Road Race Engine Build

[neophile_17]

Hey guys,

After a rather rough weekend for our race car as seen below (Heroic Fix ?winner?) the team decided to build a engine over the winter:

http://www.roadkill.com/24-hours-of-lemons-new-hampshire-the-winners-and-more-from-halloween-hooptiefest/

I'm hoping to combine the best of 3 engines that have had mishaps into a reliable road race motor that can shake off a little over-revving as well as our first motor, not drink oil like our second and third motors, and also make a little more power.

From the ashes of the following three motors I'll be stealing most of the parts:

03 Alero 3400 RIP - Held up admirably to 7 years of racing but water and winter cracked the block, now we antifreeze over the winter instead of just draining
04 Rendezvous 3400 - Leaked 2 quarts of oil and then rod knock, hoping the block is OK
06 Impala 3500 LX9 - Street only but a crappy coolant hose blew and the subsequent overheating scored cylinder walls, has the steel crank

So I'm going to layout my basic plan first and then get into details later. Bottom to top.

Oil Pan from the 03 Alero - Not a big deal but I know it works and wasn't cut too far like we did another time
Crank and Rods from the 06 Impala - I know the iron crank is fine but I've got the steel one and it's just beefier, will have to clearance the block for PM rods - ARP rod bolts
Block from 04 Rendezvous - Hoping it doesn't need an overbore, might go LX9 if it does, will clearance windage tray to work with ARP Main Studs if I can find extra M11 nuts
New Pistons and Rings from 3.4L 94 camaro - I know I'll have to cut new valve pockets and I'll probably take a little more out to get CR down to around 11.25:1 with the
Cylinder Heads and Intakes from 06 Impala - I'm going to have to Heli-coil these but the extra flow will be nice and bring the CR down some, also looking for 10mm style rockers
Cam will be the WOT-Tech Street/Strip Cam - Should be a decent match, pre 99 timing chain, and balancer
Valve Springs will be 26925 with Ti keepers - I got a deal on the keepers so going this way
Microsquirt ECU and LC2 Wideband - I need it to be right, tested, and withstand the elements so no board soldering this time around
Recycled Headers - but with v-bands and balance of the exhaust new

It's a little early to be introducing this but I'm hoping this will be a decent record that I can look back on and also maybe liven up the board a little bit.

Cheers,

Sam

[1QUICKHATCH]

Sounds like a plan! Almost the same combo my friend and I have been considering for his car!

[neophile_17]

Hello,

I got the block stripped down and I noticed something I don't remember from previous tear-downs. It looks like GM applied a paint/coating (maybe similar to Glyptol) to the block in the timing cover area and also under the oil filter in the kidney shaped area. Some of it had started to flake of in the latter which is a little concerning. I'm planning to chip the rest of the paint out of the kidney shaped area but may leave the timing chain area alone. Has anyone had a problem with this coating and/or know why it was applied only to these areas?

Thanks!

[ericjon262]

I have no experience with gyptol, but I really want to hit 24hours of lemons! it's on the bucket list for sure! I'll be following this for sure! where are you competing?

[neophile_17]

Glyptol is an electric motor armature paint that is used by some engine builders to coat certain parts of a cast iron block to aid in oil control/return. I've seen reputable engine builders argue both for and against it but everyone agrees that if it's applied to a less than optimally prepped surface the result isn't pretty. GM would have a unique opportunity at perfect prep knowing all the details of the block's history.

We've been doing the New England races for just about 10 years. We made it to a couple Mid Atlantic races in the first couple years but we're not in our 20s anymore and the tow home/go to work the next day thing doesn't work the way it used to. I really can't say enough good things about LeMons- the atmosphere is just unlike anything else. It's choose your own competitive scale during the day and a party with all the best friends you didn't know you had at night. Highly recommend!

[neophile_17]

So I came across an interesting hiccup- The piston pin diameter is larger on the 3500 than the 3.4L. That means I can't put the 3.4L pistons on the the cracked cap rods for the 3500 (without modification) and I need those rods to work with the 3500 steel crank. I could go with the stock 3400 crank and continue on with 3400 rods (wish I'd hadn't mixed up the caps) or I could refresh the 3500 which isn't as badly scored as I thought and should be OK with a light hone and new rings. Decisions... decisions...

[ericjon262]

can you ream the pistons for the larger pin? or is it just way too big? total seal has a gapless top ring I am tempted to use in my car.


