Acura RL Cam Profiles
11-28-2013, 05:16 PM
#1
Acura RL Cam Profiles
I picked up a nice set of heads recently from gerzand, out of a 2006 Acura RL and just wanted to debunk a myth regarding the profiles on the RL camshafts.
When I mic'd the cams I expected to find these profiles as they were posted on another site stated as belonging to the J35A8 in the Acura RL.
When I pulled them out of the heads I found something quite different with my micrometer.
VTEC Lobe.
Pri/Sec Lobes.
Exhaust Lobes.
Hollow Camshaft.
It's hollow all of the way through.
I was a little bit disappointed, but trusted Gerzand since he had just pulled the heads, you could tell the cams hadn't been removed as the thrust plates and bolts showed no signs of any tool marks.
I found a 2006 Acura RL service manual online and pulled the cylinder head section, and here are the RL lobe profiles per the SM.
I wanted the head section to double check the valve lash adjustment settings for these heads as well.
So I'm not disappointed at all, this obviously doesn't tell us the duration of these camshafts at all at this point.
I'm thinking about sending one of these out to a place with a cam doctor so we can get the full specs of the camshafts.
I'm also thinking more than likely in 2007 Honda simply slapped the older Acura RL heads and camshafts onto the '07-08 Type-S and called it a day, they do have different part numbers though but then so do a lot of other Acura parts that are identical between models.
The lobe heights are the same and the head castings themselves are the same as on the 07-08 Type-S. I think the pistons in the Type-S are different from the RL though, from what I've read the RL has forged pistons, but this was primarily done to be able to use less metal and make them thinner. Not sure if pistons are the same from RL - Type-S.
The only thing that might be different are the durations on the cams, which I have no way of knowing without having one put on a cam doctor to get the full profile.
There also really isn't much room for more lobe height inside of that head on the VTEC lobe. It gets really close on both sides.
When I mic'd the cams I expected to find these profiles as they were posted on another site stated as belonging to the J35A8 in the Acura RL.
When I pulled them out of the heads I found something quite different with my micrometer.
VTEC Lobe.
Pri/Sec Lobes.
Exhaust Lobes.
Hollow Camshaft.
It's hollow all of the way through.
I was a little bit disappointed, but trusted Gerzand since he had just pulled the heads, you could tell the cams hadn't been removed as the thrust plates and bolts showed no signs of any tool marks.
I found a 2006 Acura RL service manual online and pulled the cylinder head section, and here are the RL lobe profiles per the SM.
I wanted the head section to double check the valve lash adjustment settings for these heads as well.
So I'm not disappointed at all, this obviously doesn't tell us the duration of these camshafts at all at this point.
I'm thinking about sending one of these out to a place with a cam doctor so we can get the full specs of the camshafts.
I'm also thinking more than likely in 2007 Honda simply slapped the older Acura RL heads and camshafts onto the '07-08 Type-S and called it a day, they do have different part numbers though but then so do a lot of other Acura parts that are identical between models.
The lobe heights are the same and the head castings themselves are the same as on the 07-08 Type-S. I think the pistons in the Type-S are different from the RL though, from what I've read the RL has forged pistons, but this was primarily done to be able to use less metal and make them thinner. Not sure if pistons are the same from RL - Type-S.
The only thing that might be different are the durations on the cams, which I have no way of knowing without having one put on a cam doctor to get the full profile.
There also really isn't much room for more lobe height inside of that head on the VTEC lobe. It gets really close on both sides.
Last edited by mzilvar; 11-28-2013 at 05:25 PM.
11-28-2013, 07:56 PM
#5
I was also reading that the RLs were made in Japan, so that may be why the different part numbers on the camshafts.
I could weigh one if you want to compare the weights, just need to find a suitable scale.
