1969 L36 - Roller Cam
Thread Starter
Instructor
Joined: Feb 2014
Posts: 154
Likes: 1
From: Irvine CA
1969 L36 - Roller Cam
Hi Fellas,
I'm rebuilding my original L36 motor. Long story short - I'm changing the pistons in my motor as the currents ones are far too big (-36.30cc) and going back to smaller pistons to support my oval ported heads (-16.80). I didn't want to put rectangular ported ones on. The heads from my motor have been machined, have bigger 2.19 valves, and have been cc'ed at 106cc.
My machinist has suggested a hydraulic roller cam rather than going with a flat tappet. I'm open to the idea and realize I'm looking at around a $500-600 incremental vs. buying a new flat tappet if I go the roller route. I'm trying to get the compression ratio down to 10:1 (Currently 11.25:1). Car would be used to cruise around and go to shows - Not racing this thing at all. Ideally, I'd like a cam with a bit of lope that gives me some power but nothing radical or unmanageable.
Based on the above, what would you guys suggest I take a look at?
I'm rebuilding my original L36 motor. Long story short - I'm changing the pistons in my motor as the currents ones are far too big (-36.30cc) and going back to smaller pistons to support my oval ported heads (-16.80). I didn't want to put rectangular ported ones on. The heads from my motor have been machined, have bigger 2.19 valves, and have been cc'ed at 106cc.
My machinist has suggested a hydraulic roller cam rather than going with a flat tappet. I'm open to the idea and realize I'm looking at around a $500-600 incremental vs. buying a new flat tappet if I go the roller route. I'm trying to get the compression ratio down to 10:1 (Currently 11.25:1). Car would be used to cruise around and go to shows - Not racing this thing at all. Ideally, I'd like a cam with a bit of lope that gives me some power but nothing radical or unmanageable.
Based on the above, what would you guys suggest I take a look at?
Safety Car
Joined: Apr 2006
Posts: 4,057
Likes: 421
From: BC
I rebuilt the all original L36 in my 69 and wanted it stock looking right down to the smog pump. I also wanted to run a roller cam instead of flat tappet so went with a Comp XR270HR. It doesn't have a lope but has a bit of a choppy idle. I also upped the initial timing to 17 degrees and run 17 centrifugal. The original mechanical advance on the L36 was 26 degrees. With the original MS360 vacuum advance can it produces another 12 degrees so with that much initial (no ported vacuum in 69) it hides any lope there might be with a lower initial advance. I am very pleased with the cam and the performance and use Mobil1 0W40 European Formula without having to worry about blowing a cam lobe.
One thing to remember is that with the kit you get rockers, springs, pushrods, the roller lifters and cam. It sounds expensive at first but when doing a build you have to buy all that stuff anyway so just the camshaft to camshaft price really isn't much of a difference.
Last edited by CanadaGrant; Jun 8, 2018 at 11:12 AM.
Thread Starter
Instructor
Joined: Feb 2014
Posts: 154
Likes: 1
From: Irvine CA
I’m talking an incremental/additional $500-$600 more than a regular flat tappet kit. Here’s a flat tappet kit from summit:
https://www.summitracing.com/parts/cca-k11-242-3
Heres the hydraulic roller kit which is around $600 more than the flat tappet kit above:
https://www.summitracing.com/parts/cca-k11-422-8
https://www.summitracing.com/parts/cca-k11-242-3
Heres the hydraulic roller kit which is around $600 more than the flat tappet kit above:
https://www.summitracing.com/parts/cca-k11-422-8
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
You buy a roller cam. Then you buy roller lifters. Then you buy some kind of roller cam timing cover with a roller adjustable button. Then you buy nice shorter push rods. Then you buy adjustable push rod guide plates. Then you buy roller rocker arms. Then you buy better springs that can achieve the desired lift without valve float
you are not realistic if you think it is not up to a couple thousand to do a quality full roller setup
you are not realistic if you think it is not up to a couple thousand to do a quality full roller setup
Last edited by gkull; Jun 8, 2018 at 11:42 AM.
