Adrian Pettitt Posted September 10, 2021 Report Share Posted September 10, 2021 Hi my TR6 is a U.K. car with an American low compression engine that is fitted with twin H6 SU carbs. www.classicfuelinjection.co.uk offer what looks to be a very nice EFI kit that uses the original SU carbs as the throttle bodies. Has anyone used one of their kits and could review it? The response to my initial enquiry to the company has been exceptionally detailed. I’m considering changing to EFI as part of further upgrades including upping CR and a better but not wild camshaft. Is there any truth that the pushrods are longer in the USA engine and need replacing if the head is skimmed to U.K. higher CR spec? Thanks Adi Quote Link to post Share on other sites
DRD Posted September 10, 2021 Report Share Posted September 10, 2021 Depending on how much you shave off then you may need UK spec, i.e. shorter pushrods. Quote Link to post Share on other sites
astontr6 Posted September 10, 2021 Report Share Posted September 10, 2021 8 hours ago, Adrian Pettitt said: Hi my TR6 is a U.K. car with an American low compression engine that is fitted with twin H6 SU carbs. www.classicfuelinjection.co.uk offer what looks to be a very nice EFI kit that uses the original SU carbs as the throttle bodies. Has anyone used one of their kits and could review it? The response to my initial enquiry to the company has been exceptionally detailed. I’m considering changing to EFI as part of further upgrades including upping CR and a better but not wild camshaft. Is there any truth that the pushrods are longer in the USA engine and need replacing if the head is skimmed to U.K. higher CR spec? Thanks Adi My BL USA tuning book says that the Stock compression of 8.5 to 1? with a 3.460" thick head. You have to remove 0.085" to give a compression of 10.25, it should measure 3.375" provided you have done the zero deck clearance. If you have not done the zero deck clearance the compression will be 10.0 to1. It also recommends the used of BL's S2 cam with this mod. which is basically the same as a Newman PH2 cam. Bruce. Quote Link to post Share on other sites
Adrian Pettitt Posted September 11, 2021 Author Report Share Posted September 11, 2021 9 hours ago, astontr6 said: My BL USA tuning book says that the Stock compression of 8.5 to 1? with a 3.460" thick head. You have to remove 0.085" to give a compression of 10.25, it should measure 3.375" provided you have done the zero deck clearance. If you have not done the zero deck clearance the compression will be 10.0 to1. It also recommends the used of BL's S2 cam with this mod. which is basically the same as a Newman PH2 cam. Bruce. Thank you Bruce, that’s brilliant info. Quote Link to post Share on other sites
Chris59 Posted September 11, 2021 Report Share Posted September 11, 2021 And, yes, you'll need shorter push rods Quote Link to post Share on other sites
mtrehy Posted September 11, 2021 Report Share Posted September 11, 2021 It's a year since I skimmed one but I'm pretty sure I took off more than that to get to 9.5. Personally I'd burette it and calculate what you need to take off rather than rely on any 2nd hand info. Change pushrods for UK ones, too cheap to not bother Quote Link to post Share on other sites
DRD Posted September 11, 2021 Report Share Posted September 11, 2021 20 hours ago, astontr6 said: My BL USA tuning book says that the Stock compression of 8.5 to 1? with a 3.460" thick head. You have to remove 0.085" to give a compression of 10.25, it should measure 3.375" provided you have done the zero deck clearance. If you have not done the zero deck clearance the compression will be 10.0 to1. It also recommends the used of BL's S2 cam with this mod. which is basically the same as a Newman PH2 cam. Bruce. It does depend on the year, the later CF US heads were a CR of 7.5 and the head was around 3.5in high compared with the UK head of 3.4in. Quote Link to post Share on other sites
Adrian Pettitt Posted September 12, 2021 Author Report Share Posted September 12, 2021 On 9/10/2021 at 10:48 PM, astontr6 said: My BL USA tuning book says that the Stock compression of 8.5 to 1? with a 3.460" thick head. You have to remove 0.085" to give a compression of 10.25, it should measure 3.375" provided you have done the zero deck clearance. If you have not done the zero deck clearance the compression will be 10.0 to1. It also recommends the used of BL's S2 cam with this mod. which is basically the same as a Newman PH2 cam. Bruce. Hi, have I got this right? my engine number is CF4895UE, Cylinder head casting number 312388, stamped number 218227 . Rough head measure 3.471” This is a US low compression carburettor engine with the later head that has the same port spacing as the U.K. heads from a P.I.? So Bruce all of your tuning book stats correlate with what I’ve got? Can you clarify the zero deck clearance for me please? Please see some photos for reference. thanks again Adrian Quote Link to post Share on other sites
Adrian Pettitt Posted September 12, 2021 Author Report Share Posted September 12, 2021 Quote Link to post Share on other sites
Adrian Pettitt Posted September 12, 2021 Author Report Share Posted September 12, 2021 Quote Link to post Share on other sites
Adrian Pettitt Posted September 12, 2021 Author Report Share Posted September 12, 2021 Quote Link to post Share on other sites
DRD Posted September 12, 2021 Report Share Posted September 12, 2021 Looks like it may have already been skimmed. This document from Chris Witor gives a good summary of head specs. head_applications_chart.pdf Quote Link to post Share on other sites
