Inliners International Forums General Discussion Engines its turbocharged and now what? help

Hello All,

Well I have successfully turbocharged an inline 250 in my 1966 GMC SWB pickup. It runs really good and will fry the tires. I also just installed a WC T5 5 speed because I blew up the 3 speed. I am running the factory intake and exhaust manifold with a GN T3 turbo, Holley (hanger18 mod) 350cfm carb, factory points conversion ignition. It starts right up and my boost is set to 10psi.

I feel the engine is worn out. I realized this before I started, mileage unknown. I am getting blow-by from the boost causing oil to shoot out of my oil pan. I believe worn rings

I want to rebuild the engine this winter. My question?

How should I rebuild it? stock specs?, possibly forged pistons?, better head gasket? Different cam?

Would I benefit by running a OFFY intake?

Would you get a HEI and lock it out?

I wanted your opinion.

Thanks,

Shad in Nashville

Shad,
Here are my answers to some of your questions.

How should I rebuild it? stock specs?, possibly forged pistons?, better head gasket? Different cam?

Would I benefit by running a OFFY intake?

Would you get a HEI and lock it out?


Bore it the minimum needed.
Get forged, turbo type pistons.
Use a Felpro 1025 head gasket and ARP head studs.
There are lots of cam choices. Small RV style will work good, but custom ground cams are available.
A offy intake would help, but a Clifford would help more.
Rework the head. Minimum 1.84/ 1.6 valves and port the head. Lumps will also help.
Use a rebuilt HEI with working timing, devise a vac can to pull timing when under boost and apply timing when in vac.

Shad,any engine pics, to see your setup,,

X2

Need pics.
Corteco, is supposed to make head gasket for our engines.
Contact them or Mike Kirby, if they are available.
Personally I do not like the overbore which the Felpro gasket has.
4.125" bore IIRC"

Need to add breathers to your valve cover to reduce the blow by.

I had the same problem,not as bad, when I was only running 8-9 psi of boost pressure.
The stock PCV & stock valve cover breather is not enough to relieve the excess crank case pressure.

An offy will be able to go to boost faster, better response,& better than a Clifford IMO. Stock manifold, restrictive because of adaptor 2 to 1 barrel.
The GN turbo,is probably really a bit on the small side ,but will work. There 3 bolt inlet is a bit restrictive @ higher larger boost levels.
Forged pistons, always a good choice when turbo or blower charging.
Will add more later.

MBHD

x3!
Great truck man! Would love to see some engine pics as well. Would like a rundown of your whole set up also......PM it or post it here if you want.

Man that truck is bada$$!

Thanks Inliners! I have really fallin for these engines. I love the simplicity and the fact that their motion does not horizontally oppose.

There are some pics of the setup. It is quite rough in appearance. It is fully functioning. My plan was to design, fab and get running. Then rebuild, clean and dress up.

I will try to post more details in another reply.

Nice & simple!

What FP regulator are you using?Never mind I see it is a Holley,just like I used.Drill & tap the top for boost reference.

What are you using to control the boost pressure,factory wastegate actuator?

What feul pump are you using?
I used the noisy Race Holley electric red IIRC? It's pressure was 18-19 psi.

An MSD BTM (box) will work fine for your aplication

Any thoughts on an intercooler?

Need more pics to show the kid on how to make your up/"J" pipe to the turbo & basically all of your install,if possible, it would help us all out.
Thanks

MBHD

The FP reg is a modified Holley, seen in the pics below.

I am actually running the original fuel pump, it pushes 7psi all day long. I probably need to upgrade and regulate it.

My J-pipe is 2" and actually runs between the motor mount and the inner fender. That was the only way I could get a nice clean sweep and mount the turbo completely vertical.

The MSD BTM box would be nice.

Enjoy!

Boucher,
thanks for the pics, I am sure the kid & others can learn from your pics.
I discuss these types of mods to do, but w/no pics,some guys can't picture or imagine what I am talking about.

So if you have more pics of your install & mods, keep them comming!

Did you take out the heat riser valve?

I might be a bit concerned about any debree or metal disloging fron that valve area. It could wipe out your turbine wheel.

10 psi is a bit much for cast pistons, no intercooler, no methanol injection, on pump gas, what octane fuel are you using? Not impossible,just
be carefull.

I built an 80 VW 8.5:1 1.8 liter Scirocco years ago that ran up to 20 psi on 91 octane,but it had a Renault fuego intercooler.

BTW, you do need to uprade your fuel pump,or run a boost referenced line to it,7 psi from the fuel pump & 10 psi of boost,something aint right there. LOL

I take it you have the nitrofil (SP) plastic Holley float?

MBHD

Boucher,
it seems you came outa nowhere,& have gotten somewhere fast,,LOL
just curious where did you get the info for your mods & parts to use for the turbo install.
From this forum or others also?
Thanks

MBHD

Re: snowman4839,

read & look @ this thread. Manditory!!!!

You boost referenced the mechanical fuel pump as well, right?

