Anyone try this combo before? Planning a lower end rebuild.

I'm rebuilding a 350 to replace the one I have, thinking of runing 10:1 pistons and a ta-212 cam.

It'll put the DCR by my (ball parked to death) math in the 8.11:1 range (at the highest)

I plan to throw in the TA double groved front cam bearing and then just use whatever master kit bearings I can get (unless someone knows why i shouldn't).

Machine shop will do all the work for 800 (bore, hone, align bore (if needed), hot tank/check, deck, and install cam bearings) cam is 180 (I may go comp cams though and get more parts) and the master kit is about 500 on ebay (federal mogule owned parts house).

May need a crank & 1 rod though (sounds like rod knock, ain't opened it yet to see how bad. Buicks like it tight, BUT sometimes they can be reconditioned), not sure it's worth getting the balancing assembly balanced above the normal balancing with an externally ballanced engine that'll never see above 5500 RPM.

I'm gonna clean the flash off the gallery over the cam and pop in neoprene seals, but that's about it for modifications. Sorcing a pickup tube, etc. for most the oil system modifications seems like to much of a bother. Also, gonna just lap and reseal the valves, and pop the heads on (ream out any bad guides but not rebuilding (Yet)). May port match the intake manifold. I'll piece meal out of spec springs/ valves.

Basically, at this point of my project a solid bottom in and valves that work and won't fall is all I'm looking for. I would much rather spend the money for the head job on brakes, tranny, electronics, pumps, and other stupid little 40 year old stuff... I worked as a mechanic (ASE) for a while and know where it needs to go is not a port job, and till the rebuild hits 20k or so it'll accept upgrades without a hitch. And if it ain't broke don't rebuild it. Also may grab some used heads and port them myself :Brow:

My only question is what octane it'd need, so i'd like to know if someone else is running a similar build. I'm not familiar with how touchy this motor is in regards to pinging... unless someone knows if they make an add on knock sensor for HEI dizzies.

My goal is for reliability and novelty, I've got no dreams of getting a Buick to 350 + HP, and am perfectly happy if I can get the 70's specs in my 75 and pick up an MPG or two.

 

Find a set of 68-70 heads to use they will make more power than the 75 heads and might as well have them rebuilt if you are rebuilding the engine.... have them magnifluxed and then smooth them out before u have them rebuilt. Shoot for 9:1 compression and it will run fine on 90 octane much higher and it will need reduced timing.

 

If I throw down the 69-70 head what's the bother to fit the old style rockers, if I remember right those don't oil the same... and do the A.I.R. holes and exhaust manifolds work?(I'm not sure full headers are the best exhaust set-up, I need to get it running to check but I don't think low back-pressure is the best.)

I ask because my 75 oils through lifters and push rods, and I believe early years were shaft oiling only. Also, the 75 heads have some better enginering... In fact I hear both that they don't breath, and that they do. As far as I can tell, this engines main RPM hang up is the small bore.

What if I go radical and use some range rover heads? Aren't their aluminum v8's pretty similar.

9.1 static or dynamic? I'm talking 8.11 dynamic (about 168 psi that's how I do the math), 9 dynamic I know get's me past 91 (R/M)2 on many engines.

 

Used the 75 rockers lifters and pushrods. I would not cheap out on the valve job. Rover heads would require custom cam and manifolds. I would go all rover and use their fuel injection. Consider having a custom cam ground to what you want.most cams are outdated tech anyways.

 

Hehe, putting fuel injection on in California would put me into a world of hurt. It's a 75 so it has to LOOK stock (swap in a 455 in here and a cop decides to send you in for a visual inspection (that they still can do to you) that would be a $2500 minimum fine ou: )


Problem with guessing at cams is you need software/ experiance, I'd rather use someone else's pile of parts to figure it out... unless someone else on this thread has any secrets? I also am avoiding switching torque coverters and a bunch of other stuff that still works. It is a 75... it's not worth much.

I'm not talking cheap on the head job, I'm talking none :dollar: - lapping's just a clean up I do when I chasing up head gaskets I also take the time to scrape of the carbon. I was thinking though of rounding the valve guide and cleaning up any obvious flash or blockages, but racing flow benches tends to be a waste of cash. I'm just watching the scrap yards till someone with TA heads gets hit in the quarter panel.


My goal is to keep it under 15-18 hundred. And according to that 12 second buick article by Kenne-Bell they really recomended parts switching over machining on these plants.


Anyone ever weld together to 350 pans to make a deep sump? What did you do with the oil pickup?

