VX C20XE Red Top rebuild
Discussion
VX C20XE Red Top rebuild
Hi all,
I plan to rebuild one of my red tops. It has been stripped, as a college project, by my son so parts are all in a box with pistons and con rods mixed up. If I am lucky the con rod main bearing halves will be bolted back together but as for what cylinders they came from that is anyone's guess!
I want to build a fast road spec to go into a Caterham 7 I am restoring- ground up. I am only looking for in the order of 200 bhp at the flywheel. I would like throttle bodies in the equation.
Can anyone help with suggestions on who to buy parts from, what I should be considering for a good quality build and recommendations for engine management system that can be mapped if I choose to later. I am aware QED and SBD are good sources, just want to consider others if they are competitive in terms of products and their quality as well as after service and tech support.
Any advice on web sites to visit and documents to download also welcome!
thanks for reading.
Michael
Hi all,
I plan to rebuild one of my red tops. It has been stripped, as a college project, by my son so parts are all in a box with pistons and con rods mixed up. If I am lucky the con rod main bearing halves will be bolted back together but as for what cylinders they came from that is anyone's guess!
I want to build a fast road spec to go into a Caterham 7 I am restoring- ground up. I am only looking for in the order of 200 bhp at the flywheel. I would like throttle bodies in the equation.
Can anyone help with suggestions on who to buy parts from, what I should be considering for a good quality build and recommendations for engine management system that can be mapped if I choose to later. I am aware QED and SBD are good sources, just want to consider others if they are competitive in terms of products and their quality as well as after service and tech support.
Any advice on web sites to visit and documents to download also welcome!
thanks for reading.
Michael
After getting a machine shop to measure the parts in the hope they can be paired back together I would then go straight to SBD.
Their stuff just works and support is great. For that power I ran Kent cams DH1014 on both inlet and exhaust. This does require pocketing of the standard pistons or buying replacement pistons with deeper cutouts. With standard pistons I got 212 bhp and with higher compression ones from SBD I got 224. This was with no other engine modification other than ARP rod bolts and SBDs 208 throttle body kit.
The cams I suggest use the standard hydraulic lifters.
This setup was in a Westfield and the other item that made a huge difference was a Laminova oil water heat exchanger. With using the more normal thermostatically controlled air to oil cooler I had issues of over cooling the oil. With the Laminova I now have stable temps on road and track and rapid oil heating from cold.
Their stuff just works and support is great. For that power I ran Kent cams DH1014 on both inlet and exhaust. This does require pocketing of the standard pistons or buying replacement pistons with deeper cutouts. With standard pistons I got 212 bhp and with higher compression ones from SBD I got 224. This was with no other engine modification other than ARP rod bolts and SBDs 208 throttle body kit.
The cams I suggest use the standard hydraulic lifters.
This setup was in a Westfield and the other item that made a huge difference was a Laminova oil water heat exchanger. With using the more normal thermostatically controlled air to oil cooler I had issues of over cooling the oil. With the Laminova I now have stable temps on road and track and rapid oil heating from cold.
Edited by the_stoat on Friday 31st July 11:28
What he says really. The stoat knows his stuff. I'm not sure the DH1014 is still available, but Kent do an AST1612 which is a similar spec iirc and is what I've put in my C20XE, retaining the hydraulic lifters.
BHP are good for bits too, SM piston rings are good if you reuse the standard pistons and just want to replace the rings. DanST also do a bike ITB setup which comes with standalone management and would be a good bit cheaper than SBD. They'd be more than sufficient for 200bhp and there's very good support from them.
SBD are the boys though, if you want to take your build a stage further then look no further. I've had parts from QED also and they're very efficient but I don't think they build stuff anymore. If you follow SBD's social media, you'll see that they're continually developing the bits they use for the C20Xe in their race machines.
BHP are good for bits too, SM piston rings are good if you reuse the standard pistons and just want to replace the rings. DanST also do a bike ITB setup which comes with standalone management and would be a good bit cheaper than SBD. They'd be more than sufficient for 200bhp and there's very good support from them.
