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HybridZ

My official L31DETT RHD thread.


1 fast z

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  • 2 months later...

1fz what nice work you have done. From what I have read your running a copper headgasket. My question is does the block HAVE to be O ring for a copper headgasket setup...cause Iam looking for a thicker headgasket for the L28et and cant find anything except copper. I know you have to heat it up first and make sure its really clean, and also its re usable, but I havent got a for sure answer about the O ring part.

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  • 2 weeks later...

A bit of an update!

 

 

 

Well Then engine had to come back apart again. Multiple problems. The head is actually the most stable part of the build right now, ha.

 

 

 

First of all, I installed a Z32 RPS six puck disk and pressure plate about a year ago. The clutch is WAY too much pressure for the thrust bearing in the engine. THe stroker crank is trashed, because the thrust bearing wore completly through and the crank was riding right on the back of the main cap and block. I have always been carefull to not hold the clutch in when I dont need to, ie. when at stop lights, waiting for the flagman at race tracks to wave me on etc. The car needs that much clutch, so I cannot put a weaker clutch. I am in the process of designing a new style thrust bearing that goes inbetween the back of the cranks, right on the flange where the flywheel bolts to, and inbetween the block.

 

 

Next, The 440.00 dollar harmonic balencer from BHJ has failed. They make the hubs out of alluminum. I should of cought this before I installed the unit. You cannot have a press fit of about .002" from the ID of the harmonic to the OD of the crank snout, with the hub out of alluminum. When that crank and snout and the harmonic hub gets to 200 degrees, you loose all of that press fit, for the reason of material exansion difference in rates between alluminum and steel. From my calculations, it becomes .002" clearence at that temperature. The keyway in the harmonic, and on the crank was both "wallard" out. Once this all happened, the bolt got loose and the harmonic started to walk forward. I use Red high temp locktite, long custom made bolt, Thick 17-4ph stainless custom made washer, and 150 lbs of torque. Once the harmonic walked forward, and the thrust bearing on the crank was wore out, the lower timing chain sprocket mooved so far forward that the double roller custom timing chain had not been straight on the sprocket, and broke the lower timing sprocket, (also custom).

 

 

I am not sure what you guys with high pressure clutches do for thrust, but the size of the L series thrust washer is REALLY small for high pressure clutches. At the price and availibility of V07 cranks, I cannot afford to keep trashing them. I will post pics on my new thrust design also.

 

 

It also looks like that with 600 ft lbs of torque and 700 plus RWHP, that the cylinder bores are not staying round, even with an extra thick block. I have sonic tested this block to be an average of .125" walls with an 89mm bore. I am now going with an 87mm bore with another extra thick block, to maintain more cylinder wall thickness for my HP and TQ numbers. Z32 pistons will work great.

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Next, The 440.00 dollar harmonic balencer from BHJ has failed. They make the hubs out of alluminum. I should of cought this before I installed the unit. You cannot have a press fit of about .002" from the ID of the harmonic to the OD of the crank snout, with the hub out of alluminum. When that crank and snout and the harmonic hub gets to 200 degrees, you loose all of that press fit, for the reason of material exansion difference in rates between alluminum and steel. From my calculations, it becomes .002" clearence at that temperature.

 

Thanks for the all-encompassing update on the engine. You seem to have listed the same number twice here, and I am not sure if that was purposeful (and you didn't list a preferred tolerance) or if it was a typo, and the first number was intended to be a more ideal relative sizing.

 

Since your opinion as a machinist and hi-po L6 builder is respected, I wanted that a little clearer for future reference. Obviously this is all in regards to 5-600 hp + machines, but the better the data, the better the HybridZ... right?

 

 

Incidentally, are you planning on using another stroker crank at 87mm? Or were you going to try the head out on a more stockish, 2.8 liter setup? If I were in your shoes, I would be wondering if you might be able to eke the same power, with greater reliability, out of less displacement and more boost (when wanted, of course.) The answer to that question would be one benefit of the experiment, but it would also give you an opportunity to try out your new thrust washer design without risking another diesel crank.

 

Just my thoughts. If you haven't figured me out yet, I have always believed that there was no such thing as a bad idea, because any idea can shed light. Even ideas rejected entirely draw boundaries.

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JeffP already has a steel centered unit from BHJ, they can make one, they already have.

The thurst washer issue was why most JDM high HP cars ran multiple disc clutch assemblies and just dealt with the overhaul cost.

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Thats the 3rd BHJ dampner that I know has failed (mine included) for the same very reason. I spent a couple of hours repairing the keyway on my crank beacuse of it. This dampner with a SFI rating should not be failing so quickly for this reason. I had barely 5k on it.

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DSCN2377-600x450.jpg

 

 

 

 

 

This shows the bearing. Notice the difference in thickness.

 

DSCN2378-600x450.jpg

 

 

 

 

Here is both sides of the bad bearings.

 

DSCN2379-600x450.jpg

 

 

This is what they should look like.

 

DSCN2380-600x450.jpg

 

 

 

Here is what a 450.00 balencer looks like

 

DSCN2381-600x450.jpg

 

DSCN2382-600x450.jpg

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The car needs that much clutch, so I cannot put a weaker clutch.

 

Time for a multi-disk setup. I had the same problem and trashed a crank. Went to a double disc and got more clamping power with less spring pressure.

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Response from Chris at BHJ.

 

 

 

Hello Bryan,

 

Thanks for the email. We have been making the aluminum dual-pulley damper

as more-or-less a hopped-up OEM-replacement for many years now and have not

heard about any problems, except in cases where the damper has been

installed, removed and re-installed onto a crank (or multiple cranks)

several times. In cases like that, the aluminum does not return back to

size to the degree steel does and that is part of the reason we came out

with the new all-steel version. If that is not the case, then there must

have been something that came loose at some point to lead to this problem.

 

The majority of our customers are very concerned about weight and that is

what led to this damper originally being made with the aluminum outer-ring.

It was only recently that we had a request for the steel outer hub and that

customer has been installing/removing his damper almost every year since he

first bought it and that was the first production version of the part. He

is now putting the rebuilt-steel version on a Bonneville car.

 

Sorry, but we can not warranty the damper repair, but we can do the hub

replacement on the existing damper, using either the aluminum or steel outer

shell (your choice, same price). The steel outer hub is bare steel and will

need to be sprayed with clear coat or regular paint to keep it from rusting.

Standard hub replacements are $225.00 at Jobber Discount.

 

Thanks for the email and let me know what you'd like to do. If you send it

in, I will need to give you an RMA number, so it will be accepted in

Shipping.

 

Cheers,

Chris @ BHJ

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