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Barn Find Race Motor rebuild.


Nate SERE

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Blown head gasket is good in this situation. It blew instead of piston ring lands. These are domed forged pistons. Most likely they are OK considering the head gasket blew. But I do see where a valve made contact with the piston. You may have a bent valve. Can you send pics of the combustion chamber?

 

Looks like a pretty cool barn find. Aside from the lack of Carillo rods, it looks like it was built as advertised.

 

The compression ratio is probably too high for pump gas, this is probably how they blew the gasket. Depending on what was done to the head, the CR is probably in the 12.5 to 13.5:1 range.

Edited by z-ya
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Just got off the phone with Rick Trebes who built the motor. Great guy! Here is what he had to say. Motor was close to 15:1 compression, ran 108-112 octane. It cost around $15k to build. In 82 and 83 it was #5 in points for sccagtu. Racing systems was the name of the race company, they were part of Getty film. Stu Vandyne from Drake engineering dynod it at 320 hp. The rods are from electromotive, the crank is from Hubbard. Stahl headers. Hand cut pistons, titanium valves. He has pictures of the motor and the car and will be getting them to me.

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I'd be interested in seeing the combustion chamber of the E88 head.

 

The race motor I built had Cosworth domed pistons and a Bob Sharp head that was cut and the combustion chambers reworked. It was an L28 with stock stroke and 87mm bore. I cc'd the pistons (12cc) and combustion chamber (37cc). This got me to a CR of 13.5:1 with a 2mm gasket. The domes on the Cosworth pistons are huge, so I am wondering where they got 15:1 from you motor.

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That puts you around 15.5:1 with a stock gasket thickness. Even with the 2mm gasket, I had to shape to piston domes to clear the combustion chamber. Even after filing the piston domes, I still has the pistons kissing the head at high RPMs. I also had to index the spark plugs with copper washers. There isn't a lot of room left with a 12cc dome in a early E31 combustion chamber. This is why I'm curious to see which E88 is on this engine.

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I have a decision to make.  I have a well know race shop that wants my motor, minus the triple webers/cannon intake. 

 

He is offering to build me a streetable head to whatever specs I want, plus cash for the motor.   He keeps telling me that you don't street a race motor and your don't race a street motor.

 

He also had recently sold the original car to someone in New Jersey I believe.  

 

At the end of the day, I want 2 things, #1, I want my 280z to be a N/A monster that will be relatively reliable, and run on 92 octane pump gas.  #2, I want to keep the motor together as much as possible as they just don't make them like that anymore!

 

If I keep the motor and build it back to race specs, it will be useless to me as I'm not looking to run race fuel.  If I take the motor and put in flat top pistons, then I should be able to get it under 10:1 compression, and have a really fun and cool motor, but at the end of the day, its no longer the same motor. 

 

I have a solid bottom end now with f54 block so flat top pistons  and its running w/ p79 head and  stage 3 cam.  I am running the triples now and I love the power difference from the old SU's that were on there. 

 

I'm seriously considering trading the motor for a great street head, and cash.  He told me that the head would be worth around $800 that he puts together for me.   How much extra should I be looking at getting to make this deal fair for both parties?

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Well, you're looking at 600$ worth of pistons in that block, if they are undamaged. However...It's worth exactly what someone else is willing to pay for it. A good street head, with a good port job with complete flow testing numbers, is worth about what you mentioned. That does NOT include the cost of aftermarket valves, seat replacement, cam, valve springs, retainers, and lash pads...all of which need to be addressed.

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