SBD are the boys though, if you want to take your build a stage further then look no further. I've had parts from QED also and they're very efficient but I don't think they build stuff anymore. If you follow SBD's social media, you'll see that they're continually developing the bits they use for the C20Xe in their race machines.
Wow,
two fantastic replies, thank you for providing such a wealth of information.
My idea with the build is to produce a very fast but reliable road car engine. I may take it to the occasional track day but these events will be in the minority. From the details you ave provided it seems this engine spec will match and marginally exceed Caterham's 410 spec, albeit there's is derived from Ford Duratec power.
May I ask, are SBD's throttle bodies good? (silly question maybe?). What I mean is do they equal Jenvey?
Thank you again for your help.
Regards
Michael
two fantastic replies, thank you for providing such a wealth of information.
My idea with the build is to produce a very fast but reliable road car engine. I may take it to the occasional track day but these events will be in the minority. From the details you ave provided it seems this engine spec will match and marginally exceed Caterham's 410 spec, albeit there's is derived from Ford Duratec power.
May I ask, are SBD's throttle bodies good? (silly question maybe?). What I mean is do they equal Jenvey?
Thank you again for your help.
Regards
Michael
SBD's throttle bodies are reported to be very good. I have no experience, but I've not heard anything bad about them. Info below;
https://www.sbdmotorsport.co.uk/index.php/products...
It looks like they're made by Jenvey.
Another option here;
https://danstengineering.co.uk/Bike-Throttle-Body-...
https://www.sbdmotorsport.co.uk/index.php/products...
It looks like they're made by Jenvey.
Another option here;
https://danstengineering.co.uk/Bike-Throttle-Body-...
SBDs throttle bodies seem to work really well on the 2 cars I have been involved with.
@cocknose thank you for the compliment, I touch wood, have managed to create a reliable engine that seems to not care about track day abuse.
To the OP if you are going to consider track days make sure you consider oil temperature and pressure management. Oil surge if you get a bit heavy on the brakes and high oil temps can kill them. More than happy to tell you what I have done to resolve issues.
@cocknose thank you for the compliment, I touch wood, have managed to create a reliable engine that seems to not care about track day abuse.
To the OP if you are going to consider track days make sure you consider oil temperature and pressure management. Oil surge if you get a bit heavy on the brakes and high oil temps can kill them. More than happy to tell you what I have done to resolve issues.
Thank you both for your replies. I suspect per your suggestion, SBD will have their throttle bodies made outside and likely by Jenvey. As was also mentioned earlier, SBD are really the GOTO for C20XE with an excellent reputation. My original post asked in general terms about mods and parts for my engine. I was/am aware of SBD's existence but have never bought anything for my engine and therefor never purchased from them. So I thank you both for all your input.
As stated, the engine is to go into my 7. I have made provision for an oil tank in front of the passenger footwell by removing the footwell extension that came into the engine bay, should I wish to dry sump it. I may well do that at a later date but for the moment happy to stick with the sump VX provided!
I should correct myself also, I believe I referred to Caterham's Duratec 410 spec when I should have stated 420 spec. Either way, it would bee good to be in this bhp area and with an engine with long legs.
I would love to hear more about your engine specs and welcome anything you wish to share. If you would prefer to email me please do so. I believe my mail address is accessible here? If not let me know and I will pass it on. Thank you both again.
Michael
As stated, the engine is to go into my 7. I have made provision for an oil tank in front of the passenger footwell by removing the footwell extension that came into the engine bay, should I wish to dry sump it. I may well do that at a later date but for the moment happy to stick with the sump VX provided!
I should correct myself also, I believe I referred to Caterham's Duratec 410 spec when I should have stated 420 spec. Either way, it would bee good to be in this bhp area and with an engine with long legs.
I would love to hear more about your engine specs and welcome anything you wish to share. If you would prefer to email me please do so. I believe my mail address is accessible here? If not let me know and I will pass it on. Thank you both again.
Michael
KAR120C said:
I may well do that at a later date but for the moment happy to stick with the sump VX provided!
This is the one thing i would not do, at the very least get a sump with baffles in it or you could be looking at very limited engine life. There is a reason a tight Scotsman spent a lot on dry sumping! 
For spec of mine i will drop you an email when time allows.