11-28-2013, 08:04 PM
#7
Safety Car
iTrader: (7)
Join Date: Dec 2008
Location: San Jose, CA/ Charleston, WV
Posts: 4,045
Received 619 Likes
on
459 Posts
looks like the only difference between my camshaft and yours is the exhaust lift. Also my camshaft specs are more like TL-S. So there are minor difference which made that extra 3hp, but that could be because of the 11.5 compression?
https://acurazine.com/forums/3g-tl-performance-parts-modifications-112/accord-v6-6spd-build-4dr-900332/
Duration is unknown on mine also
https://acurazine.com/forums/3g-tl-performance-parts-modifications-112/accord-v6-6spd-build-4dr-900332/
Duration is unknown on mine also
Last edited by thisaznboi88; 11-28-2013 at 08:06 PM.
Trending Topics
11-28-2013, 08:25 PM
#8
looks like the only difference between my camshaft and yours is the exhaust lift. Also my camshaft specs are more like TL-S. So there are minor difference which made that extra 3hp, but that could be because of the 11.5 compression?
https://acurazine.com/forums/showthread.php?t=900332
Duration is unknown on mine also
https://acurazine.com/forums/showthread.php?t=900332
Duration is unknown on mine also
The exhaust lobe should actually be the same, looks like the mic is on the lobe wrong to measure that one. This is also a pretty rough way to measure these using a micrometer, since if you gauge it several times you're going to get a lot of different measurements depending on how you hold the mic on the lobes.
Measuring the lobe height to get lift like this is also a bit more complicated than just taking the lobe height, to get the actual lobe height you have to measure the base circle of the lobe and then the lobe like in my pics and subtract the two.
That gives the lobe height, which when multiplied by the rocker ratio gives you the valve lift.
I'm not sure what the rocker ratio is in these heads though.
11-28-2013, 09:38 PM
#9
Safety Car
iTrader: (7)
Join Date: Dec 2008
Location: San Jose, CA/ Charleston, WV
Posts: 4,045
Received 619 Likes
on
459 Posts
Just a tip put oil or assembly lube on the camshaft and wrap them up. They will start to rust out if you leave them expose. My camshaft have rust spots on the area that were after the cam seals
11-29-2013, 03:16 AM
#10
I took a few more measurements, pretty rough but here's what I've come up with for valve lift.
Intake Pri/Sec/Vtec rocker measurements..
Center of Shaft to Center of Valve lash adjusting tappet = ~40mm
Center of shaft to center of roller bearing on cam end = ~27.5mm
Intake Pri/Sec/Vtec rocker ratio = ~1.45
Exhaust rocker measurements..
Center of Shaft to Center of Valve lash adjusting tappet = ~45mm
Center of Shaft to Center of roller bearing on cam end = ~30mm
Exhaust rocker ratio = ~1.5
Camshaft base circle = ~30mm
Camshaft Journals = ~43mm
Lobe Height on Intake Pri/Sec = 5.112
Lobe Height on Exhaust = 6.389
Lobe Height on VTEC = 6.394
Translates to..
Intake Lift on Pri/Sec (max) = ~7.4124mm = ~.292"
Intake Lift on VTEC (max) = ~9.264mm = ~.365"
Exhaust Lift (max) = ~9.5835mm = ~.377"
Pretty rough numbers, I'll probably actually measure the lift once I have everything back together after the heads are PNP.
The following users liked this post:
thisaznboi88 (11-29-2013)
11-29-2013, 10:49 PM
#13
OOOOOOOOOkay now, lets begin 'j35a8 cams 101'....
I'll make this as simple as possible for those getting confused with these repetitive threads that claim that there is no difference between the j35a8 RL and TL-S camshafts.
Short answer here in this thread is that the OP is taking measurements from an 07-08 TL-S camshaft and comparing them with the specs from the 05-08 RL. The end and goodnight.
Now, for all you people who would like to see some foundation to my factual post here, please read and gain insight.
The 07-08 TL-S cams (in both years) have the exact same part numbers which are 14100-RDB-A00 for the front cam and 14200-RDB-A00 for the rear cam. These cams are in fact hollow and here's some official screenshots from Acuranews.com as well as oem service manual cam specs:
The 05-08 RL cams have two sets of part numbers (however ALL have the same specs between years). Beginning in 05 and ONLY in 05, the part numbers were 14100-RJA-000 for the front cam and 14200-RJA-000 for the rear cam. EVERY 05-08 RL camshaft is solid. Again, here are screen shots taken from Acuranews.com and an oem service manual specs:
If you scan over the information on the screenshots, the OP's mistake becomes obvious. His measurements taken from his TL-S hollow camshafts don't match the RL specs because....well, that. But, if you match his recorded measurements onto the spec sheet I listed beneath the RL camshaft above they are dead on.
