lamune engine build (can engineer guy build a motor?)

lamune wrote:

If you want to see what I came up with for the build specs, here's my spreadsheet

CR Calculator

I did not take into account the area between the top ring and piston crown which would bring that number down by something

Can you put it in a screenshot or file format instead of One Drive. I bailed on One Drive a long time ago when they started turning the auto save back on and downloading everything on the computer every time there was a Windows update. Then they turned around and wanted to charge a monthly few for going over storage limits.

Sure:

lamune wrote:

Sure:

Thank you, much better for me!

It will be interesting to see how the detonation turns out with that setup, may be OK because aluminum heads that give a bit of a break on what  you can run, but the quench will not be good at .063, I think, so will be out of the picture.  Let us know what you find out when it gets going down the road.

Did more searching on the 64 cc combustion chambers, and found very little, but some tidbits that are certainly not conclusive by any stretch.  None of the head spec lists show any combustion volumes for the iron heads, with the exception of one that listed a crate engine replacement for 290hp that had 76cc.  Did find one forum discussing it and they had totally conflicting information, with most saying it is always said to be at 53.5 plus or minus, with a couple that had actually measured, one at 55cc so odd.  A couple of people said original specs said 64cc but with no references to a source.  That fact that there is a .028 GM gasket available and listed as such on the OEM parts finders would indicate that something was different, but was it all the time or when parts ran out and got subbed?  Kind of like Christmas, open it up for a surprise!

I ran the compression calculator and it is actually easier to get into the good quench and 10.5 compression range at the same time than with the smaller chambers.  Here is what it looks like with a .039 and .028 gasket thickness, using a +7CC, two valve cut, hyper flattop, which is available and likely cheaper than the two cut with dish needed for the smaller chambers.  Still would need head and block cuts, but you need to true them anyway, so no issue, IMO.

I did sweat it out a bit when I saw that my CR came out just over 11:1. But, now I see the difference between 10.8:1 and 11.1:1 as something under 3%. Then I didn't worry as much. I'm going to fill the tank with premium and fire the thing up when I'm done and then we'll see what happens!

lamune wrote:

I did sweat it out a bit when I saw that my CR came out just over 11:1. But, now I see the difference between 10.8:1 and 11.1:1 as something under 3%. Then I didn't worry as much. I'm going to fill the tank with premium and fire the thing up when I'm done and then we'll see what happens!

I will be interesting to see, for sure. The 11.1 with aluminum heads, reverse flow cooling, and premium I would expect to be OK, but with good quench. Without quench, who knows, as it isn't really on open combustion chamber either. This should lets us know how important quench is in these motors, though.

A bit off topic, but relevant maybe, so if mods want to boot it I understand.

Here are two pictures of the head castings I am intimately familiar with from my twin turbo 340 days.

This is my original head style used with a flattop down the hole to get 8.0 to one compression.  Semi open chambers, very large ports, big valves so not a high velocity or high swirl design.  These heads got detonation at around 8-9 psi boost with no water injection on.



This the final engine head style I used, full quench pad, ports 2/3 the volume of the first pic ones, smaller valves, smaller combustion chambers, very similar to the LT-1 heads, I think.  Ran with .040 quench with a flat and pocket piston and 9.0 compression ratio.  No detonation until 14+ psi on the same gas and no water injection.

I was, and still am, surprised at just how much difference the head change could make



The open chamber heads needed nearly 50 degrees advance at low load highway cruise of 2100 rpm for max mileage.  The second heads needed about 28 degrees for the same conditions.

Did you happen to measure the actual journal diameters on the Scat crank? I haven't been able to find any actual grind tolerances for their stuff, or target bearing clearance. I looked at the factory service manual for our 1996 RM and it shows the mains at 3 different sizes with #1 larger, #5 smaller, than the other 3. Technically, they could all be same and be within the quite wide factory tolerance, but nominals tend to be good indicators of best practice. I would guess they do it to help front stability for the timing and optispark and more cooling for the heavily loaded rear bearing. For a driver, I would always go to the low end of clearance but have found a lot the aftermarket parts are set up for nearer the high clearance end for hotter motors. I had to take a big hit on a set of Eagle H beam rods I got for the 340 because the clearance was too high and was killing oil pressure (lots of oil to oil cooled turbos).