KAR120C said:
As stated, the engine is to go into my 7. I have made provision for an oil tank in front of the passenger footwell by removing the footwell extension that came into the engine bay, should I wish to dry sump it. I may well do that at a later date but for the moment happy to stick with the sump VX provided!
The original Vauxhall 20XE sump is far too deep for use in a Caterham, you'll be smashing it to bits within yards of driving. At a minimum you will need a shortened, baffled sump, ideally with "wings" to maintain the oil capacity. An Accusump may be a worthwhile investment if you can't stretch to a full dry sump system.the_stoat said:
This is the one thing i would not do, at the very least get a sump with baffles in it or you could be looking at very limited engine life. There is a reason a tight Scotsman spent a lot on dry sumping!
For spec of mine i will drop you an email when time allows.
Thank you stoat. Do you have my mail address?For spec of mine i will drop you an email when time allows.
So my spec:
Head:
QED 450v cams as these seem to give give a good torque spread
Standard valves, I should have gone wasted stem
Double valve springs, shims and lightweight cam followers from SBD
Bottom End:
High compression pistons from SBD, not the 'slippers' as I wanted to maximise longevity
Saenz rods, why seem to use the most expensive rod bolts known to man
Internal timing wheel removed from the crank
SBD external trigger wheel
Pace dry sump system - Really be careful with your sump as oil starvation is not useful
Induction:
SBD 208 kit, individual throttle bodies
Massive trumpets, sorry cannot remember the length. The long trumpets seem to help with torque, but do generate a silly amount of noise
Cooling:
Laminova oil to water heat exchanger - Best thing I ever did as heats the oil on the road and cools on track
Radtec Westfield radiator with ducting. Ignore what the internet says about air to oil coolers, if you bother to log some data you will see that even with a thermostat this engine installed in a kit car will not get oil temperature on the road. I wasted so much time and money trying to sort this out, Laminova installed and it works perfectly on road and track.
SBD exhaust manifold and silencer
This makes 225 BHP and the limiter is set to 8300, for reliability. Also power is starting to drop off so no point running higher. The mapper ran it up to 9000RPM to see where the power rolled over and it physically hurt to stand next to it given the noise!
I am aware many people claim far more peak bhp, I considered reliability and driveability. My setup is docile enough to potter round town and linear enough that it covers my lack of talent on track.
Hope this helps.
Head:
QED 450v cams as these seem to give give a good torque spread
Standard valves, I should have gone wasted stem
Double valve springs, shims and lightweight cam followers from SBD
Bottom End:
High compression pistons from SBD, not the 'slippers' as I wanted to maximise longevity
Saenz rods, why seem to use the most expensive rod bolts known to man
Internal timing wheel removed from the crank
SBD external trigger wheel
Pace dry sump system - Really be careful with your sump as oil starvation is not useful
Induction:
SBD 208 kit, individual throttle bodies
Massive trumpets, sorry cannot remember the length. The long trumpets seem to help with torque, but do generate a silly amount of noise
Cooling:
Laminova oil to water heat exchanger - Best thing I ever did as heats the oil on the road and cools on track
Radtec Westfield radiator with ducting. Ignore what the internet says about air to oil coolers, if you bother to log some data you will see that even with a thermostat this engine installed in a kit car will not get oil temperature on the road. I wasted so much time and money trying to sort this out, Laminova installed and it works perfectly on road and track.
SBD exhaust manifold and silencer
This makes 225 BHP and the limiter is set to 8300, for reliability. Also power is starting to drop off so no point running higher. The mapper ran it up to 9000RPM to see where the power rolled over and it physically hurt to stand next to it given the noise!
I am aware many people claim far more peak bhp, I considered reliability and driveability. My setup is docile enough to potter round town and linear enough that it covers my lack of talent on track.
Hope this helps.
Absolutely stoat. I appreciate your time and effort to provide the detail and advice. Thank you.
Future plans and a little history...
