Glen, Thanks so much for the invite, but I'll need a raincheck, if possible. This is going to be a quick trip, with a week spent in Cali, working on flow, seeing Dema about the cam, and visiting Don about the new girdle.
Here is an update from Dale, on the top of the engine tear down. For those that have followed the build, this is the first time we've posted actual pics of the chambers!
My wife Amy and I (yes, she's in the shop working with me on this) have pulled the FlatCad engine out of the car and started the dis-assembly process. I look at it more like a forensics process of paying complete attention to detail, looking at everything, suspecting everything and seeing what you can learn. If you take your time and really look for the minute details - they are frequently there. Sometimes you can make deductions (based on obvious facts) - other times you're applying all that you know in a creative manner to ATTEMPT to explain what you see.
Background on a Couple Key Things:
1) We have custom designed billet aluminum heads.
2) Due to this, we have custom designed head gaskets - .072 solid copper with a rubberized coating to attempt to seal the water passages.
3) Heads are O-ringed (not the block) - remember, this is a flathead.
4) We fill the engine with water at the start of the race day - and drain the water EVERY night. This is for fear that we'll seep some water into the engine (over night) and ruin it the next day. This has happened to many guys in our situation, so we're very cautious.
When I pulled to top of the motor off (blower, intercooler, manifolds, etc) - noticed we had a teaspoon of water in the bottom of the center exhaust port on the driver's side. This side did NOT have a new head gasket put on for the Ohio Mile and it was not re-torqued (as we'd torqued it at least 4 times before).
Hmmmm . . . water . . . not good. Where did it come from? We didn't see anything on the dyno, Bonneville or the Ohio Mile. Did this concern me - hell yes! Leaking intake studs? Cracked block? What?
I then pulled the plugs on all cylinders - notice a very slight amount of rust on one of the center cylinders on the driver's side. Hmmmm . . . that means that the water was also inside the cylinder . . . also not good.
Then we pulled the heads and here is what we found - yes, now I see an explanation and also realized a couple new things for next year:
See the rust in the transfer area - probably some on the seat as well
The head gasket was obviously leaking water into the cylinder - notice the discolored areas in the head and the gasket pictures (outlined in red).
Now - look at the passenger side (looks great!)
So here is what I noticed on tear down - which is why I do this by hand and I DON'T use air tools:
a) The torque on the driver's side was not what it should have been - was closer to 45 ft lbs, than 60. AND - this surely wasn't due to us not re-doing the torque many times (we did it 4 - 5 times at least) . . . during hot and cold cycling.
b) When I put the passenger head back on at the Ohio mile, I INCREASED the torque by 10 foot lbs . . . to 70 on the main/stock studs and 50 on the 7 that we added. This worked really well and the torque was maintained. The pictures show this.
Conclusions and Plans for Next Year:
1) Constant Re-Torque: No matter how many times you torque these heads - we need to check the torque after every run and ensure that the clamping forces are maintained. This also means that our new header design MUST be done in a manner that makes it easy to pull the headers. Currently, there is no way to retorque the heads with the engine in the car and the headers on.
2) Higher Torque: We're very sensitive to how much torque we use as the decks are pretty thin on this engine. Also, the seven added studs cannot be torqued like the stock ones that have the big cast-in bosses in the deck. But, we need to use the higher 70/50 torque settings . . . as this head was perfect and I didn't see any signs of gasket failures.
3) Heads - Some Rework: We need to rework the stud holes (too tight) and the stud washer setup. It is way too difficult to pull the heads - as there is too much binding within the stud holes, stud washers, thread sealers, etc.. I should be able to pull a head in about 15 minutes . . . currently it takes 3 hours on the car and over an hour outside the car. It is a TOTAL pain in the butt!
4) Adding Deck Dowel Pins: If we're going to loosen up the stud clearances, we should add 2 dowel pins to the deck - to guarantee alignment and non-movement.
5) Head Inspection: Due to the possibility of water with solid copper head gaskets, we need to pull the heads after EVERY meet - to inspect for water, oil the bores and valves, etc.. We can't afford to have even small amount of rust in the cylinders, valve seats, etc.. This needs to be a part of our standard operating procedures. It is also why it needs to be easy to pull the Dodge heads!
More tonight - as I'll now take the lower-end apart . . .
B&S
Thanks for the help Amy!
Topic: XXO/BVGC '38 Chevy Coupe Build (Read 1031155 times)