215/300 Build Recipes

Discussion in 'Small Block Tech' started by Moyock13, Apr 2, 2017.

  1. Moyock13

    Moyock13 Well-Known Member

    Jealous!!!! :D
     
  2. Dan Jones

    Dan Jones Well-Known Member

    > What makes sense here? Can I deck the 300 heads to compensate or will that produce issues with valve clearance? I'd like to keep the stock 215 10.25:1 compression ratio.

    The highest compression off-the-shelf pistons are the Oldsmobile 215 flat tops (Buick 215 pistons are dished). With the Egge L2153 Olds 215 flat top pistons and a thin shim type head gasket (0.016" compressed), you're looking at around 8:1 with 54cc combustion chambers. To get 10.25:1, you'll need to remove 16 ccs of effective chamber volume. That assumes 4 ccs for the piston valve notches but pictures show four notches so that may be on the low side. To see how much you'd have to mill the Buick 300 heads, fill a burette and pour to 38 ccs and then pour it into the Buick 300 chamber. I don't think you can safely mill that much from the heads. Alternatives would be custom domed pistons or having the combustion chambers welded up. One of my sets of heads has had the chambers welded and re-shaped. A side benefit is the new chambers have a nice big quench pad so more compression can be tolerated on the same octane fuel. There are various other stroker combinations that have better compression with the Buick 300 heads. See:

    http://aluminumv8.com/Home/Technical

    for some combinations.

    Dan Jones
     

    Attached Files:

  3. Moyock13

    Moyock13 Well-Known Member

    Thanks Dan. My biggest hurdle is ensuring that the blocks are good to build. I'm pretty sure one of the 215 blocks is going to be good, the other is so-so. And the 300 block, well it's got one pretty bad cylinder. It may need to be bored to the limit of 0.60. If not it'll need a new sleeve. Sonic testing will tell me what's up.

    Just curious, what happens if the stock 215 heads are used with flat top pistons? Seems like too much compression. Yes, I agree that milling the 300 heads would be a waste.
     
  4. 87GN@Tahoe

    87GN@Tahoe Well-Known Member

    I had my 300 sonic checked before boring .080 over for v6 pistons and the machinist said it could almost go .120 over
     
    300sbb_overkill likes this.
  5. Jim Blackwood

    Jim Blackwood Well-Known Member

    Definitely do a sonic check.
    Also check to see if those Olds pistons are at zero deck, might be some leeway there.

    Jim
     
  6. Jim Blackwood

    Jim Blackwood Well-Known Member

    If you are stroking the 215 that changes everything. With more displacement you can use more chamber volume. Rod/piston selection is critical.

    Jim
     
  7. Dan Jones

    Dan Jones Well-Known Member

    > Just curious, what happens if the stock 215 heads are used with flat top pistons? Seems like too much compression.

    That was a trick used in some of the magazine builds back in the day which claimed 12:1. I ran the numbers for the Egge flat top pistons and got a little less, 11.8:1, depending upon the assumption for the valve notch volume.

    > Also check to see if those Olds pistons are at zero deck, might be some leeway there.

    Egge L2153 pin height (inches) is listed as 1.875". Assuming nominal deck height and connecting rod lengths:

    zero deck piston pin height = deck height - (rod length + crank stroke/2)
    = 8.96 - (5.66 + 3.4/2) = 1.9"

    So the Egge pistons should be around 0.025" down the hole at TDC

    > If you are stroking the 215 that changes everything. With more displacement you can use more chamber volume. Rod/piston selection is critical.

    Ditto. More swept volume needs larger chamber volume to maintain the same compression ratio.

    Dan Jones
     
  8. Dan Jones

    Dan Jones Well-Known Member

    The Buick 215 aluminum V8 uses a "dog ear" bellhousing pattern not shared by later 1964-up GM engines, including other Buick V8s. The 1962 and 1963 Buick V6 also used this bellhousing pattern but switched to the 1964-up GM corporate Buick/Olds/Pontiac bellhousing. The Rover V8's retained the dog-ear bellhousing so the Rover LT77 (and later R380) 5 speed will bolt up using a Rover bellhousing from a Triumph TR8 or Rover 3500 sedan. Note the TR7 also used the LT77 5 speed so they are cheap and common but the the TR7 version used a different bellhousing.

