General 500F Rebuild

[tjmra]

Guys,

When I resolved my (non existent) brake problem I was in a position to get a roadworthy done on the car so I could get it registered. No problems and the car was registered last week.

Went for progressively longer drives around the local back streets and after each one checked the car over for problems. I eventually found that between 5 and 6 miles the oil pressure light would come on and stay on. Tried two sensors with the same result. Engine was professionally rebuilt with new big ends and mains etc so this is the last thing I expected.

This is a problem that I can't fix myself. I can pay to trail the car to the mechanic for him to look at or I can pull the motor out strip the covers off and take the bare motor back to him. There are pros and cons to each method, but I fear this is going to be a drawn out problem.

Talk about cruel. After 10 or so years off the road, and then a couple of years since I started the rebuild, I finally get a taste of driving the car and I have to stop. I am thinking that a static display in the garage may be the go.........

As an aside, it is good to see new people, new cars and new posts on the site. Every post and every photo helps someone somehow. If I get a sunny day this weekend I will push(!) the car out and try and take a photo or two.

Regards

Joe R

 

[Abarth 695]

Hi Joe,

I am not sure if this helps and I am no "expert" but I too find that the oil pressure goes down after a few miles.

I have an oil pressure gauge and an Abarth sump.

The first time it happened I was worried so I went back home and topped up the oil and that seemed to help, not sure if it was the level or the new oil cooling it. I find it hard to tell on the dipstick where the level is with new oil.

I use 20w50 halfords classic mineral oil.

My thoughts were that the engine was running a bit hot hence the oil was more viscous so the pump was struggling. It seemed that the more I revved the lower the pressure was.

I can only think it has to do with the oil itself thinning out. Slightly more oil has helped so maybe more oil keeps the engine and the oil itself cooler.

 

[tjmra]

695,

I only have the waring light, not the gauge. Manual says normal pressure is between 36 and 43 lbf/ sq in and the warning light comes on between 8.5 and 14 lbf/sq in. I know pressure will vary with speed and oil temp / viscosity but this is too much of a drop to be just normal running. (I use Castrol 20w 50.) I am trying to borrow a master gauge so I can check properly. Is a real pain having to deal with this now.

Regards

Joe

 

[Bambino]

On most cars with oil pressure gauges, the pressure is lowish on idle and rises as the revs rise. In extreme cases, surging may occur with a resultant big variation in oil pressure (eg: when cornering very hard) but cars designed to be driven this way are usually fitted with internally baffled sumps or are dry sumped.

Real pressure drop is usually either associated with nasty engine problems or results in nasty engine problems. Oil is like engine blood - it needs to be kept clean and you need the right amount circulating at the correct pressure. You know this already Joe, hence the air of desperation in your question.

If you are lucky, and you seem the lucky type, it'll just be a pair of dud senders. I've never trusted low pressure lights on their own and fitting a reliable gauge either to diagnose the problem or as a permanent fixture is a very good idea.

Let us know how you get on - I've got my fingers crossed for you.

Chris

 

[tjmra]

Guys,

next update on my ongoing saga. Put an oil master pressure gauge on the car and fired it up. Watched the pressure drop as the oil warmed up. Spoke the mechanic, there was nothing for it, I drained the oil and pulled the motor out. Stripped it down and then dropped the sump off to see if I could see anything nasty. What little oil that was still in the sump was black and did not feel as slick as it should have.

Took the motor to the mechanic today and his first observation was that he could see metal flecks in the oil which indicated to him (as a first thought) that a bearing had failed. The rebuild included new seals and shells etc so we won't know for sure until he pulls it down. Just have to wait I guess. I trust my mechanic, I have no fear that we will resolve whatever the issue is.

