RKT951

After finally getting my 3.0 Lindsey built motor after a year of only being able to boost to ten psi.It ended up being spark plug gap.I closed the spark plug gap closed it from .030 to .025 and was able to boost to 15 with no miss dropped it to .022 and was able to boost to 20psi thrilled to finally see what it was capable of and on a test drive it blew the head gasket. It was a cosmetic from the ground up build at Lindsey.
what a bummer.

Black51

That doesn't sound good...

What was the CR of the engine? What gas were you running in it? What injectors, fuel pump, ECU, afr, etc. was it running? Was the head/deck properly machined for the MLS? Was the engine tuned? Did LR do the steam vent mod to the head? Was the gasket coated or put on dry?

Are you positive it's the head gasket? Like bellowing tons of white smoke out the back?

lart951

what was the a/f ratio, I ran 23psi daily on a stock 2.5L for years

RKT951

The cr was 8.5 yes the head as block were all done correct. af was at 11.5 and crept up to 12.3 at the point of failure I had a data log going at the time. So it must have started to weap then failed. when it happened lots of white smoke has 72 injectors 044 fuel pump level 3 head super 65 turbo Tommorow I will start the tear down.
no steam vent,stock each with LINDSEY max chips, has was 100 octane
JE pistons pauter rods full lightened crank,mafturburner fuel control
I'm running a stock DME so my timing is what the DME dictates I should have replace the head studs with ARPs when the motor was built shoulda coulda didnt.

GPA951s

We spend alllot of money and Time making these cars the way we want them Thousands and Thousands of dollars poured into our expensive hobby... I am Right there with you and understand what you are going through. I went through TWO cometic headgaskets .when I built my car......I finally took the car to a VERY reputable Tuner, (RPR in maryland) ....I was running an electoromitve standalone. Big Turbo Big injectors... . He went through the entire car Top to bottom Including Eliminating the ISV Utilizing the factory TPS , Anyway .... The point I am trying to make is that we spend so much money on the hard parts but neglect the most important part. I will tell you that after all the frustration and of HG issues, having it tuned was the BEST money I ever spent on the car. That was 2 years ago and I have BEATING the crap out of this ting on the track and it just runs and runs flawlessly. All the hard parts are the same as when I was blowing headgakets... It just took an expert to Tune all the parts I had "as a unit" ... I now can just turn the key and it fires right up, idles perfect (better than my streetcars with an ISV) and never misses a beat on the track.. Im at 15Lbs of boost all day long (sustained) There was a time when I must of turned the boost **** on accident with I was screwing around in the interior.. and the car boosted to over 25psi when I first hit the track... it hit an over boost ... Never hurt the engine.. Once you get the car back together, I highly recommend getting it dyno-tuned by a reputable tuner that will stand behind his work. you wont regret it... and it will save you in the long run.

eman930

Not everything is what it seems with LR motors sometimes. I run 20-22psi no issues and fairly aggressive timing map for about 2 years. Recently I went to the dyno and experienced head lift. SO I took her apart added raceware headstuds torqued to 95ftlbs and will be going back to the dyno soon. Head gasket is only half the problem, IF you are using stock head studs toss them and upgrade. The factory torque specs suck and aren't very accurate and the factory studs just cant hold the torque needed to keep the head down at higher boost levels. Also I wouldn't be surprised if those max chips have overly aggressive timing maps. I'd go to something more modern that gives you control over fuel and timing.

V2Rocket

RKT951 - How much ignition advance do you run? I am 100% convinced that ALL 951 head-lift problems are from people running too much spark advance for this engine. It is compromised by head studs placed far apart and a not-great combustion chamber shape and a huge bore, but these things have to be taken into account when tuning. Even with 100 octane; octane just helps resist detonation, it's not a license to freely add more timing for a given AFR/boost pressure.

fast924s - re the head studs you're definitely right that the stock studs might need revision on a built motor. Greg B over on the 928 side did some testing on new vs re-used studs and found something like a 30 lbft difference in final torque value, though who knows what the real bolt stretch/clamp value is once the engine has heat cycled a bit.

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Generally I think people would be happier if they would run higher boost pressures and backed off the timing accordingly.

GPA951s

+1 on the head studs... The LAST time I put the engine together I set the head studs at 95Ftlbs as well... Interestingly enough I had the originally sheet for the raceware studs... 65Ftlbs.. hmmm? That's what a cast Iron 350 Chevy head bolt at 9.5 to 1 gets set at... This next engine im putting in the car I went with ARP studs.. Only because they have those nice allen heads on the top... Also 95 Ft lbs..

eman930

Yep 95ftlbs on the raceware studs. Careful doing that with the ARP's as they aren't as strong as the raceware. Also make sure to set your stud high correctly and use some quality grease when torqueing

eman930

In regards to ignition advance, Yes you need to watch it as peak cylinder pressure can lift a head if ignition is too advanced.

Thom

An AFR of 12.3:1 sounds too lean for 20 psi.

eman930

Id agree... should be no less then 11.8

GPA951s

Just wondering why you would say the ARP's aren't as strong as the Raceware? The Sheet that came came with the ARP's called for 100Ftlbs..

jimbo1111

I went through 3 bosch 044 fuel pumps in a month before finding a real one. The fakes look really good. They just don't deliver enough fuel.

Pauerman

Your culprit is trusting upon the garbage tune in the chips you use. Echoing already what's been said, if you're going to the healthy expense of building a quality 3.0L engine, why retain the very antiquated and dated engine management?? Those Max chips are garbage and frankly so are the people who stand behind selling it. Sadly you along with everyone else that's had to learn from this painful lesson will inevitably come to the conclusion (hopefully) that protecting your investment and ensuring its optimum performance means upgrading to a modern engine management system.
Sorry to hear about your failure. There are some amazing engine management options out there that would have easily prevented this outcome and allowed for you to run more than 20 lbs of boost reliably.