Where'd you find the windage tray?


Lawrenceville, GA

Heads are now on.



Windage trey on.




Charlie Burns Laton, Ca (South of Fresno)



BurnsRacing981@gmail.com

More boost. Y wont break.


Hyvinkää, FI

Paul, Thanks for the questions.  I have great friends, but when I show them something interesting about the engine or race car, they look at it and then they say, "hey you have a new calendar on the wall"!!!  It's nice to chat with someone who is truly interested.

Your questions about the heads, compression loss and cam lift are valid.  The heads are 471 castings and are a common replacement for "F" code engines.  They have lower compression than the "G" heads but that is necessary to let the engine live a little longer with reduced detonation and Tim McMaster thinks they may flow every bit as good.  Tim did a great job on these heads.  I have been running them for about 5 years now and they are an integral part of making these Y Blocks fly. The relieving does contribute to making the compression even lower, however it is necessary for the valves to clear the cylinder walls.  During a chassis dydo session for rear wheel horsepower and considering a 17% parasitic loss from all the drive train components, the little 258 cu in Y Block made 454 flywheel hp with these heads.  All this on 5 lbs of turbo boost makes me a believer in Tim's work.

Another mention was of the extra lift in the cam and whether the extra lift was necessary (requiring deeper cylinder wall relieving).  The personality of these turbo cams are quite different than normally aspirated engine cams.  First of all most of the duration overlap is eliminated.  The lobe separation is 114 and the center lines are 110 on the intake and 118 on the exhaust.  When the exhaust opens too early, the boosted charge escapes to some degree into the exhaust headers.  What the turbo setup does like is higher lift.  I have put as much lift into the valve train as I can afford.

These engine specs and choices of parts are not optimum.  Aluminum heads etc. would be nice, but I'm happy with what Tim has help me build so far.  The little 258 cu in Y ("E" motor) went 161 mph (on a 158 record) at Bonneville last September and I couldn't be more pleased .  This new build (actually, the new short block was created over 4 yrs ago) will jump two classes to "C" and the record there is 192 mph.  Will this new Y Block measure up to those aftermarket scrubs?  It did in "E", but 192 is a tall order.  I calculate it will take 650 hp to make that happen and the new short block (albeit more cubic inches at 338) won't get me there alone.  I have some changes on the top end that hopefully will push me closer to the 200 mph goal.


Charlie Burns Laton, Ca (South of Fresno)



BurnsRacing981@gmail.com

Sorry, been away for a while, but back now.
Hi, Ted, in answer to your questions, the total lift is .556 on the intake and .553 on the exhaust.  I am still using those lightened and polished stock 1.54 rockers.  They have seen 7k rpm so many times and I am very impressed that they have held together.  It would be nice to have some 1.60 or higher ratio roller rockers, but this has always been a budget race program.

You also asked about the milling of the heads.  They have just been touched up and the lugs still measure 1.00".  You also asked about the valves and they are 2.02" on the intake and 1.60 on the exhaust.  Another concern is the top ring distance to stay below the reliefs.  These Racetec pistons were ordered by John Mummert after we discussed all the requirements for this build.  The rings are of course 1.63 mm (1/16") with extra crown, flat top, and the first land is at .400"


Charlie Burns Laton, Ca (South of Fresno)



BurnsRacing981@gmail.com

Probably mentioned earlier, but what casting letters are the heads?.  Reason for asking is that in the case of ECZ-G heads for instance, it's my understanding, that valve shrouding occurs with overly large iintakes.?   I'm hardly an expert on Y-Block race engines, but I seem to recall that John Mummert, possibly (?) stated in the past that notching the block for valve clearance, often resuls in a noticeable loss in compression.. So, the extra lift at the valves may not be productive?.  As an example, a friend many years ago beveled the block in his Y-Block "D" gas racer. It didn't result in any improvement in  performance that we could see...    


Paul

WoW!  They look bigger to me!   :rolleyes






NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

Charlie.
I neglected to ask if you have stock sized valves or are they larger?  Larger than stock valves does bring valve to cylinder contact issues to the forefront much sooner.

Lorena, Texas (South of Waco)

Charlie.
What valve lift are you running and how much have the heads been milled?  My "iron head" rule of thumb for cylinder wall notching is when the intake valve lift exceeds 0.535”.  Milling the heads does force the need for cylinder wall notching sooner.  The exhaust valve typically free drops into the cylinder so no notching has been required for those.  While I prefer that the top piston ring groove to be as close as possible to the top of the piston, that does compound the ability to have cylinder wall notches deep enough for the high lift camshafts.  In those cases, I’ll have the piston ring 0.350” from the piston top.

Lorena, Texas (South of Waco)

The dial indicator shows all 16 valves has cylinder wall interference.  I started by tracing all the valve pockets in the head gasket onto the deck.




Charlie Burns Laton, Ca (South of Fresno)



BurnsRacing981@gmail.com