hot rodding a 4.3L - Page 2

Swart does have a great point that BlazerSS keeps avoiding....I would like to see pics of this vehicle along with time slips and dyno sheets. This should be easy since Blazer SS has nothing to hide.

He has pictures (CLICK HERE), I'm not doubting that he has installed what he says he has installed, just starting to really want my questions answered and not dodged.

aye, believe me eyes have gazed upon those pics, before. What about timeslips and dynosheets?

Curious as to what crank shaft he used for the stroke?

I know on the 350 you use a 400 crank to stroke, what do you use on a 4.3L to stroke it? I wouldn't mind stroking a 4.3L V6. I am also a V6 kind of guy. But I do have a limited budget.

Tim, you said stroke entirely too much in that thread! LOL

Ya, think. Lol

Boy, you stripped that 91 pretty good didn't ya! LOL I was checking out your gallery, love what you've done so far. And I just wanna say, the 350 is the right choice for that truck. DO IT!!

ya man ive heard of other ppl thinking of doing the 350 swap but i am completely serious and commited to doing this.
ive got my mind set, and i guarantee that it is going to be done. and about that guy with the v6 of course he'll be able to beat some v8's with nitrous and the supercharger n crap. but like seriously if you put that much money into a v8 it would smoke his v6 time and time again. so wat i am saying is that ya it would be fast, but a v8 with the same stuff done would be faster.

Sorry if I seem a little passionate about the v6. But I have listed my HP on this site , I just havn't put in my dyno sheets, The problem that I have, is by the time that I post something , I have changed things maybe twice. That is why there are so many different pictures of the dash and the engines.

I can't go by my last session because I found out that I had a almost completely blocked fuel line! Damn plastic fuel lines above the fuel filter! I have since replaced the lines with braid, My last session was about 380 HP at the rear wheels and that was with the fuel blockage. Disapointing!! I havn't did a new dyno since replacing the lines and adding the 36% but it is coming and I will make sure that it is video'd and posted.

What I am trying to get accross is , that if you want a 350 , get a 350, if you want to keep the 6 keep it.

I might have posted a lot of information on another forum, same sign in name , but after I post this I will try to find all of the information and compile it into one post, everything that has worked and didn't and what you need to get as a kit in order for things to work as expected (mods). Just buying and doing one mod will not give you what you were expecting, but taking that same mod and adding another will make it work.

Again I apoligize if I came off on the wrong foot.

I forgot to add , that if you do keep the v6 you can do things in steps and still drive your Blazer to work every morning. The longest that my Blazer was up on blocks was only one week. And as I always keep saying if you want the eisiest and best mod to do first . Spend 90$ and get some 1.6 roller tip rockers direct replacment , less than a hour of work sets you up for so many of the other mods, like restrictor removal, air intake, exhaust, free flow cat, and so on.

The pics that are posted are really old, just an example , the traction bars that you see are no longer angling down , they are now straight. so much has changed to the engine compartment, I think that I will wait a little while to post any new ones. I think this project is about at an end. I thought of donating my Blazer a while ago and working only on my 350 project, But I love the Blazer and I realized that I can't let it go. If you think about it what else realy comes close? Look at all of the 1st genarations still on the road! I know everybody and their mother now offer their own SUV's . Blazers still have a following!!

On the stroke question .

355 from 348. H beams.

Could you elaborate a little more. I dont understand what that means.
Thanks!

1.6 roller rockers are only $90? Where did you find them, I think I will get some, if I don't already have 'em (different motor already has roller rockers, just don't know about 1.6 or not)

quote:

ORIGINAL: Blazer SS

On the stroke question .

355 from 348. H beams.

Last I knew... displacement could only be increased by two means... By 'H beams', I think you mean that you changed the rods... 3.48" is the standard stroke... So you increased the stroke by 0.07" by rod change alone?

Seems that I left out a lot of information on the stroker thing. First the stroker kit was a custom supercharged build. The kit listed .355 as the stroke of the kit ,but the kit was stroked to the max that would be good for a supercharger. The real stroke is actually more that the .355, The stroke was obtained with the 5.7 Hbeams with v8 crank size journals , which is actually smaller than the journals that are used on the v6, the journals were then machined to get the desired stroke, the pistons were custom made to move the pin to the desired range.

First I needed to give them the measured volume of my combustion chambers and they took it from there. Just A little information , the posted size of your chambers are way off, Measure for yourself before you even think of replacing your pistons. There is a whole lot of room in our v6 blocks ( clearence ). The more that you learn about the v6 , the more you will grow to love it.

Check ebay! there is a wealth of parts on it , and 1.6 roller tips will fit. we have more than enough room from the piston to the valves, the 1.6's wake up that factory cam by making it theoreticly bigger. the factory cam is actually realy realy good. But if you go supercharged or nitrous it has to go!

Ok, so they acheived the 0.07 longer stroke, from 3.48 to 3.55, by offset grinding the crank. Yeah, 0.07 is the max you can get by doing this. Once you get the journal to the same diameter as a 350, you can do pretty much anything with the pistons and rods for cheap. The only difference between the rods in a 350 vs the rods in a 4.3L is the crank journal diameter (see below).