Le Mans Master
Joined: Mar 2001
Posts: 5,738
Likes: 644
From: Lincoln, CA
I bought my kit from http://www.straubtechnologies.com/
And used this timing cover for my BBC, https://www.summitracing.com/parts/clo-9-231/overview/
And used this timing cover for my BBC, https://www.summitracing.com/parts/clo-9-231/overview/
Le Mans Master
Joined: Mar 2001
Posts: 6,240
Likes: 1,013
From: Watkinsville, GA and Glen Cove, NY
You buy a roller cam. Then you buy roller lifters. Then you buy some kind of roller cam timing cover with a roller adjustable button. Then you buy nice shorter push rods. Then you buy adjustable push rod guide plates. Then you buy roller rocker arms. Then you buy better springs that can achieve the desired lift without valve float
you are a dumb *** if you think it is not a couple thousand
you are a dumb *** if you think it is not a couple thousand
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Intermediate
Joined: Oct 2011
Posts: 43
Likes: 3
From: Indian Head MD
You probably do not need a cam button. You can use a stepped nose Gen VI cam in your 69 427 with a retainer plate. On my 68, the holes were drilled in the block for the retainer and it was an easy bolt in deal. Does not change the fact that the roller cam investment is significant. I wanted to keep the stock duration and was able to get a cam that was very similar to stock in duration, but had significantly more lift. It runs well and idles like a stock L36.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
ZZ502 cam. https://paceperformance.com/i-625508...zz502-502.html designed by GM. 1 hp per inch. nice lope. uses Gen 6 cam retainer. 544 lift doesn't tear up valve trains. then you go buy the Hyd lifters you choose, instead of what comes in their kit.
Racer
Joined: Jul 2015
Posts: 396
Likes: 101
From: Lehigh Valley Pennsylvania
Attached is a document that compares some conservative cams. The comparison includes both flat tappets and rollers.
I went with the Lunati 20010711 which is probably too mild for what you are looking for, but the table is a start for comparing cams. Note that if the DCR reads 9.62, I did not calculate it for that cam.
One thing that is rarely talked about is the dynamic compression ratio. From what I have read, this is supposed to be around 8 or the enigne is sluggish. With my 9.62 CR, running the lunati at 6 degrees advanced got me close.
I bought a gen IV cam for my gen IV engine, but from what I have read recently, the Gen VI will work without much effort IF your engine has the threaded bosses at the first cam journal, which mine does. Otherwise you will have to get those machined into the engine. If you can use the Gen VI cam, you eliminate the need for the cam button.
I am in the process of building the engine now so I can't tell you how it will run.
I went with the Lunati 20010711 which is probably too mild for what you are looking for, but the table is a start for comparing cams. Note that if the DCR reads 9.62, I did not calculate it for that cam.
One thing that is rarely talked about is the dynamic compression ratio. From what I have read, this is supposed to be around 8 or the enigne is sluggish. With my 9.62 CR, running the lunati at 6 degrees advanced got me close.
I bought a gen IV cam for my gen IV engine, but from what I have read recently, the Gen VI will work without much effort IF your engine has the threaded bosses at the first cam journal, which mine does. Otherwise you will have to get those machined into the engine. If you can use the Gen VI cam, you eliminate the need for the cam button.
I am in the process of building the engine now so I can't tell you how it will run.
Burning Brakes
Joined: Feb 2005
Posts: 894
Likes: 91
Mentioned above, use the MK-VI stepped-nose cam, the retainer plate (no cam buttons needed), and the fasteners, along with the MK-VI "Torrington" tru-roller chain set. We use/sell these all the time now!
Thanks, Gary in N.Y.
P.S. A complete retro-hyd-roller kit WITH some lightweight tool-steel retainers can be had for between $1200.00 and $1300.00 depending on the chosen springs! We sell them all the time, Comp's cam/springs/retainers and Morels lifters. No issues to date! We use the Comp's "-8" cams for 100% stock-appearing builds, they are compatible with the OEM dist gear and fuel pump rod. Have some Vette builds out over 15 years now!
Thanks, Gary in N.Y.
