Street89vette

Short neck water pump is flat against timing cover. Considering Billet cover but looks like clearance issue. Can anyone recommend cover with nylon cam button? Cam retainer is also another issue. Double roller was grinding against block. Grinded for clearance but might get rid of the double chain. Any suggestions are appreciated.

blackozvet

you will have to use a stock style timing cover - usually the water pump will be almost touching (you can use 2 x water pump gaskets to get a few thou more clearance)

you can buy the Lunati double row with a torrington bearing if its hitting the block.

use playdough to measure the thrust clearance from cam end to the cover then buy a button. if you get a nylon button you can trim them down, or if you have an exact clearance buy a bearing cam button.

C409

..... I used the polished cast aluminum timing cover with Summit Racing brand .100" thick water pump gaskets ... I also ground down the heads of the water pump rear cover bolts ... no contact and plenty of support for the cam button .....

Kevova

If you are using a 87+ (roller) block there's a cam retainer which would eliminate the need for cam button. If you are using a roller cam you should try to avoid the "silent mesh" type chain. Thrust bearing may require additional machining or special cam gear.

mtwoolford

what style block do you have? Factory oem roller cam, one piece rear seal (86-87 and up), or earlier?

cv67

you can use a single roller most do double. Get a cover that fits or do some grinding if you have to. If youspace out one pulley it can throw everything else off, too.

C409

..... Double roller necessity depends a lot on how much valve spring pressure you have .....

Street89vette

L98 roller block and 1pc rms. 600 lift springs. last build broke the retainer with double roller timing gear. Might go back to regular chain.

mtwoolford

"broke the retainer" ?, if by retainer you mean the flat thrust plate that fits over the step on the nose of the cam and at the rear surface of the timing chain sprocket, I don't see how that could possibly even happen...and I'm not saying it didn't ..I just don't see how it could happen unless there was a mismatch of parts. Which could and I'm sure has happened.

Street89vette

agree. didn't think that would happen. Chain and gear bolted on perfectly and looked good. still not sure what happened.

C409

..... Do you have the screws that held the retainer to the block ? .....

GREGGPENN

I used a double-roller partly for this reason. ANY chain will stretch with age/time...which means you'll lose some mechanical advance. (Loss of mechanical advance is ONE reason cam manufacturers/grinders like to "build in" 4-deg of advance. So, there will still be SOME advance down the road.

C409 is pointing out the stretch will happen faster with more resistance in your rotating assembly (RA). Stouter springs will up the resistance.

In my notes from my 2010 build, it says I purchased a time cover from White Performance that worked well with my double roller. This MIGHT be the cover I used...
http://s1354.photobucket.com/user/wh...6b554.jpg.html

To be sure, you should call to verify if it will cover a double-roller w/o issue. My double-roller is a Cloyes and my cam is a Bullet grind.

Looks like the one I used on my motor anyway....

Street89vette

nice work... engine pic is great

Street89vette

will upload pics. here is the timing set i bought and installed 6-2016. I may have installed the wrong timing gear set. "Late Model" in discription

Chevy SBC 350 Late Double Roller 9 Keyway Billet Steel Timing Chain Kit(Brs/Brg)






Took block into machine shop for 383 build. Tech pointed to the front of the block and said "If your gonna keep running that double roller you will need this space ground down like this" your welcome. How did he know?

GREGGPENN

I should have included that spring pressure, cranking compression, rocker ratio, and cam ramp profile are among the things that will contribute to higher resistance when turning the motor. RPMs and even oil weight too.

Higher resistance = more value in opting for a double roller chain. More experienced builders might know even more reasons.

FWIW, the items that increase rotational effort can "rob" horsepower. For example, if you use MORE spring than necessary, it might cost a couple HP. Or...more cam (or rocker) than your heads can "breath", yada, yada, yada....

Kevova

I would be concerned with what caused cam retainer to break.

rklessdriver

Pretty obvious what happened there.

You can see the retaining plate was pinched between the cam and upper timing gear... when the upper timing gear was bolted up, it ended up pulling the cam forward into the retaining plate.....

I will bet the upper timing gear was not machined deeply enough to fully seat the torrington thrust bearing slightly below flush with the back of the gear.

Who made that timing set?

Pulling the pic description and reverse searching on google links me to an ebay seller of CHINA mfgr'd engine parts.... Not good. Not good at all.

I run double rollers on everything I build that uses a chain if possible.

On L98 based SBC builds I like the Cloyes PN 9-3545X9.
Will

mtwoolford

I think I can see it from here; the screws that hold the retainer on are supposed to be "button Head" torx bolts which are much thinner and provide clearance between themselves and the back of the timing chain sprocket; regular cap screws are too tall; I've used regular cap screws but have always ground down the heads somewhat to gain this clearance; too tall of screws would also force the sprocket forward, jamming the stepped nose of the cam into the retainer, explaining the damage to the nose of the cam, and ultimately, the broken retainer / thrust plate.