installed roller rockers on my 91 C4 L98
03-31-2011, 05:47 AM
#1
Pro
Thread Starter
installed roller rockers on my 91 C4 L98
I had posted this info in response to a post in the C4 parts for sale, thought i might as well post in C4 Tech/Performance.
I installed roller rockers on my 91 L98 C4. it has the 113 alum heads with the factory "assembly aids" to hold the pushrods in place as the engine goes down the assembly line. to the untrained eye they look like guideplates, but they're not hardened, and the slot's too wide.
I upgraded the rocker studs from the factory 3/8" to the stronger 7/16". the upper portion of the factory rocker stud is 3/8". the bottom that screws into the cyl head is 7/16". the upgraded rocker stud is 7/16" thread top and bottom. I used ARP 134-7103.
stock, the 91 L98 comes with the self-aligning stamped steel rocker arms mounted on the 3/8" studs. I decided to go with non-self-aligning, 7/16" stud roller rockers. I also chose steel rockers over aluminum, ending up with the chrome-moly versions. However, I've never had an aluminum rocker set ever wear out yet, and I've never been disappointed with the performance of any aluminum-bodied rockers that i've bought, so steel vs aluminum, this is a matter of personal choice.
Since I was going with non-self-aligning, this required replacing the assembly-aid not-really-guideplates with conventional SBC hardened guideplates, and the pushrods with hardened pushrods. I measured the stock GM pushrods at 7.194" long. so I used TFS 7.200" no problem. Remember, this is for a GM factory hyd roller cam (taller lifters than old-school SBC, therefore shorter pushrods)
no roller rockers will fit under the un-modified stock L98 valve covers (the ribbed cast magnesium ones) because of the drip tabs. you have to remove the drip tabs. although I used a die-grinder, various methods have been used to remove these depending on how cave-man you are: dremel tool, die grinder, vise-grips...
if you go with 3/8" self-aligning narrow-body RR's, as long as you trim the drip tabs, I think you'd be home free. you don't install hardened guideplates, and you could get away with re-using the factory pushrods. however, "waiver of liability" time, the rocker arm, valve train manufacturers recommend that you replace pushrods when you change out rockers. In any event be sure to use moly-lube on the pushrod seat of the RR if re-using pushrods.
Since I was upgrading to 7/16" rocker stud size, I think that narrows down the field of available RR options, e.g. I don't think anybody makes that size in narrow-body, self-aligning at a price that I can afford from a source that I trust. and I personally don't like self-aligning because i'm suspicious about valve-guide side-load wear, again a personal preference.
I've seen that regular-width RR's will fit, so i didn't order the narrow-body versions. I found that narrowing the valve-cover bolt stand-offs facilitates wiggle-room, it makes getting the VC's on-and-off a whole lot easier. This is an an easy thing to do while you have the die-grinder out for removing the drip tabs (don't grind too much on the bolt stands otherwise you'll be using that JB Weld). and similarly I used some channel-locks to squeeze the breather/PCV baffles a bit for side-to-side clearance.
to further help out with VC clearance, I found that Crower makes a shorter poly-lock. Where the magnesium C4 L98 VC slopes down at the ends, the clearance to the poly-lock to VC is REAL TIGHT. the sloping shape causes decreasing clearance. if you're going with the 7/16" rocker studs, Crower 86050S-16, around $35. they also have the shorter poly-locks in 3/8" if that's your flavor.
Since I was also installing new hardened pushrods to go with my hardened guideplates for the non-SA RR, I used moly-lube on both ends of the pushrods to help with the seating surfaces break-in (lifter & RR), and I also put some moly-lube where the pushrod slides against the guideplate.
I read that the stock L98 valve springs will accommodate the extra lift of 1.6 RR's, so I ended up going that route. Since my C4 has less than 50K miles and it's not seeing too much all-out floor-board action (yet), I didn't swap out the springs. saving that task for when I do the camshaft (or when the race-track is re-opened, whichever comes first).
When I had all of this reassembled initially and started up, I had valve lash clicking that I just couldn't adjust out, no matter how precisely I adjusted the lash, no matter which method I used. At first I swapped out the RR's (that's really how I ended up with 1.6's) and that didn't eliminate the ticking. I was able to pinpoint it with a stethoscope to a particular rocker location, but couldn't get the noise to go away no matter how much attention was paid to those rocker adjustments, very annoying.