I've have a very large collection of j-series engines at the shop and have been fortunate enough to take measurements and specs from just about every j-series motor that's ever been manufactured by Honda. I will NOT post any information unless I've seen it with my own eyes or its given with a disclaimer of possibly not being 100% accurate. I take this hobby of mine pretty serious and invest a great deal of time into not only research, but also sharing it all with you guys.
Andy informed me of these "findings" a few days back and I knew right off something wasn't accurate. Just wanted to drop in with my broom and dust pan. That's all.
To thisaznboi88, the cams you have are from the j37a1 heads as they were once mine and I pulled them out of the heads myself. Those cams are the last cams made for the second generation j-series engines that can still be used with first and second generation j-series heads yet are manufactured using Hondas newest method of using hollow splined shafts of which lobes are pressed onto. These cams are 100% identical to the TL-S cams in regards to lift but have a shorter duration for improved torque. Not to mention are even cheaper than the 07-08 TL-S cams.
And last but not least, the additional power between the RL and the TL-S comes from the camshaft. The compression ratio of the RL is 11.0:1 and the TL-S has 11.1:1. That difference is 100% given by the piston dome and yes, both pistons are forged steel with an anti-friction coating contrary to people's posts about them NOT being forged. They are, however, forged for weight saving purposes and not for strength. So don't assume they can be used in place of an aftermarket forged piston for a serious engine build.
I'll make this as simple as possible for those getting confused with these repetitive threads that claim that there is no difference between the j35a8 RL and TL-S camshafts.
Short answer here in this thread is that the OP is taking measurements from an 07-08 TL-S camshaft and comparing them with the specs from the 05-08 RL. The end and goodnight.
Now, for all you people who would like to see some foundation to my factual post here, please read and gain insight.
The 07-08 TL-S cams (in both years) have the exact same part numbers which are 14100-RDB-A00 for the front cam and 14200-RDB-A00 for the rear cam. These cams are in fact hollow and here's some official screenshots from Acuranews.com as well as oem service manual cam specs:
The 05-08 RL cams have two sets of part numbers (however ALL have the same specs between years). Beginning in 05 and ONLY in 05, the part numbers were 14100-RJA-000 for the front cam and 14200-RJA-000 for the rear cam. EVERY 05-08 RL camshaft is solid. Again, here are screen shots taken from Acuranews.com and an oem service manual specs:
If you scan over the information on the screenshots, the OP's mistake becomes obvious. His measurements taken from his TL-S hollow camshafts don't match the RL specs because....well, that. But, if you match his recorded measurements onto the spec sheet I listed beneath the RL camshaft above they are dead on.
I've have a very large collection of j-series engines at the shop and have been fortunate enough to take measurements and specs from just about every j-series motor that's ever been manufactured by Honda. I will NOT post any information unless I've seen it with my own eyes or its given with a disclaimer of possibly not being 100% accurate. I take this hobby of mine pretty serious and invest a great deal of time into not only research, but also sharing it all with you guys.
Andy informed me of these "findings" a few days back and I knew right off something wasn't accurate. Just wanted to drop in with my broom and dust pan. That's all.
To thisaznboi88, the cams you have are from the j37a1 heads as they were once mine and I pulled them out of the heads myself. Those cams are the last cams made for the second generation j-series engines that can still be used with first and second generation j-series heads yet are manufactured using Hondas newest method of using hollow splined shafts of which lobes are pressed onto. These cams are 100% identical to the TL-S cams in regards to lift but have a shorter duration for improved torque. Not to mention are even cheaper than the 07-08 TL-S cams.
And last but not least, the additional power between the RL and the TL-S comes from the camshaft. The compression ratio of the RL is 11.0:1 and the TL-S has 11.1:1. That difference is 100% given by the piston dome and yes, both pistons are forged steel with an anti-friction coating contrary to people's posts about them NOT being forged. They are, however, forged for weight saving purposes and not for strength. So don't assume they can be used in place of an aftermarket forged piston for a serious engine build.
