Jump to content
HybridZ

Compression, cam and head gasket questions??


Gixxer Squid

Recommended Posts

ok,

 

detonated my turbo, dropped an intake valve and back to square one after only 400 miles on new engine, life goes on. I am turbo challenged so here goes.

 

1. Car is currently 8.5 to 1 compression. What are advantages/disadvantages of changing all pistons to go to ratio of 7.5 (or lower) or so to 1? Is there any benefit?

 

2. http://www.headgasket.com I have 1mm gasket in car now, any problems going to say a 3mm headgasket? Anyone have any positive or negative experience with these copper gaskets. I cant seem to find anyone else with a metal head gasket over 1 mm as everything is backordered(nice way of saying discontinued I think). Bigger head gasket would certainly negate different pistons and extra expenses but I dont know what "to much " is.

 

3. thinking of changing current cam specs from .480 lift, 272 intake and 274 exhaust to .515 lift .272 intake x .490 exhaust 266 ex. 114 lobe centers. An aquaintance has this configuration and is quite happy with it. The car is down and since the engine is getting pulled, may as well make the changes now. Can I just put the cam in or do I need more additional upgraded componets? see my list below what I currently already have.

 

I was just talking to KTM a few weeks ago about meth injection becasue I was somewhat concerned about detonation and guess I was not quick enough. Here are the car build current specs. This was my first ride after having the car professionally tuned. I am waiting for the data log which I asked for last week but am still waiting but I suspect the tuner leaned the car out to much. boost set at 20 psi

 

Special P90 head designed for optimal turbo performance.

-Three angle racing valve job with hand lap and back cut on all valves. High heat coating on all valves.

-New valve guides; hardened seats; single groove euro dampner; turbo camshaft

-Blanchard grind head surface top and bottom.

-Turbo port and polish intake and exhaust runners, (swirl finish on intakes, polish on exhaust)

-Moly steel valve retainers; dual race valve springs, rod bolt set and main stud set;

- All head components that contact each other had surfaces SuperTech Microfinished to reduce wear points.

JE pistons are 88mm pistons

 

pistons are high heat coated on top and moly coated on skirts as well as micropolished

 

total seal gapless rings

 

ARP everything

 

Deck height is zero

 

1mm head gasket

 

46mm stainless swirl polished intake valves high heat coated

 

38mm stainless swirl polished exhaust valves high heat coated

 

dual race valve springs good for 7500 rpms and beyond

 

PAR connecting rods 144mm (finished rotating mass 437.5 - 438.5 grams)

 

Everything is new. Including flywheel/pressure plate bolts. Everything is new from Nissan or aftermarket.

 

New billet turbo camshaft

*I believe it has a TEP grind - .480 lift 272 intake x 274 exhaust

Garret t3/t4 turbo .60 A/r good up to 650 hp

Crank was race prepped by TEP - index grind, detail weights, enlarge and chamfer oil holes, and nitride harden.

 

550 cc fuel injectors

 

500 hp bosch fuel pump

 

Electromotive TEC 3 with trigger wheel ignition system

 

240mm wide flywheel 16 lbs properly pinned to crank.

 

= $$$$:roll:

goal=500HP give or take, come on, a little sleeper, LOL

Link to comment
Share on other sites

I was going to respond to your other thread, but I will chime in here.

 

Your current setup is fine, you just need to tune for it. You stated your AFRs were 13 to 13.5; while that is fine for an N/A application, it is death for a boosted engine. Just rebuild your current setup and retune. Target 11.5 to 12.0. Additionally, what is your timing like? I've found that you can only safely run around 20 to 22 degrees at 15 psi on California 91 octane; this is with a 7.4:1 compression engine (stock bottom and head).

 

Your cam may allow you to run more timing with your 1mm HG and flattop setup, however, you need to do dyno tuning with the ability to detect knock. A thicker HG will give you more buffer with respect to timing, but you will still need to tune with a means of detecting knock.

Link to comment
Share on other sites

I was going to respond to your other thread, but I will chime in here.

 

Your current setup is fine, you just need to tune for it. You stated your AFRs were 13 to 13.5; while that is fine for an N/A application, it is death for a boosted engine. Just rebuild your current setup and retune. Target 11.5 to 12.0. Additionally, what is your timing like? I've found that you can only safely run around 20 to 22 degrees at 15 psi on California 91 octane; this is with a 7.4:1 compression engine (stock bottom and head).

 

Your cam may allow you to run more timing with your 1mm HG and flattop setup, however, you need to do dyno tuning with the ability to detect knock. A thicker HG will give you more buffer with respect to timing, but you will still need to tune with a means of detecting knock.

 

 

You know how it is Bo, always wanting more. The AFR's that I witnessed myself were at IDLE only, not 1st-4th gear pulls. That is why I am trying to get a data log of the 2-3 road pulls that were done in the car because I cannot say with certainty what the AFR's were and don't want to start pointing fingers until I see the data for sure.

 

Basically I want the power but also want INSURANCE and if it means lowering the compression by going to a thicker head gasket or changing the pistons's completely, I am obviously willing to do this, if and only if its a neccessity. I think that going with Meth injection like I spoke to you about is the cheapest route to go as race fuel here is 6.49 a gallon, but I cannot seem to find anyone that has the right knowledge in installation more less tuning in the bay area and I want it done right.

 

As far as the timing, I am not sure what its set at and I would assume its in the data log as well which I am still trying to get.

