Menu toggle

Disaster strikes!!


ORIGINAL: Paul190H

Ok so i'm going down the used route I think. Just purchased a relatively low mileage (reputed) S2 head so i have cams and valves. My guy is going to get the valves re-profiled and I'll re-use the cams with all new chain, guides and gaskets etc. Might look at polishing the inlet tracks but the car is not going to be tuned so not sure there is any gain by just doing that?

I assume the cams sits in schell bearings and these would merit replacement?

Thanks for all your input.
Click to expand...

Byy now you should know the cams don't sit in shell bearings so remember to check the cam supports for wear and ensure the cam journals are put back into the same position on the head they should have numbers marked on them to help.
 
ORIGINAL: 924nutter

Right first thing don't number the valves with centre pop marks. I am pretty sure the edge of the crater will glow red and cause pinking, and it will be a mare trying to get the suction cup to adhere to the valve head for grinding the valves in, which will be tedious as unleaded valve seats do not grind in in five minutes I use tippex which washed off with tippex thinner when final assembly was the next stage.
Better than polishing the ports is matching the inlet to the manifold. Fit the gasket to the head and draw round the shape of the gasket on the head and remove metal up to the line and blend in but do not over polish. As it is only air entering the port the benfeits of polishing the ports is not as clear cut as it used to be on carburettor engines. When you have matched the head to the gasket do the same to the manifold. Apply the same principle to the exhaust. That is if the ports don't match particularly well. The alignment was crap on my 924 but then the 2.0l is a VAG derived powerplant.

I really cant believe that someone has apparently centre punched the valve face. A blow sufficiently hard to indent the metal cant be good for the valve.
Click to expand...

I know pinking was an issue with mechanical fuel pumps but is this still an issue with electronic fuel injection systems? Does the pump not cut out when the power is turned off meaning there is no fuel to burn?
 
ORIGINAL: david924s


ORIGINAL: Paul190H

Ok so i'm going down the used route I think. Just purchased a relatively low mileage (reputed) S2 head so i have cams and valves. My guy is going to get the valves re-profiled and I'll re-use the cams with all new chain, guides and gaskets etc. Might look at polishing the inlet tracks but the car is not going to be tuned so not sure there is any gain by just doing that?

I assume the cams sits in schell bearings and these would merit replacement?

Thanks for all your input.
Click to expand...

Byy now you should know the cams don't sit in shell bearings so remember to check the cam supports for wear and ensure the cam journals are put back into the same position on the head they should have numbers marked on them to help.
Click to expand...

Yes I saw the numbered journals, they also look to be in excellent condition.
Many thanks for the input guys!
 
ORIGINAL: Paul190H

ORIGINAL: 924nutter

Right first thing don't number the valves with centre pop marks. I am pretty sure the edge of the crater will glow red and cause pinking, and it will be a mare trying to get the suction cup to adhere to the valve head for grinding the valves in, which will be tedious as unleaded valve seats do not grind in in five minutes I use tippex which washed off with tippex thinner when final assembly was the next stage.
Better than polishing the ports is matching the inlet to the manifold. Fit the gasket to the head and draw round the shape of the gasket on the head and remove metal up to the line and blend in but do not over polish. As it is only air entering the port the benfeits of polishing the ports is not as clear cut as it used to be on carburettor engines. When you have matched the head to the gasket do the same to the manifold. Apply the same principle to the exhaust. That is if the ports don't match particularly well. The alignment was crap on my 924 but then the 2.0l is a VAG derived powerplant.

I really cant believe that someone has apparently centre punched the valve face. A blow sufficiently hard to indent the metal cant be good for the valve.
Click to expand...

I know pinking was an issue with mechanical fuel pumps but is this still an issue with electronic fuel injection systems? Does the pump not cut out when the power is turned off meaning there is no fuel to burn?
Click to expand...

