G13B valve issue

UgO_ssgti · Post by **UgO_ssgti** » April 22nd, 2008, 6:14 pm

Hi Guy.
I know you know these engine heads very well, so I need urgent help. When I was trying to loosen the camshaft sprocket screw, the sprocket jumped 4 teeth on anti clockwise direction before I realized what was happening.. I thought the clicks came from the screw..

Did I hit the intake valves with the exhaust valves or with the piston in cilinder 4??

Post by **Guy Croft** » April 23rd, 2008, 9:50 am

You might be OK!

I think:
with the camwheels on those marks pistons 1&4 are at TDC. No 4 cylinder the valves are closed and will not have opened at all because it's on compression. On cyl 1 if you turn the inlet cam anticlockwise it closes the inlet valve. I can't see the right-hand picture but I think only the inlet cam moved, right?
My advice is set the cams where they should be, turn the engine over slowly by hand and make sure nothing is hitting. Then put rubber plugs (you can squash soft paper into the plug holes) into the plug holes and wind the engine over hard with a long T bar by hand. Simple alternative to a compression test. If the plugs fire out and hit the ceiling, you're OK.

GC

UgO_ssgti · Post by **UgO_ssgti** » April 23rd, 2008, 2:48 pm

It was the exhaust that moved, and the cylinder 1 is the one on compression. I can get you some pictures.
After that, I set the timing on cams and on crank (but I'm not sure if the timing on crank is right) and turned the engine by hand, nothing hits, so start the engine and it mades much more noise than the usual.. it seemed that it was running on mechanical lifters..
Maybe a compression test is the best solution..

Post by **Guy Croft** » April 23rd, 2008, 3:03 pm

OK, if the ex cam is turned counter-clockwise it opens the valve up at TDC. Don't run it - take the head off and check.

'Better safe than sorry'. All it costs is some time and a few gaskets. You might have bent the ex valves and it will smash the engine to bits if you run it or crank it too long.

GC

UgO_ssgti · Post by **UgO_ssgti** » April 23rd, 2008, 3:35 pm

Ok, thank you very much for your time! I'll take off the head to see what I have done... I'll post the updates.

UgO_ssgti · Post by **UgO_ssgti** » April 25th, 2008, 1:40 pm

I have attached a pdf showing the risks of incorrect cam timing on this engine.

UgO_ssgti · Post by **UgO_ssgti** » May 1st, 2008, 10:13 pm

Well, with the cylinder head out I turned the exhaust cam as I said earlier and there will never happen valve contact between intake and exhaust valves because the intake ones were closed, although not totaly closed. The contact between exhaust valves and piston it seemed it never happened too because there is no marks on the piston and the piston itself have a cavity. But, when I removed the last intake valve, on cylinder 4, it offered some resistance.. I need to check if it is bended, and I´ll do the same with the exhaust ones.

UgO_ssgti · Post by **UgO_ssgti** » May 23rd, 2008, 8:18 pm

Well, I already have the engine assembled. The valves are not bended. It was said to me that I have to much clearance on exhaust valve guides and I would need to buy new valves and guides.. that would be very expensive, so I just clean up the head, prepare the valves and tried to do some work on the ports but because the lack of time I did only some details. I realized that there is a lot of work to be done on this head although it is a very good one.