Newbie w. New GN

[bryes]

Yeah, that was way harder than it needed to be.

[bryes]

Merry Christmas to everyone and thanks again for everyone's help on the timing seal fiasco, looks like we have another one to deal with.

Now that the front cover is finished I was ready  to install the cam. I was going to "dial" it in once I had it installed but I decided to do a sanity check by measuring each lobe at the maximum and minimum. I believe the cam is shot, now I'm kicking myself for not checking it sooner.


From front  back for lobes 1-12, the maximum measurements for each lobe were:

1          2         3         4         5         6         7          8       9         10       11       12
1.490, 1.485, 1.465, 1.465, 1.475, 1.464, 1.457, 1.468, 1.469, 1.468, 1.487, 1.485

Each minimum lobe diameter was consistently  right around 1.230"

The way that I see it, not only do the cam lobes vary by over 0.030",  but the maximum lift of any lifter is:

1.490" - 1.230" = 0.260".

From the factory the lift should be 0.384"/ 408".

I was really hoping to not replace the cam and thought that it would be OK since the engine only has 58k on it (supposedly), but obviously I'll have to get a new one.

Does anyone have any suggestions? I really want the cam and lifters to be made in the usa. I am OK with spending more to get a superior flat tappet variety, but I don't want to spend a mint for a roller.  I believe I am going to go with the stock spec cam because this is going to be mild motor. Any suggestions on what and where to buy would be very helpful

Thanks in advance

Bryes

[earlbrown]

Nice to see you're measuring and going over it with a fine tooth comb....


The numbers you measuring are the 'lobe lift'.  The lift numbers you've read that are published is 'valve lift' which is 'lobe lift' X 'rocker ratio'.  In our case the stock rockers are rated at 1.55:1.

So a .384/.408 cam would have .248/.263 lobes at 1.55:1....   and that to your base circle of 1.230" and you have 1.478 and 1.493 total lobe height.

It's odd that your measurements are all over the place. Usually when a lobe starts to fail it's a VERY short amount of time when you can measure the wear with a tape measure!

Just for grins take your lifters one at a time (DON'T MIX THEM UP) and put them on a flat mirror or plate glass. They should wobble slightly as the bottoms are slightly convex. If you have ANY of them that are concave or flat, that's proof it's time for a cam.

[bryes]

Thanks again earl,
Oh, that explains such a drastic difference, that pesky rocker ratio, I was wondering how they could be worn so much!

I tried putting the lifters on some plate glass (have them all #'d with a sharpie now and egg cartoned to not mix them) and unfortunately I didn't notice any of them wobbling. I wish I had some new ones to compare with though, because it seams highly unlikely that all of them are really bad.

Because I am not confident with my skills utilizing the "earl brown plate glass method", I just now also remeasured all of the lobes;  as it turns out, they were all within 0.002" of the original values in my previous post. I believe even though they are all over the place we can be confident to make a decision about the cam using those measurements.

[earlbrown]

If you're using calipers (or not real good with a mic) .002" is probably acceptable SWAG for the cam measuring.


Since you can't detect any wobble (or know what it feels like, put a lifter on the glass and spin it. If it's flat or concave it should want to resist spinning and want to flop over. If it's convex I'd imagine it'd be like a weeble wobble.

[bryes]

I've been using calipers for this.


I tried spinning the lifters on the plate glass but they are all really felt similar. I also tried to see if they'd stick with  a little oil and they all seemed similar again.

[earlbrown]

Just for shits and grins do you lifters have a hardened foot on them? I.E. there's a distinct ring on the base where a different metal has been 'glued' to the bottom.

Try holding the lifter up infront of the monitor ass end up..   then lay the body of the caliper across it and see if you can see a slight dome that way.

[bryes]

Yes they do seem to have a hardened feet.

I tried that but I still cannot, I think that this tells the tale though.

I dyed the bottom of all the lifters and then ran them over the plate glass. Each and every one of them wore off the dye on the edges but none in the middle. Even the ones that look like they have no dye removed in the picture actually have a very small strip removed from the edge.  Each and every lifter is concave.

[earlbrown]

Hardend feets means they were original or rebuilt many years ago....


....fortunat ely you caught them in time.

Good job with the layout dye.


Does your budget have room for a roller and a set of Morel lifters?

[bryes]

I should have caught this months ago, as much as I have been reading about cam failures I should have checked it sooner. I thought I'd be OK bc of the "lower" miles and the fact that the car was setting since 2001... before zinc went away in oil I guess. Now its not looking too good as far as me getting a lot of work done during my break. My wife is already ticked at me because we were supposed to take a trip and I instead opted to work on the car.  Also, I blew Christmas for her again this year because I guess when women ask for a security system they are not talking about ordering yourself an AR . But that's more for the Bitch/Whine and Moan thread.


Here's why I'll take some more convincing to justify the $500-$700 additional expense to upgrade (is there any machining necessary or will it just slide in?):

 I already have comp 980's in the heads, so I'd have to buy other springs too. For me running race oil  or adding ZDDP is no big deal. Heck, I will likely only drive the car a thousand miles or less each year, so maybe my grandchildren can worry about changing out the cam again! From everything I have read, I don't want to change the factory cam profile because my engine is stock and I have no plans of getting to the point of being able to utilize a more aggressive cam.

I'm open to entertaining  the idea though so I'd sure like to hear any opinions on the subject.

[earlbrown]

oIf you can get a wife pass I'd go 206/206 roller and not look back.



Then again I built a rocket stove on my living room carpet two nights ago because I have no need for a wife pass. My opinions might be skewed!

[bryes]

Yeah, from the sound of it skewed might be a good description


I just don't see much advantage in spending the extra $$ for this project, so I think I'll stick with the old school cam. Also, maybe I can pick up one locally to get this project back on track for this week.  I think NAPA had a cam w. lifter set for maybe $150. Any thoughts?

[bryes]

Another problem with roller lifters is the side load that it puts on the lifters, which can wear the lifter bores.  Have there been any problems created?

Earl, I noticed in that "Cam selection" thread that you recommended this kit:

http://www.fullthrottlespeed.com/customkititems.asp+kc+001BUROLLMOREL+eq

It is $819 with the springs and pushrods:
Would I be able to install into my otherwise completely stock engine without machining?

I guess I would consider it bc it comes with everything.

Also do you know where it is made? I try to not buy imported parts.

[Steve Wood]

If you go flat tappet, I would only buy U.S. lifters that have been hardened on the bottom.  Johnson has started making lifters here again.

This not Earl's favorite company but they do sell good quality parts   http://www.taperformance.com/proddetail.asp?prod=TA_V1405

For a flat tappet cam, I would pick something between 204-208 degs on the intake....will still have plenty of torque and add a bit more power between 4600-5200 rpm.

There are plenty of good oils available without resorting to using additives beyond what is in the package provided by the oil company.

[earlbrown]

Side loading isn't an issue with rollers. If it was, flat tappets would be 100 times worse.

I'll let 'teve take over with the flat tappets. I think they belong in a museum not in an engine. From years of reading and absorbing through osmosis the low 200's seem to be a good duration for a stock compression street car. The don't require the valve guides to be topped either AFAIK.

 And he's right about TA too...    There's nothing in that catalog you can't get cheaper except that stupid ass 'oil pump shim gaskets' that I wouldn't run on a Briggs 'n Stratton.