FAQs

Question:
How do we fit the crankshaft sensor? We cant see anything to attach a bracket to so we can fit it so it points upwards.
Alternatively, is it possible to rotate the trigger wheel either to one of the other possible positions around the pulley to enable us to mount it elsewhere?

Answer:
We mount the crank sensor at 6 o’clock on the engine is for a several of reasons;
1. Because we like to run everything dry sump for motorsport, we simply put an extra lug on the front of the sump pan and you have the ideal mounting position for a crank sensor.
2. This part of the engine being furthest forwards makes a nice stable position for the shortest possible mount which keeps the sensor stable. If the bracket gets longer, it would become a bit like a ruler being pinged over the edge of a desk and the bracket and stabiliser required to prevent this becomes very hefty. I have seen brackets on some engines over 13mm thick vibrate just like a ruler at specific rpms, which causes the ECU to miscount the time between teeth on the trigger wheel.
3. You don’t necessarily have to move the trigger wheel, you just instruct the ECU of the new position of the sensor. The only problem with this is that you have to calculate it carefully and then check it with a strobe.
4. The problem with mounting the sensor anywhere else in the 360-degree circle of the crank trigger wheel is where do you mount it as you have to miss cambelts, alternator belts and potentially oil fittings, then you also have the length of the bracket which we have already gone into. All of which adds to the complication.

For those engines that have to be wet sump due to regulations, we always used the tin sump pans. We fabricated two steel plates which were welded to the sump vertically and spread apart sufficiently to bolt and alloy block between them that would hold the crank sensor in the same way it does on the dry sump version. We would always make the block slightly too close so that the sensor could be shimmed away from the trigger wheel to give the optimum setting rather than aiming for the optimal gap and potentially ending up with something that was too big. Unfortunately these were only ever fabricated in the workshop and no drawings were ever done or photos taken because it was over 25 years ago.

Please see our Technical Support Section for free technical advice about crank sensors.

Question:
How do we fit the crankshaft sensor? We cant see anything to attach a bracket to so we can fit it so it points upwards.
Alternatively, is it possible to rotate the trigger wheel either to one of the other possible positions around the pulley to enable us to mount it elsewhere?

Answer:
We mount the crank sensor at 6 o’clock on the engine is for a several of reasons;
1. Because we like to run everything dry sump for motorsport, we simply put an extra lug on the front of the sump pan and you have the ideal mounting position for a crank sensor.
2. This part of the engine being furthest forwards makes a nice stable position for the shortest possible mount which keeps the sensor stable. If the bracket gets longer, it would become a bit like a ruler being pinged over the edge of a desk and the bracket and stabiliser required to prevent this becomes very hefty. I have seen brackets on some engines over 13mm thick vibrate just like a ruler at specific rpms, which causes the ECU to miscount the time between teeth on the trigger wheel.
3. You don’t necessarily have to move the trigger wheel, you just instruct the ECU of the new position of the sensor. The only problem with this is that you have to calculate it carefully and then check it with a strobe.
4. The problem with mounting the sensor anywhere else in the 360-degree circle of the crank trigger wheel is where do you mount it as you have to miss cambelts, alternator belts and potentially oil fittings, then you also have the length of the bracket which we have already gone into. All of which adds to the complication.

For those engines that have to be wet sump due to regulations, we always used the tin sump pans. We fabricated two steel plates which were welded to the sump vertically and spread apart sufficiently to bolt and alloy block between them that would hold the crank sensor in the same way it does on the dry sump version. We would always make the block slightly too close so that the sensor could be shimmed away from the trigger wheel to give the optimum setting rather than aiming for the optimal gap and potentially ending up with something that was too big. Unfortunately these were only ever fabricated in the workshop and no drawings were ever done or photos taken because it was over 25 years ago.

Please see our Technical Support Section for free technical advice about crank sensors.

Question:

I was wondering what your advice would be for my XE rebuild. I need a new head, is it worth getting a Coscast head?

Answer:

We would normally advise the use of a Cosworth head casting. Simply because we know they don’t have a problem with porosity. There are actually only a few cylinder head casting of the normal Carl Schmidt version that have become porous. The only problem is that many of these are dumped onto the second hand market and the same head castings get recirculated, so it looks like there are more than there actually are. Although you can have the cylinder head tubed and many companies are now claiming to be very successful, its the aggravation of getting it done and if it ever does become porous again, you have got to take the whole head apart again.

