• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Changing the Oil on a 100-4

Share this page

Pizzi348 said:
Ok one last stupid question - sorry. How do I pressurize the system with the ignition key off?

Thanks!
Click to expand...
:savewave: Ain't stupid
Spin the engine with the gear box in neutral using the button on the back of starter solenoid until oil pressure comes up on the car's gauge.Keoke-- :driving:
 
Thanks Keoke. I think I had my first successful oil change. I put in 8 1/8 quarts of oil. The service manual said 11 1/4 pints, then 1 pint or so for the oil filter. So based on a quick guess on my part I came up with 8 1/8 - not knowing if the modern oil filer would require as much as the original. I didn't take her out as it started to rain, but I did let it run for a few minutes and the reading on the dipstick was on the M on the word Max.

Does the car need to be warmer than that to check the oil and get an accurate reading?

Also, I think the service manual said that the oil pressure should be around 50-55 under normal running. I'm at 40 or so at idle. Does that sounds right?

Again thanks so much for your help.
 
First see what the dip stick says. Generaly Idle engine oil pressure is high at low engine temperatures but 40 PSI sounds good to me. See what she say when the rain stop and you get her up to speed and temp.--Regards Leoke
 
I was driving today, and when I started the car it was at about 40 PSI for a while. After driving about 15 miles or so, the needle moved quite a bit - I know moving is normal, but it would go down to what looks like 35 when stopped, and all the way up near 80 when driving at 3000 rpms.

Normal? Or no?
 
Well 35 at idle warm sounds OK. But 80 at 3000 RPM is a bit high. It may be that the engine's oil pressure relief valve needs a bit of attention, We will see what some of the 100 guys think.--Keoke
 
35 PSI at hot idle is fine. 80 PSI when revving is too much. The oil pressure relief valve should relieve at about 65 PSI max. It may be stuck, somebody may have stretched the spring or loaded something behind the coils to change it's effective length.
 
According to the service manual there is no possible adjustment. Is this something I should just replace?
 
There is a cup or piston and a spring, you will have to order them. I agree with Rich that is the first place I would look, but it is a pretty simple mechanism, as they say in the the manuals though, "if worn or perished renew" the two pieces can be had for less than the cost of an oil change last I checked.

Should be a bolt head under the oil filter if I remember correctly, there will be spring tension on the bolt as you pull it out, sometimes the cup at the end of the spring does not want to come out (particulalry if it is stuck and causing high oil pressure) maybe building up some oil pressure off the starter would help if you have that problem, unless it is really really stuck, in which case you have found your problem, but now have to figure out how to remove it!
 
Oh removing Valve [ Piston ] can be simplified if you use a telescoping ceramic pocket magnet. They slip inside and pull the valve right out. However, if you try to force it out using engine oil pressure you gonna make a BIG mess.---Keoke- :yesnod:-------- :laugh:
 
Can I still use my current cap nut? I was just going to buy the spring, valve, and washer.
 
Pizzi348 said:
Can I still use my current cap nut?
---Yep
, You didn't bugger it up did you?------ :laugh:

I was just going to buy the spring, valve, and washer.

--That's probably all you will need.--- :yesnod:
Click to expand...
 
Keoke said:
Oh removing Valve [ Piston ] can be simplified if you use a telescoping ceramic pocket magnet. They slip inside and pull the valve right out. However, if you try to force it out using engine oil pressure you gonna make a BIG mess.---Keoke- :yesnod:-------- :laugh:
Click to expand...

I would try the magnet first, I tried one on mine, didn't work, but yes, the possibility of a big oily mess is right there with my method.
 
OK Glemon, one of the run of the mill shop/pocket magnets May not free a stuck valve , but one with a 'ceramic' head probably will, they stick like they are glued on. Sometimes make you mad trying to free it.--Keoke
 
Ok. I changed the valve. However the psi is now at 55 when idling (from cold) and quickly gets to 60 with the slightest rev.

I'm a bit nervous to take it out the road as I was at 80psi last time.

The valve came right out with a magnet, but the new spring I got was about an inch longer than what was in there.
 
OH I think you are OK now give er a go take it easy let her get hot and then see what the oil pressure say. Do not discard the old valve for now. The new spring and the old valve may be a better combination but I doubt it--Keoke
 
Ok. I took it out and did the same thing. Once it got to temp. It went from extreme to the other down to about 40psi at idle and up to what could have beyond 90psi (around 80 I left off on the gas and coasted a bit) if I got it up fast enough. I just took it on the back roads in case I wanted to drive slower.

I'm thinking that because the new spring is longer, and it idled at a higher psi at idle and wanted to go up to 90psi - it's directly related to the size of the spring, as it smaller spring it got up to 80.


Should I cut the spring? Or is that avoiding what maybe a bigger issue. Could the oil filter make a difference? I ask because this problem seems to be related to my oil change.
 
Matt,

You should not have to cut the spring, assuming it's the right spring for your car.

I would suggest tesing the gage by temporarily attaching another gage to the line. It's not unusual for these old gages to be off a bit. I would want to know the gage is reading accurately before I jumped into any major work.

If it doesn't read the same as a test gage, then you may want to remove yours and send it in for a rebuild and calibration. I have had very good luck with Nissonger Instruments - reasonable fee and very nice folks.

Dave
 
Yes that is what it should do with a longer spring . But for some reason the pressure relief valve is not hitting its proper limit, it is following engine RPM. There have been problems in the past with the Vendors filter you are using . However, do you have a method to verify the engine oil pressure other than the car's gauge?--Keoke-??
 
I was thinking about the gauge too, but it seems weird that this related to my oil change. I know I put in the proper amount of oil, and used the weight suggested.

Keoke - I am using a K&N oil filter. I had a Purolator on there before. It was a modern filter as the adapter was already installed on my car. I couldn't find another Purolator, but I started to think it was the filter as well.

In any event I will get a gauge and test it, but do you think I should try to find a different filter? Any suggestions?
 
Back
Top