Nice job! Cool truck simple functioning set up and planning the necessary improvements. Hank is attentive and dialing you in. Not a bad thing. We are listening. Beater

http://static.summitracing.com/global/images/instructions/pax-1001839%282%291.pdf
pg 17
Boucher,
I would not lock out the timing on your HEI when you install it.
I doubt you will be able to run 30+ something degrees total while boosting.+ starting will be a pain.
If you mean lock it w/low timing say 20 degrees,then worse mileage,different ways to set-up your dizzy.
I would limit the total advance it can provide mechanically.
Run a bit more initial timeing,alloweable w/out detonation.

A lot of people do not recommend an intercooler @ low boost levels,I always recommend one.If you can install a product or item that can reduce intake temps,, do it, especially when forced induction is involved.
Low buget items I mostly look for low budget builds & the low priced intercoolers from ebay fit that bill,Example:
http://cgi.ebay.com/ebaymotors/CXRacing-...sQ5fAccessories most are made in China,they seem to work fine & have an assortment of sizes.
Also, they sell universal intercooler plumbing kits for low$$,,,look for the thicker walled tubing,mandrel bends w/rolled beads already done. Example: http://cgi.ebay.com/ebaymotors/CXRacing-...sQ5fAccessories
With most of these kits,the clamps & silcone hose are a bit cheap,but for low boost will work fine.
Methanaol injection I also recommend,especially when not running an intercooler,+ you will make more power,it will supper chill your intake temps.
http://alkycontrol.com/ http://cgi.ebay.com/ebaymotors/Alkycontr...sQ5fAccessories
top notch kits,others will work also.
Lowest priced I have seen: http://www.alcohol-injection.com/universal-stage-1-8.html

MBHD

Hank! you are going to get me right. I love it.

I am a bit confused on the boost referenced fuel part. I am going to upgrade my factory fuel pump to a high flow one. After that, do I need to boost ref the fuel pump (as listed by the paxton pdf) or is the FPR reference doing the same thing?

Here is a link to my photos of my build. Enjoy!
http://picasaweb.google.com/shadmeier/JEDTurboHuffer#

I did most of my research from reference books and the website turboforums.com. I first educated myself on the process of turbocharging and then applied to my situation. I am just glad I started with an engine that has a large error margin.

I am meeting with a local engine builder today to go over the freshen up/rebuild.

JED

It depends on what your output pressure from your new mechanical pump puts out .

If it(your new FP) puts out 14 psi,then you just need a fuel regulator that is tapped into your manifold pressure/vacuum.
With that you can run roughly 10 psi of boost pressure.

If you are going to run more boost then you will need to tap into pump like the paxton pdf.

I ran the electric race Holley pump that put out 18 psi,then all I used was a Holley FPR like you already have. I only ran 8-9 psi w/my Paxton supercharger.

MBHD

I have not got a mechanical fuel pump yet. If I can find a high psi (14) one I will get it. Any suggestions?

Well, I met with a engine builder here in Nashville. We plan to; polish and balance the stock crank, stock cam, forged pistons (from member Bob trw L -2289), bore block .030 over, check the head for cracks, freshen head up, replace any worn items, new oil pump and paint. I am sure I am leaving something out.

I am searching for a Offy 5416. I just found a very cool vintage Offy carb hat bonnet to blow through.

I plan on pulling the engine soon and getting started!

Boucher,
Don't forget to zero deck your block,having a tight quench should help prevent/supress detonation.
I know about this first hand when I ran 12.0:1 compression & had 220 to 230 PSI of cranking compression with no detonation on pump 91 octane gas.Daily driver I will add.
I actually have a positive deck of .002-.004.
Stock cam is a bit anemic.
I would run different.
Something like this but on a 115-116 lobe center
Comp cams 61-232-4
C60-252H-10
252 / 252 @ 0.006
0.474 / 0.474
206 /206
110 ,,, no good,, use a wide lobe center camshaft.
The best working of the Chev 6 manifold designs as the fuel mixture breaks up best when hitting the ends of the manifold. On other "sweeping" designs", the #1 and 6 cylinders receive a heavier charge than 2 and 5 for uneven distribution to all the cylinders
This wesite states also why I like the Offy intake
http://www.aaamarine.com/servlet/the-704/5416-discount-Offenhauser-Chev/Detail

That is the reason behind I split my Clifford intake.

Maybe I am thinking incorrect & so are the people of that website? Kinda makes sense to me though.

MBHD

Boucher,
nice pics & mods done to the Holley 2bbl.
Maybe add info to the pics to help out others for the mods?
here is a good designed wastegate/downpipe that the GN guys use,improves airflow tremendously & better boost control over the stock set-up you are using.
http://www.turbobuick.com/forums/parts-sale/302552-mpe-3-s-s-custom-fender-dump.html
For the Regals,it is a dump pipe,because there turbo is positioned different than yours,this would be sorta the exit angle you need for your set-up.

