Another thing, when you shave or deck heads, you got too use different length😅 push rods because they will not be in rocker arms seat right. That's Chevy but Fords and Chryslers too. You can shave heads and deck and gain compression, but you got change push rods.
Oh those juicy cam numbers! I wore out a pen writing them all down. That 246/252ish duration seems to be close to the sweet for circle tracks in my experiences. Nice videos, I'll be subscribing!
Thanks very much ..! I find i rush when k speak and I don’t use the proper terms sometimes! I will try to improve on my explaining and I’m glad you enjoyed the videos ! Much appreciated
Info is all in the book, if you know which one to buy. Max power from small block chevy. Some of that old trick stuff is done in different ways now. Most high performance heads are cast with valves offset. Good work hope it makes close to 600. What intake. Victor jr 1 inch spacer with a dominator might hit 600 at 7000
The cam specs sounds about right for a first gen nascar engine of the 70s. They had to go flat out for 500 miles so you couldn't get too aggressive. To day metallurgy is way more advance to let them go 9000+ as apposed to 7000 back in the day.
This is most likely a circle track engine … that had to run dart iron heads ., that same client of mine raced nascar also with an sb2.2 engine … but I think they used same car or another car for a Canadian series circle track with the 358ci above ..!
There is a lot of things involved could cause this but it was the camshaft been way too advanced making the intake valve hit the intake valve pocket .. in this case …
Steve Morris did a video talked about pro stock motors back in the day he worked on they wanted the valve to just barley kiss the piston looking for max power. Looks like all the intake valves were kissing the pistons purposely or cam timing was just wrong.
I have run as tight as .040” pv on the intake side with high rpm n/a engines BUT … great valve springs and drag race application … on an engine that down shifts and over revs like the circle track stuff ., I personally wouldn’t go tighter than .080” PV .. my opinion
Those pistons are telling you a lot about what was going on in that motor. Yes, intake valves were touching some of the valve pockets. Some of the pistons were also touching the heads in the quench area, but that could have been because the engine was getting a bit tired and clearances were very close. I am not sure I agree with you about those marks on some pistons. Normally marks on the tops of pistons like that is from debris that circulated up into the intake manifold and back down into a different cylinder. Since there is carbon on those marks the engine may have had a failure and the old pistons were just reused. My comments are just an opinion. I did work in a race engine shop for six years, so saw a few failures in that time doing tear down and cleaning. Your videos are good and you explain things very well. After I typed my comments you picked up a piston again and I agree that it showed detonation which looks like coarse sandblasting, but it was also covered with carbon deposits.
Sure the intake valves were hitting the pistons. Probably the bushing was loose in the cam sprocket and it moved while running making the intake valves hit the piston. Or nobody checked for valve clearance during assembly. In any event it was sloppy assembly job.
Circle. Track cars are always angle cutting stuff that should be flat, they trying to get hundredth's of a second to beat the competition. I live in middle eastern NC, there used to be a local track had a four cylinder class, Ford Pintos with the over head cam 2300cc, one of my girlfriends had a ex race motor, the racing was so close after three 50 lap races lap times would fall off from "normal wear" a winning car would fall off and no longer be competitive! If they didn't have enough cars to run modified and stock classes, they would run them in The same class because the stock tan same speeds as modifieds! East Carolina speedway Robersonville. I don't know if it's open anymore. I oved b-bombers class, four door Oldsmobiles, Buicks, Cadilacs Those old big cars trading paint was something to see!
Do you flow test before and after your port work? Been researching quite a bit and it seems like there’s a diminishing return when it comes to porting and slicking up the surfaces. At a certain point the smooth finish actually hurts the flow #’s
Depending on the port most of the time “ shinny “ finish hurts flow … it depends on the speed in the port ., anything more than a 60grid I would do on the intake port
Only Lunati Cams grinds their cams "Straight up" (not advanced or retarded). Always get cam card for any aftermarket cam to get right valve spring to match cam and to know what set lash. They all different.
The only thing I might try it’s the 5w30 oils ., I now have in it 20w50 I will start with that and at the end will maybe run thinner oils … it’s a different application now this build 372ci for a car that races on a frozen lake on the ice with studs on the tires …
On the new Cyl head build they are only 5/16 … the slot of the pushrods on the guideplates isnt long enough it will hit the bottom of it and force the pushrods upwards … sorry sometimes I have a hard time explaining lol on the videos but I’m trying to improve on that ! Thanks for watching much appreciated
Crane cams, iskanderan high performance cams are advanced/retarded from the factory, you have to have cam card so you'll know which springs to use, if cam advañced 2 degrees.what caused the valve to hit is tin shim head gasket trying to get higher compression by using tin shin head gasket 0.006 instead of paper/steel combo 0.35.
I will be happy with that considering pistons are 1/16 rings and no gas ports all internals for durability Std weight etc … thanks for the response your close to what I’m thinking 🤔 kinda
Is the face or head of the valves concave? I thought one piston looked like the valve kissed just at the perimeter like the valve was concaved for weight reduction but others looked like the valve was completely flat(for compression maybe) and touched all the way across. Other than that maybe they fly cut the pistons with the heads on through the guide and that's why there's carbon removed just where the valves would touch but i think you would be able to tell if that was the case. Idk im just guessing, but being out that much I'd say your right
