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Needed matching to use an aftermarket block???
Needed machining!!!
Obviously there are things you may need to do to a IAII or a Kauffman block when you get it... Boring and honing to you specific size, I am sure. I don’t know if all blocks come with same size bores? I wonder if many need to be decked to get desired compression height? My biggest question is concerning the block to head coolant holes. Pictures I’ve seen of the blocks have no coolant holes. Could different applications need different holes, and locations? I’ve read how Smokey Yunick made modifications on the small block Chevy, for better cooling (although all his stuff was hardcore racing applications. I am sure the Pontiac cooling system is similar...) My potential use of an aftermarket block would be a conservative one. I would use the .842 lifters, standard cam bore, and standard deck height. I know the bronze lifter “sleeves” cost more, even though I would be using stock .842 lifters. Would bronze hold up in a street engine? Anything I am missing? Just some thoughts, I see such a block for sale here... Thanks, in advance! |
Main oil passages should be considered as they can size issues.
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"...I wonder if many need to be decked to get desired compression height?..."
Don't know much about those blocks. But, I think I can answer this one. If you want zero deck height, after you install the crank you'll use, you'll then have to measure the distance your rod length + piston pin height will need to be, in order to put the piston top even with the deck. Doubt seriously that any block deck height can be guaranteed. As least I seriously doubt that the aftermarket block machining is that precise that they guarantee an exact deck height. But hey, if they do, and you believe it, that's great ! That way you can do the math & order the correct rod length & pin height, in advance. But, I think most all engine builders will want to actually measure the blocks, rather than taking the vendors word for it. |
I presume this has been viewed....
IA II Pre Assembly Tip Sheet http://www.allpontiac.com/online_cat...ding_notes.pdf . |
I have purchased two IA2 blocks. John's used on the Fairmont is run dry deck and reverse cooled. His is race only with nitrous. The other is a street application in my Trans AM and it's run wet and uses smaller diameter for the water holes located near the bore. We use a Cometic gasket custom made specific for us with our own assigned part number for our hole locations and sizes. My engine builder drilled the holes based on a pattern provided to me years ago by Ken Keefer.
Not the same as our specific gasket but Cometic sells a shelf gasket with 20 percent smaller cooling holes in certain locations. . |
All necessary machining processes apply.
Decking is necessary, not because you or anyone is looking for zero deck height, but because generally speaking, they aren't square. I haven't had an old or new block yet that was perfect. Usually one end higher than the other or something minor like that so even just a mild cut is needed to square things up. For that process to be done correctly, the main saddle has to be perfect, so that is checked minimum and sometimes needs addressed. Then your typical bore and hone to the size desired. When dad bought his MR1 block, all this had to be done. Don't recall needing any modifications to the oil or water holes at all. Believe it was used just as it came in that regard. |
Butler sells IA2 blocks machined, ready to assemble, you provide the specs, $4500:
https://butlerperformance.com/i-2446...tegory:1236719 . |
Aluminium block shown. And a subject brought up by the OP..... No cooling holes, drilling is required to match your heads water holes.
And stated.... "Lifter bores are deeper to allow the use of standard type "corporate" lifters." Do your homework on that subject, does that mean a 'regular' Pontiac lifter will not work ! It is my understanding the situaion has been corrected. But on very early iron blocks the lifter bore pads would not allow the use of standard Crower Pontiac solid roller lifters. Being shorter than a Corporate lifter the tie bar made contact with the lifter bore pad. In my case we machined the block for the necessary clearance. . |
So you're looking at 1500 + in labor to get ready to assemble?
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...and all this time i though Smokey cut his teeth on Pontiacs.
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In NASCAR he started with Hudson’s, then Chevrolet’s in 55, went to Pontiac when Bunkie came aboard, stayed til 62, then went with Chevrolet. Was with Ford around 1969-70, then quit nascar forever, was sick of the France Family Benefit show. He worked on other makes also, here and there. His 66 and 67 Chevelles are legandary. He piloted 50 B-17 missions, and stayed on. His war time achievements make him a great American hero, alone. His brash ways offend many. I don’t see it that way. I believe he just tells it, like it is. His life was in the middle of a lot of incredible things, war, racing, auto manufacturing, much more. |
[QUOTE=Steve C.;6103212]Aluminium block shown. And a subject brought up by the OP..... No cooling holes, drilling is required to match your heads water holes.
