Backfires

[fletcherson]

Break in lube and oil and ran for the prescribed break-in time. Drained and replaced. Loosened up 'cause I'm not too clever (obviously) and set the lash without regard for loading the lifters.

Ok, you should be ok. Loose is good on solid cams, not so on hydraulic. They need friction to spin. Sounds like it will be a nice running beast, once you get rid of the gremlins!

 

[2old2fast]

you said something about valves being loose after initial break in , did you cut open your oil filter & look for "shiney stuff"....this sounds like possibly a cam on it's way out , no vacuum , backfiring ' etc. I sure hope not...

 

[Intrepid]

Hydraulic lifters.. have you tried adjusting them while the engine is running .. I know it can get messy but a chunk of cardboard taped up in the right way helps. I always found it easier to get them right while they had pressure.

 

[dwleo]

Hydraulic lifters.. have you tried adjusting them while the engine is running .. I know it can get messy but a chunk of cardboard taped up in the right way helps. I always found it easier to get them right while they had pressure.

Oooooh, I don't hope to go this way!

 

[2old2fast]

If you're using common self locking nuts on your rocker arms , I can not tell you how much easier it is to set valves w/ poly-locks , plus they're easier on the studs , 1 of the best $25 I've spent . Look up comp cams EO IC method of setting , once you get the hang of it , it's quick & fool proof ........exhaust begins to open-set the intake , intake nearly closed -set the exhaust...

 

[dwleo]

If you're using common self locking nuts on your rocker arms , I can not tell you how much easier it is to set valves w/ poly-locks , plus they're easier on the studs , 1 of the best $25 I've spent . Look up comp cams EO IC method of setting , once you get the hang of it , it's quick & fool proof ........exhaust begins to open-set the intake , intake nearly closed -set the exhaust...

Yeah, I'm going to relash today. I already have poly-loks.
Thanks.

 

[dwleo]

It has been suggested that it is the power valve in the carb that is screwed and done probably during a backfire in the carb when the timing was wonky.
Thoughts?

 

[409T]

you said something about valves being loose after initial break in , did you cut open your oil filter & look for "shiney stuff"....this sounds like possibly a cam on it's way out , no vacuum , backfiring ' etc. I sure hope not...

That would be my first guess.

 

[2old2fast]

Most any holley or holley type carb built in the last ten years has a power valve protecter built in..

It has been suggested that it is the power valve in the carb that is screwed and done probably during a backfire in the carb when the timing was wonky.
Thoughts?

 

[Intrepid]

I would think a new type carb like that has the check valve/ball to prevent that.

 

[Intrepid]

You keep mentioning lash adjustment ,, and I don't want to offend or anything but just to be clear here for trouble shooting purposes.
Their should be no lash.
These are hydraulic lifters right?

 

[dwleo]

Yes hydraulic. Lash adjustment as a term for valve adjustment.

 

[fletcherson]

Hydraulic lifters.. have you tried adjusting them while the engine is running .. I know it can get messy but a chunk of cardboard taped up in the right way helps. I always found it easier to get them right while they had pressure.

That's how I initially learned too. Back em off till they tick, tighten till they stop, then a half turn clockwise. I wouldn't personally reccomend doing it this way with a fresh cam. There are also conflicting opinions about pre loading the lifters with oil, I've done it both ways, no real preference except I do like to be sure everything is lubed. I was trying to give a clean, simple, initial basic tune scenario to help isolate the issue. I used to have stock valve covers that we cut the center, top out of do this and rocker clips that sort of prevented excessive splatter. The clips were very over rated, lol. Loose hydraulic lifters on initial break in is a scary thought. I hope its ok. For anyone who may not understand, the (hydraulic) lifters need preload to retain pressure and contact with the cam, to spin, and break in, aka harden the cam surface. That's why you are supposed to vary the rpm, so if a lifter gets stuck, it will make it spin. (My understanding) Not spinning is one of the things that causes failure, or a wiped lobe. If anyone is unfamiliar with this seemingly simple procedure, do yourself a favor and study untill you understand. Most cam manufacturers provide tutorials and recommendations. Things can go bad very fast. A wiped lobe can create mayhem inside a fresh engine, any engine. My post is for conversation and to attempt to give a simple explanation for anyone who may not have a lot of exposure to this procedure, not to debate anyone's preference or expertise! Just trying to prevent heartache!