GMPP sells an updated "2nd design" set of hyd roller lifters at a reasonable price (PN 12371042, yup, crap, unbudgeted "emergency" expense), so, off comes the darn AC bracket, off come the valve covers, off comes the TPI, out comes the distributor, the manifold (getting the routine down), swapped out the lifters, loc-tite on the spider bolts, moly-lube on the pushrod seat of the lifter, new gaskets, RTV, reassembled it all, and voila, no ticking any more.
note: I was going to use allen-head screws drilled for safety-wire on the spider retainer bolts, but there's not enough bolt-head clearance to the bottom of the TPI intake manifold base. shucks.
Another tangent that I went off on during this whole episode, was with the initial go-round using 1.5 ratio stainless steel RR's. I couldn't get the roller tips centered over the valve stems, no matter how much I fiddled with loosening the rocker studs, nudging the guideplate over, re-torquing, just couldn't get the pair to line up for a few of the cylinders. ended up going with 2-piece adjustable guideplates (another emergency expense). in retrospect, not sure if this might've been attributable to mfg tolerance of the made-in-china 1.5 RR's. That's another reason why I went with top-shelf RR's when optioning up to the 1.6 RR's to cure the valve lash noise (which I at first thought was attributable to the made-in-china RRs, however wrongly so). but since I already had the 2-pc guideplates on there, I kept those on, re-adjusted for the 1.6RR's. I'm not sure if the GM 113 alum heads have some funky rocker-stud spacing for a couple of the cylinders, probably not.
I installed roller rockers on my 91 L98 C4. it has the 113 alum heads with the factory "assembly aids" to hold the pushrods in place as the engine goes down the assembly line. to the untrained eye they look like guideplates, but they're not hardened, and the slot's too wide.
I upgraded the rocker studs from the factory 3/8" to the stronger 7/16". the upper portion of the factory rocker stud is 3/8". the bottom that screws into the cyl head is 7/16". the upgraded rocker stud is 7/16" thread top and bottom. I used ARP 134-7103.
stock, the 91 L98 comes with the self-aligning stamped steel rocker arms mounted on the 3/8" studs. I decided to go with non-self-aligning, 7/16" stud roller rockers. I also chose steel rockers over aluminum, ending up with the chrome-moly versions. However, I've never had an aluminum rocker set ever wear out yet, and I've never been disappointed with the performance of any aluminum-bodied rockers that i've bought, so steel vs aluminum, this is a matter of personal choice.
Since I was going with non-self-aligning, this required replacing the assembly-aid not-really-guideplates with conventional SBC hardened guideplates, and the pushrods with hardened pushrods. I measured the stock GM pushrods at 7.194" long. so I used TFS 7.200" no problem. Remember, this is for a GM factory hyd roller cam (taller lifters than old-school SBC, therefore shorter pushrods)
no roller rockers will fit under the un-modified stock L98 valve covers (the ribbed cast magnesium ones) because of the drip tabs. you have to remove the drip tabs. although I used a die-grinder, various methods have been used to remove these depending on how cave-man you are: dremel tool, die grinder, vise-grips...
if you go with 3/8" self-aligning narrow-body RR's, as long as you trim the drip tabs, I think you'd be home free. you don't install hardened guideplates, and you could get away with re-using the factory pushrods. however, "waiver of liability" time, the rocker arm, valve train manufacturers recommend that you replace pushrods when you change out rockers. In any event be sure to use moly-lube on the pushrod seat of the RR if re-using pushrods.
Since I was upgrading to 7/16" rocker stud size, I think that narrows down the field of available RR options, e.g. I don't think anybody makes that size in narrow-body, self-aligning at a price that I can afford from a source that I trust. and I personally don't like self-aligning because i'm suspicious about valve-guide side-load wear, again a personal preference.
