Flat Tappet Camshaft Reliability...

[87GN_70GS]

Can also verify with a non-running engine by turning the cam by hand and verifying which direction that lifter spins/ if it spins at all.

 

[we4Mateo]

It may be "fine" to use Mobil I, or any over-priced synthetic oil in a GN, but it certainly is NOT cost effective.

In a boosted application, oil will get contaminated at least twice as fast as NA performance, so oil should be changed at more frequent intervals. You can change oil at least twice with conventional oil vs. synthetic, and neither reach the point of being "worn out", just both are dirty and full of unwanted stuff.

Other than advertising hype, I have yet to find or hear of an advantage of using synthetic oil in a GN, but there are numerous reasons why NOT to use it besides the cost difference.

I am more than glad to be mistaken but does synthetic oil not have a higher burning temperature than conventional oil? If so, then I would think one reason for synthetics would be to prevent oil coking. I know this was a problem in the 80's but seems to be non-existant on todays turbo engines when run with even semi-synthetic oil or full synthetic, ie Ecoboost Fords. Any thoughts or experience seeing turbo failures on high mileage cars? I still change my synthetic oil often but I believe there is at least some benefit, but again, I'd be glad to be wrong about this to save some $. I know my oil pressure is higher with synthetic during the summer months vs conventional (Brad Penn vs Amsoil for me) so that leads me to believe that synthetics are at least more stable with pressure and flow over a wider range of operating temperatures... And all factory Ford oil, followed recently by GM EOS, and soon to be Chrysler Corp, all have at least semi-synthetic oil as standard equipment and standard replacement. If the OEM's are going that direction, then I'd think there is an engineer somewhere saying that it's needed, at least for the extended intervals they push now a days. I'm not saying conventional oil changed frequently won't protect a TR motor, and you are an expert and I am far from that, but to say there is NO benefit to synthetic seems to be too broad of a statement.

I await my education and thanks as always for everything you do for the community, Nick. And what are some of the "numerous reasons besides price" to NOT use it?

 

[williamsGN]

Problem is most likely high lift cams and stiff springs. Stick with ZDDP, Comp springs that are recommended and nothing too steep on the cam. Running 208/208 myself.

 

[TurboDave]

I am more than glad to be mistaken but does synthetic oil not have a higher burning temperature than conventional oil? If so, then I would think one reason for synthetics would be to prevent oil coking. I know this was a problem in the 80's but seems to be non-existant on todays turbo engines when run with even semi-synthetic oil or full synthetic, ie Ecoboost Fords. Any thoughts or experience seeing turbo failures on high mileage cars? I still change my synthetic oil often but I believe there is at least some benefit, but again, I'd be glad to be wrong about this to save some $. I know my oil pressure is higher with synthetic during the summer months vs conventional (Brad Penn vs Amsoil for me) so that leads me to believe that synthetics are at least more stable with pressure and flow over a wider range of operating temperatures... And all factory Ford oil, followed recently by GM EOS, and soon to be Chrysler Corp, all have at least semi-synthetic oil as standard equipment and standard replacement. If the OEM's are going that direction, then I'd think there is an engineer somewhere saying that it's needed, at least for the extended intervals they push now a days. I'm not saying conventional oil changed frequently won't protect a TR motor, and you are an expert and I am far from that, but to say there is NO benefit to synthetic seems to be too broad of a statement.

I await my education and thanks as always for everything you do for the community, Nick. And what are some of the "numerous reasons besides price" to NOT use it?

I'm with Nick on the synth thing. What a waste. You asked about experiences with high mileage cars and turbo failures. I can add my experience since I own two high mileage GN's that I've owned for over 20 years, on for over 25. The 86 (my original) in on it's second turbo. Upgraded from the stocker to its present TE44 way back in the very early 90's. I've never used synth oil and never will. Coking?? Another myth with modern oils (non synth). If I had to guess I'd say this turbo has well in excess of 50,000 very hard miles including countless trips down the drag strip and it seems to have suffered NO ill effects and is still going strong!
My 87 was also an early 90's upgrade from stock to a TA49. It was the ONLY turbo failure I've ever suffered, and was not due to an oiling issue but rather a chunk of Champion spark plug ripping through the tubine!!
Regular oil changes every 5,000 miles and good high quality filters are all that these two have ever seen.
Both still going like gang busters, and no need for synths. Just good dyno oil and zddp.

