Tweet
Well, I have been collecting parts for the past 3 months, and am on the verge of beginning the machine work on my new 66 engine. The correct date 942 block I purchased had one cylinder sleeved, and it had crawled down as some bozo didn't step sleeve it correctly at the bottom, but I had my machine shop bore and peel it out. There are two cracks in the wall in the outside thrust face, midway up...no big deal as far as my machinist says. I now have a high grade Darton sleeve with the step on the top deck area, soon to be installed. It is a centrigally cast ductile iron, and from what I can tell these are the top end sleeves on the market. Any tips on a thermal compound to use beside the normal 0.001 to 0.003 press fit with a 50 degree temperature differential? Just wondering if there is some product to improve thermal transfer as this is a key item in sleeve to bore heat transfer. I have a 7115 GM crank, 10-20, that may need to go 20-30 due to some minor surface rust depending on how the polish goes, I am wondering if it is worth trying to find a cranshaft suppler to re-tuftride the crank, or just use it. It should be a good piece as it is the original L88/ZL1 unit. I also got a NOS set of GM 7/16" bolt dimple rods with press fit pins, coded white and painted as such on the caps....I bought at Carlisle last week. I am wondering if it is worth getting ARP wavelocs and resizing the big ends before balancing. Any tips on balance sequence for the rods/crank? It appears mallory metal was added in the past on the crank, in several of the origninal balance drill holes, and welded to secure. I don't known if I should grind the welds and start from scratch...or go from where it's at. I am using TRW L2268F pistons. Also, any input on what 3143 blueprint cam to use is appreciated. I am building the engine back to original specs, other than using the stronger crank and 7/16" bolt rods. Thx!....Craig
-
-
Re: 66 427-425 Engine Assembly soon to begin
By the way, I forgot to mention, I had the remaining material in the sleeved cylinder sonic checked for thickness, it still has a wall thickenss of 0.220 in most areas, .305 in one area, and the thinnest point is .160 between cylinders 3 and 5 (5 is the sleeved bore). I need to bore out about 0.031 radius for the new sleeve, which will be 0.125 wall thickness, before the 0.030 overbore. So I appear to have a safe margin of meat in the bore, with no apparent or significant core shift....Craig -
Re: 66 427-425 Engine Assembly soon to begin
I forgot to include the Darton sleeve site for reference, this tip came from my machine shop. I did some searching around town, and talked to other gearheads to arrive at my choice...Criss Engine and Machine in Tucson. Very nice clean shop.....and meticulous....Craig
Comment
-
Re: 66 427-425 Engine Assembly soon to begin
i have bored 427 blocks to .125 oversize for race engines with no problems. i have had customers that wanted brand new blocks bored .125 over just to get max cubes. step sleeving is the only way to go as i have seen the thru sleeving drop enought to cause head gasket sealing problems.Comment
-
Re: 66 427-425 Engine Assembly soon to begin
Unless you are going to seriously flog the engine that crank should be sufficient.
Yes, you should have the rod big ends resized.
A competent automotive machine shop has a specific procedure for steps in balancing rotating components. They will probably match the light end and heavy ends of the rods first, then, using that information balance the crank.
I have the flywheel and clutch balanced independently then included with the crank and harmonic balancer.
VerleComment
-
Re: 66 427-425 Engine Assembly soon to begin
Clem - thx for the input. The bore on cylinder 5 will be 4.50 up from 4.25 as the darton sleeve is 4.500 (+/- 0.0005). But, given my sonic checking, most areas are still .220 at the current 4.375 bore (3/32" wall thickness sleeve was installed). The thinnes point I could find was the narrowing for water flow around the core between cyls 3 and 5, and it is currentl 0.160 thick at it's thinnest point, and, I need to remove 0.031 from the bore RADIUS, which would still leave me at 0.129 wall thickness at the thinnest point, PLUS the new sleeve adds back 0.145 radius (before boring the ID of the sleeve). These Darton sleeves can run wet at 0.150 wall thickness, due to their stength. It should work out great. These blocks are meaty indeed. FYI..the original sleeve had actually dropped 3.16" since no step was machined in the base of the original cylinder. I figured the top step sleeve was the way to go, since the expansion/contaction will give into the crankcase vs grow up towards the head gasket. Plus, with the top anchored, there is no issue with the head gasket. Darton does want the gasket mating surface 0.002-0.003 proud of the deck, to improve gasket seal. This sleeve was more expensive the the typical repair sleeves.....thx again for the input!....CraigComment
-
Re: 66 427-425 Engine Assembly soon to begin
Verle - thx for the input. The one thing I do want is to balance the crank/rods/pistons separate from the flywheel, as I want to be able to replace that and have it neutral balanced later in the even I ever need to change it. I have also heard not to balance the harmonic balancer as part of the asm as the rubber inertia ring can throw it off....not sure if this is really a problem or not. Thx!.....CraigComment
-
Re: 66 427-425 Engine Assembly soon to begin
even when i stepped sleeved i always leave the sleeve .003 above the deck. i also always decked the block before boring with a deck mounted boring bar to make sure the bore is perpendicular to the crankshaft centerline. if you use a table mounted boring bar this is not required.Comment
-
Re: 66 427-425 Engine Assembly soon to begin
Craig,
They balance the crank then add the balancer and flywheel to check everything.
VerleComment
-
Re: 66 427-425 Engine Assembly soon to begin
Craig,
You may be aware of this but don't forget to have an oil channel cut on the rear cam journal. Most good machinist do this without asking but it doesn't hurt to check. You'll love the performance of this engine!Comment
Comment