1967 912 not running smoothly

For you flat four Porsche 912 fanatics

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512modulo
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1967 912 not running smoothly

Post by 512modulo »

ive resisted posting on this untill now as i was hoping to i could fix the problem since i cant i figure who best is it to ask

my car had a very recnt full service in essex but for a while now it has not been idling smoothly, and there seems to be a lot of popping from the exhaust, once the car is going it pulls well and is fine but when its hot it seems to be a bit of an effort to get it to go through the low revs. the full service i had said that everything was ok apart from the carbs being slightly tired.

im really bemused and am hoping that its nothing serious so soon after the service

any help would be appreciated before i have to take it back there the engine by the way is a 1720cc running webbers

thanks again
912uk
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Post by 912uk »

Well here goes same old story again..

sorry I know new people have to start some where.

Popping and banging. Well to a certain degree you get the odd bit, even an AJP engine has the odd bit ( Daves Car ) ... BUT I bet yours does it quite alot and can be a horrid drive when it wants to play up..

Ok

a few things Webbers are fine but not really what was on the car orginaly but hey they are there.

What Disy are you running? ( last 3 numbers of the long list please )
What exhaust?
any fancy air filters?
who did the serivce?

Ok carbs are most likely to be your problem.. When after market carbs are fitted not all the time are they the right ones.. as an example I know of one car infact 3-4 that have webbers that were not even a correct match for the 912.

Next the carbs are more likey to be worn out and will need to be rebuilt properly £150+vat each carb exchange look then up in google..

your disy might not be correct and even if it is correct a number of years service might have put a bit of wear in there and it does not help the overall ticking over

I 100% know where your comming from, since I had all this back in 1999

come back with these answers and then I am sure we can all help you from there.

I am only learning all the time myself.. just I am a few years ahead of you. :wink:
dougy
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Post by dougy »

jus something to throw in the mix here

Had same prob on my twin carb motor in my splitty bus
also a friend had same prob i found it to be one of the idle jets to be blocked by a silicone type material reulting in a real pig of a drive sometimes on 3 cylinders!!!


failing that if it was ok before the service id take it back id think the garage would be liable for any fixing costs

good luck
912uk
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Post by 912uk »

yep that's the next area jets out and see what you got


Then start with basic's when it comes to setting up the disy carbs etc etc..

but with a serice I would expect the disy to be right you may have to play with the linkage and get it balanced..

have you a balance tool for the carb is not hit the VW sites to buy one..

www.hillmanimages.com daves site has a carb balancer on there for pic ref..

all the vw shops sell them
512modulo
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Post by 512modulo »

hi there
the dizzy is a 050 the webbers have new filters fitted at the service, i had the full service at prs with balancing and set up the works cost alot of money. new plugs evrything

just going over the car this afternoon ive noticed theres oilon the lhs rocker arm carrier nearest to the front of the car every otjher part is clean, including the rhs.

maybe this has somthing to do with it?

any other ideas
512modulo
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Post by 512modulo »

sorry also the exhaust is a bursche one.
912uk
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Post by 912uk »

Well the boys at PRS know there stuff. So sounds like you need to get the carbs rebuilt.. Get them PRS to tune them up afterwards and it should sort you out for good on this one..

budget £500

you could send off the carbs your self to Carb Exchange and then put them back on the car and get the car down to PRS for a tune up..
512modulo
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Post by 512modulo »

just found some carbs on the internet for webber 44idfs for 500 quid which they say are new is this a good price?

the service at prs was great and they did tell me they were worn, the left hand bank had a fire so i realise they werent in great shape, do you think the oil on the rocker cover is anything to worry about?

ill drop the car back down to them on monday and get the experts on the job

thanks for the help.
912uk
Nurse, I think I need some assistance
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Post by 912uk »

mine has oil on the cover and I was going to drop out the engine to have a look where.. I am waiting for Uncle keith to post me the bell housing so I can run the engine up out the car??

so i can see any leaks and get them sorted..

Hmmm unless they are new I wouldn't bother

webbers are not the best they are Ok and if you buy new just make sure you buy the right ones..

other than that pick up some cheap solexs and get them rebuilt.

That should solve your probs and get you out in the car..
Graham
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Post by Graham »

The webers are ok like mark says as long as there not the ones with a 28mm choke,as for getting them re-built,I would go for carb kits and DIY,the webers seldom "wear out" like the old solexs,and they are not too bad to do,take the jet carrier's out of the top and check for blockages,and the idle jet carriers in the sides,the small slotted brass ones near the top,if one has a bit of crud in it it will run really rough,especially on tickover.
1985 MZ Simson/KH 125 Sprint bike
1302s one family owner
1963 AMC 660 Classic
1957 Peugeot TC4 race bike


Sadly gone:
74' 914/4 2.0
68' SWB 911
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