625 HP with the torque of a stocker at 3000 rpm

Does having a really hot cam affect the engine vacuum to where the vacuum booster on the brakes is useless? Just trying to learn what I can.

Thanks,
Mike

 

I've read that there is typically a 4% difference for 1 point of compression. And you need at least 12" of vacumn for the brake booster to operate.
Steve

 

I don't think I ever finished that section, and the part on the mains is missing.. I would just seal that gouge up with a little sealer.

If your expecting more than 625 HP, I would like to see more oil flowing across the bearings, for cooling.. not saying your going to have a problem, but .002 is a bit on the tight side for over 625 HP.. what's your buildup?

Tough to pin down, as camshaft plays a roll in it.. but it may be less than you think.. Compression pressure in the cylinder is directly related to torque output, and a number of factors come into play. In one motor we did a while back, the customer decided at the last minute to attempt to make it a pump gas engine.. It was a level 3 engine, with this same TA 308s cam, and our bowl and chamber worked TA STG 1 SE heads. Just for grins, we did basically what the "scholars" will tell you would be everything wrong.. (big cam, 10.4 compression, SPX intake 1000 cfm Holley ect. ect.) and had to put in a thick head gasket to get there.. we did this on the dyno, and went directly from 11.5 to 10.4, with no other changes, to quantify the torque and HP loss by dropping the compression, which was done by opening up the quench area above the pistons, which is generally considered a big "no-no".. I was surprised at the minimal effect it had on this particular engine.. those sheets are attached.. In a later reply, I will show you that that engine, equipped in later testing with a B4B manifold, actually picked up twice as much power with just a simple intake manifold port match, as it lost by dropping the compression..

Yes, I have build a number of engines and complete cars, and have always subscribed to the 10" minimum to reasonably run the brake booster, under all conditions.. a 308s will have 5-7" of vacuum at 900 rpm. Now you still will have enough vacuum at times to operate the booster (closed throttle decel, for instance) but generally speaking, you will need a vacuum pump for power brakes with a 308S.

I will have to attache the sheets later tonight, that show the difference in both the compression, and the port match on this engine, as they are in my computer at home.

JW

P.S. Love the new multi-quote reply feature of the new board here.. makes it easy to answer several questions, and keep the train of thought flowing.. :TU:

 

Hey Jim Thanks for the info i thought it was alot more. tsp sp conveter is still smoking love it.

 

Here are those dyno sheets..

Going directly from 11.5 to 10.5 compression..

Buildup is .038 over 455
308S cam
TSP upgraded TA SE STG 1 heads
headers
SPX intake
1000 HP Holley

Listed below in order are the

Low compression sheet
Low compression averages
Hi compression averages
Hi compresion sheet

 

....a little easier to read :beer

 

thanks Alan!

 

buildup is:

Sportsmans rods, 10:75:1 pistons, total seal rings
Ta Stage 2 TE heads, long tube headers
SP-2 Intake, Holley 1000HP
Ta 294-98F cam, 1.65 roller rockers

main girdle on block, ta front cover, double roller chain, soon deep sump pan, etc.

should i start worrying?

i already need a replacement main bearing (upper, cap side) because i dropped mine (darn) and dented it...

 

Hey JW....who took your avatar pic..........never shoot into da sun.......is that you standing near that car......looks like a Buick???????uzzled: :Brow: :laugh:

If that is you.....for goodness sake.....put on a shirt....your blarring white MN tan is hurting my eyes!

 

Jim, What size should the main bearing feeds be to #1 and #5? And how about the holes in the bearing shells? The hole in #5 shell looks very small.

 

Anyone? If you do need to enlarge the hole in the shell, how exactly do you do it without damaging the bearing? Do people plug the oil hole in the block deck on the one side?

Thanks in advance guys :TU:

 

no, and yes..

No, don't fool with the number 1 or 5 shell, remember, those journals only feed 1 rod each.

And yes, I tap and plug the deck oil pressure hole all the time.

JW

 

im not sure if what youre talking about is what im thinking of, the oil passage that feeds the upper end on pre 1970 cars, but if you could post a picture of those holes that need to be plugged for that it would be great.

thanks

 

what difference will the spx intake vs old sp1 intake/1050 dominator?
what size headers produced 625 hp?
what difference would hve stage 2 se alum heads made?
any new pics of work from the shop jim?
thanks

 

Thanks Jim :TU:

Steven, I went and took this pic for you. I know you're in the middle of one of these too. The yellow circle is the oil hole.

 

SPX is worth 10 HP over the new SP-1.. (with a portmatch on both) the older SP-1 needs more work in the ports and plenum, but with that will match up the the new SP-1, and the results will be the same. It trades about 10 ft/lbs at peak torque, for 10 more ponies above about 5200 and up.. I bet I have a sheet on the differences on a motor, it may be in my computer at home, or maybe here, I will look and post if I have them available..


Now, as to your second question, this motor had the STG 2 SE's on it, but I built what is basically and identical engine, with the STG 1 SE's.. differences were 5 cfm advantage for the STG 2's on the intake, 20 CFM advantage on the exhaust for the STG 2's. And of course the headers.. 1 7/8 on the STG 1, 2" on the STG 2.

I threw together a little chart, as folks often ask me if the 2's will make more power.. here's your answer. This is about as close as you could build two completely different engines.




As to your last question, I would say you would be interested in this pic.. ready to go with a 308S??



:beer

Sitting next to it on the table is George's 525... in for a "freshen" after a couple hundred passes.. and yes, those are new billet main caps.. that's what you have to "freshen" on an 800+ HP engine.. the block.. ou:

Even though it was perfect inside (I could re-use the bearings) I could lift all 5 main caps off with my fingers.. 750 lbs of torque tends to work the caps a bit.. And it's time for a new set of GRP alum rods..



MMnn... 1400+ HP with these two motors.. heck, if I had a TA alum block/STG 5 heads, a huffer or turbo setup, and a customer with deep enough pockets, I could build that much (or more) in just 1 engine.. :shock:

Those will be good days, and they are coming.. :beer

JW



Please pass the TA Alum block...

 

And as for the plug in the LH oil galley..

Here's a pic, look just under the knob of the dial indicator.. it's best to countersink that hole, and then tap with 1/8 NPT pipe tap, and use an allen head plug.. but watch the angle.. it's steep..



JW

 

Exellent onfo. Jim.
You know us Buick guys really need a new book for engine rebuilding. :Brow:
Is there any plans to do one any day soon?
Ray

 

Yes, I get asked that on a regular basis.. and something in hard copy would probably be nice for wrenching on stuff.. but the best "book" is actually this website, because it has so much info on it, that draws from so many different sources.. and it stays up to date..

That being said, once I accumulate a couple more years of data gathering, and we get the going on the new Big race motors based on the TA block that's coming (end of the year.. maybe.. :TU: ) then I will probably sit down at some point and do an A-Z book on the 400/430/455 based engines.. but it's a big undertaking, as I am sure it would be several hundred pages.

I get asked to do a resto book also.. and we uncover more and more information every day, from just the work that goes on here.. just today, I saw for the first time a 72 GS 455/auto driveshaft.. with 4 stripes on it.. two in front, and two in the rear.. nothing set in stone on that paint mark deal.. also it was very evident on this car, how the front end stuff was painted.. sloppy to say the least..

JW

 

I figured if you did any engine rebuilding book it would be twice as big if not three times as big as the last one made. A resto. book I think would probably be even bigger than that..
Good to know they may be in the works soon. I know if you did one you would try to not leave anything out. A very big job to say the least.
It sure would help alot of Buick enthusiasts out.:TU:
Ray