Please our information sheet about Coscast cylinder heads

Question:

I purchased one of your nylon relief valves for the C20XE engine (standard) a while back and now have the engine up and running with the nylon relief valve fitted but I’m a little concerned about how high the oil pressure is at warm idle. The directions say it should be 65-75psi at 4000rpm, which it seems to be but sits at 50psi at idle when warm but sometimes a bit higher. The mechanic at my local garage pointed this out to me saying that it seems to be very high for a engine at idle.

The relief valve came with washers to adjust the pressure and I have 3 washers in at the moment. So I was wondering if you could you tell me roughly what the oil pressure should be at idle on a standard engine when warm.

Answer:

Provided your oil pressure is ok at higher rpm, oil pressure at tickover being higher than expect is not a problem. The oil pressure at tickover is controlled by several things; the condition of the oil pump itself, the condition of the engine and how thick the oil is. From the information you have given, this would indicate that everything appears to be in good condition. Oil pressure is very much dependant on clearances within the engine and the oil pump itself, the larger the clearances, the lower the oil pressure would be at tickover.

Also the oil temperature would have a major effect on the oil pressure, for example to give a better indication you would need to monitor the oil temperature at tickover against oil pressure at this will give you the true indication. Also the oil grade has an effect as well, for example if your oil temperature is only say 60°C, I would expect approximately 50psi, at 80°C I would expect approximately 40psi and at 100-deg C, I would expect approximately 25psi.

These are only to give you a guide and you cannot use water temperature as this will be different to oil temperature. Even if you were achieving 50psi at tickover with 100°C and the oil pressure was stable at higher rpm, I would still be happy.

OS-NV-1-K – 2.0L/1.6L/1.4L Vauxhall Oil Pump Nylon Relief Valve Kit

Question:

I am having problems with the oil pressure on my 2.0L XE. I have new SBD inner ring and outer ring and relief valve kit. I have 5 Bar pressure at idle, cold oil and 3.1 – 3.5 Bar maximum at 4000 rpm and above.

Answer:

The oil pressures we recommend are for hot oil with an oil temperature between 80 – 120°C. This is using a 10W60 oil, fully synthetic.

Possible causes for reduction in oil pressure:

1. 1. When fitting new gears, you must be sure a genuine GM oil pump housing is used and that it is either new or in perfect condition. If the housing is worn, then a reduction in oil pressure will occur.
2. 2. The bore where the oil pressure relief valve runs must be checked to ensure that it is smooth and has no particles or distortion. Check that the relief valve runs freely within it. if not again the oil pump housing should be replaced as this shows signs of the condition of the rest of the pump body.
3. 3. You must ensure that the journals and bearings on rods and crankshaft are in good condition and within tolerance. Also that the whole engine is in a good working condition.
4. 4. If you are using a thinner oil, the oil pressure will drop lower as the oil temperature rises.
5. 5. All of the above points should be checked before attempting re-shimming as you may be disguising engine wear by carrying out this modification.

The oil pressure can be varied on the engine by adding addition washers to trim the oil pressure.

Question:

Have you ever seen the bottom cam belt pulley slipping on C20XE Standard engine used for racing? In other words the key for the pulley has slipped around the crankshaft therefore destroying all 16 Valves. As I have a couple of these engines, I wondered is this a common problem and if so what can be done to prevent it?

Answer:

We do know of the problem. It isn’t very common and usually only occurs in competition engines where the driver uses the gearbox instead of the brakes. What can happen under these conditions is that you get a shock loading through the flywheel. Sometimes the flywheel bolts will come loose, when this happens the shock continues on through the crankshaft. This will occasionally loosen the front crank bolt. On the 2.0L XE engine, the key way is only there for location, it has no strength. The gear itself is prevented from slipping by the extremely high torque setting of the crank bolt. The only other time we have seen the crank gears move, is if the correct torque procedure has not been used. Some people have even used Loctite on this bolt and that is definitely wrong and is more likely to cause the crank gear to come loose because the Loctite will usually prevent the bolt from clamping sufficiently on the crank gear. The thread of the bolt should always be lubricated and graphite grease should be placed on the underside of the head of the bolt. Then follow the torque sequence, which is laid down, on our web site (under Instruction Sheets).

We have personally never experienced a crank gear coming lose on any engines we have put together, but on our 2.0L steel crankshaft we put in a second key.

Update April 2021:

The standard 2.0L crank gear is now no longer available for either the earlier or later XE versions and we have designed a steel pulley as opposed to the original sintered version. The whole design has been changed because the original version was quite heavy and we have made the completely new version that incorporates 2 keyways to allow the use of Woodruff key (the twin Woodruff keys were designed for use with the earlier sintered drive gears on high specification engines using our steel cranks and have been maintained to give extra protection). These new versions are available with the poly-vee alternator drive pulley and can have an external trigger wheel added too.

