Is My Chassis Strong Enough?
Discussion
With my beloved now away for her long awaited body-off re-spray, the thought strikes me that, on the basis that I dont want to be taking the body off again for at least another 10 years, is there any work that I ought to have done with the chassis naked that could save money and effort at a later date??
I'm having all the obvious stuff done - shotblasting etc but one thing that springs to mind is chassis strength. The wedge chassis seems pretty robust but you do hear of cracking occasionally so, does anyone (Steve??) know of any strengthening mods or additional bracing that might be worthwhile at this stage, especially as I do hope to be fitting one of those tasty 5.2l engines at some point.
I need to decide fairly quickly so any advice in the next couple of weeks would be much appreciated.
I'm having all the obvious stuff done - shotblasting etc but one thing that springs to mind is chassis strength. The wedge chassis seems pretty robust but you do hear of cracking occasionally so, does anyone (Steve??) know of any strengthening mods or additional bracing that might be worthwhile at this stage, especially as I do hope to be fitting one of those tasty 5.2l engines at some point.
I need to decide fairly quickly so any advice in the next couple of weeks would be much appreciated.
The SEAC chassis is pretty strong as is. Fitting a roll bar is probably all you need to cope with 350 bhp. I won't know until this year if it will copy with 420+ though. I am extending the roll bar to a full roll cage anyway and that will help considerably.
The main weakness is the front down tubes as they can crack. Might be worth strengthening but you need to be very carful as access is tight when you refit steering racks etc etc.
What you will need to worry about is the suspension. This will need to be significantly uprated to prvent excessive movement and thus help keep the drivetrain in shape. Don't expect that you will have a noce docile road car at the end. You end up with a competition car that happens to be road legal!
Steve
www.tvrbooks.co.uk
The main weakness is the front down tubes as they can crack. Might be worth strengthening but you need to be very carful as access is tight when you refit steering racks etc etc.
What you will need to worry about is the suspension. This will need to be significantly uprated to prvent excessive movement and thus help keep the drivetrain in shape. Don't expect that you will have a noce docile road car at the end. You end up with a competition car that happens to be road legal!
Steve
www.tvrbooks.co.uk
Thanks Steve
I will probably be happy with 350 Hp (plus plenty of torque) but I bet you said that once! I'm having new front springs (tricky job)and uprated bushes all round on the rebuild. DG also have a remit to replace any ball-joints U/Js etc that are worn. Other than that I haven't considered "suspension upgrades" other than adjustable shocks that I can do myself. Any suggestions??
The lower suspension/chassis joints at the front are already Rose Joints and I suspect this is the reason why it already tramlines more than a 2.8 Ford Capri - (worth a drive if only to find out what tramlining is all about!) - docile it is not!
I will probably be happy with 350 Hp (plus plenty of torque) but I bet you said that once! I'm having new front springs (tricky job)and uprated bushes all round on the rebuild. DG also have a remit to replace any ball-joints U/Js etc that are worn. Other than that I haven't considered "suspension upgrades" other than adjustable shocks that I can do myself. Any suggestions??
The lower suspension/chassis joints at the front are already Rose Joints and I suspect this is the reason why it already tramlines more than a 2.8 Ford Capri - (worth a drive if only to find out what tramlining is all about!) - docile it is not!
To be blunt... if you are planning to go big engine then you need to start thinking about throwing away your current suspension and brakes, cooling system and many other things NOW if you want a car that will handle that sort of power reliably.
The SEAC suspension is a good starting point but you should go coilover on the front - the cortina spring has a habit of bending in my car rather than compressing. Which means the car's handling can be very interesting with inadvertant Scandinavian flicks quite common! Would not wish that on anyone!
You need to seriously uprate both front and rear springs otherwise the car balance will be awful. 40-50% is a good starting point for the front. +15-20% at the back. I would also consider getting some 16 inch 9J wheels so that you can control the tyre flexing better. I would consider getting a Tower View gearbox cradle mod becuase clutches will be a consumable and dropping the gearbox will become a way of life and is easier than removing the engine. Yes you can get a multiplate clutch that will last longer but they snatch badly and are likely to wreck the drive train as a result. The drivetrain and gearbox is marginal at this power. Hence I had the gearbox rebuild and strengthened.
You will also need to consider new fuel pumps and filters, etc etc etc. This is not a simple drop a bigger engine in project so beware. If you don't want to go that route then I would definitely uprate the suspension and brakes to the 350 bhp standard now. This means a bit of a rethink. To what you are currently doing.
The front spring/shock is a major problem and the only way I got round it was to persaude Dave at Tower View to make up some special shocks and springs that are a complete coil over which means they should act together in unison rather than they do at the moment. Fortunately he was thinking along the same lines so it wasn't a problem. These are basically the units that Tower View sell for Wedges but I have specified the spring characteristics for my car. I am also strengthening the mounts on the wishbone as a precaution. Poly bushes are good but they will make the ride incredibly harsh. This is not a car for creature comforts.
