Base timing on a 2TG (or others)

[Gabe]

Ok, I bought a 2TG that had been rebuilt on the cheap. When I say rebuilt, I mean the head had been given a good working over, and the bottom ent was untouched. The motor had no compression (or very low compression) across all 4 cylinders. The bloke said that all that was required was new rings.

Now, being the sceptical bastard I am, I didn't believe him. I got the engine home, pulled the cam cover off and found something that I believe to be quite odd.

My understanding is when you fit the timing chain, you first crank cylinder 1 to TDC, indicated by a groove in the crank pulley. You then wind the cams so the dots on the sprockets are pointing up, then you fit the chain.

Now, if I crank my engine by hand, the two dots on the cams are never pointing up at the same time, and only one of them is in sync with the grove on the crank pulley. It seems that there are a few points in the engines cycle, that both the intake and exhaust valves are open at the same time.

I'll try to get some pictures tonight, but in the mean time, can anyone let me know if my assumptions are correct?

Cheers,

Gabe

[airfireman1]

If the cam timing is the same as the 18rg and I believe it is. when the No1 piston is at TDC both camshafts should have the slot (near the sprocket) at the top. Do a search for 2tg cam timing and I am sure you will come up with some usefull info.
Cheers

[Gabe]

Did a search, but found nothing that helped me.
Maybe I was using the wrong search terms, don't know.

That's what I was thinking, would cam timing that far out account for stupidly low compression across the board?

[w810sc]

yeah that will do that, its pretty much the over lap of the cams (both intake and exhaust valves are open).
Reset you cams and do another comp test.
btw what was the results of your 1st comp test
fonz

[auzzi_17]

I got stuck too, this will help, have a good read

http://www.toymods.net/forums/showthread.php?t=7573