Cam chain clearance to block
06-29-2018, 08:52 PM
#31
Registered
gen 6 is a 10 bolt pattern, so how can the cover be for can gen 6 when it only had 6 bolts?
I'm asking because a gen 4 won't seal a one piece rms like on the gen 5/6 so if the cover you used was for a 1 piece RMS and only had 6 bolt holes it must have been a gen 5 cover (because gen 6 has 10 bolt holes like I mentioned earlier) from what I've found, gen 5 covers are hard to find especially one that is cheap and requires just a little clearance work, that's what I'm asking where you got it and which one it was. All the "gen 5" covers I've found are $175+.
Rooster I found out the rollmaster CS2090 is the NON nitrited version of the timing set and http://www.romacusa.com/index.html is only a single US distributor not the main US distributor so it may be found some where else for cheaper BUT they did quote me $110 for the CS2095 which is cheaper than anyone else I've found so far.
I'm asking because a gen 4 won't seal a one piece rms like on the gen 5/6 so if the cover you used was for a 1 piece RMS and only had 6 bolt holes it must have been a gen 5 cover (because gen 6 has 10 bolt holes like I mentioned earlier) from what I've found, gen 5 covers are hard to find especially one that is cheap and requires just a little clearance work, that's what I'm asking where you got it and which one it was. All the "gen 5" covers I've found are $175+.
Rooster I found out the rollmaster CS2090 is the NON nitrited version of the timing set and http://www.romacusa.com/index.html is only a single US distributor not the main US distributor so it may be found some where else for cheaper BUT they did quote me $110 for the CS2095 which is cheaper than anyone else I've found so far.
06-29-2018, 09:04 PM
#32
Registered
iTrader: (1)
Well someone should tell summit they are wrong. For the record mine are gen 6 with these exact covers.
https://www.summitracing.com/parts/nal-10230954
https://www.summitracing.com/parts/nal-10230954
06-29-2018, 10:15 PM
#34
Registered
iTrader: (1)
why not use the right chain in the first place... the Gen 6 with step nose cam/retainer system is great!!! wish all BBC were this way, to run a dbl row chain you need to clearance the block... the single severe duty chain system by Cloyes (9-3649x3) made for the Gen 6 is a brute single row true roller, multiple keyway for variety of timing positions. Just my $.002
Not pushing the timing set per say but click to read the comments since it comes with the retainer plate:
https://www.summitracing.com/parts/n...1053/overview/
and:
http://www.chevelles.com/forums/18-e...iming-set.html
When installed in a Gen VI block, excess forward travel on a Gen VI hydraulic roller cam is limited by a factory thrust plate. The reduced-diameter Gen VI cam nose indexes into the thrust plate’s center hole, and the plate in turn bolts to the block’s front cam boss. Although endplay still should be checked and verified (particularly when using thicker-than-stock aftermarket timing sets), it’s not affected by different front gaskets.
It turns out that many old Mark IV blocks also have thrust-plate provisions. Back in the day, the plate was used on rare factory reverse-rotation, geardrive, flat-tappet cam applications. Westech Performance checked out an original factory high-performance block, and it turns out the thrust plate’s bolt spacing (even though it performed a different function) is the same as on the late models. So assuming your Mark IV block is drilled with these two extra holes (as shown in the photos, approximately 2.394 inches on-center spacing), you can install a Gen VI cam and timing set in the Mark IV block using the late-GM Gen VI cam retainer. Sand the thrust-plate as needed to achieve the needed endplay (about 0.002 to 0.007 inch).
The one remaining drawback to this retrofit was the lack of a double-roller Gen VI timing chain. There was insufficient clearance underneath the factory eight-bolt Gen VI timing cover to clear the thicker double-roller chain, so until recently only single-roller Gen VI chains were available. But now Comp Cams sells a new Gen VI eight-bolt cover (PN 217) that clears its trick multikeyway billet Gen VI-style double-roller timing set (PN 7101). On the Mark IV block with a Gen VI-style cam, you would use the original 10-bolt Mark IV-style front cover with the now-available Gen VI double-roller chain.
