I completely forgot to get a picture of the insides of the valve covers to show the metal. I washed them in my spray cabinet parts washer and most of the metal is still in-tacked.
Hmmmmm. . I was under the impression that one of the major root causes of all head gasket failure is detonation. I had an 11 to 1 engine with a 4 bolt head that would blow a head gasket every time it detonated! . This was a cast Iron block and head, V8 with 10 head bolts. I blew 3 head gasket in about 200 miles. The block was true and the head was also. I was working at AC specialties and the only fix for my car was to O-ring the block. I lived in the Start of the Columbia Gorge and the start of the Cascades. I would have a 1000 feet of altitude change in about a mile. I would be climbing a hill and hear a Ping for about 5 seconds or less and that was all it took. I tried FelPro, Victor, and Detroit head gaskets. A SBC could with stand more detonation because it had more head bolts. . Good luck. . How far can you mill the heads with out changing Cam timing?
The head bolt threads for a SBC are in the deck surface. They tension, and thus deform, the cylinder walls when tightened. The cylinder wall loading, and thus cylinder wall deformation change throughout the 4 cycles of the engine. The whole structure of the engine just "moves around" a lot compared to a modern engine like, say... a Northstar.
In the Northstar, the headbolt threads are deep in the outer wall of the block. Since it's an open deck block, tension in the outer wall translates to compression on the inner wall. The loading on the bore wall doesn't change much with the various loading conditions of the engine... the block/head interface is much more stable than it is on an older engine like a Chevy. The torque + angle head bolt tightening procedure also yields tighter, more consistent clamp loads than on an older engine.
I'm also going to be using Cometic MLS headgaskets.
LS2's only have 4 bolts per cylinder and they're running 10.9 on a bigger bore than the Northstar, with a more flexible cylinder head. LS7's are running 11:1 on an even bigger bore. I think the comparatively small bore Northstar will be just fine.
Any decking of the heads or block alters cam timing. How much can be figured out by looking at the pitch diameter of the cam sprockets and the amount decked. The cam sprockets get redrilled for cam timing changes anyway... it shouldn't be a problem to have them redrilled to compensate for machining of the block surface.
The Engine I was refering to was not a SBC, But when I did reference the SBC it was the say that they did not have the same known head gasket issue. The engine was a race trim 340 in a race car. 3" tire on the front 10.5" on the rear. plastic side windows the whole bit. 69 dart. I saw the same issue with fords also I worked at a machine shop that mainly did Chevy work, so flaws of other makes was pointed out.
I know SBC's have five (and BBC's have 6!), but there are lots of engines with four that hold lots of cylinder pressure (big block Cadillacs, for instance). Hondas and lots of imports have 4 head bolts/cylinder.
The Ross pistons were heavier than I'd like. I didn't think about compression enough when I ordered the first set of CP's with deeper than stock valve reliefs. I ordered these with the same valve reliefs, but a net +3.5 cc dome. The grooves are cut for the diamond lapped TS rings that I bought. I'm going to have these coated ceramic tops & moly skirts.
[This message has been edited by Will (edited 06-20-2007).]
Will, Alan Johnson sells a pistion when combind with a .040 gasket will produce 11.8:1 Did you port your cylinder cambers, if so what did they cc at? I received my 12:1 CP pistons and will be interested to see how yours turn out.
I know Alan has pistons. His prices are competitive with what you can assemble from other aftermarket MFG's. I just wanted to do it my way. I'm going to be setting up .035 quench. When I get a heads/cams package, compression will go up to 12.5.
The Ross pistons were heavier than I'd like. I didn't think about compression enough when I ordered the first set of CP's with deeper than stock valve reliefs. I ordered these with the same valve reliefs, but a net +3.5 cc dome. The grooves are cut for the diamond lapped TS rings that I bought. I'm going to have these coated ceramic tops & moly skirts.
So what are you doing with the old pistons? Didn't you pay to get the Ross pistons coated too? What did the CR work out to be with them? Also, have you posted what the actual weights were of your different pistons you've got around? Did you ever figure out the crank balance issue you were having way back?
I know it's a lot of questions, I'm a curious fella.
I had the Ross pistons coated. They had standard ring grooves. I've already sold them. The first set of CP's has also been coated. Compression with them would have been in the low 10's. Stock is 10.5. I didn't think about it the way I should have, but I'm not going to all this trouble to build an all motor engine with less compression than stock. If I get a wild enough hair (hare?), I may build a 10:1 engine and put about 10 psi on it... Otherwise those pistons will sit on my shelf until someone wants them. Their utility is a bit limited because the grooves are cut for diamond lapped rings which are of course a little thinner than standard rings.