Regards

Joe R

 

[the hobbler]

Hi Joe R; sorry to hear of you oil pressure problem--I have dug out my old workshop manual (yes, I have an original, 1inch thick version) and it confirms my memory--with the engine running, the 'oil-light on' pressure is between 8.5 and 14psi. The light is allowed to flicker when the engine is idling hot, as long as it goes out as soon as the engine is revved above 1,000rpm.---Did your mechanic fit a new oil-pump when he rebuilt the engine? If you want the specs for the pump let me know (I have tried 3 times to put it onto the forum, with a distinct lack of success!!). Lastly, don't forget that these engines were not designed for todays very thin oils, they need a good 20/50 oil.

 

[tjmra]

Hobs,

oil is Castrol 20W 50 so that should be OK. Pump was checked and deemed to be OK. Perhaps part or all of the problem lies there, who know till we have a look? Metal fleck in the oil is still an issue though.

Regards

Joe R

 

[tjmra]

Got a call yesterday. Long and short of it was that there is some grit in the motor that has gone through the bearing surfaces. Not sure how or why but there you go. I saw the parts just before the rebuild, it looked spotless. Can't believe that after all the work that was done there could be an issue.

Have to go through the rebulid process again, not my idea of a fun time but we just have to work through it.

(At least the lightness of my steering matches the power through the rear wheels as the moment)

Regards

Joe

 

[the hobbler]

Hi Joe;
Sorry to hear the possible cause of your 'low oil pressure' problem--it is amazing what can stay in the oil-ways a and passages--I would suggest that when engine is rebuilt, for the relatively low cost, you definately fit a new oil-pump; there will be a good chance that the grit that has gone through the bearings has also gone through the oil-pump and it is just not worth the risk, and if for no other reason, at least you will know that the pump is not contributing to the problem. All the best, lut us know how it all pans out.:bang:

 

[tjmra]

Guys,

the saga continues. Engine is back and it went in today. Won't start when it is hot, I suspect I have the timing out so I will look at
this tonight or tomorrow. One step closer, it has been a lonnnnnng time.

I thought I would share a problem that I encountered with the gearbox mounts. These are the rubber guys that bolt to the side of the gearrbox
and then to the wide 'U' shaped bracket. U shaped bracket bolts to the bottom of the car.

Where the mounts bolt to the gearbox, there is no adjustment, it is a no brainer, slip them over the stud and do up the nut. What I have noticed is that the bottom part of the mount has been rubbing against the casing of the gearbox and wearing it away. One of my photos shows this quite clearly. Now this has been happening over a period of many years.

I don't think this should be the case. My other photo shows my new gearbox mounts. The one on the left is standard and the one on the right has been 'modified' by me and had part of it ground away. Now when I bolt these to the side of the gearbox there is no rubbing. Did this for both sides, the left was far worse than the right.

Is it just me again?

Regards

Joe R

 

[nathanrobo]

It is going to be a race to the end of the project or to the end of the funds.

I know what you mean! You begin your project, work out a rough figure in your head of the costs, then somewhere between that point and the end you get 'project creep'. Either something that was unexpected and needs doing or you get an idea in your head. Either way it can become a bottomless pit.

I've a project that owes me about £9K and I've not even put it together yet. I've bought parts like a set of alloys & tyres then changed my mind. The wife would hang me if she knew )

 

[RogerNZ]

The wife would hang me if she knew )

Never a truer word spoken. This could be the theme for a whole new thread....

 

[nathanrobo]

Got a call yesterday. Long and short of it was that there is some grit in the motor that has gone through the bearing surfaces. Not sure how or why but there you go. I saw the parts just before the rebuild, it looked spotless. Can't believe that after all the work that was done there could be an issue.

Have to go through the rebulid process again, not my idea of a fun time but we just have to work through it.

(At least the lightness of my steering matches the power through the rear wheels as the moment)

Regards

Joe

As the Hobler says it may not be grit. I've rebuilt a few of these engines now and it's always worth making sure that the pump is primed and that the oil pick up for the pump hasn't been bent upwards.

