conaero Posted May 13, 2011 Share Posted May 13, 2011 Hi there, I am an owner of a 1969 Opel GT, as I am sure you will know, pretty much the same as an A series Manta. Its been languishing in my garage for many years but now have resurected it and it passed its MOT yesterday and all I have to do is fit the Getrag 5 speed and I am set for Le Mans in a month. It was not till I drove it yesterday that I realised just how sluggish the car is. It has a very strong but standard engine and am looking to give it some oomph without changing the look. I have a high lift cam in it, dont want to fit turbo or EFI so it looks like I am looking at a big valve head. Can anyone shed any light on what I am looking for head wise, I hear there is a big valve 2l head that will fit, what cars would I find that on? Thanks in advance. Matt See Pic Quote Link to comment Share on other sites More sharing options...
spiney_norman Posted May 13, 2011 Share Posted May 13, 2011 There's an advert in the parts for sale section for a ported 2.2 head that I think would fit on an Opel GT block, I don't know for certain that it would fit but I'm sure someone on here will! Quote Link to comment Share on other sites More sharing options...
conaero Posted May 13, 2011 Author Share Posted May 13, 2011 (edited) I have just spoken to one of my Opel GT guys and he says that the inlet manifold on the 2.2 is too high and will cause the carb to hit the bonnet. What i need is the 2l head off a manta GTE. It has 2.0E stamped on it. I can also use the 2.0S head but the 2.0E has hardened valve seats so is the one to go for. If anyone can help me out I would appreciate it. Matt Edited May 13, 2011 by conaero Quote Link to comment Share on other sites More sharing options...
spiney_norman Posted May 13, 2011 Share Posted May 13, 2011 Not all the 2.0E heads have the hardened valve seats for unleaded, if you're going down that route you'd need one stamped with "P2E" on the side as well. Hope that helps! Quote Link to comment Share on other sites More sharing options...
conaero Posted May 13, 2011 Author Share Posted May 13, 2011 great, I appreciate that thanks. Quote Link to comment Share on other sites More sharing options...
opel2000 Posted May 13, 2011 Share Posted May 13, 2011 I have just spoken to one of my Opel GT guys and he says that the inlet manifold on the 2.2 is too high and will cause the carb to hit the bonnet. What i need is the 2l head off a manta GTE. It has 2.0E stamped on it. I can also use the 2.0S head but the 2.0E has hardened valve seats so is the one to go for. If anyone can help me out I would appreciate it. Matt Yep, your mate is correct, in fact the manifold would not even mount onto the 2.2 head..... Been there myself with one of my old 2.0S engines and 2.2 head. Surprised to hear you say it feels sluggish, I guess that depends on what you normally drive though, I've had 2.0S engines on a Weber carb and decent exhaust pushing 130 BHP (rolling road figures) I should pay a little attention to your fuelling and timing especially as you say you already have a high lift cam in it. Depending on budget I would get hold of any CIH engine head, and get it off to a company that can fit bigger valves, as far as I'm aware there never was a BVH as standard on Anything. But heads could be opened up to have bigger valves fitted. The engines can be tuned with head work and a decent carb and cam (or CarbS and cam) and would emphasise a decent free flowing exhaust, to help liberate any power gains. It would be nice to know just what Dizzy, Carb what CC engine etc you are running as previously said there are a lot of little gains to be had that really add up. Quote Link to comment Share on other sites More sharing options...
conaero Posted May 15, 2011 Author Share Posted May 15, 2011 (edited) I had the engine rebuilt about 10 years ago and the original head was cracked so they got a salvage one, which I think came from a Record. I had a look at the head markings yesterday and its says P2 on it. Now I was of the opinion that the P2E head from a 2L Manta GTE had the bigger valves and hardened valve seats to take unleaded. Can anyone shed any light on just what a P2 head that I am running is? Is it the bigger valve 2L head. The original 1.9s head I had is basically a 1.6 small valve head. So maybe I already have the bigger valved head and just did not realise. I am running a twin choke weber DGV if I had the larger head with more flow then surely I would need to rejet the carb, any ideas to what to in am running 140/55 135/50 jets. Air correction 165/160. It is going in for Sun/Krypon tune on Friday. I ran the car from the South coast up to Ace Cafe in London yesterday and apart for a lumpy stalling idle for about half an hour it ran fine and did feel that is was loosening up. My GT runs timing at TDC I did hear you need to retard it by 7 degrees if running unleaded, is this correct? Edited May 15, 2011 by conaero Quote Link to comment Share on other sites More sharing options...
