Rebuilding my '83 3.0

[Jameel]

I'm making slow but steady progress on the rebuild. I try to get at least a couple hours in every day before and after work. I mostly daydream about how far I could get if I had week stretch of free time!

Here's the status on some parts after evaluation.

Case/Cam housings: Good, I'll be putting new standard bearings in
Crank: Good. Measured up just fine, journals look good.
Cams: At Dougherty's getting ground to 964, rockers and shafts getting refreshed too
Heads: At Ollie's, not sure what they need yet
Pistons: Ordered new 9.5:1 JE's from EBS. I decided to play it safe and not go with 9.8:1.
Cylinders: Replating with Nikasil through EBS
Rods: on their way to Ollie's for a rebush
Distributor: There's like 1mm of end play, so I'll be sending that out too.

Meanwhile, lots of cleaning going on. I used my Harbor Freight coupon and picked up the blast cabinet. Had my 13-year old nephew George assemble it according to the Alvarez Youtube videos. Good info, but pretty tedious to watch. It helps to set the player on 1.5 speed. I also sprung for the Tacoma kit right away. Domino effect means I need a new compressor now too. My 20 gallon 4hp lasts maybe 1 minute before it gets winded. Always wanted a blast cabinet, and I should have found one long ago. This thing is fantastic. It's a great motivator to get nice clean parts right off the bat.

My Harbor Freight engine stand was also giving me nightmares. My yoke is a really loose fit and all I could imagine were the welds failing in the middle of the night. It was good enough for my VW engine, but this is quite a bit heavier. So I fabricated a 3/8" thick metal bracket that bolts to my woodworking bench. The bench is made from solid oak, 5" thick solid slab top, and weighs around 500 pounds. I tested the whole arrangement by lifting myself off the ground (I'm about 250lbs.) and bouncing up and down on the yoke. Solid as a rock.

Now that I've got a place to mount the case I can get busy on the fun task of cleaning.

[Trackrash]

If you are concerned about your CR you should check what CR the JE pistons actually give you.

In my case, the actual CR I obtained from the JE 9.5s was about 9.8 to 1. All other aspects of my SC motor are stock and in spec. My heads CC'd out at 89cc, with 90 being the stated number. The pistons measured as stated in the JE specs. I used one .25mm cylinder base gasket.

[Jameel]

Originally Posted by Trackrash

If you are concerned about your CR you should check what CR the JE pistons actually give you.

In my case, the actual CR I obtained from the JE 9.5s was about 9.8 to 1. All other aspects of my SC motor are stock and in spec. My heads CC'd out at 89cc, with 90 being the stated number. The pistons measured as stated in the JE specs. I used one .25mm cylinder base gasket.

Huh. Interesting. So I assume you were okay with the higher compression then. Why didn't you use thicker base shims to lower the CR?

[Trackrash]

I was actually hoping to get more than 9.5 and I have read that 9.8 is dueable on pump gas with a 95mm bore. My deck height is about 1mm, so I think I am good to go.

[Jameel]

4 hours in on cleaning the case. So far so good.

[Jameel]

The case is clean and ready for reassembly. I've got probably 20 hours in this. Seems about right according to the book. There is still some discoloration here and there, especially at the top of the case. I can understand the temptation to polish it all up, but the important thing is that its clean, right? I didn't want to use any abrasives on the case, just coarse rags, orange degreaser, brass brushes, carb and brake cleaner. My piston squirters were all free and spraying cleaner after the first soak.

[Flat6pac]

Unless the table is bolted to the floor you're not going to be stable to build out
Bruce

[Dumont]

Originally Posted by Flat6pac

Unless the table is bolted to the floor you're not going to be stable to build out
Bruce

The only way I see that working is if this guy has that mounted to something like a 500 pound French Roubo woodworking bench made out of oak. Otherwise, I agree.

[Mick_D]

What compressor did you upgrade to? I have a 4 hp with 2 20 gallon tanks in series, and it isn't enough to blast.

The bench is made from solid oak, 5" thick solid slab top, and weighs around 500 pounds. I tested the whole arrangement by lifting myself off the ground (I'm about 250lbs.) and bouncing up and down on the yoke. Solid as a rock.

