iani Posted October 23, 2021 Report Share Posted October 23, 2021 I am building a 2.5l motor for my GT6, I have the old head that came off my TR6, it has a 313247 part number. I have found an old post on here that suggests this is a late TR6 PI head, however, when I look on Chris Witor's site it shows this as a low compression carb'd African market head? Can anyone confirm this is indeed a PI head? I don't want to spend money on it if it won't be good at the end. Ian Quote Link to post Share on other sites
Tim D. Posted October 23, 2021 Report Share Posted October 23, 2021 Worth measuring the thickness. That should tell you if it is you compression Quote Link to post Share on other sites
iani Posted October 23, 2021 Author Report Share Posted October 23, 2021 2 hours ago, Tim D. said: Worth measuring the thickness. That should tell you if it is you compression 3.353" Tim, that doesn't seem to match up with any heads either. Quote Link to post Share on other sites
JochemsTR Posted October 24, 2021 Report Share Posted October 24, 2021 The 313247 ist the casting number (raised). Check the head assy number such as 218227. This number should be stamped. The original head is 3.535". In this case your head has been skimmed. If the center Inlet ports match the spacing you require and the valve ports have a nice smooth transition (which indicates a good quality casting) then you should consider it. Also depending ofcourse which CR you want to achieve. Jochem Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 24, 2021 Report Share Posted October 24, 2021 (edited) Take a look at this Acknowledgements to Chris Witor for providing this research https://www.chriswitor.com/datasheets/head_applications_chart.pdf Edited October 24, 2021 by BlueTR3A-5EKT Quote Link to post Share on other sites
iani Posted October 24, 2021 Author Report Share Posted October 24, 2021 8 hours ago, JochemsTR said: The 313247 ist the casting number (raised). Check the head assy number such as 218227. This number should be stamped. The original head is 3.535". In this case your head has been skimmed. If the center Inlet ports match the spacing you require and the valve ports have a nice smooth transition (which indicates a good quality casting) then you should consider it. Also depending ofcourse which CR you want to achieve. Jochem Thanks Jochem, this head came from an engine that I bought that was pulled from a fire damaged car. I had naively fitted the engine without adequate checks and it never ran properly, on investigation, one of the valves in this head was bent and the valve guide sheared off at the head face. The engine had supposedly been recently rebuilt before the fire, the state of the valve stems would seem to indicated this might well be true. I need a head to fit to an MM block that I have obtained, the block currently has standard bores, will need a rebore as the pistons were corroded in, not badly but a hone won't do here!. The crank was still on original grind so that should be sorted easily enough. I have a set of Maxpeeding rods, bought on offer as too cheap to not try them out, a hybrid Newman 280/300 cam, springs & followers, will have GT6 flywheel lightened, trigger wheel, thinking of fitting Nodiz ignition or stick with 123. Triple webers & inlet manifolds arriving next week. I'm hoping to have a GT6 that's fast in a straight line, I need to think about braking upgrades to prepare for the twisty bits! Quote Link to post Share on other sites
iani Posted October 24, 2021 Author Report Share Posted October 24, 2021 3 minutes ago, BlueTR3A-5EKT said: Take a look at this Acknowledgements to Chris Witor for providing this research https://www.chriswitor.com/datasheets/head_applications_chart.pdf That's why I referred to Chris' site in my first post Peter, I'm well aware of this, however, it refers to an EGR valve being on this head, I don't see where that would fit on mine. The head supports PI manifolds, I ran my PI kit on there fine, the dowels for the TB's are present. Finally, the head depth is lower, obviously it might well have been shaved Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 24, 2021 Report Share Posted October 24, 2021 2 minutes ago, iani said: That's why I referred to Chris' site in my first post Peter, I'm well aware of this, however, it refers to an EGR valve being on this head, I don't see where that would fit on mine. The head supports PI manifolds, I ran my PI kit on there fine, the dowels for the TB's are present. Finally, the head depth is lower, obviously it might well have been shaved Sorry I had misread your original post. Peter W Quote Link to post Share on other sites
astontr6 Posted October 25, 2021 Report Share Posted October 25, 2021 19 hours ago, iani said: Thanks Jochem, this head came from an engine that I bought that was pulled from a fire damaged car. I had naively fitted the engine without adequate checks and it never ran properly, on investigation, one of the valves in this head was bent and the valve guide sheared off at the head face. The engine had supposedly been recently rebuilt before the fire, the state of the valve stems would seem to indicated this might well be true. I need a head to fit to an MM block that I have obtained, the block currently has standard bores, will need a rebore as the pistons were corroded in, not badly but a hone won't do here!. The crank was still on original grind so that should be sorted easily enough. I have a set of Maxpeeding rods, bought on offer as too cheap to not try them out, a hybrid Newman 280/300 cam, springs & followers, will have GT6 flywheel lightened, trigger wheel, thinking of fitting Nodiz ignition or stick with 123. Triple webers & inlet manifolds arriving next week. I'm hoping to have a GT6 that's fast in a straight line, I need to think about braking upgrades to prepare for the twisty bits! After looking at my US BL tuning book, it looks to me that you have a low compression head? They quote a dim of 3.460" thick for 8.5 ? I would speak to Chris Whitor direct he will sort you out! Bruce. Quote Link to post Share on other sites
astontr6 Posted October 25, 2021 Report Share Posted October 25, 2021 On 10/23/2021 at 8:25 PM, iani said: 3.353" Tim, that doesn't seem to match up with any heads either. Is the actual thickness of your head 3.353" now??? as this would give a compression of over 10 to 1?? It is not very clear in the wording. Bruce Quote Link to post Share on other sites
iani Posted October 25, 2021 Author Report Share Posted October 25, 2021 5 hours ago, astontr6 said: Is the actual thickness of your head 3.353" now??? as this would give a compression of over 10 to 1?? It is not very clear in the wording. Bruce That's what I've measured it as Bruce. Quote Link to post Share on other sites
iani Posted October 25, 2021 Author Report Share Posted October 25, 2021 8 hours ago, astontr6 said: Is the actual thickness of your head 3.353" now??? as this would give a compression of over 10 to 1?? It is not very clear in the wording. Bruce Just checked again and this is correct Quote Link to post Share on other sites
JohnC Posted October 26, 2021 Report Share Posted October 26, 2021 That calc of over 10:1 assumes the chambers haven't been worked on. Just a thought. Quote Link to post Share on other sites
iani Posted October 26, 2021 Author Report Share Posted October 26, 2021 I've obtained a 219016 2500S head, I will have that one rebuilt for this engine. Quote Link to post Share on other sites
astontr6 Posted October 26, 2021 Report Share Posted October 26, 2021 4 hours ago, JohnC said: That calc of over 10:1 assumes the chambers haven't been worked on. Just a thought. The volume of the chambers s/b 41.6cc with the valves seated with zero deck clearance. Bruce Quote Link to post Share on other sites
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