Starting engine build 215 Buick

[Scofflaw Vicky]

Hello Group,

Starting engine build soon.  I have been looking over other builds, and do not see one exactly like mine. Wondering if I am off track or just came up with something a little different.

Buick 215 block
.040 bore for inexpensive GM 4.4 pistons i found, also .040 1.54 CH 0.927 pin
6.0 chevy rods with press pin for that piston (can only seem to find them in 2.10) so will be using lunati spacer bearings
3.9 Rover 28cc heads and EFI from same engine
.020 under block deck
3.9 crankshaft and front cover

Does anybody see any big wholes in this build?

Will be in very light 5 speed car driven often, and autocrossed occasionally.

Thanks for any advice in advance. Todd

[mgb260]

Never thought of the 79-82 267 Chevy V8 pistons. About same pin height as 305 but 3.5 bore. Substantial dish though,only 8.2 compression stock. .020 deck cut give what, 9 to 1, maybe 9.5 with overbore. Steel shim head gasket may give 10-10.5 to 1. Sounds good to me.

[Moderator]

Interesting!

Don't 3.9 heads have 37cc chambers? I was thinking the change to 28cc came with 4.0...

After running a 215 for >20 years, I'm thinking a bigger bore size wouldn't be a bad thing.

[mgb260]

Curtis, You are right, I assumed 28cc 4.0 heads. The 3.9 heads will subtract a point of compression. 3.7 sleeves with .036 overbore for 305 pistons routinely done. 305 std size is 3.736.

[Moderator]

In either case, check the heads for flatness because they may benefit from being skimmed.

Todd, what compression ratio were you aiming for?

[mgb260]

Todd, Also the Chevy rods have to be narrowed .100,.050 per side on the big end, bearings also.

[Scofflaw Vicky]

Yeah I forgot to include the rod milling.

Heads are 1995 10 bolt heads, and I thought all of the ten bolt heads are 28cc?

I am trying to get around 11.0 to 1 just reran the compression calculator 9.64 with composite gasket .050 and 10.52 with .020 steal gasket.

I have dish numbers for the silvolite pistons( -13cc's), but actual pistons are clevite so I will be measuring those when they get here. They look a lot like the buick pistons on top but should be much lighter with slip skirts and higher CH?

[MGBV8]

Not sure, there was a transition in 1993-94 that is a bit confusing. 1995 heads would have the smaller combustion chambers, though.

http://www.v8forum.co.uk/forum/viewtopic.php?t=133

[Scofflaw Vicky]

I guess listing head numbers would have helped they are indeed  HRC 2479's. Thanks for the link Carl.

Hoping with .040 to .035 quench area, higher compression, aluminum heads, and the 3.9 EFI supplying slightly richer mixture to 220 cid I should be safe enough to run 93 octane fuel with little worry of detonation?

Of course camshaft choices I hear also help with that?

[BlownMGB-V8]

I'm not sure steel shim head gaskets are a good choice, even if you can still get them. Now if somebody made them in stainless that might work, or in multi-layer stainless. But I don't know of any. Copper is available though and you can specify thickness. But without 0-rings? Maybe.

Jim

[Scofflaw Vicky]

Not sure I like the steelies either, easy to get and cheap, but do not inspire great confidence.

I suppose I could have engine shop deck block .030, and have pistons sit .010 over deck, and maybe have intake ground a bit as well, it seemed tall before compared to the head bolt holes?

Todd

[mgb260]

Todd, For fuel injection you want a minimum of 112LCA and a bit hotter cam than you would think to drop dynamic CR down to run pump gas. Years ago I ran the Crower 50232 in a 215 with the stock 11 to 1 pistons. Would probably work pretty good for you.