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Post by tommydp on Oct 22, 2011 7:24:41 GMT
Hi all! As mentioned earlier I'm thinking of getting a new cylinder head, a 12 H 2709 as used on the mk 2. I came across this beauty on ebay. I'm awaiting reply on possibility of having it posted to Norway. If ok I think I'll bid, if bids don't get sky high. Now, the question is can I be absolutely sure it is fitted with the big inlet valves? It should be according to the number, but if it has been reconditioned, could it be it has been fitted with inserts and the smaller valves? I'm not into cylinder head rebuilds.-) I asked about the valves' diameter too. So we'll see if I receive a reply. What do you think? The alternative is getting one from Peter Burgess. In the end perhaps that won't become far more expensive. The Norwegian "kroners" are strong compared to GBPs these days, so I'm eager to get a head now as postage is a fortune too:-) Regards, Tommy:-) www.ebay.co.uk/itm/MGB-UNLEADED-CYLINDER-HEAD-/150677834931?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2315194cb3 |
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Post by dave1800 on Oct 22, 2011 7:44:05 GMT
Tommy
You're lucky with your currency, the £ has gone down from 70 Baht to 47 Baht here so everything is much more expensive now.
I have read that an unleaded MGB head was made for the US market with a number of additional mods, but wasn't aware of one available in the UK. I think I would try and validate the part number if you can (I see time is short) perhaps someone here has access to a parts list? Or you could try a MGB forum.
At the end of the day it may prove cheaper than one from Peter B but I assume has no guarantee?
How about just getting new valve guides fitted to your current head that you know works? That way you are not introducing further unknowns and would save you a lot of money.
Regards
David
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Post by kelsham on Oct 22, 2011 15:41:40 GMT
I agree with Dave, fit new guides to the head that you know matches the parts you have. Have you got the correct distributor fitted. There are several configurations. A different head might not match.
Regards Kels
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Post by tommydp on Oct 22, 2011 16:37:33 GMT
Thanks guys:-)
He wouldn't post to Norway, so guess I'll get one from P Burgess, or have new guides fitted. Car is running well, only some blue smoke after long deceleration downhill that irritates me. A shiny, restored car shouldn't smoke:-) It got better when I installed the umbrella valve seal on cylinder one inlet though. Suppose the other guides are worn too.
The whole engine is now to mk 2 spec, including carb/ needle and distributor and it pulls very well and does not pink at all. It's amazing how steep hills it can go up in fourth without struggling at all. You got to love this car, when it behaves..
I just watched a new video on youtube from University motors regarding carb piston drop test. Interesting in deed. I understand a 1 3/4 carb piston should fall in 5-7 seconds. I'll check the assembly in the car just for fun. All my carbs have been a mix and I've never checked this before. I'm sure I have 20 carbs in pieces, so perhaps no wonder I've had some fuel issues earlier when not checking this. Yes, Dave, I know you mentioned it earlier:-)
Well, I had a look at some assemblies I've used. Two dropped in less than 3 seconds, actually. I have one original carb which seems to never have been opened. It fell in 6 seconds, so there's obviously one matched piston and dashpot:-)
Interesting for anyone running SUs I suppose.
Regards, Tommy:-)
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Post by tommydp on Oct 28, 2011 18:32:25 GMT
I've now emailed Peter Burgess regarding getting a cylinder head from him. Looking forward to that. Although car is running well now, I'm sure those valves/ guides are worn because of the occasional puff of oil smoke after going downhill in gear for longer periods.
Also, another thing got me thinking. The mixture seems to be fine now, slight rise then fall when lifting the lifting pin at idle. However, if I remove the oil filler cap the engine will stall and stop when I lift the pin indicating a too weak mixture! Does this confirm the valves/ guides are so worn they are letting unmeterd air in. I mean, what else will cause this? I have the oil breather going to the carb now, rather than the diaphragm valve.