 

Ta only makes big block heads so unless you want a 455 I don't think you will find any for a 350

---------- Post added at 07:12 PM ---------- Previous post was at 07:01 PM ----------

If you call the cam company and got a tech guy that knows what he is doing he can design a cam specific to your needs. I am doing that myself for a boosted project.

 

There are no 350 aluminum heads. If you want good flowing heads you will need to port those. Might as well work on them while you have them apart..

Call Crower for a cam after you have all the other stuff figured out.

Sean has a nice set of heads but I doubt he will sell them.

 

Eh, not to upset about not having aluminum heads on a steal block.
uzzled:

How much is it costing to get your cam custom ground?

I'm going to work on them, even port a bit. But, head work is best saved when they are the bottle-neck or really really bad. And honestly in this 350's case its OK. No leakdowns.

Upping compression and cam will get me from 160hp stock to 250-ish (70's stock) but I still haven't gotten my octane answer... With 10:1 pistons do I just asume 90 octane like the 70 model? Or does nobody know the 350 well enough to say... surely someones tried this?
o No:



:bla:Half the auto repair industry is sales, and normally 1/2 of build cost is in parts that add 1% to overall performance. It's like jetting/tunning you carb is nearly free, and for 90% of cars more effective than spending 2000 on ignition mods or just poping on another mass-production jetted carb. Buying parts or such is easy, knowing how to use it and what the limits are is the hard part.

It's like the "internet," everybody on the internet making money off it tells you how great "the internet" is... when it's just a bunch of wired together servers they are charging you for.

 

alot of it depends on cam and dynamic compression about octane . or could setup for E85 and have over 100 octane with some loss in mpg.custom ground cams will be alittle extra,say 50 or so more but you will have a better cam for your combo.also you still will have to measure how far down the cylinder the piston is and add the cc of combustion chamber is the find gasket thickness to find actual compression since it is weel know that the blocks are not all machined to spec and you could have an extra .050-070 more deck height then replacement pistons are designed around.With the possibile aluminum heads ta might make you can run higher compression and still run the same premium fuel if it happens.

---------- Post added at 03:38 PM ---------- Previous post was at 03:35 PM ----------

if your going to up compression that high shoot for 350 plus hp .ported heads will help this goal. we have seen small cams with ported heads and big valves make 350- 400 hp with lower compression.

 

You need to CC all your parts and do the math to get your actual CR. With build tolerances the real number will vary. Your stock pistons will NOT provide 8.5 CR unless the piston tops are level with the deck surface at TDC. On these Buick 350's, .040" deck clearance is roughly 1 point compression. So, if your stock piston sits .060" down the hole, subtract about 1.5 point from the advertised number of 8.5. You have 7 to1 compression.
That's why I keep saying to you guy's, you have to zero deck the block. Or buy taller pistons. If you buy off the shelf 10 to 1 pistons from sealed power they are the same height as stock, just smaller dish. But you will not get 10to1 from them if they are .060" down the hole.

My engine measures 9.6 CR with the Crower level 3 cam I need 94 octane WITHOUT alcohol to not get pre-ignition.

 

Like I said before shoot for 9:1 and it will be fine on 90 octane and if you want to run lower octane then 8:1

 

I'm NOT talking static compression, so the piston choices of 8:1 or 10:1 are not really what I'm worried about. I know block cut's ex. effect this and you'll almost always be off.

I'm talking DYNAMIC compression, and every motor has different levels of DYNAMIC compression it can take. This is auto shop 201, not 101.
http://www.hotrod.com/pitstop/hrdp_0706_pitstop_compression/

I need to know about what levels a Buick can take. 8:1 is the rule; I am calculating to 8.11:1 which is why I'm nervouse that the 10:1 pistons are simply never going to work... but they put those on this very engine in 1970 and very close in 71 when GM hardened exhaust seats and went full unleaded. I don't know what the 70 took... I'm not going to Zero deck cause I'm cheap on this rebuild and plan to go big with it later in life.

My stress is 91 R/M/2 is as good as I can get in my part of Cali. the airboard bans a lot of stuff.
Part of me is thinking of just tracking down a stage 1 manuel and going with blueprinting the motor to that.
I just want more HP than the stock 160, and that's not hard... 250-300 and I'm more than happy. But maybe I need to take the gains from some other source even...</SPAN>

 

Go with your original plan with 10 to 1 pistons or hyperutectic pistons and the 212 cam. Then the rest will be tuning. This is a well proven combo. Jim from trishield did a similar engine with big valve heads and a 60 cc chamber at 9.6 to 1 with the 212 cam and got a 360 HP/400lbs engine. Total pump gas engine.dyno proven and post is on this site.so 250 is easy to get if you try .

