cam and rockers getting away with murder

[PapaSmurf]

Hey guys, here is the situation. I have 3 cams. Two of them have significant wear on one or more lobes. One of them seems flawless. The rockers on the head that the good cam came from each have one horizontal line in them at the center from running loose lash. I know best practice is to regrind the cam and the rocker arms. I have seen first hand what happens when you don't. However I have also seen it magically work out alright every once in a while.

 

The cam in question is internally oiled so it will not be able to be reground. The question I am posing is, since the cam itself appears to be in great shape, can I polish it, regrind the rockers, and install with any hope of it lasting for a while? Is there something I can coat the lobes in to raise my chances of success? I know that re grinders tape off the mains and dip it in a phosphate solution. Parco Lubrite-2. I've heard is used. I'm just looking at possibilities that won't break the bank.

[JMortensen]

I ran a reground internally oiled cam on reused non-resurfaced rockers for years. Don't see the problem... ???

[BRAAP]

I ran a reground internally oiled cam on reused non-resurfaced rockers for years. Don't see the problem... ???

 

 

+1.

[PapaSmurf]

+1.

 

 

Thanks guys, I just don't have the money to send the cam in this month and really want to bolt this head on I'll just polish the lobes and rockers and see what happens. I've had drastic wear occur relatively quickly in the past by neglecting these things. I'm a bit gun shy, I rather like this new engine

 

edit: I just re-read what you said. I've had offers from locals saying they would regrind my cam for me keeping the stock profile (which is what I want anyways) But that they couldn't do it if it was internally oiled. I'd imagine the holes in the lobes for oil might cause issues with their equipment. I'm certain a professional regrinder would be able to overcome this but my wife would murder me if I spent any money on my Z right now.

Edited May 3, 2010 by PapaSmurf

[BRAAP]

Thanks guys, I just don't have the money to send the cam in this month and really want to bolt this head on I'll just polish the lobes and rockers and see what happens. I've had drastic wear occur relatively quickly in the past by neglecting these things. I'm a bit gun shy, I rather like this new engine

 

Just be sure the lobes are each receiving adequate oil, (thoroughly clean out the cam internally if internally oiled or the spray bar if external), and most importantly, verify proper rocker geometry. If the lobe is wiping off either end of the rocker, neither the cam or rocker will last very long.

[JMortensen]

If you want a stock cam my brother-in-law probably has 10 internally and externally oiled cams in good used condition. I'm sure you could work out a deal. If you're losing a lobe, you should replace the cam. Email is MatM AT m2differentials.com. He's pretty busy right now but I'm betting he has a bunch out in the shed...

[PapaSmurf]

Just be sure the lobes are each receiving adequate oil, (thoroughly clean out the cam internally if internally oiled or the spray bar if external), and most importantly, verify proper rocker geometry. If the lobe is wiping off either end of the rocker, neither the cam or rocker will last very long.

 

 

Thanks braap! You tell me everything I want to hear! I usually get tackled when I hint that I want to save money and cut corners. I'll just finish up a quick and dirty port n polish and clean out that cam. I may switch to the other set of cam towers so I can run both internally and externally oiled. Just to be sure it's super lubed.

[Xnke]

Make sure you keep the rockers with the mating cam lobe, otherwise you will get a little wear, if not more than a little wear.

 

For a given cam, as long as the cam doesn't change, the rockers don't change, then keep the rockers paired with their respective cam lobes and you shouldn't have a bit of trouble.

 

PS, you only get jumped on when the cost of doing it right is not that much more than doing it cheap...I know, I used to take the cheaper route every time till i realized that it wasn't actually cheaper in the end.

[PapaSmurf]

Make sure you keep the rockers with the mating cam lobe, otherwise you will get a little wear, if not more than a little wear.

 

For a given cam, as long as the cam doesn't change, the rockers don't change, then keep the rockers paired with their respective cam lobes and you shouldn't have a bit of trouble.

 

PS, you only get jumped on when the cost of doing it right is not that much more than doing it cheap...I know, I used to take the cheaper route every time till i realized that it wasn't actually cheaper in the end.