The following users liked this post:
eclypse (12-04-2013)
11-30-2013, 03:24 PM
#14
OOOOOOOOOkay now, lets begin 'j35a8 cams 101'....
I'll make this as simple as possible for those getting confused with these repetitive threads that claim that there is no difference between the j35a8 RL and TL-S camshafts.
Short answer here in this thread is that the OP is taking measurements from an 07-08 TL-S camshaft and comparing them with the specs from the 05-08 RL. The end and goodnight.
Now, for all you people who would like to see some foundation to my factual post here, please read and gain insight.
The 07-08 TL-S cams (in both years) have the exact same part numbers which are 14100-RDB-A00 for the front cam and 14200-RDB-A00 for the rear cam. These cams are in fact hollow and here's some official screenshots from Acuranews.com as well as oem service manual cam specs:
The 05-08 RL cams have two sets of part numbers (however ALL have the same specs between years). Beginning in 05 and ONLY in 05, the part numbers were 14100-RJA-000 for the front cam and 14200-RJA-000 for the rear cam. EVERY 05-08 RL camshaft is solid. Again, here are screen shots taken from Acuranews.com and an oem service manual specs:
If you scan over the information on the screenshots, the OP's mistake becomes obvious. His measurements taken from his TL-S hollow camshafts don't match the RL specs because....well, that. But, if you match his recorded measurements onto the spec sheet I listed beneath the RL camshaft above they are dead on.
I've have a very large collection of j-series engines at the shop and have been fortunate enough to take measurements and specs from just about every j-series motor that's ever been manufactured by Honda. I will NOT post any information unless I've seen it with my own eyes or its given with a disclaimer of possibly not being 100% accurate. I take this hobby of mine pretty serious and invest a great deal of time into not only research, but also sharing it all with you guys.
Andy informed me of these "findings" a few days back and I knew right off something wasn't accurate. Just wanted to drop in with my broom and dust pan. That's all.
To thisaznboi88, the cams you have are from the j37a1 heads as they were once mine and I pulled them out of the heads myself. Those cams are the last cams made for the second generation j-series engines that can still be used with first and second generation j-series heads yet are manufactured using Hondas newest method of using hollow splined shafts of which lobes are pressed onto. These cams are 100% identical to the TL-S cams in regards to lift but have a shorter duration for improved torque. Not to mention are even cheaper than the 07-08 TL-S cams.
And last but not least, the additional power between the RL and the TL-S comes from the camshaft. The compression ratio of the RL is 11.0:1 and the TL-S has 11.1:1. That difference is 100% given by the piston dome and yes, both pistons are forged steel with an anti-friction coating contrary to people's posts about them NOT being forged. They are, however, forged for weight saving purposes and not for strength. So don't assume they can be used in place of an aftermarket forged piston for a serious engine build.
I'll make this as simple as possible for those getting confused with these repetitive threads that claim that there is no difference between the j35a8 RL and TL-S camshafts.
Short answer here in this thread is that the OP is taking measurements from an 07-08 TL-S camshaft and comparing them with the specs from the 05-08 RL. The end and goodnight.
Now, for all you people who would like to see some foundation to my factual post here, please read and gain insight.
The 07-08 TL-S cams (in both years) have the exact same part numbers which are 14100-RDB-A00 for the front cam and 14200-RDB-A00 for the rear cam. These cams are in fact hollow and here's some official screenshots from Acuranews.com as well as oem service manual cam specs:
The 05-08 RL cams have two sets of part numbers (however ALL have the same specs between years). Beginning in 05 and ONLY in 05, the part numbers were 14100-RJA-000 for the front cam and 14200-RJA-000 for the rear cam. EVERY 05-08 RL camshaft is solid. Again, here are screen shots taken from Acuranews.com and an oem service manual specs:
If you scan over the information on the screenshots, the OP's mistake becomes obvious. His measurements taken from his TL-S hollow camshafts don't match the RL specs because....well, that. But, if you match his recorded measurements onto the spec sheet I listed beneath the RL camshaft above they are dead on.