[Jameel]

Originally Posted by Flat6pac

Unless the table is bolted to the floor you're not going to be stable to build out
Bruce

We'll see. It's a massively heavy bench, but I've already planned to add an outrigger/leg if need be. Thanks for watching out for me.

[Jameel]

Originally Posted by Mick_D

What compressor did you upgrade to? I have a 4 hp with 2 20 gallon tanks in series, and it isn't enough to blast.

I didn't yet. Still using the 4hp 20 gallon. I get maybe 1 minute of blasting. Lately its been blast for a minute, clean for 10, blast for 1, rinse and repeat. Just been waiting for a sweet deal on a compressor to pull the trigger.

[Jameel]

So I've made a bit of progress on this rebuild. Got all my parts back from Ollies, EBS and John Dougherty and I've got the short block together. Here's a couple pics.





I've also CC'd my heads and piston domes. Here's where I'm running into a bit of a quandry.

The plan was to build Wayne's Upgraded 3.0 CIS engine. So I had my cams reground to 964 profile by Dougherty and I bought 9.5:1 JE pistons to mate up with my original cylinders plated with Nikasil by US Chrome through EBS. Heads and rods were rebuilt by Ollies. Bottom end got cleaned and new bearings, crank just got cleaned.

The cylinders were not remachined on their ends, just blasted, so their height is the same as before. Group 6.

Head-cylinder mating surface was cleaned up by Ollies, it doesn't look like they took much off, perhaps a thou or two just to clean up (just guessing, there wasn't a number on the invoice) They all measure .095" from surface A to B. I couldn't find a spec on this measurement. Any idea what this should be?



I cc'd my heads and piston domes with the oversight of Lee Schlabaugh of Stalltek. Lee has been my mentor through this whole process and I would be lost without him. So I'm confident my numbers here are correct. Lee also ran some theoretical numbers for me but this was before we had a deck height measurement.



So yesterday I finally had a chance to measure my deck height on #1. Here's what I came up with:





Bore: 95mm
Stroke: 70.4mm
Deck height to flat: 0.80mm (measured off cylinder top at TDC down to flat at perimeter of piston)
Quench: 1.90mm (measured with clay at left/right edges of piston)
V1 Swept volume: 499cc
V2 Deck height volume: 5.76cc (using 0.80mm deck height)
V3 Cyl. head volume: 89.2cc
V4 Piston dome volume: 39.5cc

Deck height and quench measured with NO copper gasket or shim at base of cylinder. My Victor Reinz gasket set (I'm also using the Wrightwood racing set for the viton parts) did not come with copper base shims, but rather these black colored shims that seem to be made from aluminum? They are .30mm thick.



Using Bruce Andersons formulas I came up with 9.99:1 CR. My goal is 9.5:1 CR, and those are the pistons I spec'd when I ordered from EBS. I don't know how verify if I got the right pistons or not. There is no dome volume listed on the spec sheet.

Here's where I'm a bit confused. Which deck height number to use? Because when I measure to the lip off the cylinder head I get .80mm, but when using the clay I get 1.9mm. Wayne calls the clay method "deck height" so which number should I be using?

Aside from that, it looks like my compression ratio is too high, and my quench is also too large. So I've got the worst situation. Can someone explain how, especially with no shim under the cylinder, that my quench is almost 2mm? If anything, it should be too tight, given that my heads have been machined (albeit perhaps slightly). I don't understand how the quench space can be reduced by half a millimeter (sounds like I should be around 1.5mm) without machining a bunch off the head. That's also going to increase my compression ratio, when I need to go the opposite direction. Then I would need to machine some off the top of the pistons to open up the combustion chamber.

I'm just not sure how I could be so far off on quench (especially without base shim/gasket) and still end up with a higher compression ratio? I would think if the compression ratio were that high, that my quench would also be either right on, or too close.

I'm a bit paranoid about running anything over 9.5:1 for fear of detonation. I want this to be a long lasting engine.

[Trackrash]

Nice writeup. Looks like you are covering all the bases.

I just went through this myself, a couple of things, I discovered.

Those base gaskets are probably copper, just with some coating.

I bet if if you re-measure your deck height with the gaskets you will be close with the deck height you want. My deck was identical to yours with out the gaskets.