Interesting:-)
Regards, Tommy:-)
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Post by dave1800 on Oct 29, 2011 0:15:05 GMT
I think that by removing the oil filler cap you are creating less resistance for the air from the oil breather to enter the carb, hence weakening the mixture slightly. Now when you lift the pin it is weakened further, hence it stalls. I could be wrong with this explanation but it seems logical at least to me. Why are you going down the head replacement route instead of replacing the guides / valves? Regards David Also, another thing got me thinking. The mixture seems to be fine now, slight rise then fall when lifting the lifting pin at idle. However, if I remove the oil filler cap the engine will stall and stop when I lift the pin indicating a too weak mixture! Does this confirm the valves/ guides are so worn they are letting unmeterd air in. I mean, what else will cause this? I have the oil breather going to the carb now, rather than the diaphragm valve. Interesting:-) Regards, Tommy:-) |
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Post by tommydp on Oct 29, 2011 6:22:52 GMT
Hi Dave!
I agree that sounds logical. Perhaps I should keep the diaphragm valve for the ventilation, rather than using the carb vacuum. This is the only thing which is not to mk 2 spec now. Anyway, those valves and guides are well worn I suppose, I could clearly see a gap between valve and guide when rocking the valve sideways, as I put that extra oil seal on.
The reason for getting a cylinder head from Burgess is, first of all I know it will be OK and well reconditioned. Secondly it's down to money/ economics. To have a head overhauled here will actually not be much cheaper than getting one from him. Everything is expensive here, you would not believe it.. and our currency is strong compared to GBP these days.
Good to see you on here, Dave! I hope you are well and not too badly affected by the floods we're watching on the news.
Best regards, Tommy:-)
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Post by dave1800 on Oct 29, 2011 7:06:13 GMT
Thanks Tommy. It looks as though one of the Burgess heads is a new casting (non exchange basis) so may be a cheaper option for you given postal charges; I assume it comes with all the guides etc.
We were affected by the floods around a month ago now; not far from where I stay in N Thailand some people lost their cars and houses were flooded to around 4ft, not nice at all. I just had to use a pump to hold the water at bay so nothing more than a few inches in the garden. All this water has now reached Bangkok some 400 miles away and friends there have had to evacuate their homes and have no idea what damage will be done. It could be a month before it recedes, no-one really knows.
Now the supermarket shelves are emptying and thousands of factories are out of commission. I just hope the car doesn't need any spare parts as Honda and Toyota are shut down.
If you need a new hard disk for your computer, best get it now as there is likely to be a shortage world wide as somewhere between 25-40% of the production comes (or came) from Bangkok factories.
regards
David
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Post by kelsham on Oct 29, 2011 8:21:16 GMT
Tommy I tried fitting the diapraghm valve to my car with ex M.O.D. engine, fitted with high compresion pistons, new correct distributor.
New diapraghm and fitted to valve. I began to smoke from the exhaust badly. I did not use the correct early cam oil separator.
Went back to simpler arrangement and all was well.
Regards Kels.
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Post by dave1800 on Oct 30, 2011 7:49:53 GMT
There's a lot of confusion on the MGB websites about the types of crankcase ventilation. Clearly it is important not to mix the two ie if you use the PCV then the first type of oil separator is essential (make sure it's cleaned out). The second type uses the constant depression of the carb to create a small negative crankcase pressure. This type has a filter in the crankcase cover plate but I am not clear if there is a restrictor in the cover or not. Some posts say there is others not. From what I can ascertain it is important that the ventilation system only creates a low vacuum, through a low volume of air being sucked into the inlet manifold / carb as both systems affect the fuel mixture. If the engine is very worn then the PCV seems to cause more problems and higher oil consumption. Here is a good link to how the PCV works Confused? Me too! Regards David mgaguru.com/mgtech/engine/cv103.htm Tommy I tried fitting the diapraghm valve to my car with ex M.O.D. engine, fitted with high compresion pistons, new correct distributor. New diapraghm and fitted to valve. I began to smoke from the exhaust badly. I did not use the correct early cam oil separator. Went back to simpler arrangement and all was well. Regards Kels. |
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