Overly aggressive cams and springs that are just too heavy are what kills the flat tapped cams going into these cars!!!!! Geezz, even my 87 is still on it's original everyting (including cam lifters and springs) at 135,000 miles. Still pulls hard all the way to it's 5,000 rpm shift point. This valve sping mania that everbody suffers is also a myth.
I believe this strongly enough that the original block that I'm putting back together for my 86 is going to have a mild 202/202 cam and STOCK rated springs.

 

[we4Mateo]

I'm with Nick on the synth thing. What a waste. You asked about experiences with high mileage cars and turbo failures. I can add my experience since I own two high mileage GN's that I've owned for over 20 years, on for over 25. The 86 (my original) in on it's second turbo. Upgraded from the stocker to its present TE44 way back in the very early 90's. I've never used synth oil and never will. Coking?? Another myth with modern oils (non synth). If I had to guess I'd say this turbo has well in excess of 50,000 very hard miles including countless trips down the drag strip and it seems to have suffered NO ill effects and is still going strong!
My 87 was also an early 90's upgrade from stock to a TA49. It was the ONLY turbo failure I've ever suffered, and was not due to an oiling issue but rather a chunk of Champion spark plug ripping through the tubine!!
Regular oil changes every 5,000 miles and good high quality filters are all that these two have ever seen.
Both still going like gang busters, and no need for synths. Just good dyno oil and zddp.

Overly aggressive cams and springs that are just too heavy are what kills the flat tapped cams going into these cars!!!!! Geezz, even my 87 is still on it's original everyting (including cam lifters and springs) at 135,000 miles. Still pulls hard all the way to it's 5,000 rpm shift point. This valve sping mania that everbody suffers is also a myth.
I believe this strongly enough that the original block that I'm putting back together for my 86 is going to have a mild 202/202 cam and STOCK rated springs.

Excellent. That's what I was looking for. Pretty sure I'll be making the switch back, with zddp still though. And I used 75lb valvesprings from TA when I did my cam and it pulls very well, even past 5k rpm, but I don't take it much past. I'm running an Erson 208/208 straight up and and down and probably should have went with less cam. Heads are port matched and that's it.

 

[MCH86GN]

I'm having a 206/206 flat tappet CAM getting installed at Aggressive Performance. I talked it over with Bruce and he said that he has installed flat tappet CAMs and had high success rate. Unfortunately, I had to drive a fair number of miles with low oil pressure due to a lifter being unseated from the bore. When the lifter came out, the push rod remained seated and the rocker shaft snapped in to. I was on I-75 in Detroit when it happened and I didn't trust the area I was in, so I drove until I felt safe and then had it flat bedded home. Most likely driving with the low oil pressure damaged the stock CAM. I don't know. But come spring, I'll have a 206/206 flat tappet with my Champion Ported Irons so in theory I should pick up some power.

 

[we4Mateo]

I've had great luck with my flat tappet cam but I may still go roller on the be motor I'm working on. I battle the back and forth though as I don't like the clicky rollers. And they all do it.

 

[Hotrodbuick]

Roller cams are very nice just depends on what you plan to do with it. If you plan to race a lot an drive on the streets occasionally then roller is way to go. If you plan to mostly drive around town and have some fun then flat tappet way to go. I just put a custom comp cam in mine 212/218 flat tappet and I believe it has reverse #3 lobe on it because they had a lot of failures with that lobe as mentioned before. Also you can buy oil still with the high zinc in it. Kendal GT oil has high zinc and they say its better to buy it rather than mix it by adding the additive because just adding it doesn't mix with the other oil like it does when it's already bought. Just my input on this.

 

[m233roller]

Clicky rollers?? I ran a 206-206 billet roller for 7 years and now run Mike's 210-215 ductile roller with Morel roller lifters and I wish you could hear it. It is absolutely as quite as ANY flat tappet cammed engine Iv'e ran and Iv'e ran and heard afew in my 21 years of building these engines. Roller cam with GOOD roller lifters and valve train set up properly is just as quite as a flat tappet cammed engine.
This is a street car and Iv'e put over 5,000 street miles on it this year with NO noise issues period. Yes Kendal is just one of the oils out now that claim HIGH zinc levels but do they quote any numbers?? NO !!!

 

[jpwalt1987]

Clicky rollers?? I ran a 206-206 billet roller for 7 years !

