[L67] double row timing chain benefits

[Wombles]

Hi guys.
I know its a usually asked question but what are the advantages of a double row timing chain?
Builder would like to know.
Im currently building an engine up with a 'Stage 2' cam from MACE. Will most likely have 105 springs or LS springs. Will be a fairly tough engine.. Starting off with 10 PSI with an overdrive kit then when its run in it will get 19 PSI. So would a double row be better in this or will a single row be fine. Will be deleting the balance shaft and maybe even the tensioner.

Also how much of the timing case gets removed?

Cheers guys!

 

[jas98]

is your builder an engin builder?lol.....i would have thorght he "should" know.....

anyway i think its just stronger, you dont kneed a tensioner, and you have to remove the balance shaft but if you do its best to get everything balanced pretty darn good...sure some say they didnt do it and its fine but then theres others that regret it big time

 

[sleepinvt]

do you actually have to remove the balance shaft and weld the rear plug, or can it just be disabled?

 

[Decicrate]

When you start to use bigger profile cams and heavier valve springs you put more strain on the timing chain. The standard single row chain tends to stretch and the tensioner wears very quickly under the increased load.
The wearing tensioner will add particles to the oil and the combination of chain stretch and the worn tensioner will allow for the cam timing to change slightly.
The whole timing case assembly needs to be removed.

If the engine is out, it is quite easy to plug the oil feed to the balance shaft and delete it all together. If the engine is in the car and the rear balance shaft bearing is in good condition just leave the shaft in and remove the drive gear.

 

[cander24]

Decicrates advice above is spot on.
Dont muck around, go with the double row straight up. Heavier valve train will chop out a single row tensioner in no time. This setup does NOT use a tensioner. You will then likely run into clearance issues with the chain wheel scraping the inside of the timing cover, oil pump. This can be overcome by machining down the face of the oil pump cover or using 2 timing cover gaskets to space it off a little more. Use genuine GM gaskets here, not aftermarket ones.
As above, if you're doing the work with the motor in place, just remove the drive gear off the end of the balance shaft and it will effectively just sit there doing nothing. Better would be to remove the shaft all together. If you go this way you'll need to then also block off the rear balance shaft bearing oil supply. This can be done a few ways but I prefer to cut a thread in it with an intermediate tap (8mm from memory) and dont cut it all the way through, leaving some of the thread depth not fully cut (hence using a starter or intermediate tap). Then I screw in a socket head grub screw until it locks up in the thread which was not fully cut. This uses the same principle of a tapered pipe thread. Make sure the grub screw goes in far enough so as to not protrude out the back and hold off the rear main plate seal.
If you do a search on here and L67 Torque ive given this advice with pictures a few times in the past.
Hope that helps.
Cheers

 

[Wombles]

Cheers guys. Thanks for that!

 

[greasemonkey24]

holy ship!!! so glad i seen this thread i was intending to fit my double row myself and had no idea about whats involved lol (amature) haha cheers!!!