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Date Name Message
25/12/2005 23:40:56   julian   According to "practical classics" the jury is out on the V4 engine / unleaded suitability. How can I tell if the engines in my 2 newly accquired 96s have been modified to run safely on unleaded? Please.  
26/12/2005 10:50:38   john wyatt   There is no way to tell without taking the heads off, assume they have not and use additive if it bothers you, unless they are very good engines and you do a lot of miles in your car do not worry about it too much, the effects of valve seat recession take a very long time to have any effect on your engine.  
26/12/2005 11:16:42   James Ayres   There have been many postings on unleaded on this site. I have tried to search for them to no avail! I wonder if Alec could include something in the technical section?  
26/12/2005 11:18:24   Senor Burt   The jury returned from their deliberations many years ago and returned a verdict of guilty on the charge of not being able to run on unleaded without valve recession on the V4 engine.
I don't know what 'a long time' is, but taking the heads off and redoing the valves is a messy and expensive business. Use additive. It won't harm the car if it has been converted and will save you a lot of money in the medium term if not.
Some claimed not to have had any problems running on unleaded, but I suspect they either hadn't put that many miles on the car or drove like my granny (deceased).  
26/12/2005 14:17:06   john wyatt   Dont think I agree with the one about saving a lot of money in the medium term, you have to consider the cost of buying additive against the possibility that you actually experience valve seat recession, no one I know of nor my mates in the trade have actually experienced a classic car with this phenomenon other than in performance engines, as I say if it bothers you use it, I use it in my rebuilt 1740 as it is a very good engine, chances are in a standard 96 with somewhere between 40-200000 miles on it you will experience other problems long before you need to redo the valves.  
03/01/2006 19:41:57   Julian   I really appreciate your help on this one lads. The engine has done 79,000 and is coming out anyway, so I may as well remove the valves, check them out, regrind the seats and fit new seals etc. As for the unleaded issue, I will use an additive just to be on the safe side. (julianuzzell@yahoo.com)  
03/01/2006 23:28:54   Senor Burt   If it hasn't been converted, get valve seats put in while the heads are off. It's not that expensive.  
04/01/2006 12:34:19   Richard   Get the heads done with the seats if you are going to do a fair amount of miles in it. They run pants on low octane unleaded, I have driven a few vega unleaded engine cars and they were pathetic.
If you want a more efficient engine, some porting on the exhaust port and a free flow exhaust may work. Dont alter the inlet port or valve size. The idea is to reduce the engines pumping effect. Then get the ignition and carb set up correctly. A higher compression ratio helps thermal efficiency, but if you are using low octane fuel this may not be a good idea.  
04/01/2006 12:34:20   Richard   Get the heads done with the seats if you are going to do a fair amount of miles in it. They run pants on low octane unleaded, I have driven a few vega unleaded engine cars and they were pathetic.
If you want a more efficient engine, some porting on the exhaust port and a free flow exhaust may work. Dont alter the inlet port or valve size. The idea is to reduce the engines pumping effect. Then get the ignition and carb set up correctly. A higher compression ratio helps thermal efficiency, but if you are using low octane fuel this may not be a good idea.  


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