How fast should the pushrods spin?

[robk46]

Just fired up our fresh rebuilt engine last week. It now has a ****ping 150 miles on it. We have some valvetrain noise at idle, louder out of gear than in gear. Car runs great, with good vacuum (15 in drive) and oil pressure (28 in drive with 10w30). We reused our 1000 mile old 204/214 cam with new sealed power lifters, and broke the motor in with 30wt oil, EOS, and lots of molly lube.

We pulled the valve covers and belt to see if we could locate the "sewing machine" tapping noise coming from the motor. #1 intake and #5 intake pushrods seem to be spinning slower than the rest. I haven't measured preload yet, but aside from having the heads shaved .008, Nothing was changed on the valvetrain geometry. This cam and sealed power lifters ran super quiet in the engine prior to the rebuild, which was caused by a smashed #1 rod bearing. The mains were turned .010, and the rods .020. We went with Wiseco .020 pistons.

Did we make a mistake running that cam? I'm thinking we did, and have parked it to avoid any damage. I'm sick to my stomache worrying about this stupid engine. . . Got any advice? Anyone near me want to give me a second opinion?

 

[dr_frankenstein]

sorry to bring the bad news.

yup it was the cam.

once a flat tappet cam breaks in it stays with those lifters forever.

cant just put new lifters on it and re break it in, dont work that way.

cams got to come out and a new one needs to go in.

no running engine until its out and replaced. if you do your just filling the engine with cam/lifter material.

bummer man.

A.j.

 

[robk46]

I agree. I feel so stupid. I pulled the break in filter apart, I found no ferrous metal in the filter, just the usual break-in glitter. I'm going to order a new Edelbrock kit today, and pull the pan and intake, front cover and cam to make sure the bearings are still good. Actually, I think I might just yank the engine. . . What would you do?

 

[dr_frankenstein]

I agree. I feel so stupid. I pulled the break in filter apart, I found no ferrous metal in the filter, just the usual break-in glitter. I'm going to order a new Edelbrock kit today, and pull the pan and intake, front cover and cam to make sure the bearings are still good. Actually, I think I might just yank the engine. . . What would you do?

well it sounds like you caught it in time, i would try to swap it while still in chassis. I dont know exactly what I would do, as I dont have a GN or TR - but if you feel confident enough to inspect bearings etc under the car with the pan pulled off I say go for it.

im sure other members will chime in soon and give you better advise.

good luck,

:biggrin: A.j.

 

[SIXBANGR]

used cam info

Crane Cams web site says you can use new lifters on a good used cam. I have done it on several cars I have owned. Never had an issue. Of course yours may not have worked. Take a look at the lifters, they will tell the story.