Please see our shop for Pre93 version & Post93 version of our crank gear.

Question:

The cam guide roller wheels disintegrated at idle following some fast driving, the engine stopped instantly. The crank & cams still turn. Is it worth replacing just the guide wheels and belt and try to start the engine or do you recommend I take the valves out and have a look. I didn’t really want to disturb the head unless I really had to. Can I change the rollers to the metal ones?

Answer:

Please see our shop for replacement idlers for the XE (both pre & post 93) & 1.6L/1.4L Vauxhall engines

The best thing to do would be to fit the new metal idlers onto new bearings & re fit the cambelt. Do a compression check to see if any of the valves are bent. If they are ok, then just fit a new cambelt If not, then unfortunately you will have to remove the head & go from there.

Question:

Do you have a cure for noisy hydraulic lifters apart from replacing them with new ones?

Answer:

The follower works by retaining a certain amount of oil within it and the clearance between the inner and outer walls of the hydraulic component control the operation of the follower itself. If the tolerance was too close the follower would jack up and open the valves and if the clearance is too large, the follower will fail to control the valve clearance correctly and get the rattling sound that you have heard. When the engine is stored for a period of time, any valves that are held open will gradually cause the follower to empty of oil even when the follower is in good condition e.g. if stored for several weeks or months, this would be normal even on perfect followers. As the follower becomes worn, the oil will seep out faster causing the follower to be less efficient, so if the follower rattles every time you start the engine up, even if left for only a couple of hours, it is an indication that you have worn followers and need to be replaced. Somewhere between these two states of a few hours before they rattle and a few days/weeks before they rattle is an idea of the amount of the wear. As the follower wears, the valves won’t operate as effectively as they should do and you will be loosing engine performance. If they rattle all the time, this will cause other severe engine damage.

We would suggest replacing the whole lot. The main reasons for this, is that they are considerably cheaper than they used to be and if you replace them one at a time, if you are lucky enough to find the ones that are rattling, I am sure the others won’t be far behind.

Please see our shop for the cam followers we can supply.

Question :
I’ve got 2 C20XE engines built in different years, one has 26,00 mm high lifters, the other one 26,50 mm high ones, they look a little bit different inside. Can I use your hydraulic lifters CMFL-1 on both engines with no trouble?

Answer:
Our CMFL-1 follower is a genuine GM supplied component, there were variations on some GM parts but they are all designed to run on all the XE engines and this the follower is the one we have used for many years. It is the lightest version and should run successfully in any GM engine of this type.

We never use re-ground cam profiles as the base circle of the camshaft has to get smaller to do this. One of the problems associated with re-ground cam profiles is that the follower can sit too high in the cylinder head potentially causing 2 problems; the first being the cam follower runs out of travel and the second is that the oil supply does not reach the follower correctly and therefore does not fill adequately. These problems are normally discovered after installation of the cam profile and when fitting new cam followers, the owner believes it is a problem with the follower when in fact it is the cam re-grind itself.

Our CMFL-1 follower is a genuine GM supplied component, there were variations on some GM parts but they are all designed to run on all the XE engines and this the follower is the one we have used for many years. It is the lightest version and should run successfully in any GM engine of this type.

We never use re-ground cam profiles as the base circle of the camshaft has to get smaller to do this. One of the problems associated with re-ground cam profiles is that the follower can sit too high in the cylinder head potentially causing 2 problems; the first being the cam follower runs out of travel and the second is that the oil supply does not reach the follower correctly and therefore does not fill adequately. These problems are normally discovered after installation of the cam profile and when fitting new cam followers, the owner believes it is a problem with the follower when in fact it is the cam re-grind itself.

Question :
Can you tell me how much a 1.6L 16v Ecotec engine weighs without manifolds & how high it is?

Answer :
The weight varies quite a bit according to flywheel modifications. For example, our engine with dry sump system fitted, lightweight flywheel, clutch & fuel injection is 90kg. Height again varies, but if I give you the height excluding the sump pan, it is approx 440mm high. The dry sump pan we do is a minimum of 65mm at its smallest (wet sump pan likely to be closer to 100mm deep).

Question :
Are the C20xe and C20ex the same motor?

Answer :
There is a 20XE and a C20XE, effectively they are the same engine and the C denotes a catalyst. Any other number and letter combinations would represent a different model of engine.