I've seen that regular-width RR's will fit, so i didn't order the narrow-body versions. I found that narrowing the valve-cover bolt stand-offs facilitates wiggle-room, it makes getting the VC's on-and-off a whole lot easier. This is an an easy thing to do while you have the die-grinder out for removing the drip tabs (don't grind too much on the bolt stands otherwise you'll be using that JB Weld). and similarly I used some channel-locks to squeeze the breather/PCV baffles a bit for side-to-side clearance.
to further help out with VC clearance, I found that Crower makes a shorter poly-lock. Where the magnesium C4 L98 VC slopes down at the ends, the clearance to the poly-lock to VC is REAL TIGHT. the sloping shape causes decreasing clearance. if you're going with the 7/16" rocker studs, Crower 86050S-16, around $35. they also have the shorter poly-locks in 3/8" if that's your flavor.
Since I was also installing new hardened pushrods to go with my hardened guideplates for the non-SA RR, I used moly-lube on both ends of the pushrods to help with the seating surfaces break-in (lifter & RR), and I also put some moly-lube where the pushrod slides against the guideplate.
I read that the stock L98 valve springs will accommodate the extra lift of 1.6 RR's, so I ended up going that route. Since my C4 has less than 50K miles and it's not seeing too much all-out floor-board action (yet), I didn't swap out the springs. saving that task for when I do the camshaft (or when the race-track is re-opened, whichever comes first).
When I had all of this reassembled initially and started up, I had valve lash clicking that I just couldn't adjust out, no matter how precisely I adjusted the lash, no matter which method I used. At first I swapped out the RR's (that's really how I ended up with 1.6's) and that didn't eliminate the ticking. I was able to pinpoint it with a stethoscope to a particular rocker location, but couldn't get the noise to go away no matter how much attention was paid to those rocker adjustments, very annoying.
GMPP sells an updated "2nd design" set of hyd roller lifters at a reasonable price (PN 12371042, yup, crap, unbudgeted "emergency" expense), so, off comes the darn AC bracket, off come the valve covers, off comes the TPI, out comes the distributor, the manifold (getting the routine down), swapped out the lifters, loc-tite on the spider bolts, moly-lube on the pushrod seat of the lifter, new gaskets, RTV, reassembled it all, and voila, no ticking any more.
note: I was going to use allen-head screws drilled for safety-wire on the spider retainer bolts, but there's not enough bolt-head clearance to the bottom of the TPI intake manifold base. shucks.
Another tangent that I went off on during this whole episode, was with the initial go-round using 1.5 ratio stainless steel RR's. I couldn't get the roller tips centered over the valve stems, no matter how much I fiddled with loosening the rocker studs, nudging the guideplate over, re-torquing, just couldn't get the pair to line up for a few of the cylinders. ended up going with 2-piece adjustable guideplates (another emergency expense). in retrospect, not sure if this might've been attributable to mfg tolerance of the made-in-china 1.5 RR's. That's another reason why I went with top-shelf RR's when optioning up to the 1.6 RR's to cure the valve lash noise (which I at first thought was attributable to the made-in-china RRs, however wrongly so). but since I already had the 2-pc guideplates on there, I kept those on, re-adjusted for the 1.6RR's. I'm not sure if the GM 113 alum heads have some funky rocker-stud spacing for a couple of the cylinders, probably not.
Last edited by rpoL98; 03-31-2011 at 06:00 AM.
The following users liked this post:
Nilak (12-25-2022)
Nice write up and documentation.
03-31-2011, 08:44 AM
#3
Melting Slicks
Good info. Did you find the cause for the ticking noise in one of the lifters, then?
Also, why would S/A rockers cause more valve guide side load wear than non S/A?
Also, why would S/A rockers cause more valve guide side load wear than non S/A?
03-31-2011, 09:13 AM
#4
Also interested to know if you were able to 'cure' the ticking? Or at least identify it as a lifter issue vs lash adjustment?
I just had a similar thread about 1.6RR ticking on my LT1. It sounds like 1 or 2 rockers are out of adjustment and only does it at idle on a hot motor, and even then not always but usually after extended idle. More than one reply to my thread indicated that what I was hearing is normal and that it is the nature of the beast to tick a bit with roller rockers. I will be pulling the valve covers again and try to identify/readjust a suspect rocker.
I just had a similar thread about 1.6RR ticking on my LT1. It sounds like 1 or 2 rockers are out of adjustment and only does it at idle on a hot motor, and even then not always but usually after extended idle. More than one reply to my thread indicated that what I was hearing is normal and that it is the nature of the beast to tick a bit with roller rockers. I will be pulling the valve covers again and try to identify/readjust a suspect rocker.