I plan to start on my 7 in about a year. At 64 that is really not my best life decision but there are reasons I shall not disclose here. Needless to say, I will be retired or retiring at that time and look forward to the project to fill a little of that retirement time. I am not in a massive hurry which may frustrate the hell out of some, you know, those that long for such a dream. But I have built and owned two 7's in the past so this is, to an extent, known territory. Although both my past 7's were 1700cc Super Sprint spec cars (using Ford 1600 711M blocks) from the late eighties. The first car incidentally cost me about £4000 to build, sourcing all running gear parts myself and building the engine myself. I sold it for £7,500 about 18 months after build! How thing have changed!! Reg for info was Q971 OBP. Would love to know where it is now. The second car went back to Caterham and I lost £125 on it plus all the time and effort to build. Sadly I didn't put many miles on that one as we went into recession and with a young family it was difficult to justify.
Future plans and a little history...
I plan to start on my 7 in about a year. At 64 that is really not my best life decision but there are reasons I shall not disclose here. Needless to say, I will be retired or retiring at that time and look forward to the project to fill a little of that retirement time. I am not in a massive hurry which may frustrate the hell out of some, you know, those that long for such a dream. But I have built and owned two 7's in the past so this is, to an extent, known territory. Although both my past 7's were 1700cc Super Sprint spec cars (using Ford 1600 711M blocks) from the late eighties. The first car incidentally cost me about £4000 to build, sourcing all running gear parts myself and building the engine myself. I sold it for £7,500 about 18 months after build! How thing have changed!! Reg for info was Q971 OBP. Would love to know where it is now. The second car went back to Caterham and I lost £125 on it plus all the time and effort to build. Sadly I didn't put many miles on that one as we went into recession and with a young family it was difficult to justify.
I view electricity as witchcraft, so would always go with a generic loom from the manufacturer of the kit. I do know people who gave made their own loom and it can be done with time and patience.
On the brakes front you usually split front to rear on a 7, as if you do diagonal splitting you will need to be spot on with your calculations, to size the caliper piston area for the correct balance. As you probably know the rears on a 7 do very little.
Good luck with the build and it is never too late. My 70 year old father has been seen driving mine on track.
On the brakes front you usually split front to rear on a 7, as if you do diagonal splitting you will need to be spot on with your calculations, to size the caliper piston area for the correct balance. As you probably know the rears on a 7 do very little.
Good luck with the build and it is never too late. My 70 year old father has been seen driving mine on track.
Blow a few cobwebs off and here we go...
So a Westy with a red top.., poor little thing is going to get a baptism of fire when it finally gets on track next year, so in order that it last a bit longer than 5 minutes can I request informed comments on the best sump to use. I know I need it baffled but where to source, real world experiences preferred, if I need to I can fab up but time is valuable for me. I may need a guard as well as it looks like kerbs may be scary close.
It is going to get a few nice bits but the budget does have a limit. Inlet will either be DanSt or SBD, currently on 45s although I may run a season on these if I can find someone in the SE who knows what they are doing and can RR set them, sorry to say a few of the RR operators near me are chips n decats which isn't what is needed. I am getting the Custom Cages 2025 FIA jobbie, responsible for my sons safety and he is a dad now so no compromise. Finally when I get TBs I am considering the Elite sequential, with perhaps Geartronics on paddles (will require throttle actuator). Yep budget blown.
in summary
Sump?
RR tuner for Webers in SE
Any experience on the Elite Seq' 5SE box
Thanks all
So a Westy with a red top.., poor little thing is going to get a baptism of fire when it finally gets on track next year, so in order that it last a bit longer than 5 minutes can I request informed comments on the best sump to use. I know I need it baffled but where to source, real world experiences preferred, if I need to I can fab up but time is valuable for me. I may need a guard as well as it looks like kerbs may be scary close.
It is going to get a few nice bits but the budget does have a limit. Inlet will either be DanSt or SBD, currently on 45s although I may run a season on these if I can find someone in the SE who knows what they are doing and can RR set them, sorry to say a few of the RR operators near me are chips n decats which isn't what is needed. I am getting the Custom Cages 2025 FIA jobbie, responsible for my sons safety and he is a dad now so no compromise. Finally when I get TBs I am considering the Elite sequential, with perhaps Geartronics on paddles (will require throttle actuator). Yep budget blown.
in summary
Sump?
RR tuner for Webers in SE
Any experience on the Elite Seq' 5SE box
Thanks all
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