opel2000 Posted May 15, 2011 Share Posted May 15, 2011 Heads..... I have no knowledge about the 1.9 or 1.6 as I've never had them... What I can say though is that of all the 2.0 heads they were all pretty much the same 2.0S 2.0E the only real difference would be the later 2.0E heads that were fitted with hardened valve seats. Unsure just what engine no. or what year the hardened valve seats came in at on the 2.0E but I've seen the damage first hand that the happens to the earlier valve seats due to unleaded and even with a so-called additive to the petrol. And yes timing should be retarded, I used a hill in Leicester that I used to drive up regularly and used to back off the dizzy until it wasn't pinking going up the hill, that way I knew I had optimal advance without pinking, figures are all well and good to set up to (i.e 7 deg retarded) but not always optimal in the real world. Weber DGV carb is a superb item, simple and very efficient, and yes mate you are correct in saying that "You may need re-jetting if increasing the flow". The way you describe your drive yesterday sounds like you may have a few ignition/timing/fuelling issues due to the "lumpy stalling idle" The Krypton tune will help sort out any issues you have here, but will unfortunately set up the ebgine for lean/emissions type running where it is possible to get engine running better (more power) and still be within the emissions range for car/engine/year by simply adjusting the mixture screw on carb slightly. Ideally a rolling road would sort out this but poss best left until a later date when any other mods to increase power have been completed. As for jet sizes, I've no idea what sizes you would require, the last time I had one of these on the rollers they had to drill the idle jets out (due to not having the next size up) due to a bad idle due to increased flow through the engine. Thinking of which, it could be your high lift cam causing lumpy idling, especially when cold. GT is a lovely car, nice lightweight body and should go reasonably well with the CIH set up well, especially with the long geared 5 speed box. Quote Link to comment Share on other sites More sharing options...
2908642343 Posted May 15, 2011 Share Posted May 15, 2011 Hi; The best person to discuss Opel GT's with is Gil Wesson in the USA. http://www.opelgtsource.com/ Gill has just finished building a replica Conrero. Have known Gil for many years. John Quote Link to comment Share on other sites More sharing options...
conaero Posted May 15, 2011 Author Share Posted May 15, 2011 (edited) Yes, I have known Gil for many years, ordered alot of parts from him. I have found out why I was down on power, the accelerator was not turning the carb to fully open, more like 70%, now she flies when you put your foot down. The power off the mark is still flat, but I will get the tuning guy to retard the ignition by 7 degrees then start from there. Can any of you tell me what heads you have? its stamped on the head to top right of spark plug no. 2. Still trying to track down what this P2 head is. Edited May 15, 2011 by conaero Quote Link to comment Share on other sites More sharing options...
2908642343 Posted May 15, 2011 Share Posted May 15, 2011 Send Gill a mail and he will tell you! Quote Link to comment Share on other sites More sharing options...
conaero Posted May 16, 2011 Author Share Posted May 16, 2011 It turns out it is a 2L unleaded head off a 1985/86 Rekord or Carlton. Either way its great news as I have my increased gas flow and the unleaded capabilities. Just need to get the timing changed from TDC to -7 BTDC Quote Link to comment Share on other sites More sharing options...
CalCol Posted May 18, 2011 Share Posted May 18, 2011 Just need to get the timing changed from TDC to -7 BTDC Is this a GT first sold in Europe or in the US? You can tell easily - if it has sidemarker lamps at the rear it's most probably a US market car, no sidemarkers mean probably a European car. Anyway, if it's from the US market you can probably run on unleaded at TDC - no need to retard the ignition - or at the most only a couple of degrees retarded. The best fuel generally available in the US when the GT was sold was 92 octane, which is equivalent to around 96 UK octane. The early US cars needed 92, the later cars (1971 and on) needed only 88. Since standard unleaded is 95 you're not that far away already. Cheers, NIck Quote Link to comment Share on other sites More sharing options...
conaero Posted May 22, 2011 Author Share Posted May 22, 2011 It's a 69 us model. I have got it running about 5btdc and it seems happy there. Quote Link to comment Share on other sites More sharing options...
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