Because the thrust-plate cam retention solution is a set-it-once-and-forget-it solution, with a Gen VI double-roller chain now available, anyone ordering a custom roller cam for an early Mark IV block with the two extra holes in the front cam journal boss might well consider ordering the custom cam machined with the late-style nose.
It turns out that many old Mark IV blocks also have thrust-plate provisions. Back in the day, the plate was used on rare factory reverse-rotation, geardrive, flat-tappet cam applications. Westech Performance checked out an original factory high-performance block, and it turns out the thrust plate’s bolt spacing (even though it performed a different function) is the same as on the late models. So assuming your Mark IV block is drilled with these two extra holes (as shown in the photos, approximately 2.394 inches on-center spacing), you can install a Gen VI cam and timing set in the Mark IV block using the late-GM Gen VI cam retainer. Sand the thrust-plate as needed to achieve the needed endplay (about 0.002 to 0.007 inch).
The one remaining drawback to this retrofit was the lack of a double-roller Gen VI timing chain. There was insufficient clearance underneath the factory eight-bolt Gen VI timing cover to clear the thicker double-roller chain, so until recently only single-roller Gen VI chains were available. But now Comp Cams sells a new Gen VI eight-bolt cover (PN 217) that clears its trick multikeyway billet Gen VI-style double-roller timing set (PN 7101). On the Mark IV block with a Gen VI-style cam, you would use the original 10-bolt Mark IV-style front cover with the now-available Gen VI double-roller chain.
Because the thrust-plate cam retention solution is a set-it-once-and-forget-it solution, with a Gen VI double-roller chain now available, anyone ordering a custom roller cam for an early Mark IV block with the two extra holes in the front cam journal boss might well consider ordering the custom cam machined with the late-style nose.
Last edited by SB; 06-29-2018 at 10:28 PM.
06-30-2018, 01:23 PM
#35
Hey Baja.. I wasn't trying to offend you, and if I did, my apologies... I use the Cloyes in my Gen 6 builds and have never had an issue ... that being said if you do use your dbl row, I'd say make sure you have sufficient clearance for potential unknowns, chain whip, stretch etc etc... and also if your block has been align bored/honed will be helpful to know how much (even new blocks need some love sometimes) they make chain kits for .002" to .010" .... happy boating!!!
Prepping for surgery.
06-30-2018, 01:45 PM
#38
Thanks. I don’t mind grinding but I’m wondering if the Rollmaster unit is suspect. I’m curious of the longevity of the Torrington bearing. Perhaps it’s handy for drag cars for ten seconds at a time but I want to keep this engine until it melts from old age.
06-30-2018, 04:47 PM
#40
Registered
First off I owe crude intentions an apology, I was wrong, I had my numbers reversed. Mark 4 covers have 10 bolts and the ears for a 2 piece seal, a gen 6 has a 6 bolt cover and no ears for a 1piece seal, AND a gen 5 has 10 bolts and no ears for a 1 piece seal.
Rooster, Eddie Young uses the rollmaster 2095 with a stock gen 6 cover that they clearance the webs on the inside of the cover..... Post #16
Timing set for gen v block with step nose cam
Per Romacusa the CS2090 is the same as the CS2095 but it's not nitrited, I can't verify this though as there only one distributor.
I called Cloyes and they only have a single roller .250 pin.
I also called Howard's and their sets are made by SA gear so it's basicallyba SA gear set and Eddie Young says the gears are good BUT the chain gets sticky (see above link).
Mike tach, also said that there are two different cam retainer plates. I think this is related to cam end play?
Timing set for gen v block with step nose cam
Rooster, Eddie Young uses the rollmaster 2095 with a stock gen 6 cover that they clearance the webs on the inside of the cover..... Post #16
Timing set for gen v block with step nose cam
Per Romacusa the CS2090 is the same as the CS2095 but it's not nitrited, I can't verify this though as there only one distributor.
I called Cloyes and they only have a single roller .250 pin.
I also called Howard's and their sets are made by SA gear so it's basicallyba SA gear set and Eddie Young says the gears are good BUT the chain gets sticky (see above link).
Mike tach, also said that there are two different cam retainer plates. I think this is related to cam end play?
Timing set for gen v block with step nose cam
Last edited by Mohavvalley; 06-30-2018 at 08:25 PM.
