Hi, here is an interesting question regarding the 207 engine in my 35 Master Coupe. In the process of replacing my valve cover and push rod cover gaskets, I noticed the oil pipe for the valve rocker arms has a crimp in it (see picture). It certainly appears to be intentional.
Questions: - has anyone ever seen this type of thing before? - could it have been done to keep more oil on the valves/rockers? - was this an aftermarket trick for better performance? - is there any harm being done by it being crimped as this pipe appears to channel excess oil back to the pan?
That was a common practice years ago to get more oil to the valve train/rocker arms. You would have to check as to how much oil is getting to the rocker arms with hot oil and the engine at a fast idle. Probably best to leave well eough alone or remove rocker shafts and check for wear and sludge.
John, Gene was exactly right, I believe all the return pipes were crimped in order to make sure the rocker system was oiled well. If you engine has some sludge, might be a good idea to take the rocker assembly off and clean it good inside and out. Not a very difficult task, just take pictures and pay attention as to how all comes apart, location of springs, intake and exhaust rockers, etc. Torque all the bolts back to specs. I completed that on my 35 207 chevy engine and it oils very well and even all along the rockers. As I understand all early engines that used non-detergent oil developed sludge over time. After I rebuilt my engine I changed over to a detergent oil. All seems well.
Hey Bill, good to hear from a fella hillbilly! :) Appreciate the feedback. My engine seems fairly clean, but having more oil on the top end seems like a good idea. I found and bought a NOS oil pipe on eBay. I will keep in my parts bin. Love this group and love my "damn money pit" Chevy! :)
A cat may have 9 lives but my Chevy has 35 reasons why....... $
Crimping the line is merely an attempt to mask the problem, if there even is one,
The rockers are fed by gravety via the loop over the top in the line as the oil flows back to the holes in the head and ends up in the pan. Unless there are other symptons of the oil not getting to all rockers it is not the fault of engineering but more than likely sludge.
Crimping the line in hopes of feeding the valve train instead of letting gravity do the job as intended is merely an attempt to create pressure in the line by adequately closing the line sufficient to overcome the restrictions in the valve train (rockers, etc).
I doubt it servers very well because the restriction(s) is still there. What is needed is for the rockers and all parts feeding the valve train to be removed and cleaned out so the oil will feed adequately with no assestence other than gravity. Any pressure created by crimping the line will go the path of seast resistance. The runt rockers may still be sucking hind teat.
Hi Charlie, thanks for the feedback. I am a bit confused. I think it is the return line that is crimped? If it is the return line, then would it not leave more oil in the top end? At this point, it looks fairly clean and I do not want to tackle taking apart as I am currently chasing a trans noise.
The feed line s the small line tthat is not crimped Your overflow line is crimped and if too much oil would be delivered it will flow out of the vent hole on top. At continued high speed driving then a little oil will flick out of the valve cover vents. Later models had a clip over the vent hole to force the oil down. As I originally said if oil is coming out of most of the hlos on top of the rocker arms with hot oil at a fast idle I would not worry about it.