03-31-2011, 10:56 PM
#5
Pro
Thread Starter
Joe B.:
i didn't disassemble the suspect lifters. I did notice when adjusting the valve lash that some of the original lifters seemed "spongier" than others, i.e. that it was almost too easy to tighten up the add'l half-turn, or full-turn.... as if the spring was too easy, or, too much clearance between plunger and lifter body (or less build-up of crud?). i was just happy that the noise went away.
regarding my paranoia of valve guide side wear: one of the supposed benefits (and it is debated) of the roller tip is that it can't apply a dragging force across the valve stem tip face, i.e. pull towards intake valley, or push towards the headers since the tip rolls. however, I suspect that the alignment guides of the self-aligning rocker tips (roller or non-roller), since it uses the valve stem tip for maintaining alignment instead of guideplates, when the pushrod wants to go slightly sideways, the valve-stem tip then keeps the pushrod in its' plane instead of the guideplate, but then that means the valve stem tip is exerting a sideways force, the valve guide is then experiencing a side load (towards front or back of motor), and valve guides do wear, leading to oil burning (excepting the valve stem seal...). that's my theory. now whether you only will see that wear if you change your oil once every 20,000 miles and drive for 2 million miles, that's a separate analysis best left to TV commercials (IMHO).
jmgtp:
since it was ticking (pretty noticably) before I swapped out the lifters regardless of which lash adjustment spec/method used (including FSM, i'm talking strictly non-bubba methods), and after I put in the new lifters, using the lash adjustment of the FSM, instantly the ticking was gone. that tells me it was the lifters.
I'd agree that going from stamped steel to full roller rockers you're opening yourself up to additional valve train noise that can't be eliminated by non-bubba methods, i.e. "the nature of the beast" live with it, but, for the clicking that I was getting, it seems something was out of tolerance, and since it was the second set of brand-new RR's, that kinda rules the RR's out as the cause. Also, with both sets of RR's, it was always the same area, e.g. "seems like it's coming from the #6I or maybe the #6E", as an example. and it was just a couple of the positions. most of them were sewing machine quiet.
the stethoscope was pretty useful in ID'ing it down to within a ~2" radius, i.e., "it has to be one of these 2...". I toyed with the idea of replacing just a couple of the lifter pairs, but when i priced them out (wanting to stick with GM's or name-brand), for the price of a handful of lifters, you could almost just get the whole set of GM 2nd design.
again, this is just my own experience, I'm sure others have divergent experiences, etc.
i didn't disassemble the suspect lifters. I did notice when adjusting the valve lash that some of the original lifters seemed "spongier" than others, i.e. that it was almost too easy to tighten up the add'l half-turn, or full-turn.... as if the spring was too easy, or, too much clearance between plunger and lifter body (or less build-up of crud?). i was just happy that the noise went away.
regarding my paranoia of valve guide side wear: one of the supposed benefits (and it is debated) of the roller tip is that it can't apply a dragging force across the valve stem tip face, i.e. pull towards intake valley, or push towards the headers since the tip rolls. however, I suspect that the alignment guides of the self-aligning rocker tips (roller or non-roller), since it uses the valve stem tip for maintaining alignment instead of guideplates, when the pushrod wants to go slightly sideways, the valve-stem tip then keeps the pushrod in its' plane instead of the guideplate, but then that means the valve stem tip is exerting a sideways force, the valve guide is then experiencing a side load (towards front or back of motor), and valve guides do wear, leading to oil burning (excepting the valve stem seal...). that's my theory. now whether you only will see that wear if you change your oil once every 20,000 miles and drive for 2 million miles, that's a separate analysis best left to TV commercials (IMHO).
jmgtp:
since it was ticking (pretty noticably) before I swapped out the lifters regardless of which lash adjustment spec/method used (including FSM, i'm talking strictly non-bubba methods), and after I put in the new lifters, using the lash adjustment of the FSM, instantly the ticking was gone. that tells me it was the lifters.
