My series II Mog plays host to a 125BHP Fat twin cam but the chassis is not up to it!! You can feel the floor move at speeds above 60 mph! I intend to fit a JLH chassis kit but will that do? Are there any more areas that need attention? I don’t really want to fit a cage (well, not yet). Is it worth seam welding the body? And I’m I right in thinking that that involves seam welding all panels which were originally spot welded?
I know I need a strong stiff chassis so that the suspension controls the handling, not the body twisting, but I’m not sure just how far to take it, it’s only 125 bhp after all.
What have other people done?
It’s a 4 dr saloon by the way.
Jim
chassis strengh
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
By using this site, you agree to our rules. Please see: Terms of Use
-
plastic_orange
- Minor Legend
- Posts: 1405
- Joined: Fri Sep 17, 2004 8:34 pm
- Location: Broughty Ferry
- MMOC Member: No
If car is in sound condition it should be ok. If not then pay attention to sill construction, A+ B posts, chassis legs and centre crossmember. Any of these areas suspect, then you can get movement - if all is well there, then further investigation is in order - is it something out of balance - prop shaft, centre bearing collapsed if using Fiat component, wheel balance, suspension loose?
I'm sure Jonathon can advise further.
Pete
I'm sure Jonathon can advise further.
Pete
[img]http://img.photobucket.com/albums/v436/sinky_aps/4e634210.jpg[/img] [img]http://img.photobucket.com/albums/v436/sinky_aps/MorrisRain4.jpg[/img]
Jim,
The chassis killer is torque and not out and out bhp. Your Fiat motor is relatively heavy and has loads of torque. You should seam weld all chassis joints from th engine bay upto the central x member. The wrakest point of the minor is the area around the steering rack and where it meets the floor pan. This area often splits, especially I,m afraid the Fiat TC motors.
Our chassis kit replicates the boxing panels of the steering rack area plus a full width inner floor panel which stiffens up the floor pan and bulkhead x member. The difference is amazing giving lighter more accurate steering. The kit must be welded in and necessitates the removal of engine and box. You may well benefit from our under engine x member which minimizes chassis twist. Please ask if you need more info.
The chassis killer is torque and not out and out bhp. Your Fiat motor is relatively heavy and has loads of torque. You should seam weld all chassis joints from th engine bay upto the central x member. The wrakest point of the minor is the area around the steering rack and where it meets the floor pan. This area often splits, especially I,m afraid the Fiat TC motors.
Our chassis kit replicates the boxing panels of the steering rack area plus a full width inner floor panel which stiffens up the floor pan and bulkhead x member. The difference is amazing giving lighter more accurate steering. The kit must be welded in and necessitates the removal of engine and box. You may well benefit from our under engine x member which minimizes chassis twist. Please ask if you need more info.
-
Alec
- Minor Legend
- Posts: 2148
- Joined: Thu Apr 15, 2004 7:29 am
- Location: Oswestry, Shropshire
- MMOC Member: No
Hello Jim,
do you have very stiff suspension?, which would then feed more load into the body.
If not, I would first closely look to the integrity of the shell, as I'm assuming that you can feel the seat move when you refer to the floor moving.
As I understand it, the seal welding process was to braze up all the spot welded seams and this did make for a much stiffer shell. It is, of course a major amount of work. The other weak area, I would guess is the front as the grille panel and wings are bolted not welded to the base structure. I would imagine if those were welded as one this would improve the front end torsional strength?
Alec
do you have very stiff suspension?, which would then feed more load into the body.
If not, I would first closely look to the integrity of the shell, as I'm assuming that you can feel the seat move when you refer to the floor moving.
As I understand it, the seal welding process was to braze up all the spot welded seams and this did make for a much stiffer shell. It is, of course a major amount of work. The other weak area, I would guess is the front as the grille panel and wings are bolted not welded to the base structure. I would imagine if those were welded as one this would improve the front end torsional strength?
Alec
Jim,
I've got a 4 door with the FIAT twin cam currently pushing out about 170 BHP with similar torque and although it is now having considerable welding work done (due to age mostly rather than fatigue) the chassis handled the power very well. You shouldn't feel the floor moving, I used to get a bit of scuttle shake at idle when the engine was 'throwing' but nothing really at speed. However I did brace the chassis with a strengthening bar from the crossmember to the rear spring hangers, some bracing underneath the front floor, additional strengthening on the sills and I sleeved the fixing bolts for the engine mounts that run through the chassis. On yes and my front crossmember is actually a piece of angle iron - heavy but everso effective for those little shunts when people park too close.
Given there is the extra power I feel there is little to be lost from some additional strengthening in the right areas.
Jonathan,
have you got any picys of the boxing panels and inner floor panel as installed, they'd be interesting to see?