Same if you measured the big end of the rods.

I may also give Summit a question about it, as they can get the information easier than the public can.

I didn't measure the crank journals or big ends of the rods. We did pre-assemble it and check the clearances which were all within tolerance based on the FSM specs. I used Clevite performance bearings for the mains and rods (MS-909P/CB-663P) and as I recall most of the results were in the middle of the tolerance range for a new install.

There isn't a LT1 specific crank nor bearings from Scat or Clevite, it's all just 86 and on one-piece SBC for both manufacturers. If there are some LT1 specific optimizations that would be interesting to know. I do have the original crank sitting around that we could take some measurements off of.

Here is what the 1996 RM factory service manual says about it for 5.7, 4.3 is different.

Crank
  Mains   #1         2.4484-2.4493   .0007-.0021
             #2,3,4    2.4481-2.4490   .0009-.0024
             #5          2.4479-2.4488   .0010 .0027

  Rods     All          2.0978-2.0998   .0013-.0035

On a street engine that won't go north of 5000rpm even, likely barely to 4000, I would shoot for about .0002 above the low end spec for clearance measured at center of bearing.  Some like to measure at 11 and 1 o'clock, but then the obround of the bearing can be in on it.  Some high perf bearings have a lot of abound in them for better oil wedge.

On the 63-64cc iron heads, I found that somewhere on the internet but couldn't attribute it to anything legit. If you think about the way the motors were setup, the iron head motors had a more torque-oriented cam so you've got more dynamic compression at lower RPMs and with the reduced heat transfer you'd need to be more conservative on static compression, so with a thinner head gasket than the aluminums the 63-64cc number made sense to me. At one point I was mixing and matching shortblocks and heads as I had ended up with a 383 shortblock with stock piston height, 10CC reliefs in the pistons and 54cc aluminum heads and I couldn't get the compression ratio AND quench height right with the aluminum heads, but I could with the iron heads (at that larger CC number).

Is the front main bearing clearance tighter for better load capacity of the accessory drive?

Maybe lamune still has the iron heads from the donor motor to measure CC on to see what they are. Would be interesting. I hope they are 64 as that does seem to get a bit easier to work out the parts.

The front main thing has to be related to the accessory drive forces and bearing looseness having some bad influence on something critical in the front, I think. I doubt any rebuilder would grind the journals different sizes unless you insisted, though. Funny that the crank allowances are looser than the bearing clearance allowances, though. Having that small a change from journal to journal might show that the engineers had started working to much tighter specs and tolerances, but manufacturing was still decades behind. By the time the LS engines got settled in, it appears the manufacturing started to get caught up to the designs.

I just did a pair of compression calcs based on the guess that the iron heads are probably 64cc (at least some of them) and that the aluminum are 33.5cc.  I used the theoretical piston to deck distance of .024 down hole. .028 gskt on the iron and .048 gskt on aluminum.

Interesting that the results show the iron heads at a touch under 10 compression ratio and the aluminum at a touch under 10.7 ratio.  .7 less compression in iron heads vs aluminum is right about what many engine builders will tell you the detonation change in materials gives on the same engine, so this is probably the one thing we have seen that actually makes some sense related to what parts were actually used.  In some of the reading I have done, I did run across some comments about the iron heads being at 10, but not many, and all official stuff seems to say 10.5.  To the marketing folks of the day, those numbers were probably close enough to both be called 10.5, so not surprising there either.   I think this may just be what we will find out once some parts get measured on OEM part teardowns.  The quench on the iron heads does turn out much better at .052 compared to .072 for the aluminum.

The ability to get a .039 head gasket, which is not stock size for either head material, sure looks to me like there are some smart folks at the gasket companies, or the knowledgeable engine builders pushed them for a gasket that would make it possible to make a zero deck LT1 with good quench, which is the normal best place to be for many builders.  With either of the stock head gaskets it is virtually impossible to do.

Speaking of specs that show up, I found lots of different information out there on stock specs for the cams.  According to the factory service manual for our 1996 RM, the cam is really small for lift, and they don't list duration.  Lift listed as  .414/.428. on stamped bathtub 1.5 rockers.  If the GM stamped rockers are like the Mopar ones were, they will also be somewhat under the 1.5 ratio so probably not even that much lift.