You don't happen to still have that 206/206 do you? I am looking to buy one.

 

[m233roller]

Sorry guy, Sold it along time ago. Thanks Anyway.

 

[MCH86GN]

I've had great luck with my flat tappet cam but I may still go roller on the be motor I'm working on. I battle the back and forth though as I don't like the clicky rollers. And they all do it.

So far so good. CAM installed and break in procedure complete. I will pick my car up tomorrow evening, pending the weather. The biggest bummer is that I will not get a lot of driving time, because winter is coming. However, I will drive whenever possible for the next two months or until the snow comes. I just want to get comfortable with car, no hard driving. It probably is not absolutely necessary, but I am going to have my TT chip updated for my new CAM specs.

 

[TTipe]

I'm with Nick on the synth thing. What a waste. You asked about experiences with high mileage cars and turbo failures. I can add my experience since I own two high mileage GN's that I've owned for over 20 years, on for over 25. The 86 (my original) in on it's second turbo. Upgraded from the stocker to its present TE44 way back in the very early 90's. I've never used synth oil and never will. Coking?? Another myth with modern oils (non synth). If I had to guess I'd say this turbo has well in excess of 50,000 very hard miles including countless trips down the drag strip and it seems to have suffered NO ill effects and is still going strong!
My 87 was also an early 90's upgrade from stock to a TA49. It was the ONLY turbo failure I've ever suffered, and was not due to an oiling issue but rather a chunk of Champion spark plug ripping through the tubine!!
Regular oil changes every 5,000 miles and good high quality filters are all that these two have ever seen.
Both still going like gang busters, and no need for synths. Just good dyno oil and zddp.

Overly aggressive cams and springs that are just too heavy are what kills the flat tapped cams going into these cars!!!!! Geezz, even my 87 is still on it's original everyting (including cam lifters and springs) at 135,000 miles. Still pulls hard all the way to it's 5,000 rpm shift point. This valve sping mania that everbody suffers is also a myth.
I believe this strongly enough that the original block that I'm putting back together for my 86 is going to have a mild 202/202 cam and STOCK rated springs.

I would like to see a set of irons out of a car that ran roller spring seat pressures (135lb) for a reasonable amount of miles ( maybe 50,000 miles).I know thats not likely because race cars usually rebuild about every 10k or less. I would expect excessive seat recession on nice ported heads.If the seats don't move air then the heads won't either. I'm struggling with roller vs non-roller. For a street car that can run 10's I like some reliability.

 

[WIKEDV6]

I would like to see a set of irons out of a car that ran roller spring seat pressures (135lb) for a reasonable amount of miles ( maybe 50,000 miles).I know thats not likely because race cars usually rebuild about every 10k or less. I would expect excessive seat recession on nice ported heads.If the seats don't move air then the heads won't either. I'm struggling with roller vs non-roller. For a street car that can run 10's I like some reliability.

I just opened up a motor yesterday, the bore still has the cross hatches in them. I am not sure who built it or how many miles but the cam wiped lobs already.


Another buddy installed a fresh motor with new cam last month. He claims that he did everything as he should and he had no issues for the first two hundred miles. Since then the cam went flat, the lifter were sunk in at the bottom and make all kind of top end noise, bend push rods and broke the rocker shaft.


Also few months ago another buddy here(SilverbulletGN) with bone stock motor with 80K miles, the car ran great but he took the motor out do a frame off restoration. While at it, he wanted to change the heads to champion and do the timing chain and so on. I told him to check the cam. He said why the car ran great. Well I told him to check anyway and guess what I believe #3 exhaust lobe was on its way out.


I would strongly suggest that if you going to cut corners to save few bucks, don't do it on the cam. Do it elsewhere. Trust me you will be glad you did. I know there is a lot of nay Sayers here but this is what I have seen in my experience. I am not an expert in anything, I am not a mechanic either. I am just an Accountant that plays with his toys so take it for what it’s worth.

Just my $.02

Prasad

 

[TTipe]

I just opened up a motor yesterday, the bore still has the cross hatches in them. I am not sure who built it or how many miles but the cam wiped lobs already.


Another buddy installed a fresh motor with new cam last month. He claims that he did everything as he should and he had no issues for the first two hundred miles. Since then the cam went flat, the lifter were sunk in at the bottom and make all kind of top end noise, bend push rods and broke the rocker shaft.