Regards,
Wal
I've got a 4 door with the FIAT twin cam currently pushing out about 170 BHP with similar torque and although it is now having considerable welding work done (due to age mostly rather than fatigue) the chassis handled the power very well. You shouldn't feel the floor moving, I used to get a bit of scuttle shake at idle when the engine was 'throwing' but nothing really at speed. However I did brace the chassis with a strengthening bar from the crossmember to the rear spring hangers, some bracing underneath the front floor, additional strengthening on the sills and I sleeved the fixing bolts for the engine mounts that run through the chassis. On yes and my front crossmember is actually a piece of angle iron - heavy but everso effective for those little shunts when people park too close.
Given there is the extra power I feel there is little to be lost from some additional strengthening in the right areas.
Jonathan,
have you got any picys of the boxing panels and inner floor panel as installed, they'd be interesting to see?
Regards,
Wal
Cheers Chaps.
Alec - the suspension is far from stiff, consisting of non-adjustable bolt-on nasties!!
I'm really not very happy with the way the car has been put together so a full rebuild is certainly on the cards! I'll fit one of Jonathon's kits and work my way through, seam welding and bracing as required.
I like the idea of additional bracing bars under the floor Wal. How did you reinforce the sills? I've seen box section welded to the between the inner and out sill on a convertable but I'm not convinced.
I'd rather have a chassis that’s a bit over Engineered than under!
Oh dear.... that sounds like a lot of work.. better get a kettle in the garage!
Cheers,
Jim
Alec - the suspension is far from stiff, consisting of non-adjustable bolt-on nasties!!
I'm really not very happy with the way the car has been put together so a full rebuild is certainly on the cards! I'll fit one of Jonathon's kits and work my way through, seam welding and bracing as required.
I like the idea of additional bracing bars under the floor Wal. How did you reinforce the sills? I've seen box section welded to the between the inner and out sill on a convertable but I'm not convinced.
I'd rather have a chassis that’s a bit over Engineered than under!
Oh dear.... that sounds like a lot of work.. better get a kettle in the garage!
Cheers,
Jim
I've had about half of Jonathon's (JLH) chassis strengthening kit (the half that can be added without removing the engine and I've got no movement.
I'd be interested to know Wal, what you did to get the engine up to 170bhp and whether it's still usable as an everyday runaround? I've got a standardish T/C but some performance bits waiting to be added at some point in the future.
I'd be interested to know Wal, what you did to get the engine up to 170bhp and whether it's still usable as an everyday runaround? I've got a standardish T/C but some performance bits waiting to be added at some point in the future.
Jonathan,
have sent a PM with my email address - most grateful for picys.
Jim,
in order to strengthen the sills I cut out the bit with the round holes in and replaced it with a solid plate that was slightly thicker, making sure it was welded on to the front door post and the centre pillar. But you need to make sure the door openign is braced before you do this otherwise it shinks and the door won't closed properly. I did similar on the rear door sill as well. Its a bit crude but it did the job.
dp,
basically I spent a lot of money and a lot of time. The basic facts are:
Rebuilt and balanced bottom end with 1600cc raised dome pistons for higher compression.
I started with the big valve FIAT Arbath 130 head.
Head flowed and ported by Guy Croft - complete with triple valve springs, race cut valves and guides (for the best gain in power get this done)
Vernier pulleys.
GC3A cams (Guy Crofts).
Pair of 45 Weber DCOEs.
2.5" stainless steel tubular 4 into 2 exhaust with freeflow twin silencers.
Both the water and oil cooling have been improved but brakes are standard - no only kidding.
To be honest it is very driveable. I use it as my everyday car - though not for work as I don't drive to work. The worse thing is the steering is heavy (big fat tyres) and it does get a bit noisy on long trips. But it'll poodle along at 30mph in 5th gear and still pull away if required. It idles happily at about 800-900 revs but does get hot in traffic but doesn't boil. OH yes and it shreds diffs doing the quarter mile and don't mention the fuel bill.
Crikey I'm more passionate about my car than I thought - pills please nurse.
Regards,
Wal
have sent a PM with my email address - most grateful for picys.
Jim,
in order to strengthen the sills I cut out the bit with the round holes in and replaced it with a solid plate that was slightly thicker, making sure it was welded on to the front door post and the centre pillar. But you need to make sure the door openign is braced before you do this otherwise it shinks and the door won't closed properly. I did similar on the rear door sill as well. Its a bit crude but it did the job.
dp,
basically I spent a lot of money and a lot of time. The basic facts are:
Rebuilt and balanced bottom end with 1600cc raised dome pistons for higher compression.
I started with the big valve FIAT Arbath 130 head.
