Timing chain loose due to line bore

[Ididntdoit]

The timing chain has slack on both sides generally in my experience one side is always tight even when "at rest"- With a strait edge across the gears the opposite side will tighten up and the measured side will deflect by about 3/16".  This is a new comp cams magnum timing set. The block was freshly machined/line honed and could have been done before too (dont know blocks history) should i try another set? Not worry about it? Does anyone make a shorter set? Again, it is not as loose as a worn out set but just seems looser than any other "new" installation i have done before. Then again, i've never had a block line bored before.

[machoneman]

Cloyes and other suppliers offer (Summit, Jegs, etc.) special undersize timing sets for line-bored engines:

"Cloyes offers Tru-Roller sets with reduced center-to-center distances of .010 and .005 inch. These are intended to address issues caused by excessive line boring but I’ve rarely had to use them. On several occasions, customers have requested the reduced center-to-center sets from other manufact-urers to correct a perceived loose-chain problem. However, the standard Cloyes timing chains and parts remedied the problem."

http://diyford.com/ford-fe-engine-timing-systems-ultimate-guide/

[Ididntdoit]

I guess the question is - how loose is acceptable?

[machoneman]

Rollmaster's Page 2 has a good explanation: http://www.romac.com.au/pdf/Centre%20Distances.pdf

[machoneman]

Added the note since I think it was Barry R.'s quote.

Cloyes and other suppliers offer (Summit, Jegs, etc.) special undersize timing sets for line-bored engines:

"Cloyes offers Tru-Roller sets with reduced center-to-center distances of .010 and .005 inch. These are intended to address issues caused by excessive line boring but I’ve rarely had to use them. On several occasions, customers have requested the reduced center-to-center sets from other manufact-urers to correct a perceived loose-chain problem. However, the standard Cloyes timing chains and parts remedied the problem." Btw, think this was Barry R's quote.

http://diyford.com/ford-fe-engine-timing-systems-ultimate-guide/

[Barry_R]

Some guys will disagree - but I have had by far the best luck with Cloyes products, whether in their own boxes or reboxed as Ford Motorsports.  I have had at least a 90% success rate when providing a standard Cloyes set to customers looking to go .005 or .010 under because other brands were too loose.  I have sold very, very few of the undersize sets as a result.  There are some very pretty billet looking parts out there, but the dimensionals are simply not correct or consistant.

[Ididntdoit]

Got a fresh Cloyes on the way now - I will report back as soon as its in my hands and installed - I talked to my machinist and he concurred - said in all his years he has only used 3 shorter sets out of 100s of motors of all makes....He also said they only had to line hone my block...

[CaptCobrajet]

Just honing the mains would not shorten it materially.  I agree with Mr. Barry that the Cloyes stuff is the best and always has a better fit than the others.  I am not in love with the Ford Racing offering because they have split rollers.  Even the Summits (Cloyes gears) have a true roller chain in them.   The Cloyes gears are a few thou larger in diameter than most others.  You can check the diameter with a dial caliper and two 1/4-inch drill bits.  The circumference of course changes by about three times the diameter, which effects the tension fairly quickly.  Once you get a good fit, take the chain back off and drop it in a bucket of oil overnight.  You will thank me in 50,000 miles!

[Ididntdoit]

Just to close the loop on this - the new standard chain fits perfectly - anyone want a "new" comp cams magnum set - from china?

[machoneman]

That's good to know.

I'd sell it to a Chevy guy.....tell him it's a trick unit for a SBC