 

James

Link to comment
Share on other sites

500whp? I'd say you for sure need to drop the CR down. Especially considering the sh*t that we call premium here.

 

 

LOL, isnt that the truth. We pay some of the highest prices in the country for gas and all we get is 91 octane.:wink:

 

Does that octane booster at Kragens work or is it crap?

Link to comment
Share on other sites

LOL, isnt that the truth. We pay some of the highest prices in the country for gas and all we get is 91 octane.:wink:

 

Does that octane booster at Kragens work or is it crap?

No idea, but personally I don't like the idea of octane boosters or methanol or anything like that on a street car, since you never know when you're going to run out.

 

Also, with the octane booster, you're never going to get a good tune, since the octane rating of the gas will keep changing with the proportions of booster and gas.

Link to comment
Share on other sites

LOL, isnt that the truth. We pay some of the highest prices in the country for gas and all we get is 91 octane.:wink:

 

Does that octane booster at Kragens work or is it crap?

 

Where in California are you? E85 is starting to become available in Cali - WAY cheaper than race gas.

Link to comment
Share on other sites

Where in California are you? E85 is starting to become available in Cali - WAY cheaper than race gas.

 

 

Not available in my area till April 09. What is the cost of this compared to 91 octane? Any modifications I have to make to run this?

 

Valve retainer came apart, scroll to bottom of thread for pix http://forums.hybridz.org/showthread.php?t=143857

Link to comment
Share on other sites

  • 1 month later...

I want to bring this back up. What is the deal with copper head gaskets? You have to o-ring your block? What is this and how much does it normally run?

 

What are the benefits over your traditional metal head gasket ( http://www.courtesyparts.com/head-gasket-1mm-required-p-227527.html ).

 

Also I have an 87mm bore (1mm oversized) will a 91mm bore head gasket (like the one listed above) NOT work/be beneficial for me?

 

Just a few questions seeing as in how the z store has there metal head gaskets back ordered till June 19th and the KAMEARI ones are way to expensive.

 

Any advice on any of this, or where to find other metal head gaskets would be greatly appreciated.

 

Thanks.

Link to comment
Share on other sites

I had a 2.5 mm copper head gastket made from copperworks. It cost $265.00. I am having it installed next week. I am currently running 18psi boost with more soon to come once I get things dialed in.

 

http://www.headgasket.com/faq.html Morty made mine in about 1 1/2 weeks.

 

Guess I will be the Guinni Pig on this one. I had a 88mm made, I think he can make anything. I am rather anxious and hoping it works out. I had a felt gasket in there before and half the water holes where covered up. I had to have two addtional holes on the copper head gasket opened up. Look at the top picture and the head gasket on the bottom. Why would the felt gasket have all the water holes covered up on the spark plug side of the block???????

 

p1010212.jpg

 

p1010215k.jpg

Link to comment
Share on other sites

Did you have your blocked o-ringed or is the gasket already pre-set in?

 

 

No, its not o ringed. In talking with the Morty, he says its not necessary with these head gaskets.

 

My instructions for installing is to heat the gasket with a torch till anadized red and scrub excess residue off and then spray with a gasket sealer that has copper in it...Wait one hour before torquing to specs.

 

He seemed fairly knowledgable, you could give him a call. We will see how it turns out:shock:

Link to comment
Share on other sites

My instructions for installing is to heat the gasket with a torch till anadized red and scrub excess residue off and then spray with a gasket sealer that has copper in it

 

Heating till red make the copper go very soft, I do the same with my turbo spacer copper gaskets.

 

Nigel

Link to comment
Share on other sites

There isn't anything wrong with your setup, just your tune. Get that squared away, as no matter how tough you make the weakest link (headgasket) it will simply break the next link (bearings) if (or rather WHEN) you detonate with pump gas and no proper tune.

Anyone building a turbo car needs to know how they are supposed to be tuned and have proper equipment to monitor it. It only takes a tenth of a second on a bad tune to pop a headgasket or kill your bearings. I am not exaggerating.

Copper gaskets work fine; they may be a little more difficult to install versus MLS, but they are cheaper and easier to manufacture when dealing with a very custom or low volume application.

 

SIDE NOTE: I've seen foolish guys put a full twin-turbo system on a car such as a brand new G35. They can't wait for the dyno tuning scheduled the next day so they go out and "let 'er rip". Forty-five minutes later they are calling a tow truck to come get their new $30k+ car with $15k+ in mods that has a shattered motor spread over the last 1/8th mile they made down the back road. Detonation will kill any motor no matter how strong the internals. They all rely on a thin film of oil over a limited bearing surface area.

 

I would recommend you just build it for E85 to reduce your chances of detonation. You can raise the boost levels dramatically versus Kali pump crap, too. With all the money you spent, it only makes sense.

 

Make sure you are watching your wideband! Most people's eyes are half glued to the wideband in boost to avoid a blown motor. With all new parts like that, your tuner should have told you to break your motor in first before placing a final full boost tune on it. It is undoubtedly going to change as it breaks in, loosens up and seals up.

Link to comment
Share on other sites

I am waiting to get her running again. Originally E85 was going to be my choice but after talking to Pearson, there E85 station is going to be delayed for who knows how long. I am probably going to go Bo's route now and just do the meth injection. When I get it going I will dial down the boost to 12 from the current setting of18 psi on california 91 ocatne crap till I get it tuned properly. Great Advice. The engine does have about 450 miles on it already though except I changed the cam profile and did some additional clean up by unshrouding the valves and had it on a flow bench.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...