Tired of cracking cylinders!

[Chip Birks]

Heres my info...
2276
44x37.5 Street Eliminator heads(R.I.P.)
Kawell Cam
T04 Turbo
48 dellorto sidedraft
Huge Drilled jets
MSD 6AL timing locked at 24
8 to 1 c/r
so, almost every time we run this motor it seems to crack a cylinder or two.  Its last pass was truely catastrophic buring a hole through my my 3/4 head in the 4 chamber.  It seems to do this if we run more than 20 psi.  I'm thinking its a possible fuel pump issue cause obviously its buring a little lean...If i put the same exact jets into my almost identical 2054 it runs rich and is definitely not popping cylinders, it has a brand new pump of the same type, also running 22+ psi boost.  We are not newbies to the turbo type 1 stuff, this is a new motor and we just can't keep it together.  Does this sound like a pump issue to anybody else?  We are trying to get this together for a race next weekend and would really prefer to put it away this winter in one piece.  Thanks guys.
Chip

[JVance]

A wide-band O2 set-up might be a good investment to pinpoint the actual problem (e.g. whether it's running out of fuel up top or a jetting issue).  If you're spending a lot of time above 20 lbs of boost, would you consider stronger cylinders?...that at least may be more forgiving.

[Frallan2]

I think you have identified the main issue yourself.
Running lean.
OR you do not have the timing you think you have, when driving.

Now there are som basics you can do to verify it. Get a fuel pressure gauge with isolator so you can observe the pressure at top end.
Do it with low boost.
It could also be your needle inlet valve in the carb.

So the best investment giving a lot of value for money is a Innovative LM2 or second hand LM1. On this nice instrument you can log the AFR and take away all guesswork.
It costs much less than your broken head.

So stop guessing, which is also what I am doing in my proposals and try measuring and finding facts.

[2stroke]

what kind of head studs do you have?

[Chip Birks]

I actually have an LM-1 with aux box.  Unfortunately it destroys computers when I've used it in the past...I've recently gotten a new laptop and will be setting it all up again.  I'm telling you though, I don't think its jetting, the jets have been soldered in at the ends and then been drilled huge.  Read HUGE.  Needle valve could be sticking though.  I have a fuel pressure gauge, under boost the pressure goes from about 2 at idle to around 6 under boost.  I have a holley red pump and reg. I know not the best, but they have worked for us for many, many years.  This pump is a few years old though and may be due for change, the car is race only, 1/4 mile, so it is under boost for short durations.  Head studs are 10mm.  Thanks for the replys guys, We appreciate the suggestions.
Chip

[bauerbus]

What kind of Fuel?

[Chip Birks]

115 octane leaded, not sure the brand, comes from a local station here in UT.  Worked good for us for many years in our other turbo machines.

[bauerbus]

Maybe Ohio Tom wil Chime in I think He uses the same carb setup.   Hey Tom !!!!!!!!

[FITNESSFORYOUTOO]

Do you have a fuel regulator to increase the fuel pressure as the boost rises? Do you have a gross ball inlet valve in the carburetor? I used to run the Dellorto 48 side draft and if you do not use a boost sensitive regulator you will split cylinders every time.

I found it was hard to get the regulator set right so it does not go lean or spill fuel out on the fender. I would never run one again, I would run a Holley and be done with it, plenty of other people have had good success with them though.

You can make a Holley blue regulator into a boost sensitive one by drilling and tapping the atmospheric vent hole then routing a hose from it to the pressure side of the intake manifold.

[fiatdude]

I remember a friend running a sidedraft on his turbo system with high boost -- he ended up running without any jet stack just so that he could get enough fuel into the motor -- spent alot of time on the dyno getting it right

Me thinks it is time to either go FI or 4 barrel -- it's just a bridge you've came to -- either back it down and live with it there or call somebody and order some new parts -- you're buying enough of other ones that you keep breaking.

Think about it -- even a NA four banger datsun 510 of my friends runs dual sidedrafts so it won't run lean

[fiatdude]

Carcraft make a boost sensative cap for the regulators works ok -- They have had the most sucess with the side drafts from way back

[turbo_bob]

Holly pumps do wear out, could be a flow problem.
Try setting the timing to 20, use VP C-16 fuel, cold spark plugs.

[tw]

Your not going to get enough fuel volume with that setup. When you put bigger jets in. It will only get worse. (sucking the bowl dry)

Tony

[J. Matsko]

Also check your timing i know you said it was locked out at 24 deg. but do you know that your degree wheel is acurate what i have done was to confirm the tdc is in fact tdc. take and modify a spark plug to be able to stop the piston as you roll it over by hand put a mark on your crank pully then turn the engine backwards till it stops put a mark there, then measure the distance between the marks cut it in half and that should be TDC i have found alot of crank pullys to be off a couple of degrees and when you are tuning these hi hp engines with a locked out distributer 2 degrees will kill your cylinders.
Also it seams like the red pump will not provide enough fuel, the blue pump feed my 2276/ with an 830 holley and 28-36 lbs of boost with no issues.
Good luck, Jerry

[Frallan2]

These are all good suggestions but we are all guessing..

