Bill Ball

I was thinking just misting the walls, but I suppose his teaspoon will get immediately dispersed if he fires it up.

mark kibort

120psi is all my 4.7 had, thats why i was so excited when i got 155 with the 5 liter part euro motor!
the 4.7 had 170,000miles of very hard use, but still made 240rwhp with all the euro top end stuff.
the 290rwhp was much more fun with the 5 liter though!

let us know how the start up goes? really weird? this is a CIS beast? i thought it was a US 82.

hacker-pschorr

I cannot imagine how much fuel it would take to wash out the cylinders like that.
I was experimenting with my fuel a couple of years ago (when my boost was only 10psi). I ran my car for quite a while in excess of 9:1 air fuel (gauge only goes that high). It gets to a point where you will not see black smoke because all the fuel does not burn. You end up with raw fuel dripping down the exhaust (fun on the dyno when it ignites!!).

ew928

Absolutely dumb N00b question.

How do the rings get oiled?

soupcan

Splash oil from the crank, and oil squirters on some engines. Windage throws oil everywhere, oil control ring (third ring) cleans most oil but leaves enough to lubricate 1rst and 2nd rings.

WICruiser

If there was that much fuel washing down the cylinders what condition is the engine oil?

For fuel to wash down the walls it must be unburned and not all of it ends up in the exhaust, actually a lot ends up in the crankcase.

Check you oil level and also smell - it could be that the oil level is not high but the oils lubricating properties are significantly diluted (gasoline is a very bad lubricant). Getting it running may be nice but if you take out all the bearings it will still be a major engine rebuild.

Tails

I have been briefly following this thread, but did not have the time to give it time to sink in regarding the loss of compression in all cylinders.

I believe that Garth has hit on the fix to get compression. It is an old "trick" to add oil via the plug hole to seal the rings to the bore, if an engine does not fire up when you have spark, fuel etc.

I have used it quite a few time to get old engines going when they have not been operated for a long time (no oil on cylinder walls).

As the engine rings and cylinder bores are splashed lubricated and the excess oil is removed by the oil scraper rings to leave a residue oil film it does not take too much fuel excesss to wash off the oil film and destroy the seal between the ring and cylinder walls. (Note for interest: some large bore internal combustion engines have oil directly injected through the cylinder liner wall).

Initially, as a check after adding the oil to each cylinder, see whether the engine fires up. If it does do not run the engine too long in case it is excessive fuel washing away the oil film.

Internal combustion engines are designed to have a specific air/fuel ratio to achieve complete combustion of the fuel, so when this ratio is exceed by excess fuel, for any reason, or if the fuel is not sufficiently atomised to achieve complete combustion then not all the fuel can or will be burnt during the ignition stroke, which will remove or partially remove the oil film on the cylinder walls.

So, if the engine fires up I would shut if down and would then determine whether there is excess fuel getting into all the cylinders, as if you continue to run the engine it will continue to destroy the boundary lubrication between the rings and the bore thereby causing blow-by and further excessive ring and cylinder wear by entering into a degenerative spiral of excessive wear by the blow-by adding to removal of the oil film by burning it off as well thereby causing even more wear etc.

The is also one more problem that could occasion if you continue to run the engine, that is too much polishing of the cylinder walls by the partial removal of the oil film. If the cylinder walls become too polished then the oil film cannot be maintained on the cylinder walls which can lead into the degenerative wear spiral.

Hope this helps.

Tails 1990 928S4 Auto

Tass 928

I may not get a chance to get out to the garage until Monday morning before work ( I try to start every workday with an hour of playing in the garage). I'll post the results once I get to the office. I did get to put some oil in each cyl and throw the bat charger on.

fingers crossed...

Tass 928

Well..no good news to report. It almost fired then went back to just cranking. Strong oil mist coming out of the exhaust. I rechecked compression in number one and it was back down to 60 pounds, so the gain from oiling was only temporary. The plug was dry though. I was expecting it to be oil-fouled.

The borescope should be here today or tomorrow, maybe that will reveal something. If I have to pull this motor and rebuild it it is likely I'll just scrap it and look for something bigger to put the effort into.

Stan.Shaw@Excell.Net

What size motor(s) will your new SC setup work with? Isn't it specific to the 4.5L motor size more or less?

Dennis Wilson

Dave,

Before scrapping the 4.5 I would have another look at the SC setup. Specifically, check to make sure it isn't pressurizing the crankcase. Using the stock vent system (which works on vacuum) will not work if connected on the boost side of the intake. Also, the setup with the CIS is going to be critical to proper operation.

Dennis

Dennis

AO

I really doubt you'll see anything useful/informational via the boroscope, you're either going to have to open it up or find the culprit.

I haven't had this happen to me, but I believe if the Fuel Damper/Regulator blows a seal it will suck fuel through the vacuum system and into the intake which could cause a wash-down... Did you disconnect the vacuum line and check for fuel leaks?

Dennis Wilson

Andrew,

This is a CIS system so no damper/regulator.

Dennis

hacker-pschorr

IMO a track car that is already this modified - scrapping CIS would be my next step. In fact, I'm doing so on my 79

Tass 928

At this point the S/C has been removed. I wanted to take that out of the equation. Isn't my main problem the lack of compression?