Can't Rev 18rg!

[DaveSpec]

Alright, so another problem so far with my beloved new 18rg...
Have rebuilt the engine and run it. Runs ok, backfires through the exhaust everynow and then and has stopped backfiring through the carbies. Took it for a run the other day and i couldn't rev the engine. I dont have the tacho connected yet so im not sure at what rpm i get to but i'd say its around 3000rpm and the engine wont rev anymore, it just sound like theres too much fuel and it cant burn it properly.
Not sure if its the carbies - rebuilt 45mm twin webbers
or the ignition advance - seems to be running ok on the idle at around 13degrees
or the value timing - this part is most concerning to me because the guy before me blew two pistons because the timing slipped.
For I have the timing so that the piston is on TDC and the intake camshaft is about 5mm from being at TDC (aligned with the arrow on the cam bearing cover) and the exhaust cam is about 3-4mm before the same spot.
I'm not sure if the chain is worn but it does hit the top of the tappet cover sometimes so im not sure if this is caused by the tensioner or the chain or if toyota just likes that sound??

anyhelp would be greatly appreciated because i love these cars and cant wait to drive her

[airfireman1]

Chain should not hit the cam cover, Chain may be worn an stretched but also the tensioner may be worn, chain are easy to get. Holden V8 think it was 253 not sure will fit the top and standard 18 fot the bottom. Tensioners are unobtanium.
Cam timing tool is the go.I bought one from the good ol USA but I am sure some one on your side of the country has done the same

[DaveSpec]

Hmm might see if i can track a timing tool done.
Not really sure how these tensioners work on these engines but the ex owner said it was the tensioner that allowed the chain to slip and the adjustment screw has been fillin in with some sort of silicon adhesive so i dont trust it a whole bunch

[airfireman1]

Cam timing is critical and also cam chain slackness can alter timing, if the adjuster is faulty it is not doing its job properly. Try sleeka spares for a secondhand adjuster and the green 18r service manual is invaluable for setting the timing and chain tensioner correctly. Just a slight amount of incorrect timing can make a huge difference in power output.
The 18rg should pull hard all the way to 8000rpm

[MorGo]

The tensioner should be installed so that there is only few mm of slack in the chain between the cams.Then there is no possiblities to have loose chain/timing.
Oil pressure just takes care of the fine tuning of the chain tension.

[DaveSpec]

When i start at TDC i can get the chain nice and tight with not much play between the cams but as i turn the engine over by hand, about when the cams are not pushing any of the values down, i get heaps more slack than i should, maybe a cm between the cams.

[4th surf]

Dave with what you've written I think that you've probably answered your own question and it really sounds like a timing issue. Even with the twin webbers not jetted correctly she should still "Rev like a chainsaw" and "Bark like a really angry dog". You have an issue with worn or incorrect timing chains as there is no way you should have 10mm of movement at rest, 3-5 maybe but 10? You'll destroy the engine there.

Add to post check wear on the gears themselves too

[ToyTA22]

SleekaSpares has new timing chains, top and bottom for $70 + $15 post on ebay.
If you contact him direct he may do a deal on chains and gears for you. He is good to deal with.
As mentioned by 4th surf, gears do wear as well and can cause premature wear on new chains.

I have no business links with Sleekaspares except being a happy customer.

[Wil8115]

#1 In. Lobe points to 9 o'clock, #1 Ex. Lobe points to 3 o'clock. Both cams should
have that little notch at/very near 12 o'clock.

Need to tighten your slipper on the left until those notches are at 12 o'clock.
I doubt your chains are that stretched.. but if they are..

bottom chain is same as 18RC. top chain is same as 21R-22R early tall deck-98 link double row.
Not the single row or the short deck 22R(85-95) if you guys ever got those.

[DaveSpec]

That is very helpful wil, thanks will try it tomorrow. i'm not use to these types of tensioners so wasnt sure when its right or not. The bottom chain has been replaced but the top one has an unkown history so im not sure about it but i an get it very close to the value timing without using the tensioner so i'll give this another go

[Omegaman]

Also to take note of, is that the tensioner, must be primed in oil before fitted. This gives it it tension properties.