I'd agree that going from stamped steel to full roller rockers you're opening yourself up to additional valve train noise that can't be eliminated by non-bubba methods, i.e. "the nature of the beast" live with it, but, for the clicking that I was getting, it seems something was out of tolerance, and since it was the second set of brand-new RR's, that kinda rules the RR's out as the cause. Also, with both sets of RR's, it was always the same area, e.g. "seems like it's coming from the #6I or maybe the #6E", as an example. and it was just a couple of the positions. most of them were sewing machine quiet.
the stethoscope was pretty useful in ID'ing it down to within a ~2" radius, i.e., "it has to be one of these 2...". I toyed with the idea of replacing just a couple of the lifter pairs, but when i priced them out (wanting to stick with GM's or name-brand), for the price of a handful of lifters, you could almost just get the whole set of GM 2nd design.
again, this is just my own experience, I'm sure others have divergent experiences, etc.
Last edited by rpoL98; 03-31-2011 at 11:02 PM.
04-14-2011, 04:36 PM
#7
Burning Brakes
I don't know why I couldn't find this thread last night.
I have run into the same problem with the spongy lifter. Great write up!
Are those GM lifters a GMPP part or just GM? How much did you pay for them?
Thanks,
Jeff
I have run into the same problem with the spongy lifter. Great write up!
Are those GM lifters a GMPP part or just GM? How much did you pay for them?
Thanks,
Jeff
04-14-2011, 05:38 PM
#8
Melting Slicks
[QUOTE=rpoL98;1577222384]Joe B.:
regarding my paranoia of valve guide side wear: one of the supposed benefits (and it is debated) of the roller tip is that it can't apply a dragging force across the valve stem tip face, i.e. pull towards intake valley, or push towards the headers since the tip rolls. however, I suspect that the alignment guides of the self-aligning rocker tips (roller or non-roller), since it uses the valve stem tip for maintaining alignment instead of guideplates, when the pushrod wants to go slightly sideways, the valve-stem tip then keeps the pushrod in its' plane instead of the guideplate, but then that means the valve stem tip is exerting a sideways force, the valve guide is then experiencing a side load (towards front or back of motor), and valve guides do wear, leading to oil burning (excepting the valve stem seal...). that's my theory. now whether you only will see that wear if you change your oil once every 20,000 miles and drive for 2 million miles, that's a separate analysis best left to TV commercials (IMHO).
Makes sense. The valve is now doing the job that the guide plates did.
regarding my paranoia of valve guide side wear: one of the supposed benefits (and it is debated) of the roller tip is that it can't apply a dragging force across the valve stem tip face, i.e. pull towards intake valley, or push towards the headers since the tip rolls. however, I suspect that the alignment guides of the self-aligning rocker tips (roller or non-roller), since it uses the valve stem tip for maintaining alignment instead of guideplates, when the pushrod wants to go slightly sideways, the valve-stem tip then keeps the pushrod in its' plane instead of the guideplate, but then that means the valve stem tip is exerting a sideways force, the valve guide is then experiencing a side load (towards front or back of motor), and valve guides do wear, leading to oil burning (excepting the valve stem seal...). that's my theory. now whether you only will see that wear if you change your oil once every 20,000 miles and drive for 2 million miles, that's a separate analysis best left to TV commercials (IMHO).
Makes sense. The valve is now doing the job that the guide plates did.
04-14-2011, 09:55 PM
#9
Pro
Thread Starter
reply to Jeff/MyFirst90coupe:
GM Part No. 12371042.
it's a GM part number, I suspect it's sold as a service package for your local Mr Goodwrench, it's avail from any GM parts counter. I got mine from GMPartsDirect.com for around $205, plus a $22 handling charge, and since i'm in Hawaii, the shipping was $27. if you're in the Lower 48, your S&H should be a lot less.
at Scoggin Dickey they're selling it for $220 right now for this part number.
this part number comes with the 16 lifters, 8 dog bones, retainer spider, and the bolts for the spider.
I think that a single pair of quality lifters (for one cylinder) goes for about $60-$70/pr.
GM Part No. 12371042.
it's a GM part number, I suspect it's sold as a service package for your local Mr Goodwrench, it's avail from any GM parts counter. I got mine from GMPartsDirect.com for around $205, plus a $22 handling charge, and since i'm in Hawaii, the shipping was $27. if you're in the Lower 48, your S&H should be a lot less.
at Scoggin Dickey they're selling it for $220 right now for this part number.
this part number comes with the 16 lifters, 8 dog bones, retainer spider, and the bolts for the spider.
