18R-G Oil Pressure Initial Start Up Problem

[eeelie]

Hi guys, I spent endless years building a 1974 Toyota Corona with an 18R-G engine swap. My project came to a stop a year ago when I first started the engine and had an oil pressure problem that I have not been able to resolve. I'm hopeful that someone here might be able to help me out

I don't have any oil pressure on initial start up, I have an analogue gauge fitted at the pressure switch and it reads 0 whilst at idle to the point the top end starts rattling and I turn it off. First start I primed the system with the coil lead off on the starter and it idles at 60psi. It takes a good minute or two priming on the starter to get a reading on the pressure gauge. Once pressure is there it starts and runs fine. I can still use this method to run the engine but is obviously wrong.

Here is a list of things I've done to try and resolve the problem.
•Oil filter housing stripped and bypass valve checked for sticking.
•Oil filter replaced with K&N with anti drain back diaphragm
•Oil pump stripped, pressure relief valve checked for sticking, gasket to block replaced.
•New oil pump fitted.
•Camshaft oil way core plugs checked.
•Various grades of engine oil.

Does anyone have a drawing or knowledge of the oil gallery. An engine builder has suggested the likely cause is a bung missing from an oil gallery?

I really would like to finish my project but this problem is causing a spanner in the works. I'm now even considering a different engine option.

Sorry for the long first post. Here's a couple of pictures of my build.

I'll happily revisit anything I've looked at before. Any help or suggestions greatly appreciated.




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[eeelie]

I've seen this before, but it doesn't detail any gallery bungs, like the ones at the end of the cams.

Does anyone know what the item is I've circled red?

No rattle from the chains so I don't think I'll be loosing pressure there

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[davew7]

My guess if you do not have oil to the top end, that you have gasket material or RTV, something, blocking the oil port that goes up to the head. Try using compressed air to dis-lodge. If that does not work. You will probably have to remove the head and clean the port with a rifle cleaning brush. But either way you still have $hit it the oil system. The only way to be sure is a complete engine stripe. Also I believe the plug circled is actually threaded in Vs press fit.

[eeelie]

I'll post an update just in case it helps anyone else out in the future.

I located the item in the oil gallery circled above, this is the top chain oil nozzle, it screws directly into the head behind the oval cover on the timing chain housing.

The engine has not been run for over a year so prior to starting I primed the oil system by cranking the starter with no coil lead. It took about 20 / 30 seconds to build up pressure on my analogue gauge.

Whilst it was cranking with pressure I was checking for oil out of the top chain spray nozzle and found nothing. I unwound the nozzle from the head and cranked again. This time oil poured out the hole indicating oil was making its way into the head oil gallery
After cleaning out the top chain oil nozzle I used the airline gently into the head oil gallery. Nozzle refitted and now squirting oil I went for an engine start.

Once started I get 60 / 65psi of oil pressure within 2 to 3 seconds. I left the engine for 3 hours and started again. I once again had 65psi oil pressure within a couple of seconds of starting and the engine runs smoothly with no noises. I pulled the rocker cover off and could see plenty of oil had made it into the head and over the cam assembly's.

Not sure what I've done but it didn't do that last year. Fingers crossed it will be okay after leaving it for a couple of days If it does start with zero oil pressure that doesn't build up, I'm already concluding it could only be a faulty anti drain back oil filter valve.

Does anyone suggest a good oil filter for the 18RG engine?

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