Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 leak down test

Y'all might recall this last fall my M3W started burning 1 quart f oil about every 200 miles (actually it had started long before that). I checked the compression and it was 80 lbs on both cylinders which everyone agreed is normal. Anyway, I was working out of state and then when I got back it was too darned cold to god work on the M3W

Today I did a leak down test. On the port side I get 100 in and about 92 on the cylinder... I thnk I am hearing air escape through the intake. On the starboard side I get 100 and 94 and the hiss appears to be on the exhaust side. So I am thinking this may be a trip to Morgan of New England for some engine work.

While I have things open.... how do I replace the cam belt"? I see three red divits on the cams but they do not seem to have any relation to anything else.

The easy start cams hold the valves open slightly until the engine fires and gets above about 400 rpm. So a leak down test won’t work.

figured out how to change the timing belt what a PITA. The tensioner has so little play that you have to fight every bit of it.

That is what I was told about a compression check and then everyone said to do a leak down. It appears I may have been on tooth off on the center cam. It was clear the orginal belt was wearing out.

Seems like there is a way: The easy start mechanism used by S&S is essentially the same as used by H-D.

https://www.hdforums.com/forum/engi...-leak-down-test-with-easystart-cams.html

A 6 and 8% respective leak down rate is not bad at all. Doesn't seem to be worth a teardown based on the leak down. But your level of oil consumption seems extraordinarily high, and worthy of inspection.

It was the oil consumption that got me started on this. It makes me wonder if it is the valve guides.

There may be other ways of doing a leak down compression check with easy start cams but this is how I did it:

1. Take the rocker and cam chest covers off and spark plugs out.
2. Rotate the engine until a cylinder is at TDC (marking on the cambelt drive sprocket and both valves closed).
3. Back off the exhaust valve rocker adjustment a few turns so there is free play.
4. Do the leak down compression check on that cylinder, you may need to restrain the crank from moving under air pressure with a socket on the crank sprocket nut.
5. Same procedure with the other cylinder.
6. Secure the rocker pivot nuts, refit spark plugs and covers.

What Ian explains is exactly as in the document I have send.
Do not worry about the loss of 8% That is actually very good.
It can be more upon till 15 or 20 % with a leak down test.
There are more reasons for loss in pressure with a leak down test.
When you did a proper leak down test as explained then there is no problem in the cylinder so do not open the engine.

The oil use of nearly 1 liter? ( US Gallons or Imp ? ) in 200 miles is frightening.
Nearly impossible that valves are a problem you should see that at the exhaust. As a lot of white smoke.
No smoke - or only when cold - in that case probably the valves are good.

I lost oil too and found that when parked.
I had a problem with the hose clamps at the oil tank and changed them all to an other type and used 2 of them at each point IN and OUT.
The most important one is the big one [ IN ] at the top because there is 3- 4 Bar pressure on it.

I used special Boltza Hose clamps and they were the only ones who finally solved my problem.
They are ugly but do their job.
I looked for you on amazon.com but could not find them, but - To see what I mean - have a look at :

https://www.amazon.fr/Boltza-colliers-serrage-plaqu%C3%A9-passante/dp/B0B8DY8HP2?pd_rd_w=XiJpr&content-id=amzn1.sym.9d33c282-f4cb-47c9-bba8-60e74e550e84&pf_rd_p=9d33c282-f4cb-47c9-bba8-60e74e550e84&pf_rd_r=HRDZVEHCTM743B2Y1G32&pd_rd_wg=Cc4gc&pd_rd_r=09ec1bfb-2e29-4f64-be83-b624807b481e&pd_rd_i=B0B8DY8HP2&psc=1&ref_=pd_bap_d_grid_rp_0_1_ec_pd_rhf_ee_s_rp_c_d_sccl_1_4_i

I doubt that any of the rubber oil hoses will have 3-4 bar pressure in them Herrie. The Suction hose is drawing oil from the tank to supply the oil pump, so lower. The Return hose is scavenging oil from the sump to return it to the tank and will be about tank pressure. The air vent at the top of the tank is vented into the crankcase, so will be a a similar pressure. The crankcase is vented, via restrictor and into the throttle body and then to atmosphere, or inlet pressure. Not sure what pressure the crankcase runs at but it won't be much if vented to atmosphere.

Agree that good quality hose clamps are certainly recommended, the pipes they fix on to are mostly not serrated and any hose coming loose will be very bad for engine life!

Most leak down compression testers do give ways of checking various parts of the engine, such as squirting some oil into the cylinder bore to test for faulty piston rings. I suppose you have checked closely for leaks though rcmatt? If the engine was burning that amount of oil it would show up as blue smoke. The base gasket of the cylinders often leak and causes a fine mist leak that isn't that easy to locate.