 

Read Gary Farmers post on cam shafts. He has done the math for the cams mentioned. I don't know how the CA formulated fuels will relate to the dynamic number.

 

What's the name of the camshaft post, couldn't find it?

http://www.rbracing-rsr.com/compstaticcalc.html

Ok, went and did some research, would someone let me know I got the specs right o No:. I figure it will have to bore out to +.3 and that's with the 10:1 pistons and the cc's I got off a Jeep dude with a 350 buick and some web searching.

Right in the sweet spot 7.5-7.9 DCR depending on how I play with things, that assumes I'm right the TA-212 closes at 62*
http://www.wallaceracing.com/dynamic-cr.php

 

Check open chat for 350 camshafts thread

 

Here's what I have on the TA 212-350 cam:



Using this calculator: http://www.wallaceracing.com/dynamic-cr.php

Enter in the info, and the IVC will be 66* @ 4* ICL advance.

I put in a generic .030 overbore for 3.83 bore, and of course the 3.85 stroke and 6.387" rod length.

Boost and altitude remain at 0 to get the N/A DCR @ sea level (0 elevation).

I get 10.14:1 SCR @ 8:1 DCR.

With a quench platform, I hear you can get away with around 8.25:1 DCR such as with sbc's and such, but the Buick 350 has an open chamber design, which should put it around 8:1 borderline, taking into account the smaller combustion chamber size. While this does not eliminate the need for quench, it does help alleviate the lack thereof.

Common consensus is somewhere around 7.6-7.8 dynamic is the acceptable and optimal region, though polishing the pistons and combustion chamber and eliminating any hot spots will help this too. Could probably run closer to, if not dead on, 8:1 DCR this way. Otherwise, I'd shoot for 7.6-7.8:1 DCR.

I wouldn't want to get any less than 7.5, so here's the SCR @ 7.5:1 DCR: 9.48:1. Anything higher than this, but less than 10.14:1 is where you want to be.

Static compression ratio of 9.48:1.
Effective stroke is 2.95 inches.
Your dynamic compression ratio is 7.50:1 .
Your dynamic cranking pressure is 146.16 PSI.

Static compression ratio of 10.14:1.
Effective stroke is 2.95 inches.
Your dynamic compression ratio is 8.00:1 .
Your dynamic cranking pressure is 158.97 PSI.

Gary

 

I ususally just use the compression calculator at Summit. It may not be spot-on, but it's close.

http://www.summitracing.com/popup/calcsandtools/compression-calculator

Notice the more you bore it, the more the compression increases. I've asked around and I don't think they increase the dish size with overbores, so use the same calculations for dish.

I use this formula for calculating CID, then convert it to CC: I take .7854 x diameter (bore) x diameter x stroke (depth) then multiply by 16.387 to get the CC's. You can get dish size this way.

Example: Speed Pro's '10:1' cast slug shows a 3.050 wide by .085 deep dish. So it's .7854 x 3.05 x 3.05 x .085 x 16.387 = 10.18 cc dish for those pistons. They also have 1.835 CH.

Typical untouched Buick 350 head cc size is 58, which goes up or down with cleanup, shaving, etc.

Typical composite head gasket is .040 thickness.

So if we took a typical budget build scenario with untouched parts, it would look like 9.73:1 SCR with .040 deck height, .040 gasket, 58cc head, .030 overbore, and 10.18cc dish.

Less than this if the deck height is higher, which seems to be the case when taking untouched blocks into consideration, and depending on which year the block was cast.

I took my deck calculations at what the book says the stock deck height is, which is 10.187".

Others here say it's a bit higher than that for the earlier blocks from '68-'74 or so, then from '75-'80 it's even taller, so I dunno.

This should give you a little something more to go on now though.

Best wishes.

Gary

 

Thanks Gary! That's the kinda input I was looking for. My issue is in San Jose, CA i haven't found anyone who knows the powerplant.if I can get the 9.73 static, I think that'd be pretty golden at 7.69 DCR. I just really would rather have a lower CR than have to dial back timing... CA is hot and at 104 all summer it's best to be conservative in a hot running Buick.I also know these mid-70's plants are almost all on the edge of detonation stock.With a buick torque is a-ok, but picking up horses is hard and my main focus is just to get it to spool up respectably.