I've have a very large collection of j-series engines at the shop and have been fortunate enough to take measurements and specs from just about every j-series motor that's ever been manufactured by Honda. I will NOT post any information unless I've seen it with my own eyes or its given with a disclaimer of possibly not being 100% accurate. I take this hobby of mine pretty serious and invest a great deal of time into not only research, but also sharing it all with you guys.
Andy informed me of these "findings" a few days back and I knew right off something wasn't accurate. Just wanted to drop in with my broom and dust pan. That's all.
To thisaznboi88, the cams you have are from the j37a1 heads as they were once mine and I pulled them out of the heads myself. Those cams are the last cams made for the second generation j-series engines that can still be used with first and second generation j-series heads yet are manufactured using Hondas newest method of using hollow splined shafts of which lobes are pressed onto. These cams are 100% identical to the TL-S cams in regards to lift but have a shorter duration for improved torque. Not to mention are even cheaper than the 07-08 TL-S cams.
And last but not least, the additional power between the RL and the TL-S comes from the camshaft. The compression ratio of the RL is 11.0:1 and the TL-S has 11.1:1. That difference is 100% given by the piston dome and yes, both pistons are forged steel with an anti-friction coating contrary to people's posts about them NOT being forged. They are, however, forged for weight saving purposes and not for strength. So don't assume they can be used in place of an aftermarket forged piston for a serious engine build.
I'll tell you what, lol I'll believe you when you show me some pictures of RL camshafts that meet the dimensions of that spec sheet you showed.
Regardless we're talking about .172mm difference in lift between the TL-S and supposed specs that you're posting, which translates to a maximum lift value difference of .0097" (after multiplying by rocker ratio) which is about the same as the .008-.010" that the valve lash specs are, it's ridiculous.
Last here are some pics to show these came out of RL heads.
It just so happens that Honda stamped the VIN on a plate attached to the heads and serialized these heads with sequential serial numbers. Here's a pic of the head with the VIN attached to it to show which engine these cams came out of.
That spec sheet also says nothing of which engine those cams are from. The one I posted in my first post came directly out of the 2005 - 2008 Acura RL service manual from the manufacturer.
Last edited by mzilvar; 11-30-2013 at 03:36 PM.
11-30-2013, 05:41 PM
#15
Safety Car
iTrader: (7)
Join Date: Dec 2008
Location: San Jose, CA/ Charleston, WV
Posts: 4,045
Received 619 Likes
on
459 Posts
So for the Mdx camshaft does it mean that it has a boarder power band at the cost of top ends power?? Where as the tls makes more power in the top end with the longer duration?
And yes.I do have your camshafts Thabks again.
And yes.I do have your camshafts Thabks again.
Last edited by thisaznboi88; 11-30-2013 at 05:48 PM.
11-30-2013, 07:02 PM
#16
http://www.tildentechnologies.com/Ca...rformance.html
11-30-2013, 08:03 PM
#17
i'll tell you what, lol i'll believe you when you show me some pictures of rl camshafts that meet the dimensions of that spec sheet you showed.
just as i could say i want a video of you removing the cams out of those heads or there's no way of knowing that the cams were never replaced in those heads prior to you ever getting them.
regardless we're talking about .172mm difference in lift between the tl-s and supposed specs that you're posting, which translates to a maximum lift value difference of .0097" (after multiplying by rocker ratio) which is about the same as the .008-.010" that the valve lash specs are, it's ridiculous.
that's not the point here. The point is that they're bigger and not only that, the rl motor produces slightly more power which means that its not only the lift of the cams that could be responsible, but could also be the duration.
I'm really not sure why you're defending such claim without knowing the true background of those heads. As mentioned, i've taken two sets of these cams out of rl heads (four cams total) and they do coincide with the specs i've given above. Sorry.
last here are some pics to show these came out of rl heads.