    There were three different GM bellhousings used behind the 215 (3 speed, 4 speed, and dual pattern 3 and 4 speed). Be aware there are several versions of the T5, including models made for AMC, Mopar, Ford, and GM. The Ford T5 had a narrower bolt pattern than the GM T5s that used the wider Muncie 4 speed pattern. Note that GM switched to the Ford pattern T5s in the mid 1990s. The 4 speed and dual purpose 215 bellhousings will directly mount a GM T5 (with the wider Muncie 4 speed botl pattern) and D&D makes an adapter that will bolt the Ford T5 to a 3 speed and dual purpose bellhousings. TransDapt also made a dog ear bellhousing and D&D makes a similar bellhousing. Dellow in Australia also makes a bellhousing for Toyota 5 speeds (e.g. W50, W58).

    > What about the 300? Will an OEM bellhousing accept the T5?

    If it has the Muncie 4 speed pattern, it should mount a GM T5.

    Dan Jones
     
  9. Moyock13

    Moyock13 Well-Known Member

    Looking at the cylinder skirt that extends into the lower portion of the 300 block, looks pretty thin. I checked the bore and it's stock at 3.75". Just doesn't look like it would support a lot of overbore without failing.
     
  10. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Looks are deceiving, and don't forget when you overbore say .100" you're only taking off .050" per side of the diameter, which is less than 1/16".


    Derek
     
  11. Moyock13

    Moyock13 Well-Known Member

    True that. it just looks like a weak link. Eventually I'll get both the 300 and 215 to the machine shop for cleaning and a sonic test. And after that I'll know more about my immediate direction.

    Has there been any successful Eaton M90 installs on a Buick 215? I think Jim has provided a few links in the past. There's a M90 off of a 3.8 T Bird on cl in my area. I know that a new S/C is probably better than a used one, but when there's a budget involved beggars can't be choosers. Any tech on that?

    If all the 215 needs is a hone, original pistons could be reused. With new rings of course. ;)
     
    300sbb_overkill likes this.
  12. Jim Blackwood

    Jim Blackwood Well-Known Member

    I went .050" over on my 340 and wouldn't be real comfortable with any more. Personally I think trying to keep at least .100" in the cylinder walls is a good idea.

    The M90/215 combo can be very potent. 16+psi of boost is very possible. At that level boost comes in early and heavy, so it's like running an engine twice as big just about as soon as you come off idle. That's with a 2.8" blower pulley and about a 6 or 6.5" crank pulley, I'd have to check my notes.

    Issues at that level were: keeping the head bolts tight; they just wouldn't stay put. And eventually, erosion of the top ring land on one piston (cast). This was on an Olds engine with 8:1 pistons IIRC.

    Jim
     
  13. Bzltyr

    Bzltyr Member

    I may be able to hook you up with 300 block and 64 300 heads
     
  14. Moyock13

    Moyock13 Well-Known Member

    Sweet! Thank you.
     
  15. Bzltyr

    Bzltyr Member

    I am in AZ on the other side of the continent.
     
  16. Moyock13

    Moyock13 Well-Known Member

    Would you consider shipping the heads? How much would you want for them?
     
  17. Bzltyr

    Bzltyr Member

    I have no problem shipping the heads. I do not know their history so I will have to get them checked out by my machinist. I don't want to sell them unless I know they are good. I will have to do some research to come up with a price. Are you in a hurry?
     
  18. Moyock13

    Moyock13 Well-Known Member

    Thanks. No hurry.
     
  19. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Any update on this project?
     
  20. Moyock13

    Moyock13 Well-Known Member

    Sadly, no updates. Been in one of those lulls where the days fly by, but nothing in the garage gets touched.
     

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