Crane 1.6 rockers gone bad!

[AaronGTR]

Well, I'm putting the stock rockers back in and they are pedestal mount so I don't have to set lash or pre-load with them. If I go back to adjustable rockers in the future that will be good to know though. Thanks for the tip.



For the cam gear, if the stock one wears faster, and the bronze gear wears even faster than that, whats the point of using the bronze gear? I don't want to have to tear my engine apart to get to that gear and replace it constantly.

In the original discussion about the cam gears and billet steel cams, there was a link to an article that suggested that cutting a small slot in the part above the gear and lining it up over where the two gears mesh would allow extra oil through for more lubrication and may slow down the wear. Anyone think that's worth a try? Maybe get a new stock gear and install that and check it again in 5-10k miles and see if it's wearing the same? BTW, anyone have the part number for the stock 3400 drive gear? I can't find it in the catalog on gmpartsdirect and rock auto only lists a couple of washers under oil pump drive gear in their catalog.

If I end up continuing to have problems with it, I may decide to ditch the billet cam and go to a reground solid core cam from the store. OF course that would entail pulling the engine, which I don't have the facilities for anymore so I'd have to take the car somewhere which is a whole 'nother ball o' wax that I don't want to deal with.

[jp_grasshopper_007]

you should still bleed your lifters. and fast wear of the oil pump gear is better than wear on your cam. is that gear really that hard to change? I'm not sure, that's why I ask, changing the gear isn't that bad but I don't know how hard it is to get the housing out of the block

[jp_grasshopper_007]

are you going to use different pushrods? to short a pushrod w/stock rockers is really going to be bad

[AaronGTR]

Yes, I already ordered them.

Just got off the phone with Smith Brothers push rods actually. He said the measurements I wrote down where close, but still a few thousandths off... they have much more accurate measurement equipment than me of course. He's going to make them exactly the same length as the stock ones. I asked him about the oil holes too. He said they only offer 80 thousandths, or an oil restricted 40 thousandths. He said the stock holes were about 91, and that an 11 thousandth difference shouldn't affect my oiling.

I've heard of people shimming the spring in the oil pump before to slightly increase pressure. I wonder if that might be a good idea for me? Or maybe start running 10W30 instead of 5W30? I live in Florida now instead of Michigan, so it never really gets cold enough for the oil to get thick, and it heats up and thins out very fast. I just don't know what to do... I don't want to have any more of these problems in the future.

Your question about the oil pump gear... YES, it is a major PITA to change! Basically I can't get to it without pulling the LIM, so I'd have to pull that every time the gear needed changing. Which means new gaskets, draining the coolant, disconnecting fuel lines, etc, etc... it's an all day job.

[SappySE107]

Why are you going to use stock length pushrods and why are you paying for new pushrods when stockers would be fine with the stock rockers?

[ForcedFirebird]

Why are you going to use stock length pushrods and why are you paying for new pushrods when stockers would be fine with the stock rockers?

Is the MMS cam re-gound?

[IsaacHayes]

Why are you going to use stock length pushrods and why are you paying for new pushrods when stockers would be fine with the stock rockers?

x2 ...

[SappySE107]

No but even the stage 1 NA MMS cam needs .030 longer pushrods.

[ForcedFirebird]

No but even the stage 1 NA MMS cam needs .030 longer pushrods.

And Aaron has 1/16" (.0625") SHORTER pushrods, right?

I would guess pushrod length is the blame.

[SappySE107]

Well, with the adjustable rockers you can do that I suppose but switching back to stock rockers means it would be way off. It would be best to use an adjustable pushrod to come up with the exact length needed.

[SappySE107]

Aaron, did you grind the guideplates to clear any binding on the pushrods themselves? 1.6:1 doesn't work with the stock guideplates and with your pushrod length, it might be putting stress on the rocker and pushrod. Just another thought:P

[AaronGTR]

Why are you going to use stock length pushrods and why are you paying for new pushrods when stockers would be fine with the stock rockers?

Uh, because the stock pushrods are pretty weak and I don't want any flex or for one to break. I am using a much larger cam than stock and 290lb open pressure springs... thought some good stiff pushrods would be good insurance.

Is the MMS cam re-gound?

No, they are new billet steel cores. Hence the reason for the concern over oil pump drive gear wear. Don't need to worry about that with a regrind.



I'd like to know why milzy's cam is supposed to need longer pushrods than stock, since it's not a regrind? I've never heard of this. Also to the best of my knowledge most people running those cams are doing it on stock pushrods. Anyway, no I didn't do any grinding on the guide plates. I didn't need to, there was no interference through their range of motion, and I didn't see any abnormal wear on the pushrods or guide plates. It didn't even touch the back of the guide, only the sides.

[AaronGTR]

Well, with the adjustable rockers you can do that I suppose but switching back to stock rockers means it would be way off. It would be best to use an adjustable pushrod to come up with the exact length needed.

What do you mean by "way off"? And how is that going to affect things? I mean, is it really going to affect how it runs? Or am I just going to lose 3 hundreths of an inch of lift or something?

And how am I supposed to use an adjustable pushrod to figure out what length I need with fixed height rockers and hydraulic lifters? And where am I supposed to find one? I was under the impression that they don't make checking push rods short enough for our engine. I'm just very frustrated and I'm tired of problems with this flippin' engine. I need this thing running by next friday and I don't have time to mess around. Should I just call my pushrod place and ask them to add .03" to my push rods, assuming they haven't already made them? They are supposed to ship them out tomorrow.

[SappySE107]

Id guess .060 longer but guessing is for amateurs. I modified the comp 5.800-6.800" pushrod length checker using their pushrod tools.

You are still using the journal OD as the max lobe height. To achieve your lift, you must cut the base lobe down shorter than stock, no matter if its a regrind or new billet piece. I had a stage 1 MMS cam here, though it was supposed to be a stage 2. I speced it and it requires .030 longer pushrods. Otherwise, you have no preload. Not only do you lose lift, but you also lose duration. If you need longer pushrods, then you may have no preload at all, and never actually tighten the pushrod down when the lifter is on the base circle.

stiffer is good but your cam isn't that extreme and your springs aren't that stiff. 290# isn't much really.

[AaronGTR]

I still don't get why the base circle has to be lower than stock to achieve the lift I'm at. I thought that was part of the reason to use a new billet core instead of a regrind was that they didn't have to grind down the base circle? Anyway, I have a stage 1 boost cam, and no one has spec'd that so how do we really know if it's lower or not? I guess I need to get a checker rod of some kind from somewhere. I don't have time for that right now though.