If you add this type of DP, your turbo will spool faster because the stock adaptor makes a sharp 90 degree turn right after the turbine wheel.
You can also, port/smooth out the factory inlet turbo piece to the compressor wheel,people have seen gains by this also.
This link below shows extensive porting on the turbo also & other items, very informative.
http://www.turbobuick.com/forums/engine-tech/258301-follow-my-port-polish-project.html

MBHD

wow, that downpipe is beautiful. the problem is that I would have more wrapped up in it that the whole turbo and exhaust!

I started pulling the engine the AM. First timer here, and I learned the hard way that you should have a 1/2" bolt handy to plug the rubber fuel line when you cut it!

I am really excited to pull the engine, have it rebuilt, paint / clean up the engine bay and re-install it.

I picked up a cool vintage Offy carb bonnet and I plan on using to blow thru.

Until next time,

Boucher,
I am not wanting for you to buy that DP, just to try & copy that design to help w/turbo spool up faster & flow better than the stock set-up you are currently using.

Don't need to use stainless, but a low cost alternative to using pricey 304or more $$$ 321 stainless is 409 stainless,or use mild steel as you have already.
I am pretty sure you could just purchase the flange w/wastegate valve from some Turbo Buick forums,just an option to think about.

Have fun doing your project & take your time & do it correct the first time if possible.

MBHD

an old bird that I call my "Rod-Father", always tells me. Shad, "Do it right, do it light".

Thanks Hank.

the engine is pulled!

Damn, it takes to long to prep for the removal and the actual removal was all of about 5 minutes. I went ahead and bought a engine load leveler and it worked awesome. With me doing the job by myself, it help out tremendously. On to the next step.

Boucher, thanks for the pics.
I'm curious on what your method was for fabbing the up-pipe. It looks like you got it where you wanted and used duct tape to hold it together? Is there a trick that I don't know about like weld-through tape?

I ask because I just finished 2 uppipes for my Supra and I had a very difficult time.

fabbing my up-pipe was alot of test fitting. On my pipe I had many different angles on both planes. One of the direction/angle of the pipe and two when you have two pipes that are curved with flat ends, rotating each of the pipes for a butt weld will give you a different angle also. So I mocked up a pipe with cardboard the exact diameter of the pipe. Another thing that I did was when ever I got two pipes that needed to be butt welded, I took a sharpie and made a straight line down both pipes.

As far as the duct tape. That flange was a bit loose and I needed a little spacer to make it hold in place. Then I cut away a 1/4" strip and did a spot weld, then another 1/4" strip on the opposite side and spot weld. That was enough to hold it in place.

Bouncher
What did you do for the carbs throttle shaft? As to keeping it from leaking under pressure.

Just a link for throttle shaft mod

http://home.windstream.net/mcfly/sealingTBI.htm

MBHD

Boucher that all looks good. I'd like to know what increase you felt or otherwise noticed when you put the Turbo on?
Better milage?
More power?
Run smoother?
Any difference at all?

I got these in today. They are a set of old stock TRW L2289F .030 over forged flat top pistons. I am so pumped. Thanks again to Puerto Rico Rob!

Good score on hard to find forged pistons!

check out that box! I love it.

Hey Boucher, any idea when the machine shop will have your motor finished?

Very good score!

I think that is the same guy that has a set of the TRW forged flattop 307 SBC pistons for a good price?

I know on the 307 forged TRW pistons flat top pistons I still currently have in my Camaro, they were pretty heavy & have a thick crown.
IIRC,me & a friend milled out .100" on the inside underside of the crown,just to lighten them up.

My 307 SBC same pistons have seen ,Nitrous,high compression & low compression w/a Paxton supercharger.

MBHD

Are the standard bores of the two engines (250 inline 6 and 307 sbc) the same?

they should be. The stock bore of the 250 is 3.875 and a .030 over would make it 3.905.

Suggestions needed:

Unfortunately the sweet pistons did not come with any rings. Robert said to run a 1/16, 1/16, 3/16 ring set.

What are my options for rings? For those who have boosted, what is recommended to run?

Thanks,

Boucher

I think those pistons use bigger rings (thicker). Aren't they 5/64, 5/64 and 3/16 ?
Plasma Moly top ring and conventionals elseware. Tom

Try this
http://cgi.ebay.com/ebaymotors/HASTINGS-...=item43a48dc66f

Same company also has a cheaper set of moly rings listed.

TRW lists that piston as follows:
1.655" CD
.073" cup
ring stack: 1/16, 1/16, 3/16"

The L2396F (250 truck):
1.655" CD
.073" cup
ring stack: 5/64, 5/64, 3/16"

The L2314F (8.5:1 307") is slightly different:
1.672" CD
no cup
ring stack: 5/64, 5/64, 3/16"

The L2272F (12.5:1 racing 307"):
1.675" CD
.450" dome
ring stack: 1/16, 1/16, 1/8"

Good information.
I have used the 2314F and thought they used the same rings.

Ok. I looked back at my emails with Robert and he typed, ".073 deep with no chamfer.Comp. distance is 1.655 and uses 1/16 x 1/16 x 3/16 rings."

Also, on the side of the box reads "TRW Basic Ring Set T-8113M"

So, if that helps any....