 

I was going to keep them mated, but if I regrind them it won't matter. I just don't want the tick. I have like 30 old rockers I figure I can practice on them, rig up a way to get them resurfaced. I've seen people do it with belt sanders but I have to do more research.

[PapaSmurf]

crap

 

I finally got it all together, bolted onto the block, cam installed, timing chain everything. And I just went to adjust the valve lash and check the wipe patterns. I got the valve lash proper on all the valves but one, it's too tight, and I've run out of adjustment. The wipe pattern is all screwed up. The exhaust valves are fine but the intake valves are all wiping toward the front tips of the rockers, where the rocker meets the lash pad. Some are going past the pad on the rocker onto the unpolished surface by a tinsy bit. I'm thinking these brass valve seats may have slipped too far into the head. I have a new set of .180 solid lash pads from msa but that would just exacerbate the problem wouldn't it? Undersized lash pads would be what I want? Am I screwed here? Does this head need new valves and seats? Any recommendations?

[BRAAP]

Usually while the head is off the car, it is much MUCH easier to verify wipe patterns on the work bench using a set of head stands vs on the block in the car.

 

What thickness of lash pads are you using currently? Lash pads from stock cams? Lash pads for stock cams have a dish under them and are .120" thick, there is only one lash pad thinner at .100", but if the cam lobe is running of the valve end of the rocker, even this lash pad is not enough.

 

What head casting is this? If it is a P79 or P90, is there is chance that you or someone may swapped some or all valve from a different head? If the head is not a P79 or P90, disregard this question.

 

If your head does have the brass intake seats, remove that head, do NOT run it. Those brass seats can and do loose their press fit in the head and fall out, end up cocked in the seat bore, holding the valve valve open and in some cases trashes the head on the running engine. When a head comes into my shop with those brass intake seats, I will not touch that head unless those seats are going to get replaced, period! I have have seen the results of many L-series that have dropped those seats.

[PapaSmurf]

Usually while the head is off the car, it is much MUCH easier to verify wipe patterns on the work bench using a set of head stands vs on the block in the car.

 

What thickness of lash pads are you using currently? Lash pads from stock cams? Lash pads for stock cams have a dish under them and are .120" thick, there is only one lash pad thinner at .100", but if the cam lobe is running of the valve end of the rocker, even this lash pad is not enough.

 

What head casting is this? If it is a P79 or P90, is there is chance that you or someone may swapped some or all valve from a different head? If the head is not a P79 or P90, disregard this question.

 

If your head does have the brass intake seats, remove that head, do NOT run it. Those brass seats can and do loose their press fit in the head and fall out, end up cocked in the seat bore, holding the valve valve open and in some cases trashes the head on the running engine. When a head comes into my shop with those brass intake seats, I will not touch that head unless those seats are going to get replaced, period! I have have seen the results of many L-series that have dropped those seats.

 

 

Thanks braap, This is an e88 from an l26 in my hurry to get it built up I forgot they came with brass seats, I didn't want to check the wipe pattern till it was bolted on for fear of bending or otherwise damaging a valve with it sitting on my cramped work table, I thought it might be slightly more accurate with everything together. Anyways I'm thinking this head is trashed till it gets new seats. It is using the stock lash pads, the cam and rockers are from my p79 though that shouldn't effect it. The valves are stock I know this because it took many hours to get all the lead deposits off them - now I wish I hadn't, that was probably the clearance I needed. I was hoping for a high compression head but there is no way I'm running this on my shiny new f54 block.

I'll start work on the p79 I suppose.

 

*edit - I just remembered where this head came from. I purchased the engine 2 or 3 years ago in oregon from an ass who scratched the 6 in l26 into an 8 so that it read l28. I wasn't fooled when I made the purchase, but when I got the motor home and got the oil pan off I saw a mangled mess of destruction, the block was bad. I saved the head, the head I have now learned is also bad. What a waste of money.

Edited May 11, 2010 by PapaSmurf