Push rod through rocker

[413 belvedere]

Yes that appears to be a problem. How does the pushrod fit in each one. I could see if it fits tight in the upper one there could be some binding going on an viola popped rocker arm. There is a difference between small and bigblock rockers. But I am not 100% sure what it is whether its overall length or if it has to do with the diameter of the cup on the arm itself. I think you are on the right track.

Seems to fit good in lower one, now quite as Good in upper, am thinking it pushing right on edges of upper and causing it to break through

 

[miller]

Don't know about the SB stuff, though on BBs, stock push rod ball ends (rocker end) is 5/16". I'll stick with my non-oiling push rod thoughts. Run what you want. Bad deal it's harder to find solid push rods in dif lengths...or just flat real expensive.
Also have pretty much used Mopar stamped rockers, never a problem, even with normal wear. Even cleaning off up to .005" rub surface for the valve, don't hurt a thing. Know the metal in the rockers are right! Can't say on those 'new' ones, or where their made.
Just about think 'something' positively wrong, with the ball socket on the rocker pushed out like those.
Good find on the rocker differences! I'll keep track of all this...with interest.

 

[Ski 61701]

Im curious where your machinist got the original set of rocker arms. Im going to be building a 383 next year and im going to need rockers. I think sealed power is the only one making these anymore and they are made in the states or overseas. I might have to rethink my build. Someone had mentioned Trend p rods. I know if you go to Smith bros website you can pick and choose just about any style end you could dream of. Cant go wrong with either company but pics are worth a 1000 words. Hope you get this ironed out today

 

[66chargerpat]

When I did my 66 383, it had some strange looking pushrods. Can't remember if both ends were small or just one. don't remember if it was the lifter or rocker or both. One was smaller for sure. My 69 383 had the same ends on the pushrods. On the 66,I went all the later model stuff. I don't know if RBs had the small stuff from 66 on down. Pat

 

[Ski 61701]

I think either 66 or 67 on down had different lifters which required different pushrods. I remember 30yrs ago working at a parts store / machine shop there were different part #s for the lifters. If memory serves me correctly you could run the earlier push rods in the later lifters but not the other way around. Im sure the lifter manufacturers now a days have probably done away with the earlier lifters due to lack of demand and now one size fits all.

 

[413 belvedere]

I think either 66 or 67 on down had different lifters which required different pushrods. I remember 30yrs ago working at a parts store / machine shop there were different part #s for the lifters. If memory serves me correctly you could run the earlier push rods in the later lifters but not the other way around. Im sure the lifter manufacturers now a days have probably done away with the earlier lifters due to lack of demand and now one size fits all.

Could be the issue, maybe he ordered late model lifters and push rods and early model rockers, I'll be talking to him later I hope, I'll let you know

 

[Ski 61701]

I dont think the difference had anything to do with the rockers (as long as its for a hydraulic cam), it was more towards the pushrod cup in the lifter, If I remember correctly the cup in the lifter was smaller in diameter to where the pushrod came to a (for lack of better words) a point, not the typical ball end that everyone is used to nowadays. Do you have the old rocker arms to compare to, or do you have any friends that might have some BB rockers that you can look at to definately figure out if you have SB or BB rockers?

 

[Joeyt66]

I'd say push rod length. You can get a push rod length checking tool pretty reasonable at the usual places, Jeg's , Summit and many other places. Good Luck !

 

[413 belvedere]

Talked to the engine builder he said the rockers should be the same from all years, he didn't remember which brand he ordered both times, said he would order more and see which ones show up, well I just decided to go with new roller rockers, 440 source, hope they are OK.

 

[413 belvedere]

I'd say push rod length. You can get a push rod length checking tool pretty reasonable at the usual places, Jeg's , Summit and many other places. Good Luck !

He checked and set up the pushrod length when he built it

 

[khryslerkid]

And hopefully the valve spring retainer to seal clearance.

He seems to know what he's doing. Something's missing.

I've heard of tight valves bending pushrods.

 

[413 belvedere]

And hopefully the valve spring retainer to seal clearance.

He seems to know what he's doing. Something's missing.

I've heard of tight valves bending pushrods.

I think he does, he builds allot of the drag strip motors around here and he had a 440 stroker motor going together while my motor was there, but maybe he is good on race motor just not on stock motors. I can push the valves open by hand and he said he really didn't think there was to much spring pressure for stock rockers.

 

[IQ52]

Wait, you can push the valves open with the valve springs installed? The Mutha' Thumper is a hydraulic roller roller cam and if you can push the valves open by hand you have way to little valve spring pressure. That cam should have about 130# on the seat and if you can push that open by hand you are one mean SOB.

 

[miller]

Ahhh...love it!

 

[413 belvedere]

Wait, you can push the valves open with the valve springs installed? The Mutha' Thumper is a hydraulic roller roller cam and if you can push the valves open by hand you have way to little valve spring pressure. That cam should have about 130# on the seat and if you can push that open by hand you are one mean SOB.

Pretty sure it's a hydraulic flat Tappit cam, but yes I can push the valve open by hand, just momentarily and just enough to unseat it

 

[khryslerkid]

Do your springs have an inner spring (dampner)?

Here's the specs on your cam

https://m.summitracing.com/parts/cca-cl21-600-5

 

[IQ52]

Pretty sure it's a hydraulic flat Tappit cam, but yes I can push the valve open by hand, just momentarily and just enough to unseat it

Yeah, there it is two pages left in the catalog. Hydraulic Flat Tappet, Mutha' Thumper 21-601-5, 287/304, 235/249 @ .050" .497"/.483", 107 LSA. Turns out there are two Mutha' Thumpers, hydraulic flat tappet and hydraulic roller.

I'd really check those valve spring pressures. The suggested single spring, 911-16, has even more seat pressure than the 925-16 alternative dual spring that is suggested as an upgrade. If valves are floating and hitting pistons, that will punch the pushrod right through the rocker arm.

Stealth heads are notorious for the pushrods hitting the intake runners of the heads. There isn't enough machined clearance on the outside of the runner in the pushrod pinch area. When that happens all kind of nasty things can happen.

 

[khryslerkid]

Might finally be on to something. Op stated there was a backfire at 5,000 rpm when all of this takes place.

 

[Ski 61701]

I looked at the specs for the cam. I didnt see what valve springs they recommend for the cam. I looked at summit's web page for the entire kit they show valve springs but no part# for them. If the pic is correct its just a single spring with maybe a dampner inside hence his ability to push on the spring. It would be interesting to see what the specs are of the spring needed. Im still leaning towards the too small of a pushrod cup in the rockers as being main culprit. Maybe if springs are not strong enough this increases the problem. IQ 52 is a much better person to answer that question since im sure hes seen quite a few variations of valve train mixes and matches over the years

 

[khryslerkid]

In Summits add, click on suggested parts. They're showing comp 911 which is a single spring with an inner dampner. 373lb rated spring.