My heads also measured out at 89cc giving me a CR of ~9.8 to 1 with one .25mm base gasket, which is what I wanted.

In your case going to a .5 base gasket will probably give you the 9.5 CR you want.

To answer your question, you are measureing the deck height correctly, at the edge of the piston. However the clearance at the side of the dome will be something like 2mm.
Keep up the good work.

[Jameel]

Thanks Gordon. I read some of your posts about your build. I'm going to scratch off a little of the coating and see what lies beneath.

Are you not worried about detonation with the 9.8:1 CR coupled with the 2mm quench? I was under the impression that we want the combustion gasses to get squeezed out of the perimeter (the dome portion of the piston) and swirled around, and that a larger space here promotes detonation. Quench or squish should be between 1 and 1.5mm. But I'm no expert. Just mimicing what I've read in Wayne and Bruce's book.

What octane are you running? Single plug?

[Dpmulvan]

What nozzle are you using in your blast cabinet ? Havnt seen that one before. I needed some more air in my shop so I bought a large tank off craigslist then a 17cfm compressor pump from hf for $160. Good luck with your build!

[Jameel]

Originally Posted by Dpmulvan

What nozzle are you using in your blast cabinet ? Havnt seen that one before. I needed some more air in my shop so I bought a large tank off craigslist then a 17cfm compressor pump from hf for $160. Good luck with your build!

Call Mike at the Tacoma Co. I bought the upgrade kit from him for the Harbor Freight cabinet.

[Trackrash]

Originally Posted by Jameel

Thanks Gordon. I read some of your posts about your build. I'm going to scratch off a little of the coating and see what lies beneath.

Are you not worried about detonation with the 9.8:1 CR coupled with the 2mm quench? I was under the impression that we want the combustion gasses to get squeezed out of the perimeter (the dome portion of the piston) and swirled around, and that a larger space here promotes detonation. Quench or squish should be between 1 and 1.5mm. But I'm no expert. Just mimicing what I've read in Wayne and Bruce's book.

What octane are you running? Single plug?

I'm running single plug with Weber 40s.

I don't believe there is much difference in 1 or a 2mm clearance between the dome and head as far a squish and quench. I don't know if it is possible to get 1mm dome to head with these pistons without the edges hitting. From what I know the squish and quench is more of an issue with bathtub design heads? Porsche used the shape of the piston in their SC and Carrera motors to achieve a swirl for more complete combustion. Maybe others with more expertise will chime in.

The deck height, as measured on our motors, is more of a piston to head clearance for safety issue. Generally 1mm. Although some have run less(.8mm) with out problems.

As far as my CR and detonation goes, yes that can be a cause for concern since I am using 91 octane fuel. My thinking is that the original S motor ran 9.8 to 1 CR with carbs and an old school cam that has quite a bit of overlap. My motor follows that same philosophy. The key, for me is to be conservative with my ignition advance curve.

[Trackrash]

Here was my piston to head clearance being measured.

The black lines are the "deck height".

[Jameel]

Great info Gordon. I ducked out to my shop early this morning and had another go at measuring. This time I took twice as long and made sure all my ducks were in a row. I had some errors before.

I used the .012"/ 0.30mm copper gasket at the cylinder base. Scratched off a little of the black coating to verify it is indeed copper.

Starting with a little more clay I did two rounds and got two close numbers which averaged out to 1.74mm. That's more like it.

I also measured down to the groove again several times, both at TDC and while rocking the crank, letting the piston raise the caliper stem until it reached TDC. Both times, and both sides I got within a couple thou of 0.046"/ 1.16mm, so that's the number I stuck with.

So 1.16mm translates to 8.22cc deck height volume (at 95mm bore)

So here's what I ended up with.
Head Volume: 89.2
- Piston Dome Volume: 39.5
+ deck height volume 8.22
=Combustion Volume: 57.92
+ Swept Volume 499
=556.92
/ Combustion volume 57.92
= 9.6:1 Compression Ratio

My largest head volume is 89.8cc which makes 9.5:1 CR

Bruce/Wayne says they should all be within .1 of each other, so looks like I'm pretty much there.

[Trackrash]

Great. Looks like you are ready to get it together.