Could you imagine the feeling if you knew for sure it was going lean?
Or being able to tick off in your check list the spark advance and knowing 100% for sure it was at 24?
Fuel pressure to the carb is 100% OK through all run.
Or having the LM1 show rich and nice all the way.
How about duct taping it so you can do a quick check going over the line and not logging? Maybe not the main recommended thing but it could work.
How a LM1 can mees up your PC is a new thing. Are you sure about that? What does Innovate say about that? Tried their forum?
Must be a rare occurance and I am sure they want to know about it and for sure they should be able to help in some way.

Then next step would be to run it at low boost and again measure if it was going lean or not after every change?
Only one change at the time.
Measure what you see and most likely you will hit the change that makes a lot of difference.
Now quite often problems sneak up on us and it is the unfortuanate combination of two or more problems but when they add up, we go over the limit.

Sorry J. Matsko. You are the only one taking approach to re-check everything and not take chances.
Good suggestion to re-check exact timing.

[fiatdude]

If you take a 2276 at 14 lbs of boost the engine now thinks it is a 4552 (Your at 2 bar)

When your a 20 lbs of boost your at 2.4 bar and your engine now thinks it is a 5527 -- -- Here is the question -- -- How many 4.6 or 5.0 NA mustangs have you seen running a single side draft??

And that is my last thought for the day

[FITNESSFORYOUTOO]

If you take a 2276 at 14 lbs of boost the engine now thinks it is a 4552 (Your at 2 bar)

When your a 20 lbs of boost your at 2.4 bar and your engine now thinks it is a 5527 -- -- Here is the question -- -- How many 4.6 or 5.0 NA mustangs have you seen running a single side draft??

And that is my last thought for the day

That was a good one! Exactly why I switched to a Holley.

[Chip Birks]

Wow!  Thanks for all of the replies!  Honestly I would love to go EFI and be done with the whole carb thing...in fact I'm putting together 2 new cars that will be just that.  I am running a boost sensitive regulator.  The carb was tweaked by Dave Kawell, and has been setup to run turbo'd.  We have run it at low boost, 12 psi.  It runs 12.5's super consistently.  Unfortunately, we pulled a 2054 out of the car that ran 11.30's all day long, hoping that we could go a bit faster with the big motor.  the 2054 can take the boost...why not the 2276?  Oh well, we'll get it figured out.  thanks for the thoughts everyone.  Looks like we've definitely got some work ahead of us.
Chip

[Frallan2]

If your problem is cracked cylinders it is NOT linked to you running a side draft carb.
A problem in the carb, yes but not just because it is a Weber or Dellorto.

...and please do not compare a turbo draw through turbo with a larger NA engine.
The physics around how they work are quite different.

I respect the Kawels 100%  and then even more since the day they ran low 9s in Blackie with a side draft. If this engine was set up by them, nothing fundamental is wrong in the design.

If you do not find what causes your problems here on this setup, you might very well be in for a surprise if you go EFI.
Please consider som logical and systematic troubleshooting in stead of shooting from your hip.

[camch]

on my 2276 we busted about 10 cylinders before finding out the wastegate was the problem,i do run a holley 750 dp with 85 primarys and 95 2nds at 14 lbs of boost and my car runs 6.40's in the 8th,the wastegate was sticking on us and would not open correctly,hope this helps

[Ohio Tom (DdK)]

Chime!!!!!.

I always recommend that you setup a fuel pressure guage where you can read it during a pass. Either permanent or temporary, it will show you what's going on with your fuel delivery system. (no guessing).
I used to have similar issues with my sidedraft setup.
Now that I know for sure things work properly, I can run the thing hard all day and not worry about killing the motor. Same motor has been together for 4yrs now w/o issues.

[Eric Madson]

Chip

I think you are getting some good stuff here. I talked to your dad about this as well. The one item you need to watch...I found this the hard way long ago...Cimas will only handle so much pressure. ( around 20 to 26 lbs ...I found consistant failure regardless of measured exhaust temp ) We used a targat of 1300 degrees in the exhaust merge on the turbo. Getting different cylinders changed how much pressure we could use while still looking at 1300 degrees of exhaust temp.The best is a set of after market cylinders. VW Paradise can get that as well as others. The other simple answer if you dont have time to change cyilineds is too turn down the boost at this time. 

Another point was fuel pressue. I began to use a poppet valve style fuel log with a return along with a big pump on a holley. Also set up a big pump that had a return on the pump along with a regulator latter on as we ran more boost. I know a sidedraft will only take so much at the needle and seat...thats a limit as well.

Turn it down and bring it to Grand Junction.. the flier is in the event section...thanks for the pm.

[turbotype1]

Throw that pump as far as you can...It is in no way any kind of performance pump.Maybe NA but not Turbo.If that combination worked for you in the past, consider yourself lucky. IMO that IS your problem...it might be showing pressure but there is no one home as far as volume goes.