Update, phoned the garage and they have confirmed that whomever punched the marks have taken the burrs off as can be seen by the small rings around the crater. So they obviously knew a bit about what they were doing. They did miss a couple so they will ensure they are all smooth.
Good point though, thanks!
 
Knock sensors retard the ignition by 2 degree increments, roughly speaking, and if you have something in the combustion chamber contributing to pinking the engine or more correctly the DME will adjust itself using its 3D map so pinking doesn't ocur, and prevent it self destructing, but why build something in so that the engine is permanently running below it's optimum ignition advance?
 
Years ago I watched and apprentice (the proper kind) mark the valves of a 16 cylinder diesel like that, the engineer came back and gave the lad such a blasting!

Seems he had been told to mark everything - all the bolts, push rods, pistons, cams everything had been punched, several items had been bent as well.
 
Wow, today I have learnt something new - I wouldn't even have considered that being an issue. Great advice! [:)]
 

ORIGINAL: 924nutter

Knock sensors retard the ignition by 2 degree increments, roughly speaking, and if you have something in the combustion chamber contributing to pinking the engine or more correctly the DME will adjust itself using its 3D map so pinking doesn't ocur, and prevent it self destructing, but why build something in so that the engine is permanently running below it's optimum ignition advance?
Click to expand...

Yes you're absolutely right, the garage will ensure any remaining burrs are removed, pointless not making it perform as well as it can if the head is already off!
Cheers
 
Hi folks, is it possible to purchase the little green injector caps? A couple of mine are damaged from previous seal replacement and having tried to remove one I can see why! Any tips on removing with out damaging them further and advice on where to get some would be great!
Enjoy the sun!!
 
E Bay sell service kits look for Fuel Injector seal kits or similar, i bought a set of seals and caps circa £10
 
Hello all, well a quick update, the S2 is up and running again, replacement head and cams, gaskets chain and guides[:)] also had the servo painted whilst the inlet manifold was off. Would like to post some pics but cannot see the icon on the message pop up box which allows me to insert the URL from photo bucket. Am I missing something? Will itemise costs as well if anyone is curious.
Cheers
Paul.
 

ORIGINAL: Frenchy

an old favorite 2000 series quartz that must be 30 years old
Click to expand...

I wear a Tag 2000 automatic of decent vintage (not sure of the exact date). I like the way it looks (stainless steel and gold), and appreciate the fact that there are 250 odd (or however many) little cogs and springs all whirring away inside it.
 
You must log in or register to reply here.

Posts made and opinions expressed are those of the individual forum members

Use of the Forum is subject to the Terms and Conditions

Disclaimer

The opinions expressed on this site are not necessarily those of the Club, who shall have no liability in respect of them or the accuracy of the content. The Club assumes no responsibility for any effects arising from errors or omissions.

Porsche Club Great Britain gives no warranties, guarantees or assurances and makes no representations or recommendations regarding any goods or services advertised on this site. It is the responsibility of visitors to satisfy themselves that goods and/or services supplied by any advertiser are bona fide and in no instance can the Porsche Club Great Britain be held responsible.

When responding to advertisements please ensure that you satisfy yourself of any applicable call charges on numbers not prefixed by usual "landline" STD Codes. Information can be obtained from the operator or the white pages. Before giving out ANY information regarding cars, or any other items for sale, please satisfy yourself that any potential purchaser is bona fide.

Directors of the Board of Porsche Club GB, Club Office Staff, Register Secretaries and Regional Organisers are often requested by Club members to provide information on matters connected with their cars and other matters referred to in the Club Rules. Such information, advice and assistance provided by such persons is given in good faith and is based on the personal experience and knowledge of the individual concerned.

Neither Porsche Club GB, nor any of the aforementioned, shall be under any liability in respect of any such information, advice or assistance given to members. Members are advised to consult qualified specialists for information, advice and assistance on matters connected with their cars at all times.

Porsche
Lockton
Pirelli
Officially approved
Oracle Finance
WEX Esso
Collecting Cars
Back
Top