However... they may end up being just right for the Sealed Power rings which have very good thickness tolerancing for an OTS ring. I'll have to see what the groove width comes out to...
Indeed! So, did you ever figure out where you went wrong on the balance? Have you kept your piston weights written down somewhere? I was hoping to have that documented in here somewhere for future reference. I don't know why, just seems like it may be useful to somebody someday, maybe even me. Thanks for the update.
The crank that got F@#%ed up was the result of a miscommunication between myself and the shop and the balancer's lack of experience with that sort of work (lathe vice drill).
There isn't anything *wrong* with the current balance setup. I just need to figure out why my math isn't giving the same result as the measurement. The measurement is perfectly valid... but also on hold because the piston weight will change yet again.
Daggonit, I was just going to post that the bottom of the oil manifold (plate between lower crank case & oil pan) was flat and only had the heads of the main bolts sticking through it.
Originally posted by Will: Daggonit, I was just going to post that the bottom of the oil manifold (plate between lower crank case & oil pan) was flat and only had the heads of the main bolts sticking through it.
I appreciate the intent to answer Actually, you told me something that wasn't obvious in his pics. He has long studs protruding through instead of bolt heads. I should be able to wack quite a bit off the overall height.
I'm sure I'll still have questions when I start rebuilding it. I am going to study you guys' threads first.
Edit - I forgot to ask - so you think my two-stage dry sump will work?
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[This message has been edited by toddshotrods (edited 07-10-2007).]
The early engines through '95 have stud headed bolts at all locations in the inner two rows. The windage tray bolts to these studs. In the (I think) '96 and later engines, the windage tray was redesigned to bolt under the heads of all 20 main bolts. The stud headed bolts were replaced by conventional bolts except for one location which is where the oil pickup support bolts.
Have you ever looked into a after market harmonic balancer? It looks like the small block ford as the same snout diamiter.
Darrin
I hadn't. There's nothing wrong with the stock one. It doesn't carry nearly as much of the engine's MOI as the flywheel and can be replaced with the engine in the car should I find a suitable replacement. It's also the crank pulley, provides the clamp load on the oil pump drive sleeve and has the journal on which the front main seal runs.
ALWAYS DOUBLE CHECK EVERYONE'S NUMBERS, EVEN YOUR OWN!
CP was about to make me pistons with a net 11+ cc dome... I had to be very assertive in convincing them to recheck their numbers... hello 13.5 compression.
The real number is a NET ~3.5 cc dome for 11.5 compression.
GM uses 3 pin sizes in FWD 4.6L I am wondering what rods you are using? I like the GM rods and have a lot of sets, but I may build a 00 engine. I have soooooo much more I can do with the PCM.
As near as I can tell, GM doesn't sell the pins separately, do they? My manuals show them as NS, only available in a piston assembly. If you have a good p/n for the first generation pins I'd be interested.
John Stricker
quote
Originally posted by AJxtcman:
GM uses 3 pin sizes in FWD 4.6L I am wondering what rods you are using? I like the GM rods and have a lot of sets, but I may build a 00 engine. I have soooooo much more I can do with the PCM.
I'm not using any '00 or later hardware. Eagle rods are for '99 and older pins.
Thanks The only rods avalible are 99? I have not looked for them. I have only one set of the 99 and prior. Now what size pin is the best? smaller or bigger? Smaller is or can be lighter, but the surface area is less. The larger has more surface area, but is heavier. The S/C motor uses a large pin.
The Eagle rods were made for the '99 and older engines... before the Y2K engines even came out. Since they all have the same bearing bore diameter and length, only the pin is different.
Dunno the design considerations behind going to a smaller pin on Y2K engines, but they did go to a bigger pin for the SC engines as you observe.
I wanted Hank the Crank ceramic piston pins, but they went out of business or something.
If you're going high revving low torque, you can get away with a smaller wrist pin. High torque (esp supercharged!) requires larger pin to reach 100k mile reliability.
I think the 2000+ engines might have been originally designed with a higher rev limiter than the <99's
DIMENSIONS 93-99 Pin. dia. Inch 0.8658 00-03 pin. dia. Inch 0.8266 03-08 pin. dia. Inch 0.9053-0.9055 This is from the late 03 engine update 4.4L Pin Diameter 0.9448-0.9449 . 4.6L info Connecting Rod Length Center to Center 5.9449 in Connecting Rod Bore Diameter - Bearing End 2.2495-2.2501 in Width 0.8572 in . I am just throwing this out. I am not sure what is the best way to go. Big pin dia with light weight aftermarket pin? The rods all look the same just the small end is different. Maybe the next engine I build for my self. hmmmmm.
Actually, you told me something that wasn't obvious in his pics. He has long studs protruding through instead of bolt heads. I should be able to wack quite a bit off the overall height.