My .02...Pete

[akabuzz]

I thought you had to retard the timming down to 18-17 at over 20psi. ?

[Marty]

I thought you had to retard the timming down to 18-17 at over 20psi. ?

No

[gangforward]

Chip - say hi to your dad for me - Eric's comment about EG Temps is a good one.  Are you cracking the same cylinder all the time?  If so you could have a lean issue in that cylinder and at higher boost due to your intake setup.  Exhaust temps is a great way to find out.  I had to make many changes above 25 lbs boost to keep all four cylinders fat and happy.  Jetting changes would not fix it - changing volume and intake design made a big difference. 

Remember the difference in motor size may not sound like much - but in fact the motor is almost 11% larger than the old one.  Good luck.

[2stroke]

what is your piston/cyl clearance?

[QuickKafer]

Chip

I think you are getting some good stuff here. I talked to your dad about this as well. The one item you need to watch...I found this the hard way long ago...Cimas will only handle so much pressure. ( around 20 to 26 lbs ...I found consistant failure regardless of measured exhaust temp ) We used a targat of 1300 degrees in the exhaust merge on the turbo. Getting different cylinders changed how much pressure we could use while still looking at 1300 degrees of exhaust temp.The best is a set of after market cylinders. VW Paradise can get that as well as others. The other simple answer if you dont have time to change cyilineds is too turn down the boost at this time. 

Another point was fuel pressue. I began to use a poppet valve style fuel log with a return along with a big pump on a holley. Also set up a big pump that had a return on the pump along with a regulator latter on as we ran more boost. I know a sidedraft will only take so much at the needle and seat...thats a limit as well.

Turn it down and bring it to Grand Junction.. the flier is in the event section...thanks for the pm.

Eric,
   Tell him about that super slick trick that you used on those Mahle cylinders that you used with the 51 lbs of boost at the Dyno Session!   I think all you did was cryo them by sticking them outside over a cold Grand Junction winter, right?  LOL!

See you in Vegas!
Scott Faivre

[turbo_bob]

I thought you had to retard the timming down to 18-17 at over 20psi. ?

I run 19 degrees total beyond 20 PSI, one degree more and it looses too much power. Every engine is different, I/C or no I/C, blow through or draw through, EFI, fuel brand.

[Sam]

Your not going to get enough fuel volume with that setup. When you put bigger jets in. It will only get worse. (sucking the bowl dry)

Tony

Thats my take, my N/A 2332 runs the bowels dry on DUAL 48 dells, I have to set my floats a tick up, just so I can make it through a 100YD sand race...

[Squirmn German]

Here is the question -- -- How many 4.6 or 5.0 NA mustangs have you seen running a single side draft?Huh?

The style of the carb has NOTHING to do with his issue.

[FITNESSFORYOUTOO]

I say get at least a Holley blue pump, does the car have 1/2" fuel lines? That red pump is not up to the job of 20 psi of boost. Personally I always knew immediately if my car went lean because it would pop and the minute I heard that I let off and saved my engine. I did have sleeves on the top of my barrels so they would not split though.

[fiatdude]

The style of the carb has NOTHING to do with his issue.

Could the cfm of the carb be an isssue or how about just how much fuel will flow through that itty-bitty needle and seat.

Pull the damn fuel line off the carb and just see how far and how much the pump will squirt gas into a 5 gallon bucket -- if in 30 seconds there isn't any drop off in volume or pressure -- -- then you move on or if there is a drop off or it's just barely dribbling -- -- it's new pump or lines time

My pardners spent over 250 hours on a dyno getting their side draft into the high nines -- not alot of people are that committed -- and their solution was to use a alcohol injection system to get some more fuel into the motor -- run no jet stack at all and I forget where they got a huge needle a seeat from and modified the carb to acccept it.

I'm not saying it can't be done -- it's just at a certain HP level there is a easier path to travel

Crap this is almost starting to be a carbolitical discussion -- I'm done -- I can't stand the attack ads  --  You guys figure it out on your own

[FITNESSFORYOUTOO]

I feel anytime you have to put a band-aid on something like boosting the fuel pressure just to keep the fuel bowel full you are asking for problems.

My old car had two complete engines with 48 side drafts and it was just too much trouble for me to have to change the fuel pressure every time I wanted to turn the boost up a little.

I changed both over to Holley 600 CFM carbs and never looked back, that was the best decision I ever made, I never had one problem after I dialed the Holley in, no more fuel running out on my fender or running lean.

[Jeremy_Owen]

I think you are just past the limit of a standard cima/mahle cylinder. The dell will do it, but you may need to find a dyno. Using a chassis dyno allowed me to tweak my fuel system and side draft to put enough fuel and air into a 2332 to make over 500 to the tire. I got the dyno time free but I still spent over 400 bucks on fuel on the rollers. I don't think trying over 350hp on stsndsrd cylinder is a good idea. And I don't think your fuel system is gonna be up to task much above that. Call me at 757 515 5164 and I will tell you how I got the carb to flow the fuel.