350 v8 crankshaft rod journal diameter = 2.0986-2.0998in
262 v6 crankshaft rod journal diameter = 2.2487-2.2497in

Here's an illustration I drew up quick of what we are talking about for those wondering:

With this, you need to get longer rods and possibly change the pin location (depending on the rods) for the wrist pin that connects the rod to the piston. Also, you'll need to specify 350 v8 rods and bearings.

And while higher ratio rockers do add lift, they do not add duration or affect the overlap. Overlap and duration being HUGE for any forced induction application. Just increasing the lift alone will give decent gains on a stock or slightly modified motor, but if you aspire to do anything bigger/better, spend the money up front for a larger aftermarket cam because you'll save money in the long run.

Blazer SS, thank you for the clarification. Please understand that this was not something that I enjoy doing, but it is necessary to keep the information listed on this forum accurate.

No problem. Hence the word forum. Thanks for the diagram.

Another word of advice. If you plan on having your heads done ( porting, bigger valves, springs ) LEAVE THE INTAKE VALVE SIZE ALONE!!!! ( VORTEC) Work on the exhaust side, YES. but do not increase the valve size on the intake side. You will hurt more than help the flow of the heads. I found this out the hard way ( wallet ). I went with 2.02 intake and 1.6 exhaust, what happened is that I shrouded the intake valve by making it bigger! You would think that all that you had to do was deshroud the intake valves, Wrong! Once that was done , my whole chamber size was changed and it was a domino effect from there! Compression was off, pistons had to be changed, Port both sides but only change the exhaust valve size.

Exhaust evac, very important to forced induction engines, we also need a wide LSA for great performance. again forced air only!! Normally aspirated go with more valve overlap.

Get a valve spring job! Check your seat pressure, closed and open, factory springs are notorious for unequal seat pressures, Replace the factory rockers! If only to replace them with the same specs, again notorious for being off . Go with a good aftermarket set, if they say 1.5, 1.6 they usually are. The factory rockers could be as low as 1.4. Meaning your valves are not opening as fully as they should.

Why I say get roller tips? If your Blazer is a 98 and below and you have non adjustable rocker studs you can replace them in less than a hour! If you have adjustable studs go with full roller rockers. I can't remember the years that came with rollers (trunions) but I think it is 2000 and above? Just having all of the valves open and close as they should will greatly improve on your performance.

Thanks for the clarification.
That makes alot more sense now.

I have a '93 4.3L V6 and a bare V6 block (unknown origin) both sitting in my garage. For some reason I think the bare block is aluminum. I'll have to check it out tonight.

Sorry, the point is I am going to be rebuilding one of them. I was serious when I said I like the V6 engine. Gobs of power from it. Plus its about 100 pounds lighter then a V8. Eventually this rebuilt engine will go into a off-road toy. I want it light as possible.

Try a Edlebrock set, Intake, cam, and rockers, Higher comp pistons will release the beast. Have fun with it!

I have been looking at the various cam kits out there. I want to keep it TBI. I'll have to check out the Edelbrock stuf. Been looking at the Crane cams lately. I like thier truck avenger series.

Just remember that on those stroker cranks that they are offset ground, so it is taking away from the strength of the factory crank. For forced induction it would probably be best to stay with the stock crank.

I considered installing a 350 engine in my ''''91 Blazer but after I did some research, I chose not to start a  project of that magnatude and build a strong "bolt in"  4.3L instead. I ned two engines, a brbuildable 4.3L ( w/o balance shaft) to build while keepinmg the original 1991 engine in the Blazer to drive while building the other.  I have collected about $600 worth of internal engine parts for the new engine while they are still avaliable.  Many parts for the 4.3L also fit a  350 V8 engine, no availability issue there.   It will take me about a week to switch engines and have the new engine running strong enough.

Optional 350 V8 installation:
Assuming a well rebuilt 350 engine will cost $1700, including the core. 
A new radiator for a V8.....$300.
An auxillary transmission oil cooler will be needed...$200.
(possible transmission rebuild...$1800)
A 350 V8 oil pan for a 4WD Blazer...$500..
A special off-set oil filter adapter for 4WD...$50.
Kiss your 4WD engine oil cooler goodby.
Headers and exhaust system for a V8...$700.
A Power-Trax No Slip differential...$500.
(Or a  8.5 rear axle assembly...$1000)

Total:  From  $3950 to $6550. plus labor cost if any.
And you can forget about passing a emissions test. 
.

You better think it over about "dropping in" a V8. If I was going to go to that much trouble, a Chevrolet Rat Motor 427 or 454 V8 would be my choice. 

Nothing like resurrecting a thread from the dead!  Over two years old!!  Not the record, but damn close.

And duntov, are you quoting GM list price for those components cause one would have to be pretty damn desperate to spend that kind of coin for the parts listed.  Tim (hanr3) did a complete rebuild on his 4L60E in his 2000 for 1/10th the cost of what you quote for a rebuild...  V8 conversions are not for the timid DIYer.  Prices like you quoted above are just astronomical and completely unrealistic for the type of person that would be looking to do such a modification.

Check out JagsThatRun.com for proper pricing.

step one: get $1000
 
step two: go to craigslist
 
step three: ??????
 
Step four: profit