I know you've got it sorted now, but for other DIYers doing this job, before you put the engine back in, make sure that the oil pick up for the pump is not bent and is right down into the bottom of the sum. Fill it with oil on the bench and take out the oil pressure switch, then fill the gallery with oil (this back fills the sump) then turn the engine by hand (backwards a few turns) then forwards until oil comes out of the orifice where the Oil Pressure Switch goes then onto the top of the cylinder head. It's now primed and ready to start.

My view is that if you are going to the effort of doing a rebuild, you might as well change everything you can, which means that it'll be some years before you think about it again. I've currently got four engines I've been rebuilding (don't ask), in the two standard engines (500 & 595), the only part that has been left in is the camshaft (although if this has scoring where it mates the oil pump, i'd change that too. The other two engines only have the bare block remaining as they've both been built into 750cc.

It's also very worth finding a good engineer to press in hardened valve seats and flash the head.

 

[tjmra]

Engine is in.
Drove it 4 miles.
Starter is now stuffed.
Grrrrrrrrrr.

Joe R

 

[Bambino]

Starter is now stuffed

:bang:

You must have been a very, very bad boy in a previous life.

Chris

 

[tjmra]

You're not helping.

 

[tjmra]

All,

it lives!

Starter motor took over two weeks to repair and I put it in this morning. Motor cranked but would not fire up. Plenty of spark, static timing looked good so I took the carb off had a look, found nothing, put it back and lo and behold it fired up.

Having borrowed a timing light, I used it to adjust the timing. Short of it was the car was OK starting when it when it was 'cool' but after a short drive, it refused to start afer sitting for 10 minutes.

Only way I can get it to start is when I set the static ignition and didn't even think about the timing light. Don't pretend to know what is going on here but I have one theory that I will check tomorrow.

For the moment I don't care. This arvo the car ran, started hot, no oil pressure issues no leaks and nothing fell off. Best of all, strangers smiled and waved as we drove by.

It may be premature but I may have turned a corner here.

Tomorrow I have another look and go from there. I will report back on my progress. Now I can't wait to come across a new 500 on the road so I can terrorise it............





Regards

Joe R

 

[Bambino]

Excellent news - another road warrior up and going

Now don't go speeding or you'll get a ticket. Come to think of it, if I got a speeding fine in a 500, I'd frame it - they must be quite rare ...

Seriously though, congratulations on a job well done.

Chris

 

[tjmra]

Thanks Chris.

 

[jjacob]

Hi Joe,

Maybe I can help with your hot start issue. In general once the engine is hot you should not add any choke or touch the gas pedal until the engine starts, then blip the throttle a little to keep the engine running once it starts.

Ignition timing and idle mixture will effect how easily it is to start the engine. My stock 500L when cold starts before the engine even makes a full revolution. When hot, it starts within 3 seconds of turning over.

Ignition timing: You need to have the dwell set correctly. If you have an electronic ignition then you can bypass this. If not, I highly recommend that you install one before proceeding. I used the Pertronix system which works great. Points removal should be the first modification anyone does to a 500. Dwell affects timing.

Forget about static advance (10 degrees). You need to set the engine up for maximum dynamic advance. This is 18 degrees. On the pulley locate the TDC mark. Now make another mark 25mm clockwise from that mark. This is 18 degrees BTDC. Loosen the distributor so it can be turned (but not too loose). Install your timing light. Start the engine and rev the engine to at least 3000 rpm. Aim the timing light at the mark on the timing case and turn the distributor until the 18 degree mark you made lines up with the mark on the timing case. Tighten the distributor down and recheck the timing.
Idle Mixture for stock carburetor: If this is too lean or too rich it will also make hot starts difficult. With the timing set first, and the engine running, turn the idle speed down as low as possible, but still with a smooth running. Now turn the idle speed mixture out until there is no increase in engine rpm. Now start turning the mixture screw in in 1/4 turn increments until you just hear a decrease in engine rpm. Now turn the mixture screw out 1/2 turn. Your done.
This should put your engine in a good state of tune and improve starting in general
John