John's comment may well be the issue. We have new k-liners in our heads and Ferrea stainless steel valves on both sides, And as said, we lost couple of push rods at the starting about an half hour after previous run. But, last weekend went without problems on the engine side . Chevy parts keep breaking...

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)

Intake and exhaust?


Lawrenceville, GA

There is probably a lesson here for the guys running turbos and anyone doing the machine work including myself. The guides in Robi's heads were not set-up on the tight side, at all. It appears that the additional heat made by the turbo is causing the valve stems to grow more that expected. This results in sticking valves and bent pushrods.

It appears that guide clearance needs to be in the .0025" range to be safe.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

Well I figured out my issue with my engine.  I had valves sticking in the guides.  No big deal just pulled the heads off and had the guides reemed a little and now it is running top notch.  We just headed to my hometown with the dyno this weekend and pulled it there with the old ford.  Pulled the trailer and dyno like a champ.  The turbo charged y-block was a big hit.  It drew a lot of attention.  everyone was suprised at the power it is putting down.  We had a twin turbo chevelle on the dyno that put down 831 wheel horse power.  Naturally that just provoked me now.  He is a friend of mine from back home and I will not be out done.  I might not beat that but I will try my best.  There is some video of the dyno in action on youtube if you search Robi's Repair.  I had really never seen a rail car before and I got to drive two of them on the dyno.  What a rush!!!

There is some good info about spark plugs and heat ranges here

http://www.championsparkplugs.com/charglossary.asp?kw=Heat+range

As, we have had Champion RF14YC plugs now and when we took those of, they were very close to be melted if those pictures are exact . So, we will definetely move to colder plugs but that means that we have to start the engine with hotter ones due E85 fuel and that we don't have any cold start enrichments. Then, after engine is warm, we can change to colder ones

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)

I like your attitude, Hutz! Keep going .

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)

I am starting to think that John might be right about my problem with the bent push rod.  This problem did not start until I switched my spark plugs.  The first set of plugs I was using I would have this problem when I wasn't even under boost.  It would act up at about 3,000 rpm in vacuum.  Now I could run the engine all day at 3-6,000 rpm and engine would run very smooth and content.  I didn't have this problem until after a few dyno runs at 12 lbs of boost.  I think I am going to go with a 8 heat range ngk plug and see what happens.  I am confident about 20 psi.  The engine is built with the best parts and I as long as I keep my tune and afr at the right specs I don't see and parts breaking with 500-600 wheel horse power, which is were I am hoping to be at 20 psi.  Don't worry the y-block world will be the first ones to know when I hit that mark or SCATTER my engine trying!!!!  No worries it's just a bunch of iron when it comes down to it.  (and a little money too) but that's PAPER!!  LIVE FOR NOTHING OR DIE FOR SOMETHING.  (STALLONE)

HollowHead,

While replying to Charlie I recalled a situation with piston clearence being to tight and causing the piston to drag in the hole after shut down. When you make a hard pass and go straight back to the pits and shut the engine off the heat will build some. Just a thought. When I was in Hawaii I helped out a fellow with a 71 Firebird running an Oldsmobile engine. Basicly a Super Stock car. After a pass we had a quick disconnect water inlet on the block and carried a water tank with a 12V electric pump in the chase vehicle. Once connected the radiator drain was opened. As we towed the car back to the pits the hot water ran out and was replaced with cooler water. We never had a problem with the pistons again and were on top for quick turn arounds during eliminations. We always started with a cool block. Just a thought, I'm sure the Twin Turbo's make some heat. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

I think you are correct in basic theory Charlie but there are examples that seem to indicate the Y, if correctly prepped, will take a lot of boost. My new block was in a boat with a 6v-71 GMC supercharger on it. Ted can possibly shed some light on this.
As far as the twin turbo is concerned I just wondered if there was a shot of fuel or something that would hold back the piston on restart and cause the two bent push rods. Perhaps the piston to wall clearence needs opened up a bit. The extra heat that is generated after a hard pass and shut down could cause expansion of the piston slug causing it to drag in the block. They say it ran fine all the way through and on the way back. It was on a later restart that the miss developed.
Of course you know I'm no expert and not really that informed about these things. All I can do is recall the past and theorize the cause. I just want to see some 9's and maybe 8's out of this awesome rig. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Moonshadow, that's what we consider as a reason too. And, someone has to discover the limits, so Hutz, we are keeping the thumbs up for you and your experiments. It's very highly possible, that we will also raise our boost level at the next race and we hope we don't break anything .

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)