If the suspension is not upto it, then the car balance will be all over the place and it will be very hard to drive on the limit especially when breaking when weight transfer is a major issue. I also have a rear anti-roll bar which is a another big improvement and helps stop understeer.
As for U.Js and ball joints. Replace them anyway. They are not expensive and it is easier to do with everything in bits. For UJs use the Hardy Spicer units with grease nipples. Anything else lasts about 2 minutes!
Brakes will need a big upgrade as well. Even the SEAC ones which are not bad are not upto the job either.
So... if you are serious about a big engine then start planning now. Nearly all the goodies on the 520 ended up being custom made or developed for the car by Tower View. The good thing for you is I paid the development costs!
The 520 build story will be in next month's Sprint for all you Wedge fans.
Steve
www.tvrbooks.co.uk
The SEAC suspension is a good starting point but you should go coilover on the front - the cortina spring has a habit of bending in my car rather than compressing. Which means the car's handling can be very interesting with inadvertant Scandinavian flicks quite common! Would not wish that on anyone!
You need to seriously uprate both front and rear springs otherwise the car balance will be awful. 40-50% is a good starting point for the front. +15-20% at the back. I would also consider getting some 16 inch 9J wheels so that you can control the tyre flexing better. I would consider getting a Tower View gearbox cradle mod becuase clutches will be a consumable and dropping the gearbox will become a way of life and is easier than removing the engine. Yes you can get a multiplate clutch that will last longer but they snatch badly and are likely to wreck the drive train as a result. The drivetrain and gearbox is marginal at this power. Hence I had the gearbox rebuild and strengthened.
You will also need to consider new fuel pumps and filters, etc etc etc. This is not a simple drop a bigger engine in project so beware. If you don't want to go that route then I would definitely uprate the suspension and brakes to the 350 bhp standard now. This means a bit of a rethink. To what you are currently doing.
The front spring/shock is a major problem and the only way I got round it was to persaude Dave at Tower View to make up some special shocks and springs that are a complete coil over which means they should act together in unison rather than they do at the moment. Fortunately he was thinking along the same lines so it wasn't a problem. These are basically the units that Tower View sell for Wedges but I have specified the spring characteristics for my car. I am also strengthening the mounts on the wishbone as a precaution. Poly bushes are good but they will make the ride incredibly harsh. This is not a car for creature comforts.
If the suspension is not upto it, then the car balance will be all over the place and it will be very hard to drive on the limit especially when breaking when weight transfer is a major issue. I also have a rear anti-roll bar which is a another big improvement and helps stop understeer.
As for U.Js and ball joints. Replace them anyway. They are not expensive and it is easier to do with everything in bits. For UJs use the Hardy Spicer units with grease nipples. Anything else lasts about 2 minutes!
Brakes will need a big upgrade as well. Even the SEAC ones which are not bad are not upto the job either.
So... if you are serious about a big engine then start planning now. Nearly all the goodies on the 520 ended up being custom made or developed for the car by Tower View. The good thing for you is I paid the development costs!
The 520 build story will be in next month's Sprint for all you Wedge fans.
Steve
www.tvrbooks.co.uk
Thanks again Steve - sadly I cant afford all the goodies at the moment so I will have to be selective; however, your advice will not be wasted! I will be keeping the car for the foreseeable future so if I cant do everything now there will be other opportunities later! I think a trip down to Tower View will be in order in the not too distant future and I am looking forward to the Sprint article.
Shayes - on the basis that you must have somewhere close to 350hp??, have you modified the suspension at all and how does your beastie handle??.
Russ
PS. Shayes - do you think Tim L will forgive me when he finds out F171DGK is no longer Red!!
Shayes - on the basis that you must have somewhere close to 350hp??, have you modified the suspension at all and how does your beastie handle??.
Russ
PS. Shayes - do you think Tim L will forgive me when he finds out F171DGK is no longer Red!!
No probs. I may seem to be a little forthright about upgrades but I belive that if start adding the sort of poer and performance that I have to have to start thinking about the car as a whole otherwise it can rapidly become a death machine. Too many TVR owners seem to think that adding a big engine is all there is to it. I have also had a lot of conversations with my insurers moddified vehicle dept. They basically said... modified engine without equally modified brakes, suspension and anything else and no insurance. The 520 is on a standard 390SE premium which seems to say the approach I have adopted is the right one or something.
The 520 will be at Tower View for the next few weeks or at least until the end of Jan having its rebuild to the 2002 spec. I'm actually doing the suspension down there tomorrow morning. Feel free to go down and have a snoop round. It ain't exactly pretty at the moment but it wasn't designed to win a concours.
As for Mr Hayes... unless he has done some more work apart form a chassis rebuild, his 500 engine was rated at 300 bhp. That in a SEAC is comfortable providing you have bigger brakes and a suspension in first rate condition.
The problem is that beyond that is getting into breakage land. I have had some pretty strange looks already when I mention that I plan over 400+ bhp through an LT77 gearbox that is supposed to start breaking at around 300 ish but all you can do is do as much as possible to get the odds in your favour. The 520 did some 31 sprints/hillclimbs this year and I had to withdraw from 5. It has done some 8000 miles in total this year and to be honest has not been too bad in terms of reliability. The biggest mistake I made was not further upgrading the suspension and brakes. But time and money was a real issue as the engine work went 100% over budget. It cost me about twice what I reckoned. The existing spec coped but it started breaking and wearing very very quickly and that was a big surprise.