I think that a single pair of quality lifters (for one cylinder) goes for about $60-$70/pr.
Last edited by rpoL98; 04-14-2011 at 09:59 PM.
06-19-2011, 09:58 PM
#11
Advanced
Member Since: Oct 2009
Location: Brantford Ontario
Posts: 62
Likes: 0
Received 0 Likes
on
0 Posts
Nice write up and good information. Sorry for what might seem like a stupid question but, Why did you do this? Was it just step one in a list of things to do? The stock lifter is a hydralic roller lifter, is there anything wrong with this part?
I have been thinking of going to roller rockers and a cam on an otherwise stock engine. Do you think I could get a few ponies out of that?
I have been thinking of going to roller rockers and a cam on an otherwise stock engine. Do you think I could get a few ponies out of that?
06-23-2011, 02:10 PM
#12
Burning Brakes
So you had pretty much had rocker noise until you went with the 2 pc guide plates? I'm fighting this issue again with my rebuilt motor.
Last edited by MyFirst90coupe; 06-23-2011 at 02:13 PM.
06-24-2011, 02:12 AM
#13
Pro
Thread Starter
Stu 91 drop top:
main objective was to get away from self-aligning stamped steel rockers and go with normal SBC roller rockers. I personally don't like the self-aligning design. also wanted 7/16" rocker studs instead of 3/8". I did this project in conjunction with an Edelbrock TPI base & SLP runner install. and headers. and shift kit. etc. a runaway spiraled out-of-control project.
if your stock hydraulic lifters are fine, then they're fine. mine evidently were marginal. the car ran fine before this whole evolution.
usually a cam change will result in significant power improvements, but it is of course possible to choose the wrong cam (bigger is better syndrome) and end up worse off. I've done that too, but not lately. sorry for the belated reply.
MyFirst90coupe:
I went with the 2-piece guide plates because the first set of roller rockers I bought & installed didn't line up with the valve stem tips. very disappointing. so I needed the individual adjustability to get them lined up. at least the 2-piece guide plates are cheap.
then I fired it up and noticed the valve lash noise. I immediately attributed the noise to the made-in-china roller rockers, so with much swearing, gnashing of teeth, etc, I bit the bullet and ordered a set of Comp Cams RR's, decided what-the-heck might as well get 1.6 ratio, same cost.
when those arrived, since the 2-piece guide plates were already on the heads, I left them on, but had to do some more adjusting to get everything lined up perfect.
started it up again, still had valve lash noise. crap! new rockers, new pushrods, old lifters. process of elimination. so I got a set of those 2nd design GM hydraulic roller lifters.
installed those, buttoned it all up. fired it up, valve lash noise gone.
admittedly, that leaves some unanswered questions, like:
- do I need the 2-piece guide plates with the Comp RR's, or would they line up just fine with regular guide plates?
- with the new GM lifters, if I put the made-in-china RR's back on, would it still be quiet?
it's working just fine now, so I'm not going to mess with it.
until maybe when I do the camshaft...
main objective was to get away from self-aligning stamped steel rockers and go with normal SBC roller rockers. I personally don't like the self-aligning design. also wanted 7/16" rocker studs instead of 3/8". I did this project in conjunction with an Edelbrock TPI base & SLP runner install. and headers. and shift kit. etc. a runaway spiraled out-of-control project.
if your stock hydraulic lifters are fine, then they're fine. mine evidently were marginal. the car ran fine before this whole evolution.
usually a cam change will result in significant power improvements, but it is of course possible to choose the wrong cam (bigger is better syndrome) and end up worse off. I've done that too, but not lately. sorry for the belated reply.
MyFirst90coupe:
I went with the 2-piece guide plates because the first set of roller rockers I bought & installed didn't line up with the valve stem tips. very disappointing. so I needed the individual adjustability to get them lined up. at least the 2-piece guide plates are cheap.
then I fired it up and noticed the valve lash noise. I immediately attributed the noise to the made-in-china roller rockers, so with much swearing, gnashing of teeth, etc, I bit the bullet and ordered a set of Comp Cams RR's, decided what-the-heck might as well get 1.6 ratio, same cost.
when those arrived, since the 2-piece guide plates were already on the heads, I left them on, but had to do some more adjusting to get everything lined up perfect.
started it up again, still had valve lash noise. crap! new rockers, new pushrods, old lifters. process of elimination. so I got a set of those 2nd design GM hydraulic roller lifters.
installed those, buttoned it all up. fired it up, valve lash noise gone.
admittedly, that leaves some unanswered questions, like:
- do I need the 2-piece guide plates with the Comp RR's, or would they line up just fine with regular guide plates?
