Gert’s Engine Rebuild & Upgrade (Chasing 300Hp, yes another one sorry)

[lvporschepilot]

Fabulous work! Glad it worked out for you. Undoubtedly an engine which will be used as a reference for many years to come!

[vmax]

Can you post the final spec/build sheet for your engine?
What fuel will you use?
Excellent results. I am sure you are thrilled.
I'll bet you can't wait to get it in the car.

[jpnovak]

Great work. When will you be accepting heads for porting jobs?

[PFM]

Gert,

That is a great job!!!! You went through some pain to get there but what a great finish. I see a request for a final build sheet, X2 for me on that request.

With that power curve it should be a blast to drive.

Stay tuned,

PFM

[tadd]

Another curious soul wanting to know your fueling plans. You're right in the neighborhood of the CR I've been thinking about.

t

[Gertvr]

Thanks to all the kind words, yes I can't wait to go drive the car but the ever present Murphy's law struck and I have 2 oil leaks to fix before I put the engine back this weekend. The one is easy as I had the cam tower oil spray-bar plugs threaded and its weeping out the plug close to the oil cooler, the other one i still need to find the origin of, but its somewhere on the cam tower as well.

Great work. When will you be accepting heads for porting jobs?

I don't think i will give up my day job for head porting yet, credit needs to go to Bill @ Xtreme for the final head results, i came close but the final results are his .

I will be using a race gas / pump gas mix either 50/50 or 60/40 for normal driving and 100% race gas for DEs. Please feel free to comment if you think this blend will not be sufficient for the CR I'm using.

I will post the final engine spec later when i have more time.

Cheers

Gert

[jpnovak]

Ahh I did not realize you had Bill at Extreme finish the heads. I thought that was your work.

I think the race gas blend will be fine for your compression considering the twin plugs. Just be careful in the humid heat of the summer. How much total timing are you delivering at max advance?

[Gertvr]

Timing at Max advance is 30 deg. It backs back off to 26-27Deg at high Rpm.

[jpnovak]

Thank you for the numbers. I am running similar numbers on my motor.

Do you run a timing retard box? How do you pull timing from a mechanical distributor?

[Gertvr]

Jamie,

I'm not sure about the mechanics of it, no timing box involved. Maybe Mike can chime in with the details.

[MBruns]

The drift in timing as it called is kind of a natural act with the analog systems like the MSD, as the event is happening at upper RPM it seems to lag a bit behind, you can't see it unless you watch it during a full pull on the dyno. so if you have your timing set at 30 deg. total we can bet on 2 - 3 degrees less at full RPM. some systems are much worse and they don't even know its happening.

Mike Bruns

[PFM]

Gertvr,

This has been a great project but I have a question on the pistons and the deck height as posted. If your deck height of 1.98 mm as posted is correct the compression on the motor is down quite a bit from the posted 11.5 JE pistons shown. JE specs the deck height at .040" the 1.98 mm is .0779" .

If this is correct the compression would drop to 10.19 to 1. The JE deck height is not measured as the dome clearance as you checked but rather the distance from the flat above the ring glands to the top of the cylinder.

Did you have the pistons set to .040" or some other height?

I ask because of the fuel discussion, if the installed height makes the motor 10.19 to one race fuel mix with pump gas may not be a problem at all.

Stay tuned,

PFM

[Jeff Alton]

It also depends on Cylinder head volume after machine work and second plug holes etc.....

The only way to know is to accurately measure the CR.

Cheers

[MBruns]

His deck is .043, his piston to head clear. is 1.9mm, I poured all his vol. including above the top ring area, his C/R is 11.3, the pistons are not off the shelf from JE but close.

Mike Bruns JBRacing.com

[lvporschepilot]

Originally Posted by MBruns

The drift in timing as it called is kind of a natural act with the analog systems like the MSD, as the event is happening at upper RPM it seems to lag a bit behind, you can't see it unless you watch it during a full pull on the dyno. so if you have your timing set at 30 deg. total we can bet on 2 - 3 degrees less at full RPM. some systems are much worse and they don't even know its happening.

Mike Bruns

There's a fine balance between getting timing right at peak torque, adding more timing after that, and then pulling some out before peak bhp. As an example: if peak tq is 5500rpm and the motor is running 27 degrees timing, I add three more degrees after peak torque by 6k, then slowly back timing off from 30 through to peak bhp of say around 7500.

I have never been able to do this with mechinacal advance. Motec, Haltech, Electromotive Tecr3 or the like has always been required to get it surgically accurate. Kudos to one who gets this straight with mechanical advance!

[cyber2213]

What's kind of spark plug had you use???

[Jeff Alton]

Originally Posted by MBruns

His deck is .043, his piston to head clear. is 1.9mm, I poured all his vol. including above the top ring area, his C/R is 11.3, the pistons are not off the shelf from JE but close.

Mike Bruns JBRacing.com

Well, there you go! Good to see it got done properly. I, for some reason, missed the part that you guys did the work!

Cheers

[Gertvr]

Originally Posted by cyber2213

What's kind of spark plug had you use???

Champion C57A

[Gertvr]

Originally Posted by Jeff Alton

Well, there you go! Good to see it got done properly. I, for some reason, missed the part that you guys did the work!

Cheers

In my excitement I didn't mention all the details After having numerous problems with the Wossner pistons i contacted Mike at JB Racing and they specified and sourced JE pistons for the build. I sent them my cylinders, rods, heads, big end bearings and cams to do a mock build on a bottom end they have in the shop.

Mike mocked up the build, measured all clearances, piston to valve piston to head etc and as he mentioned also measured all the volumes.

When I received the parts they were already clearance checked, the only measurements i had to do confirm were my deck height, piston to valve and piston to head clearances.

The deck height ended up being slightly taller than his mock up at the shop and reduced the CR to the 11.3.

I tried to upload some more pictures to a previous post but were unsuccessful so i am adding them here:

Half the fun was getting to the dyno, my wife was happy to swap cars for the weekend:



At the Dyno:






Cheers Gert

[lvporschepilot]

Boy that is one cold spark plug. Did you get your oil leak figured out? Great pics!