I just heard back from Lloyd Elliot about cams and I had also asked about combustion chamber volumes for the iron LT1 gen 2 heads. He said the ones he has checked ran from 62-65cc, so I think that would pretty much put the question to bed about that. It also makes a zero deck, flattop piston with good quench and piece of cake which can be seen in the second example compression calc in an earlier post.

I did CC the iron head at one point but I don't seem to have recorded the number. I can do it again if I have time at the shop as the carcasses of the heads are still sitting next to the parts washer.

I could also chuck the stock cam in the lathe and use a dial indicator to at least get the actual lift numbers. According to my research though, I came up with this table and the cam I picked sort of ends up right in the middle:

Code:

LT1 Cam                Stock (B-body) Stock (F-body) Erson E119826 Chevy Perf 10185071 LT4 Hot Cam
Intake duration (.050)  191            203            208            208                218
Exhaust duration (.050) 196            210            214            221                228
Intake lift             0.418          0.476          0.480          0.474              0.492
Exhaust lift            0.430          0.479          0.480          0.510              0.492
Lobe Separation Angle   111            115            114            112                112

Nice chart, very handy, thanks.

I have been digging into the cam numbers a bit deeper with some of the stock grinds as reference to see what characteristics they kept the same and what they changed for the various vehicles and performance levels of the cams. Sometimes it is useful to look at factory cams that are for a similar purpose like heavy vehicle, light vehicle, towing, high performance, turbo,etc to learn some engine characteristics.

The one parameter, that doesn't normally show up in the specs, that was interesting to me was the overlap at .050 lift, as I had an guess that it may be something of interest because of the high velocity ports in the stock heads and small chambers. EG, easy to blow through in overlap with high inlet stream velocity, like a very weak boosted engine. A clue certainly was when I saw the factory cams increase the separation angle when they increased lift and duration for the lighter cars compared to the heavy B bodies.

I found specs for 3 Melling stock replacements that closely match the specs for the factory cams on the specs I had for the factory ones, but listed more details. They were the B body 191/195, and two Camaro/Vette cams of 202/208, and 201/208. All three had near identical overlap at .050 of -14.5 to -15.0. Seemed like the starting point for the street driven stockers to keep the low end, idle, and emissions good. The overlap at .050 dropped quickly when I started looking at higher rpm range rated, higher lift and duration cams, which makes total sense.

The problem is that I haven't been able to find any cams with lower durations but substantially higher lift and even -10 overlap at .050.

I did do a search to see what effect the rocker ratio has on duration at .050, and found that it doesn't effect the seat contact points but will change the .050 duration some, but not as much as it does lift and not as much as just a change in duration does when you look at overlap area "under the curve". Best info I could find said the difference in duration at .050 lift when going from 1.5 to 1.6 ratio is about 2 degrees of duration, which I think would mean 1 degree on each end of each duration curve so 2 degrees more overlap at .050. If I did the math right that should be about a -13.0 degrees of overlap at .050 and less area under the curve than if it was on 1.5 rockers with the -13.0 so pretty good.

So what you wind up with when you take the Melling MC1336, 201/208,.446/.459,117 separation and pair it with 1.6 ration lifters is a 203/211, .475/.489, 117 separation cam which is kind of interesting for a low rpm hauler/cruiser with high gearing. Quite stock like power curve, but a bit more duration and quite a bit more lift when compared to the 191/195, 214/228, 111 separation stock B body cam. They would have very similar overlap at .050, which might be a big deal in these engines, in this kind of use.

One big question is if the Melling MC1336 is up to having 1.6 rockers on it, as it is a stock replacement level cam, although not a particularly cheap one. Any comments on durability would be greatly appreciated. It would be under 300# open spring pressure and roller tip Sportsman 1.6 rockers. It is isn't particularly fast ramps, so if the materials are decent, I would think it should hold up to roller lifters, but experience may show otherwise.

Ok, after a few weeks hiatus I got back to the shop. Got the oil system primed and intake installed. I ran into two problems I could use some help with from the group.

#1 - I lost my notes that showed the bolt/stud layout on the intake. I know where some of the brackets were, but we have 1 long stud, several short studs, and bolts. If anyone can remind me what's supposed to go where that'd be great. The drawing in the service manual isn't detailed enough.