Head flowed and ported by Guy Croft - complete with triple valve springs, race cut valves and guides (for the best gain in power get this done)
Vernier pulleys.
GC3A cams (Guy Crofts).
Pair of 45 Weber DCOEs.
2.5" stainless steel tubular 4 into 2 exhaust with freeflow twin silencers.
Both the water and oil cooling have been improved but brakes are standard - no only kidding.
To be honest it is very driveable. I use it as my everyday car - though not for work as I don't drive to work. The worse thing is the steering is heavy (big fat tyres) and it does get a bit noisy on long trips. But it'll poodle along at 30mph in 5th gear and still pull away if required. It idles happily at about 800-900 revs but does get hot in traffic but doesn't boil. OH yes and it shreds diffs doing the quarter mile and don't mention the fuel bill.
Crikey I'm more passionate about my car than I thought - pills please nurse.
Regards,
Wal
Wal,
V. Interesting thanks for the detailed info. I've got the triple springs, race cut valves and guides but couldn't afford to go the GC3A and twin 45 route. How useful are the vernier pulleys - would you get them again for the money and are they GC ones? Also are both cams GC3A or just the inlet?
I got hold of an F.I. plenium/manifold from a HF turbo and am toying with megasquirting together with a GC3A inlet. Got to do a few more down-to-earth things first though.
V. Interesting thanks for the detailed info. I've got the triple springs, race cut valves and guides but couldn't afford to go the GC3A and twin 45 route. How useful are the vernier pulleys - would you get them again for the money and are they GC ones? Also are both cams GC3A or just the inlet?
I got hold of an F.I. plenium/manifold from a HF turbo and am toying with megasquirting together with a GC3A inlet. Got to do a few more down-to-earth things first though.
dp,
both the inlet and outlet cams are GC3A, although I know you can get good results running just the inlet with a high lift profile. GC recommended this and I tried it for a year or so, while I saved up, with a high lift Alquati cam on the inlet and a standard cam on the exhaust the results were good. Running the high lift on the exhaust does make a difference but you get the majority of the benefit (I'd guess at 70%) just from running the high lift inlet and at half the cost. The 45s were a bonus as I was running 40s and they were at their limit. The vernier pulleys are GC ones and yes they're good but to be honest probably better than I need. If the cam boxes and cams are dialled in and stamped then you can get the timing good enough with the standard cam wheels and the veniers are a bit of a bonus. It would probably be the last thing I'd invest the money on - get the cams or the carbs and sort the exhaust before getting the veniers and you'll probably find you don't really need them - look nice and professional though.
I've thought about injection but to be honest my car is pretty much as far as it will go in this spec and to go over 200hp will mean either a 16 valve head (which is reverse port) or supercharger which means a piston and valve change or a K Series. All of which are too much work and cost at the moment. Oh yes there's always nitrous - hmmmm not sure.
If you do put the injection in let me know how you get on.
Regards,
Wal
both the inlet and outlet cams are GC3A, although I know you can get good results running just the inlet with a high lift profile. GC recommended this and I tried it for a year or so, while I saved up, with a high lift Alquati cam on the inlet and a standard cam on the exhaust the results were good. Running the high lift on the exhaust does make a difference but you get the majority of the benefit (I'd guess at 70%) just from running the high lift inlet and at half the cost. The 45s were a bonus as I was running 40s and they were at their limit. The vernier pulleys are GC ones and yes they're good but to be honest probably better than I need. If the cam boxes and cams are dialled in and stamped then you can get the timing good enough with the standard cam wheels and the veniers are a bit of a bonus. It would probably be the last thing I'd invest the money on - get the cams or the carbs and sort the exhaust before getting the veniers and you'll probably find you don't really need them - look nice and professional though.
I've thought about injection but to be honest my car is pretty much as far as it will go in this spec and to go over 200hp will mean either a 16 valve head (which is reverse port) or supercharger which means a piston and valve change or a K Series. All of which are too much work and cost at the moment. Oh yes there's always nitrous - hmmmm not sure.
If you do put the injection in let me know how you get on.
Regards,
Wal
-
Peetee
- Minor Legend
- Posts: 3428
- Joined: Fri Nov 22, 2002 9:20 am
- Location: Southampton
- MMOC Member: No
PaulK and I were discussing chassis strength the other day and it occured to us that the kick plate which is only a cosmetic panel is a bit of a waste. Feasably this panel could be made structural and continue (with an appropriate fabrication) behind the rear quarter panel to meet the inner wheelarch/back seat. Not only would this add strength but it would also eliminate two areas where water can get to the sills.in order to strengthen the sills I cut out the bit with the round holes in and replaced it with a solid plate that was slightly thicker
Older and more confused than I could ever imagine possible.