframes can be just as strong or stronger then weld in units. Especially since alot of us do-it-yourselfers are not accomplished welders who do not know how to control things like porosity, penetration, and the heat affected zone.

 

I just installed a Chassis Engineering Mustang II on my 52 Chevy Car and everyone of my buddies that helped me and that have seen it say that it is the best they have ever seen. I'm not sure about the weld in but the CE front end was easy to install.

Sam

 

They bolt the new z06 subframes in, and thats got more power than my stock small block. I think they also bolted in the v8 front wheel drive cadillacs, and being front wheel drive that would put a lot of torque on the bolts. I am an Icar certified welder and have welded for years, but if I have to weld something at home that is important, I have my brother do it. He is a pipefitter and honestly the welder I have is not the best. You also have to worry about corrosion more with welds. Sorry for dragging on but I think that now if they bolt it on there is a reason, because they could laser weld it for cheaper. Suspension points flex and welds don't. Just my two cents.

 

Okay so what I'm hearing is that in the general scheme of things, bolt-ins are NOT inherently weaker than welding it in.

Good to know, I think I'm going to grab the wrenches instead of the welder.

 

correct ^

ive had both. they both are strong and work great.

 

With correct SAE strength bolts, bolts are stronger than weld. In most cases the welds will hold but the metal around it is far less strong.
My opinion.

 

A few years ago when RB's was still in the PNW and still in business I took a long look at their display chassis with the bolt on front crossmember at Puyallup Goodguys and was impressed with it.

I've suggested the bolt on units to a lot of guys who either don't weld or don't have access to a welder. The cost difference is quickly negated when you have to pay a welder to weld on your less expensive crossmember.

With the bolt on unit a couple of guys with a half inch drill and a hand full of wrenches and a tape measure can usually swap front ends in a day and have a roller at the end of the day. The skills required are being able to measure correctly and drill a hole in the right spot.

 

The bolt in kits are designed for ease of installation and for certain frame types. If you research the Chassis Engineering kits, you will see the riveted in stock cross member on early Chevy frames was by design. The top hat frame flexes a bit so they riveted the crossmember in to allow a small amount of movement with the frame. With a welded in member the flex movement is transfered to the frame area around the member and increases the chance of metal fatigue and tearing. That is where the bolt in kits help. Either way is just as safe and probably won't give you any trouble. On a side note with my own research, all the failure complaints I have found discussed on line are with weld in kits.

 

I'm bolting a Jag front end under mine. I'll take some pictures, just remind me.

 

Yeah I'm using the Jag front end too. But I want to do away with those rubber mounts and bolt it in solid. I like that it'll be rigid with the frame, but still removable by unbolting it. I guess I want my cake and eat it too.

 

took a little welding to get it to the bolt in point, but it's bolted in...

TECH.... or something like it. Jag suspension in a 57 Buick

what cake are you speaking of? Even with the rubber mounts it's a great handling suspension. Rides and handles great... I'm a big fan of doing them the way the factory did them. It's nice to be able to unbolt the whole thing.

Put almost 3000 miles on my Buick this weekend... it performed awesome.

 

"they" ??

Apples and oranges. Welded in correctly, no point in bolting. Bolted in correctly, there would be no reason to weld..........

 

I used to worry about the strength of the bolt in or the chance of it coming loose or something but my CE M2 works just fine, never another thought about it..I think both styles have there place in different chassis where called for.

Zman--Badass Buick!!

 

Yep.

its easy to do a swap for a later front end into your classic too... un-bolt from a donor truck in the junkyard, bolt it up to your classic (with an extra hole or two)... instant disc brake front end.

 

True talk, true talk.

 

Hey Matt, Did you get the answer you were looking for? having worked for a shop that sold and installed both, and have had most "street builders" happiest with the bolt on. just thought I would get yer mind workin'... Bowtie40

 

My Jag front end is bolted in as per original jag design.
It's in a '49 Lincoln.