#2 - and the far bigger problem: the stock valve covers don't fit. Height is tight but might work- it's less than 1/4" clearance between the cover and the rocker stud nuts. The main problem seems to be  twofold. The head studs stick out a bit which interfere with the cover's tube, and the rockers themselves are so wide that the webbing won't clear them. I'm sure one of you has run into this problem and can hopefully recommend an aftermarket alternative that will clear the rockers and also still fit under the cowl. I can hope, anyway.  

Edit #1 - How about the Corvette LT1 composite valve covers? Would that be an option here? (they are kinda stupidly expensive though)

1. LT1 stud layout should be on shbox.com.
2. Cut, trim or bend the stock webbing to fit. People do it all the time.
3. Unless valvetrain noise is a big deal, I wouldn't bother with the composite covers.

Sherlock9c1: thanks, that diagram is exactly what I needed.

I had a similar thought last night and since I have several sets of the stock valve covers, I took tin snips and cut the webbing out. I didn't realize the tubes aren't fixed to the top either. I was able to free the tubes from the webbing and went back to the shop.

Using a sophisticated measurement technique involving a space age material called Play-Doh I was able to qualitatively determine that the stock covers will clear the rocker lock nuts. With the separated tubes we were able to mount them in isolation and determine that they just barely clear the studs. So we're good.

Plan is to simply cut the webbing out and then I might machine some replacement tubes and tack them to the cover. How that works out depends on what we find in the scrap pile.

Even better - wrap the space age material in clear plastic kitchen wrap. That's how I verified oil pickup clearance in the pan.

Ok, well, after some debate and estimating how long it would take to machine up some parts, I went ahead and just picked up a set of composite valve covers.

Ironically they didn't fit either. Again, after much debate and discussion, I made the call to stick them on the milling machine and clearance them. There are oil deflector tabs molded into it that we machined flat. The baffles around the breather elbow also needed a little modding.

Valve covers installed. I really do think they look a lot nicer than the stock ones. So I guess that's a plus.

@lamune, the pics aren't working...

Working for me...

Now I can see them.

Looking good!

So this week's time was spent on test fitting as many things as I could. The hard part now is remembering where all the little bits went.  

things are lining up so far. Found a few minor things that need to be taken care of. There were two questions that I had after seeing things come together.

Should I mount the oil pressure switch now because doing so is super easy, or leave it off so I don't accidentally shear it off when I put the motor back in? (assuming that is a plausible thing)

The exhaust manifolds go "up" and sit very close to the valve covers. On the Vette they go straight down, so you don't have a hot exhaust manifold sitting right next to a 'composite' valve cover. That material seems to be fiberglass reinforced cast resin, which should be really quite durable- but maybe it's an excuse to ditch the manifolds and get a set of headers. Or at least come up with some way to protect the covers from the heat.

I would look at getting other exhaust manifolds, or headers. The other option is to swap the metal valve covers back in. If you leave the resin ones in place, and they melt, you can always go back to metal ones. 

Put the engine in, then the sender. You will not forget to install the sender for long.

Did you pack your oil pump with vaseline to guarantee oil pressure on startup?

Forgetting where little things go is a symptom of a long term build.

Fred - we primed the oil system before the intake went on, so we're ok there.

The manifolds do have integral heat shields, but they aren't intended for this use.

Realistically, there are several scenarios we could exercise here. Probably the most effective thing to do would be to get some metallized heat blanket material and make a "tea cosy" wrap for the manifolds. That'd probably cost $50 and would likely work just fine.

However given the fact that my project here has taken on Apollo-program levels of budgetless financing, what if I did go with a set of headers? Take cost out of the equation- what would be the negatives of switching over? The only things that come to mind would be possibly increased under hood temperatures and increased exhaust noise.

Clear Image is a local business. I'm looking at the stainless steel Gen II Tri-Y headers with the high-flow cats as a possible option.

Make sure they pass inspection.

Clear Image headers are the best designed headers for this car, period. The fact that he is local to you is even more of a bonus. Although it's not cheap, it's money well spent, especially if you keep the car for a bit to amortize the cost.