It just so happens that honda stamped the vin on a plate attached to the heads and serialized these heads with sequential serial numbers. Here's a pic of the head with the vin attached to it to show which engine these cams came out of.
andy and i both discussed this earlier today and went over the vin. It's broken down into being an 06 rl. Sean in the parts department of mcdavid acura here in plano, tx told me today over the phone that he has never seen honda substitute a part for another....he's been with acura for a very long time and i would believe him over anyone else about this. I will however (in your defense) admit that another unofficial "engine builder" of honda engines has mentioned several times in his posts that honda is known for substituting parts. But he's by far not an honest man so i'm not choosing to believe his statement on this one.
This tells me that the cams being exchanged with the hollow cams is more than likely what happened here. And i know you said there were signs/indications that made you believe that they had never been replaced but if they were done at the early miles of this engines life or even many years ago, this would also be a possibility to duck under.
that spec sheet also says nothing of which engine those cams are from. The one i posted in my first post came directly out of the 2005 - 2008 acura rl service manual from the manufacturer.
what spec sheet are you talking about?
just as i could say i want a video of you removing the cams out of those heads or there's no way of knowing that the cams were never replaced in those heads prior to you ever getting them.
regardless we're talking about .172mm difference in lift between the tl-s and supposed specs that you're posting, which translates to a maximum lift value difference of .0097" (after multiplying by rocker ratio) which is about the same as the .008-.010" that the valve lash specs are, it's ridiculous.
that's not the point here. The point is that they're bigger and not only that, the rl motor produces slightly more power which means that its not only the lift of the cams that could be responsible, but could also be the duration.
I'm really not sure why you're defending such claim without knowing the true background of those heads. As mentioned, i've taken two sets of these cams out of rl heads (four cams total) and they do coincide with the specs i've given above. Sorry.
last here are some pics to show these came out of rl heads.
It just so happens that honda stamped the vin on a plate attached to the heads and serialized these heads with sequential serial numbers. Here's a pic of the head with the vin attached to it to show which engine these cams came out of.
andy and i both discussed this earlier today and went over the vin. It's broken down into being an 06 rl. Sean in the parts department of mcdavid acura here in plano, tx told me today over the phone that he has never seen honda substitute a part for another....he's been with acura for a very long time and i would believe him over anyone else about this. I will however (in your defense) admit that another unofficial "engine builder" of honda engines has mentioned several times in his posts that honda is known for substituting parts. But he's by far not an honest man so i'm not choosing to believe his statement on this one.
This tells me that the cams being exchanged with the hollow cams is more than likely what happened here. And i know you said there were signs/indications that made you believe that they had never been replaced but if they were done at the early miles of this engines life or even many years ago, this would also be a possibility to duck under.
that spec sheet also says nothing of which engine those cams are from. The one i posted in my first post came directly out of the 2005 - 2008 acura rl service manual from the manufacturer.
what spec sheet are you talking about?
11-30-2013, 08:08 PM
#18
It's true there's no way I can prove the cams weren't swapped at some point during the engine's life, that is absolutely positive.
The 05-08 Acura RL service manual page, (screen capture in my first post) shows the specs per the SM matching up with the specs that I measured on the camshaft itself.
The other spec sheet (first picture I posted) only shows specs of a camshaft, but does not show what engine it belongs to like all of the other spec sheets in your post for the J32A3 and the J35A8.
I suppose I could be wrong, I actually considered selling these as Type-S cams for like $350 and buying a brand new set of RL cams to see if there was any difference. I decided against it once I found the Acura RL service manual and verified the cam lobe heights against the service manual specs, since they were the same.
The 05-08 Acura RL service manual page, (screen capture in my first post) shows the specs per the SM matching up with the specs that I measured on the camshaft itself.
The other spec sheet (first picture I posted) only shows specs of a camshaft, but does not show what engine it belongs to like all of the other spec sheets in your post for the J32A3 and the J35A8.
I suppose I could be wrong, I actually considered selling these as Type-S cams for like $350 and buying a brand new set of RL cams to see if there was any difference. I decided against it once I found the Acura RL service manual and verified the cam lobe heights against the service manual specs, since they were the same.
Thread
Thread Starter
Forum
Replies
Last Post
BobbyGraham388
4G TL (2009-2014)
12
10-22-2015 05:05 PM
sockr1
Car Parts for Sale
22
10-01-2015 01:31 AM
asahrts
Member Cars for Sale
0
09-04-2015 05:55 PM