Steve
www.tvrbooks.co.uk
The 520 will be at Tower View for the next few weeks or at least until the end of Jan having its rebuild to the 2002 spec. I'm actually doing the suspension down there tomorrow morning. Feel free to go down and have a snoop round. It ain't exactly pretty at the moment but it wasn't designed to win a concours.
As for Mr Hayes... unless he has done some more work apart form a chassis rebuild, his 500 engine was rated at 300 bhp. That in a SEAC is comfortable providing you have bigger brakes and a suspension in first rate condition.
The problem is that beyond that is getting into breakage land. I have had some pretty strange looks already when I mention that I plan over 400+ bhp through an LT77 gearbox that is supposed to start breaking at around 300 ish but all you can do is do as much as possible to get the odds in your favour. The 520 did some 31 sprints/hillclimbs this year and I had to withdraw from 5. It has done some 8000 miles in total this year and to be honest has not been too bad in terms of reliability. The biggest mistake I made was not further upgrading the suspension and brakes. But time and money was a real issue as the engine work went 100% over budget. It cost me about twice what I reckoned. The existing spec coped but it started breaking and wearing very very quickly and that was a big surprise.
Steve
www.tvrbooks.co.uk
Not red??? What colour will it be?
I find my car handles as well as I expect it - 2001 had me mainly in my race car - so I can just recall that my SEAC is incredibly planted in corners. I mean that it always feels that there are four wheels (16x9 OZ) with all tread fully connected to the ground.
Of course, when provoked into a 2nd gear corner and full throttle it comes round and round and round.
I've always had predictable understeer and stupendous grip from the rear (bar the above 2nd gear circumstance).
Yup 300bhp using the original gearbox and SEAC suspension, revised braking system and big rotors and callipers (bigger and more efficient the better) from Raven and ACT induction stuff. The latest mod is gearbox and engine mounts that hold the gearbox and engine. Quick story follows:
Last year a pinking noise started happening after many months of inconsistent use I discovered that the engine mount had broken (over a year ago now) and that had subsequently twisted the gearbox mounting(s) such that the whole engine/box was rocking fore and aft under acceleration making the pinking sound that I couldn't fix for months with super unleaded and retarted ignition...
Steve - I'm curious as to how different the 390 chassis is to the SEAC chassis in relation to the suspension modifications you're suggesting and all the other mods you've done to your car.
to be continued...
I find my car handles as well as I expect it - 2001 had me mainly in my race car - so I can just recall that my SEAC is incredibly planted in corners. I mean that it always feels that there are four wheels (16x9 OZ) with all tread fully connected to the ground.
Of course, when provoked into a 2nd gear corner and full throttle it comes round and round and round.
I've always had predictable understeer and stupendous grip from the rear (bar the above 2nd gear circumstance).
Yup 300bhp using the original gearbox and SEAC suspension, revised braking system and big rotors and callipers (bigger and more efficient the better) from Raven and ACT induction stuff. The latest mod is gearbox and engine mounts that hold the gearbox and engine
. Quick story follows: Last year a pinking noise started happening after many months of inconsistent use I discovered that the engine mount had broken (over a year ago now) and that had subsequently twisted the gearbox mounting(s) such that the whole engine/box was rocking fore and aft under acceleration making the pinking sound that I couldn't fix for months with super unleaded and retarted ignition...
Steve - I'm curious as to how different the 390 chassis is to the SEAC chassis in relation to the suspension modifications you're suggesting and all the other mods you've done to your car.
to be continued...
...
Although I do concur about a half or full roll cage to provide an incredible amount of stiffness. It's still on my shopping list and I know CIRKS found a big difference in his 450SE after the half cage installation.
Hopefully my SEAC will be around for a sprint and track day or two this year.
Cheers
Sean
Although I do concur about a half or full roll cage to provide an incredible amount of stiffness. It's still on my shopping list and I know CIRKS found a big difference in his 450SE after the half cage installation.
Hopefully my SEAC will be around for a sprint and track day or two this year.
Cheers
Sean
quote:
Steve - I'm curious as to how different the 390 chassis is to the SEAC chassis in relation to the suspension modifications you're suggesting and all the other mods you've done to your car.
They are essentially the same chassis as my 390 was one of the last made before the 420SEAC appeared. The main difference is the rosejointing on the suspension. This was done to mine about 4 years ago and was a tremendous improvement. Anyway just come back from Tower View and it is no wonder I thought I had a knackered suspension: the front two springs had compressed by a couple of inches and they differed in height by about 1 inch. The shocks had about 1-2 inch movement before anything happened and a couple of bushes on the rear suspension had seized. It's rebuild and strengthen time. Also interesting that I beat all my previous PBs this year with the car in this state!
Steve
www.tvrbook.co.uk
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