And stated.... "Lifter bores are deeper to allow the use of standard type "corporate" lifters." Do your homework on that subject, does that mean a 'regular' Pontiac lifter will not work ! It is my understanding the situaion has been corrected. But on very early iron blocks the lifter bore pads would not allow the use of standard Crower Pontiac solid roller lifters. Being shorter than a Corporate lifter the tie bar made contact with the lifter bore pad. In my case we machined the block for the necessary clearance. I guess my basic most question(s) are where the deck coolant holes are drilled? Stock locations? Something different from stock, something improved? Steve’s post number 4 tells A LOT! Nothing about coolant holes, though, Smokey’s improved small block deal placed pipe plugs in the forward large deck holes, but drilled like 1/4” holes to make no air pockets formed. This allow coolant being drawn into the block to be mostly forced to the back of the head, and then into the back of the heads, flowing forward to the intake crossover, and then through the thermostat. Moroso sells a it that eliminates the crossover, making a “Y” tube that picks up where the crossover started on the heads, some how making coolant flow through each side of the engine better. Not sure anyone uses it any more. My potential combination won’t be a racer of any, hopefully just another 10 second Trans Am that could embarrass some know-it-all’s at the drag strip, when I so desired, mostly just driving for fun. Still need $115.00 more, for freeze plugs and the special oil pump shaft That $4500.00 Butler deal looks good. But still needs more $$$ spent on it... |
This put a larger delta on stock vs. aftermarket block.
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Yep,
You really have to weigh the other advantages to see if it's the direction you need to go. They are obviously immensely stronger than a stock block. I like the fact that the bore size can finally mimic that of a BBC or 385 series Ford so now we can have bore sizes that unshroud the valves and help cylinder head flow. I also like the fact that even with that said, there is still plenty of meat left for multiple overbores and cleanups. No lifter bore braces required for those that like big solid rollers. I also like that these blocks have the ability to accept ridiculous sized crankshafts without modification, and a bigger crank than you could ever dream of stuffing in a stock block. With all that said, you are no longer stuck with 500 cubes, which is dicey in a stock block, and you aren't stuck at a HP level that a stock block starts to show weakness. Really depends on what you're after. In dad's case, he has a large stash of Pontiac blocks and could have went there when his last 455 bit the dust. When he decided he wanted something big that a stock block couldn't provide, it made the decision easy. The larger the cubic inch, the easier it is to make a certain power level without the need to be radical on the camshaft and compression, so the engine becomes more docile to drive. Eventually we are going to get to a point that there won't be a decent selection of stock blocks to choose from anymore, and that is already coming to bear. Would be nice if someone would come along and make a price friendly aftermarket block, maybe something that doesn't need to be as tough as an MR1 or IA. |
Well I got my question answered. I read the assembly tip sheet that Steve C. Provided (carefully this time). It said to drill deck cooling holes to match holes in the heads you are using..,
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I believe the $1500.00 in extra machining costs for an aftermarket block is a real number and can be justified. At $75.00 an hour, which is probably about the average shop labor rate, nationally, that's 20 hours. Using manual machining tools and equipment, it could easily take that long to do a super detail, every issue addressed, full race prep on any aftermarket block. 3 hours to do a perfect line hone job. 2 hours to bore to size. 4 hours to torque plate hone. 3 hours to square deck and surface. 1 hour to hone lifter bores. 2 hours to layout and drill the deck. 1 hour to dress and install cam bearings. 1 hour to de-bur and blend all the oil passages. 2 hours to completely de-burr, remove all casting flash. 1 hour to final clean. That's 20 hours and I am sure I left some detail items out such as verifying dimensions. Most people buying aftermarket blocks can and will do over half this stuff themselves which cuts the cost in half. Also, some don't care if everything is absolutely perfect. Some don't de-flash and de-burr. The IA II blocks come machined to within factory tolerances. To build a stock block into a real race engine, you would perform all the same operations and still have a finished product that may not be strong enough for your racing needs, especially if that included an aggressive roller cam.
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