Problems with the new drag engine - HELP! (long)

[drzed]

Where do I start?

 

I finally blew my other engine in the drag car a few weeks ago - pushed the stock style head gasket out the side when I leaned it out "just a little bit more" looking for that extra 10th. Worked good for 2 1/2 years and 100's of runs.

 

Now this forced me to finish up my 3/4 done project engine that I've been working on in my free time for the last year. It is as follows:

N42 block .020 over

used JE forged pistons

9mm rods - prepped

diesel crank

P90 head - mild port work

SS valves

turbo regrind cam

mls head gasket

ARP head studs

custom intake manifold

550cc injectors

SDS

and lots more stuff!

 

Sooooo anyway, after finishing it up and dropping it in I fired it up last week and tried to break it in. Right away I found that the fuel map was way off (I changed from a 2 bar to 3 bar map sensor and from 370cc to 550cc injectors) and it had a slight miss even when the mixture knob was used to fix the AFR. I did recalculate the RPM fuel and MAP fuel values BTW. So to break in the rings I quickly butchered the fuel curve close enough to drive at part throttle up and down the road a few times. The temps and oil pressure always looked good so I parked it and tried a few things to find the slight miss - checked magnet position, checked fuel pressure, checked timing and rotor/cap alignment etc - all OK.

 

So I pulled each injector lead one by one to confirm that each cylinder was doing its share of the work and they all pulled down about the same amount. Shut the engine down and checked the plugs. 1 and 2 where clean and lean (too lean) and 3 thru 6 where black.

 

Now I started to assume a fuel problem on 1 and 2 so I made a rednexx injector testing station (pics to follow tomorrow) but they all flowed within 1 to 2% of each other. Reinstalled fuel rail and injectors and fired it up. Same miss.

 

Let it cool and out come the plugs this AM. Same conditions. Compression test comes out within 3 psi of each other. OK there.

 

Changed spark plug leads even though the others worked fine last month just in case - no better.

 

Getting a little concerned!

 

Let engine cool and pull valve cover to retorque head. 60ftlbs as per ARP's info using their lube. Most didn't take much but first stud on drivers side took a little and then SNAP! Oh oh? I thought I broke a stud but couldn't believe that could happen. Instead when I pulled up the stud it came complete with all it's threads and all the threads out of the block. $#^*%!

 

So to finish this off I just finished pulling the head off to find piston 1 and 2 VERY clean (steam cleaned?) and the gasket in very good condition with no visible damage or leakage. Now I could easily see why #1 was maybe leaking a little water with one stud almost pulled but why would #2 leak? Can't find any cracks and couldn't find any during prep work either. Besides I've never had a head crack from 1 cylinder through a water jacket and into another. Also wasn't really missing any noticable amount of water from the rad

 

So here is the dilema.

 

Do I helicoil the block and try to save it? I'd like to try. Has anyone done this?

 

Do I reuse the gasket as many of us on here have in the past?

 

Has anyone had a gasket leak a little water and then seat up when retorqued? (my old engine would leak about 1 tea spoon every pass externally but nothing internally - just left a small water stain down the side of the block)

 

Is the miss related to the 2 clean cylinders or ?

 

Does any of this make sense or am I just up late and rambling? (Wifes in bed so I have no one else to tell eh)

 

Any suggestions?

 

Pics of head, block, and gasket to come tomorrow at work. On dial up here.

[510six]

I would look into having a time sert rather than a helicoil put back in the block as the time sert repairs are much stronger than a heli coil

 

http://www.timesert.com/

 

I would get a new headgasket and check the head for warpage.I had a miss between # 3-4 cyl on a N20 motor due to a .003 head warpage that was missed due to an untrue straight edge.Every time I have used a NISMO SS headgasket I have had to use a little stop leak in the coolant to stop a bit of seapage.Get a can of carb cleaner and check the area between the intake and exhaust valves very carefully, you might even want to use a magnifing glass.If all else fails get the head pressure tested.

[drzed]

510six thanks for the reply.

 

Is there any other ways to test for cracks other than pressure testing? Anything with dye etc?

 

What product did you end up using to stop the water leak? Is S.top Leak a brand name? Do you know if the gasket was leaking between the gasket and the head, the gasket and the block, or in between the layers of the gasket? I'm curious because I can't find any obvious paths of leakage anywhere on the gasket surface. The High Tack is still in place with no erosion.

 

I'm thinking about just dropping the head back on (after fixing the threads) with a stock style gasket just to break the engine in and run the last 6 nights of the season at the track. This would at least confirm if it is the gasket or the head causing problems.

[drzed]

Pics as promised. Gasket looks good - hard outline all around cylinders. Block and head also show a definate sealing line although its not as easy to see in the pics. Also included is the rednexx fuel injector test bench (or new fangled still?).

[510six]

I would check the head with a good staight edge and a set of feeler gauges anything over .002 should be resurfaced.The stop leak I use is this, it looks like coffee grounds.

 

http://www.barsproducts.com/product.cfm?id=38