P.S. A complete retro-hyd-roller kit WITH some lightweight tool-steel retainers can be had for between $1200.00 and $1300.00 depending on the chosen springs! We sell them all the time, Comp's cam/springs/retainers and Morels lifters. No issues to date! We use the Comp's "-8" cams for 100% stock-appearing builds, they are compatible with the OEM dist gear and fuel pump rod. Have some Vette builds out over 15 years now!
Last edited by GOSFAST; Jun 9, 2018 at 06:14 AM. Reason: C
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Yes a little over board on $2000. But that is when you are using billet timing set 900 dollar lifters comp cams top of the line push rods. Bee hive springs. Chromoly 10 degree retainers and locks. Lash caps. Pro magnum steel roller rockers. ARP high psi rocker studs.
I have had a comp cams roller cam get a flat lobe after breakin. They are just mush metal. So I only use billet steel sleeved dizzy gear cams. So you have to use a poly or roller tip fuel pump rod. I also use manley race or pro flow valves stainless steel valves because they are lighter weight. Then you are actually exceeding $2000 just in parts.
I've just seen so many crappy parts fail over the past 30 years. Lifters and cheap aluminum roller rockers. Cheap double roller timing sets that are stretched out in just a few years. Cheap dual springs that loose 25 pounds of seat pressure.
I'm a firm believer in you get what you pay for. Labor is so expensive to fix things down the road. Why not build it the best the first time and not have failed parts
I have had a comp cams roller cam get a flat lobe after breakin. They are just mush metal. So I only use billet steel sleeved dizzy gear cams. So you have to use a poly or roller tip fuel pump rod. I also use manley race or pro flow valves stainless steel valves because they are lighter weight. Then you are actually exceeding $2000 just in parts.
I've just seen so many crappy parts fail over the past 30 years. Lifters and cheap aluminum roller rockers. Cheap double roller timing sets that are stretched out in just a few years. Cheap dual springs that loose 25 pounds of seat pressure.
I'm a firm believer in you get what you pay for. Labor is so expensive to fix things down the road. Why not build it the best the first time and not have failed parts
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
He speaks the truth. Maybe theres cheap mass produced stuff for less but why risk it?
For a mild cam I wouldnt bother with a roller, opinions may vary. Noones putting 50k miles on them?
For a mild cam I wouldnt bother with a roller, opinions may vary. Noones putting 50k miles on them?
Last edited by cv67; Jun 9, 2018 at 03:08 AM.
Thread Starter
Instructor
Joined: Feb 2014
Posts: 154
Likes: 1
From: Irvine CA
Thanks Everyone! Been learning so much these past few weeks due to my engine rebuild situation. Rebuilding this motor is both exciting and crazy at the same time - I just want to make sure I make the right the decisions on rebuilding this thing.
Thread Starter
Instructor
Joined: Feb 2014
Posts: 154
Likes: 1
From: Irvine CA
In all reality it will probably take me in the realm of 15ish years to put 50k miles on this car. I’d say it will probably get in the ballpark of 3-4K miles per year. I don’t have to have a roller - just exploring all my options since now would be the time to make the change.
Racer
Joined: Jul 2015
Posts: 396
Likes: 101
From: Lehigh Valley Pennsylvania
In all reality it will probably take me in the realm of 15ish years to put 50k miles on this car. I’d say it will probably get in the ballpark of 3-4K miles per year. I don’t have to have a roller - just exploring all my options since now would be the time to make the change.
That is exactly why I went to a roller. I have a 69 350 that I bought in 79. It turned 50,000 on the way home. I got it cheap because it ran badly. It had wiped the cam. I have about 22,000 on it in 39 years. I am constantly pulling the distributor on it to prime it because i left it set too long without starting it. I have to find high zinc oil. Protecting the cam in it is just a pain.
I got my 73 in a box (some assembly required) with 78,000 on it and........a wiped cam. I hope to have this one running by the end of the year, and I hope to drive both a lot more now that I am retired, but I see both sitting all winter in the northeast. I am assuming the roller will be more forgiving.