- with the new GM lifters, if I put the made-in-china RR's back on, would it still be quiet?
it's working just fine now, so I'm not going to mess with it.
until maybe when I do the camshaft...
Last edited by rpoL98; 06-24-2011 at 02:43 AM.
06-24-2011, 11:25 AM
#15
Burning Brakes
No, I even used Comp guide plates too.
I have a new shortblock with the GM lifters (same kit you used) and LT4 hotcam. I still have noise.
Had the same noise on the old shortblock after I installed the rollers, found a spongie lifter just like you did. Replaced them, still had the noise after many preload adjustments. Engine started blowing oil out of the valve covers so I figured a new shortblock would solve all my problems...not so much. Pics above are of the "new" engine.
Ironically I have gone through almost the same exact sequence as you, bought the cheap chinese rockers on Fleabay, blamed them for the noise. Bought expensive Comp rockers, still had the noise. Bought lifters, still have the noise. So the only component that I do not have at this point is the 2 pc guide plates.
They are on the way now though.
06-25-2011, 03:56 AM
#16
Pro
Thread Starter
wow, that's exactly what my RR's looked like before I went to 2-pc guide plates. ****-eyed, or, "askew".
kinda implies that on 113 cylinder heads, the rocker-stud, and valve spacing isn't standard SBC.
and I really thought it was the made-in-china RR's (yup, also sourced from fleaBay). now I know.
thanks for answering THAT question.
separately, what size injectors are you running with the LT4 HOT cam? I see the RR's are 1.6.
kinda implies that on 113 cylinder heads, the rocker-stud, and valve spacing isn't standard SBC.
and I really thought it was the made-in-china RR's (yup, also sourced from fleaBay). now I know.
thanks for answering THAT question.
separately, what size injectors are you running with the LT4 HOT cam? I see the RR's are 1.6.
Last edited by rpoL98; 06-25-2011 at 03:59 AM.
06-25-2011, 08:22 AM
#17
Melting Slicks
This alignment issue makes me wonder. Maybe GM had a reason for using the "guide plates that aren't really guide plates" and self aligning rockers on the engine. Also reintroduces the side loading question.
I have 24# multecs on my 1.5X1.6 SA RR'd Hotcammed, modded L98.
I have 24# multecs on my 1.5X1.6 SA RR'd Hotcammed, modded L98.
06-25-2011, 09:54 AM
#18
Burning Brakes
I have the 22lb bosch III's from FIC. Still working on the tune with Mick but I really have not driven it much due to the noise in the topend and the tune so I can't tell you how well it runs right yet.
06-25-2011, 03:49 PM
#19
Pro
Thread Starter
thanks. only reason I was asking about the injector size is because I also have a L98 TPI w/ LT4 HOT cam in another car, although w/ 1.5RR's, and I went with 30# and I can say for a daily driver, that's too big (another lesson learned). pulse width at idle is too short to be effectively ECM-controlled. that's all.
thanks again.
thanks again.
Last edited by rpoL98; 06-25-2011 at 07:00 PM.
07-29-2016, 08:05 PM
#20
Instructor
wow, that's exactly what my RR's looked like before I went to 2-pc guide plates. ****-eyed, or, "askew".
kinda implies that on 113 cylinder heads, the rocker-stud, and valve spacing isn't standard SBC.
and I really thought it was the made-in-china RR's (yup, also sourced from fleaBay). now I know.
thanks for answering THAT question.
separately, what size injectors are you running with the LT4 HOT cam? I see the RR's are 1.6.
kinda implies that on 113 cylinder heads, the rocker-stud, and valve spacing isn't standard SBC.
and I really thought it was the made-in-china RR's (yup, also sourced from fleaBay). now I know.
thanks for answering THAT question.
separately, what size injectors are you running with the LT4 HOT cam? I see the RR's are 1.6.