I had heard of Glyptol, I've just never used it. I probably won't use it until I do a full engine build for the Fiero, which may be years down the road still.

[neophile_17]

I'm starting to reconsider the high compression decision. High compression does sound bad*** but I don't think it's going to make the extra power that I originally supposed. Looking through a several calculators only a couple percent can be gained. I've basically convinced myself that the 3% increase in displacement I get from the 3500 will more than make up for keeping LX9 stock compression. The LX9 has a more modern ring package that would save power compared to the iron head 3.4L stuff and the oil squirter is a nice bonus. I could probably have opened up the holes on the 3.4L pistons to accept the 3500 pins but in the process I think I've come up with a better way forward.

And now I can build a stock 3400 backup motor with fresh bearings and seals should we ever need it- and probably pay for it by sticking with 87 octane.

[neophile_17]

Yesterday I took bore measurements of the 3500 (LX9) block and 3400 (LA1) block. It was initially a little depressing because both blocks showed 0.002" out of round on all cylinders which is double the service spec I found. However, I compared the numbers form the two blocks and for the same location and angle the measurement they are within 0.0002" of each other. These blocks led pretty different lives so having a max of 2 ten-thousands of an inch difference for each of 72 measurements is pretty incredible. What I suspect (and fervently hope) is that torquing the heads and other accessories distorts the bores and that once that happens everything is within spec. I was thinking about making a "torque plate" out of a junk head to test out this theory but I'm curious if anyone else has run cross this or taken accurate bore measurements that I could compare against?

[SappySE107]

A torque plate does matter for the top of the bore. About 1" or so. I forget how much exactly but I use one for the engines I build. I also make sure to put the rings down in the bore a little more when gapping so I don't have to bolt the plate down to do those.

[neophile_17]

Thanks Ben!

That's in line with what I've been reading as well. Wasn't what I was hoping for but I'm getting the impression that 0.001" out of round isn't necessarily cause for concern. I'm tossing around the idea of putting the LX9 crank in the LZ4 block with new rods (LX9 rods are press fit) and rings and building that up. Any idea what the balance factor of these engines should be? V8s seem to all be 50% but 60 degree V6s seem to be different with numbers between 35% and 50% depending on crank design.

[neophile_17]

Tax return money came in so I made a couple of parts orders. Purchased the rods and a Pre-99 crank timing gear from GM. Microsquirt, TimeSert 1812CORE, and gauges are also on the way. I had already bought 10mm rockers from the JY but they are a straight design not offset like the LZ* so I'll just TimeSert the heads to handle my valve springs. I figured it was time for a full set of gauges once I realized nothing in the old Fiero gauge pod actually works and good data should help us keep this thing together. More updates once I get the stock LA1 buttoned up and off the engine stand.

[neophile_17]

Any idea what the balance factor of these engines should be? V8s seem to all be 50% but 60 degree V6s seem to be different with numbers between 35% and 50% depending on crank design.

According to the 60 Degree V6 Chevrolet Power Service Manual the Balance Factor is 50%. HTH

I practiced adding Time-Serts to a couple LX9 heads that will go on the "Stock" LA1 bottom end or what I'll probably end up calling the little engine from here on out. When I went to Time-Serts the LZ* heads there was a pretty significant difference in the cutting and tapping feel. The LX9 heads are softer. I probably wouldn't Time-Sert them again if using a milder valve spring and cam. I did end up cutting one of the holes a little too deep (shaft collar slid) but I only lost one thread on the rocker bolt so more than enough engagement.

Piston rings for both engines should arrive tonight along with the filing tool. Hoping to get the little engine buttoned up in the next 10 days.

[neophile_17]

I went to order my cam bearings from WOT-Tech and I find out that the standard width coated bearings don't seem to be available any more. Can they be special ordered or are they discontinued? If no longer available what is my next best option for a standard width bearing. My cam spacers don't work with the wide bearings. It looks like my options are standard Durabond, Mahle/Clevite, and Sealed Power but I'm open to others.

[neophile_17]

I decided to order the SBC coated bearings and I'll trim them down before installing them in the bearing spacers.

Since I'm going to aftermarket gauges the standard GM oil pressure sensor wasn't going to work and it's not NPT. Fortunately it looks to be the same as the LS sensor for which there are tons of swap parts. Will post back as soon as I get my adapter can confirm.