Bent exhaust pushrods.

[Maxhawkins28]

Hi there new to this site but I am at the end of my stock 1958 348 engine rebuild and only my exhaust pushrods are being bent. when i sent the heads into a shop those are the only valves they replaced and it seems to me the stem is to long and rocker arms are sliding off a friend told me I might need shorter pushrods and adjustable rocker arms I'm just a bit frustrated with the whole ordeal can anyone lead me in the right direction here thanks.

 

[Don Jacks]

The valve train on that W engine is already adjustable.Can you post a picture of the valve stems as installed please? I'm wondering if they got the wrong valves ,and put them in the engine.

 

[Phil Reed]

348-409 are different lengths. Intake are short and exhaust is longer. Compare the 2 lengths and you can see the difference.

 

[Maxhawkins28]

I know they are different lengths . and I will post some photos soon.

 

[wristpin]

Are you bending the pushrods turning the engine over by hand or while adjusting rockers prior to start up or when? What are the circumstances? Maybe im being dense. Usually am.

 

[Maxhawkins28]

Well I have it all assembled and went to start it and heard this noise coming from the valves so I removed the rocker arm cover and sure enough the rocker arms had been slid off the valves and bent push rods only on the exhaust valves . changed them out and it did it again so that's where I am at. Going off valve adjustment from the shop manual.

 

[Don Jacks]

Is it bending the exhaust pushrod on all cylinders,or just a few? It sounds like either the valve springs are going solid,or the exhaust valves are hitting something.Use compressed air and check for bent valves before you put any more parts in.Something is seriously screwed up here.

 

[wristpin]

As mentioned....wrong valves? Rocker studs pulling out of head?

 

[Ishiftem]

There is some type of mechanical interference somewhere. Springs going solid, retainer hitting top of valve guide, valve hitting piston, pushrod binding against the guide hole in the head, slot in rocker hitting rocker stud, etc. Once you find where it's hitting, then you can work on the why.

 

[Maxhawkins28]

Did see a few of the studs were pushed... Maybe 1/4 in on one but there were only three I believe that were moved I just put them back in with tool j6880 but yeah I will need to do some further searching of binding parts. Thanks everyone so far .

 

[Maxhawkins28]

 

[Maxhawkins28]

 

[Maxhawkins28]

 

[Maxhawkins28]

Note the surface rust I had just got them back and was pretty mad they looked like this.

 

[wristpin]

Got close ups of studs? Pictures of rockers removed from studs? Whats top of stud to where stud goes into head?

 

[wristpin]

Rust on springs too. The retainers dont look properly seated on valve stems either.

 

[Jim Sullivan]

You can easily check the spring installed height to check for too long of a valve stem.

 

[Maxhawkins28]

 

[Maxhawkins28]

 

[Maxhawkins28]