Backfire/intermediate shaft

[diesel_lv]

I'm running a hydraulic roller cam n Comp Cams said to run a bronze gear on intermediate shaft. After less than 5k miles, I started car Sun evening, 130 miles from home and immediately had backfiring out the throttle body. Had it towed home following morning and found bronze gear worn to a knife edge. Ordering a new Hughes shaft w "Melonized" gear. I'm sure that the backfire was from the large amount of play in the gear, but is it also possible for it to have jumped one tooth on the bronze gear? There are no chips on the edge and I see no place on the circumference face of the gears has worn to a smaller diameter.

 

[MoparLeo]

How tight is the distributor drive shaft bushing ? The bronze gear is for when you are not using a cast iron camshaft. To wear the drive gear out there must be a drag on something in the camshaft drive gear/oil pump assembly.
Did you manually prime the oil pump before installing the distributor ?
What are you going to do about the metal that is now in the oil pump and possibly bearings ?

 

[diesel_lv]

How tight is the distributor drive shaft bushing ? The bronze gear is for when you are not using a cast iron camshaft. To wear the drive gear out there must be a drag on something in the camshaft drive gear/oil pump assembly.
Did you manually prime the oil pump before installing the distributor ?
What are you going to do about the metal that is now in the oil pump and possibly bearings ?

I initially called 440 Source as that's where I purchased the original. He recommended Hughes melonized. He said that the increased resistance of the high volume oil pump is what caused it to wear so fast. Both he and Hughes tech agree on that. Hughes recommends standard volume/pressure oil pumps in their add to reduce wear on the drive gear. As for the ultra fine brass shavings, I've changed my oil n filter twice during last 5k miles. I'm gonna change it again before installing new intermediate shaft and hope for the best. The melonizing is a chemical process and both 440 Source tech n Hughes tech stated it can be run w roller cams and is generally a one time install, won't wear out like bronze and won't hurt cam drive gear.

 

[493 Mike]

I asked in the past and was told the cam MUST be virgin for the melonized drive to last. Be sure to check that out.
Mike

 

[diesel_lv]

I asked in the past and was told the cam MUST be virgin for the melonized drive to last. Be sure to check that out.
Mike

Hughes ad n tech reiterated that "all" metal from previous gear had to be gone from cam gear. Carb cleaner n q-tips till they come up clean.

 

[wagonman]

I think you may need to pull the cam to get that metal transfer off the gear. A Dremel and some fine polish may do the trick.

 

[diesel_lv]

Well, replaced gear and unfortunately still get a noise from the intake that "sounds" like a backfire. But I don't see any flame and it does have a miss to it. Checked timing chain by rotating crank while watching rotor and almost no slack, so doubtful that timing chain jumped. I'm going to pull valve covers and check there. Hydraulic roller w roller rockers. Maybe something loose there. Either way, I think I'm gonna pull engine n transmission for the winter. Clean n inspect everything. If everything is good, costs me oil, coolant, gaskets n my time. If something is bad, then it needs to be addressed anyway. And paint the heads. They were left aluminum, but I like painted better.

 

[Fran Blacker]

Maybe your back fire messed a plug up.

 

[diesel_lv]

Maybe your back fire messed a plug up.

Possible. It's very odd though. Parked it at bar, running great all day. Came out and starter solenoid not working. Jumped it w screwdriver and started but literally immediately started the backfire/miss. I'll check them too. Thank you. 1st thought was fuel injection, but it's throttle body batchfire, so it would not effect one cylinder. I'll start it and use my heat gun n check headers also.

 

[Cranky]

Can't imagine there's that much more load on the shaft when using the HV pump. If it's gone in 5k miles with the HV pump then it might last 10k miles with a stock volume/pressure pump? I ran a roller cam in a race car with the HV pump and after a full season of racing the Wednesday night AND weekend programs AND turning 7300 on every pass, the shaft looked just fine upon tear down at the end of the season. This was with a 660 lift cam and double springs with damper setup....but don't remember what the spring pressures were.

 

[diesel_lv]

Did heat check, #8 no heat. Pulled rocker cover. Broke exhaust pushrod. They don't just break. Smith Brothers pushrods. The cup was laying right on top. So now I've got to figure out if lifter failed or just a faulty pushrod. Any suggestions other than yanking intake to check on roller lifter? No bends, no sciffs, looks perfect. Broke clean at the exact spot where the shaft for the cup ends.

 

[Don Frelier]

Usually pushrods bend/break because the valve is sticking/hung or hitting the piston.
So I would suggest checking the valve/guide fitment. But you'll likely be checking everything.
I'm not familiar with those style pushrods but it looks like maybe the end gets pressed on?

 

[diesel_lv]

Any suggestions for checking exhaust valve to see if it's stuck? Without pulling head.

 

[Don Frelier]

Rope in the cylinder and an external spring compressor and take it apart.
My external compressor isn't great with heavy springs though... made for everyday vehicles.
Otherwise the head has to come off.

 

[diesel_lv]

Called Smith Brothers and we've narrowed it down to me ordering 5/16" instead of 3/8". Gentleman said that whoever took my order didn't ask a couple questions. Spring rate n cam lift.