Adrian Pettitt Posted September 13, 2021 Author Report Share Posted September 13, 2021 10 hours ago, DRD said: Looks like it may have already been skimmed. This document from Chris Witor gives a good summary of head specs. head_applications_chart.pdf 151.78 kB · 4 downloads Hi, what makes you think that? Bruce’s dimensions suggest that it should be closer to 3.375” after skimming for a CR near 10/1. I can’t find any chart that combines both my casting number and head stamp? Thanks for any advice, clearly I don’t want to take it off if I don’t have to! Adrian Quote Link to post Share on other sites
Chris59 Posted September 13, 2021 Report Share Posted September 13, 2021 About the fuel injection equipment : I'm tempted by the use of this kind of system on my Range Rovers (classics !) V8 to run on ethanol fuel. Any feed back about this ? Quote Link to post Share on other sites
Adrian Pettitt Posted September 13, 2021 Author Report Share Posted September 13, 2021 1 minute ago, Chris59 said: About the fuel injection equipment : I'm tempted by the use of this kind of system on my Range Rovers (classics !) V8 to run on ethanol fuel. Any feed back about this ? I emailed the chap and got a very comprehensive reply. He’s actually quite close to me and I can go to his workshop and have a look at a conversion sometime. I’ll post again when I’ve had a look. I quite like the simplicity of the system being inserted between the manifold and carbs. I want to see what I can get on SUs with a higher compression ratio and decent cam first. Quote Link to post Share on other sites
astontr6 Posted September 13, 2021 Report Share Posted September 13, 2021 20 hours ago, Adrian Pettitt said: Using a Vernier as a depth gauge, you should be able to get a more precise measurement? As your head is stamped up 313288 which looks to come from a Saloon. I would speak to Chris Whitor directly as he is a guru on those engines as he used to race. He no doubt can give you the CR but I also note that your car has SU carbs which means to me that some form of tuning has already been done on your engine. Has the camshaft been changed? Bruce. Quote Link to post Share on other sites
DRD Posted September 13, 2021 Report Share Posted September 13, 2021 (edited) 2 hours ago, Adrian Pettitt said: Hi, what makes you think that? Bruce’s dimensions suggest that it should be closer to 3.375” after skimming for a CR near 10/1. I can’t find any chart that combines both my casting number and head stamp? Thanks for any advice, clearly I don’t want to take it off if I don’t have to! Adrian Yes its a bit odd as your casting number doesn't match the head number of 218227 - but I would tend to go on the head number rather than the casting as I guess they may have been used for different applications; your casting number is for a 2500 head. Edited September 13, 2021 by DRD Quote Link to post Share on other sites
Adrian Pettitt Posted September 13, 2021 Author Report Share Posted September 13, 2021 9 hours ago, astontr6 said: Using a Vernier as a depth gauge, you should be able to get a more precise measurement? As your head is stamped up 313288 which looks to come from a Saloon. I would speak to Chris Whitor directly as he is a guru on those engines as he used to race. He no doubt can give you the CR but I also note that your car has SU carbs which means to me that some form of tuning has already been done on your engine. Has the camshaft been changed? Bruce. That’s the problem Bruce I’ve no idea what’s been done. My measurements were with a vernier so are pretty good. I suspect you are correct that it’s from a 2500 saloon. Quote Link to post Share on other sites
mtrehy Posted September 13, 2021 Report Share Posted September 13, 2021 why are you worrying about it? have you had it apart - do you know it is standard bore, standard pistons, unmolested chambers etc? anything can happen to these cars over 50 years that's why the sensible thing to do is measure it all when you have the head off, calculate the required chamber volume for your chosen CR and skim it to that. Quote Link to post Share on other sites
Adrian Pettitt Posted September 14, 2021 Author Report Share Posted September 14, 2021 12 hours ago, mtrehy said: why are you worrying about it? have you had it apart - do you know it is standard bore, standard pistons, unmolested chambers etc? anything can happen to these cars over 50 years that's why the sensible thing to do is measure it all when you have the head off, calculate the required chamber volume for your chosen CR and skim it to that. Fair point! Worried? No! Simply trying to understand its origins from the build info prior to pulling it apart. Thanks Quote Link to post Share on other sites
astontr6 Posted September 15, 2021 Report Share Posted September 15, 2021 On 9/13/2021 at 8:34 PM, Adrian Pettitt said: That’s the problem Bruce I’ve no idea what’s been done. My measurements were with a vernier so are pretty good. I suspect you are correct that it’s from a 2500 saloon. It might be better if you give me a phone call on 01628-667259 to discuss further? Bruce. Quote Link to post Share on other sites
Adrian Pettitt Posted September 15, 2021 Author Report Share Posted September 15, 2021 10 hours ago, astontr6 said: It might be better if you give me a phone call on 01628-667259 to discuss further? Bruce. Thanks Bruce, I’ll give you a buzz. Cheers Adi Quote Link to post Share on other sites
astontr6 Posted September 16, 2021 Report Share Posted September 16, 2021 11 hours ago, Adrian Pettitt said: Thanks Bruce, I’ll give you a buzz. Cheers Adi If you tried last night we were out at our local group meeting but I am in today except when dog walking? Bruce. Quote Link to post Share on other sites
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