Also few months ago another buddy here(SilverbulletGN) with bone stock motor with 80K miles, the car ran great but he took the motor out do a frame off restoration. While at it, he wanted to change the heads to champion and do the timing chain and so on. I told him to check the cam. He said why the car ran great. Well I told him to check anyway and guess what I believe #3 exhaust lobe was on its way out.


I would strongly suggest that if you going to cut corners to save few bucks, don't do it on the cam. Do it elsewhere. Trust me you will be glad you did. I know there is a lot of nay Sayers here but this is what I have seen in my experience. I am not an expert in anything, I am not a mechanic either. I am just an Accountant that plays with his toys so take it for what it’s worth.

Just my $.02

Prasad

I'm trying to see if iron seats are living for a reasonable amount of miles under the spring load (130 psi) required for a roller cam.

 

[m233roller]

I went 34,000 miles on a 206-206 roller cammed engine with Champion irons on it and when I took it apart the valves were just fine. Lots of street miles and quite a few 1/4 mile passes.

 

[TTipe]

I went 34,000 miles on a 206-206 roller cammed engine with Champion irons on it and when I took it apart the valves were just fine. Lots of street miles and quite a few 1/4 mile passes.

Thanks for the response.I will continue to build my new engine in peace.

 

[LEGACY_GN]

Installed flat tappet in 1992 with champion heads and stiffer springs. 40k miles and no problems till 2007. Wiped cam lobe. There has to be truth to the ZDDP being removed from oil as the timing matches up. I run roller now. Don't feel like messing with it or worrying about it.

 

[scot w.]

I just got done re-building the engine in my car after the bearings were starved of oil due to the stock oil pan during Auto-X's..... I installed a COMP 206-206 flat tappet cam with Z-paste on the lifter surfaces & cam lobes, Installed the cam and lifters then made a mark on each lifter with a black sharpie and turned the cam to view that the lifters were turning. One lifter (can't remember which one is supposed to turn in the opposite direction as the rest) some lifters turned more distance than the others so I swapped them around until they all moved pretty much the same distance as each other. This is a very important step because if for some reason one does not turn and you start the break in process that lifter will more likely take out that cam lobe.
Proper cam break in with 10w30 and 2 bottles of ZDDP during break in and the first 100 miles, changed oil and added 1 bottle of ZDDP and all is well so far..

We also tested the LBS of each valve spring (2-sets) before each one was installed on the head.

My oil pressure Hot at idle in Drive is about 25-30 psi....

 

[TTipe]

I just got done re-building the engine in my car after the bearings were starved of oil due to the stock oil pan during Auto-X's..... I installed a COMP 206-206 flat tappet cam with Z-paste on the lifter surfaces & cam lobes, Installed the cam and lifters then made a mark on each lifter with a black sharpie and turned the cam to view that the lifters were turning. One lifter (can't remember which one is supposed to turn in the opposite direction as the rest) some lifters turned more distance than the others so I swapped them around until they all moved pretty much the same distance as each other. This is a very important step because if for some reason one does not turn and you start the break in process that lifter will more likely take out that cam lobe.
Proper cam break in with 10w30 and 2 bottles of ZDDP during break in and the first 100 miles, changed oil and added 1 bottle of ZDDP and all is well so far..

We also tested the LBS of each valve spring (2-sets) before each one was installed on the head.

My oil pressure Hot at idle in Drive is about 25-30 psi....

Obviously with a flat tappett cam your dealing with spring pressure with respect to spring height and the lack of chemistry in motor oils.I suspect for a flat tappett 206/206 with about .480 lift and 110 LSA you probably require about 110 psi on the seat. Oil molecule destruction is worse (high flash point) with a flat tappett than roller. The actual GM valve spring print shows 78 psi as "on the seat nominal load". At 110 psi on the seat you are 41% greater than factory nominal on the seat which may be within the design safety factor limit.Bottom line oil chemistry and lifter rotation are paramount to flat tappett cam and lifter survival.The roller cam lobe ramp rate dictates spring rate to avoid lifter bounce. The required on the seat load and spring lift rate required for a roller also force a higher on the seat pressure of about 135 lbs (nearly double the factory nominal on the seat load). I was trying to survey "roller folks" to seat if premature valve seat pound out was a concern.Its tough to know because race engines don't accrue many miles before rebuild.