Ok, no work done this weekend and probably not next weekend either - but I did order a set of headers from Dan. We'll see how that works out. I'll have to start thinking about how to heat-shield various things. My friend suggested the starter solenoid as one thing that might need protection, which didn't seem obvious.

Insulate anything within 6 inches of the header pipes. I use the aluminized cable insulation with a Velcro closure. They make them in numerous sizes. You can even put them around the brake lines if they are close to the headers. There is also aluminized tape for close areas. I have insulation on all soft, and electrical parts around my headers for the 454. Most of it is good to 1000 deg. in a proximity (not touching) situation. There is a starter blanket that covers the starter and solenoid made from the same material with a Velcro closure for easy installation. If you want to do short sections, put a tiewrap on one, or both ends to keep the insulation from moving, and the threads from fraying. You can get spark plug boots to augment the metal ones that come with the car, and for the plugs without the metal boots.

I have seen LT1s with headers that have melted the looms on every wire in the engine compartment. It really looks ugly when you see what looks like dripping liquid plastic on the wiring harnesses.

Got the motor home now for final assembly, so I guess we're getting closer to being done!



Waiting for the headers and some insulation material as per Fred's suggestion.

Glad to see your getting near the end of it and hopefully will soon see some great results.

As I am getting ready to start my complete driveline upgrade/rebuild this winter I do have a question for you and others about the original pulling of the engine.

The plan is to pull engine and trans together, I do have good picker and tilter, but in the past I have run into some vehicles where you can't do that unless the vehicle is very high off the ground so the trans tailshaft doesn't hit the floor and prevent it from coming out. It is always a pain to lift it more with engine tan trans dangling, it seems. Anybody got a decent idea how high I need to put the 96 RMW to have it come out without hitting?

Parts list is essentially complete but still need to get to the shop I want to use to see if they do this small a job and if they want to supply most of the parts (need to get near mail order prices though as tight budget). Hopefully, they will want to do both as I always try to keep stuff local if I can afford it so we can keep these places in business.

I can't say for sure booster- I stupidly pulled the motor out in pieces. I'd guess you'd need at least 12-16 inches of clearance to tip the stack out of the bay. Probably on the lower side if you pull the rad and condenser.

I forgot to add a note about the hole for the engine temp sensor. The Vette has that sensor on the driver's side head instead of the passenger side as I noted before. Plugging the open hole was obviously easy. Getting the plug out of the other hole not so much. Put a square bit on it and wrenched with a breaker bar and turned the square hole round. Pounded in an extractor and just ripped it more. Drilled through it, pounded in another extractor and just tore it up more. So I took a punch and hammer and started folding the steel ring that was a plug into itself. Smashed it into a ball, then grabbed it with a vice grip and it shot right into the head. Thankfully the plug is steel and the head is aluminum, so I was able to use a magnet and a hook and get it out after an hour of fiddling. Mangled the threads up pretty nicely in the process but a chaser cleaned it up.

I never would have expected that. My thought up to that point was that the steel plug would be like a tap in that aluminum head and there's no way it could have gotten stuck like that.

I'm now ensuring liberal use of anti-seize on anything that goes into aluminum threads.

Personally I pull the engine and trans separately on B-bodies. The work you have to do to remove the rear cross member you'd have to do either way.

I need to start thinking about the ignition wires situation, particularly with the headers coming. I wasn't running the wires behind the manifold anyway, and the wires were kind of a mess just draping around the outside- the 90 degree spark plug boots were pointless when running the wires that way. I don't think the common 8mm and larger wires we have today would run in the factory channels anyway.

Two things that I was thinking of were the MSD 8.5mm silicone wires in a cut-to-length kit with the straight high temp orange spark plug boots, or alternatively the Accel 8mm cut-to-length kit with the ceramic boots with the 135 degree bend. Though I'm not set on either one if someone has a better suggestion.

I like the MSD wires. The custom made ones with the straight plug end can be bent to almost any angle you need. I have used/made several sets and been very happy with them and the ability to bend them to fit around headers and other protrusions at the head.

https://www.jegs.com/i/MSD-Ignition/121/31183/10002/-1

Maybe there is something like these available for 8.5mm wires with no name or Chevrolet on them
https://www.jegs.com/i/Proform/778/302-640/10002/-1

Thanks Joel. It's kind of hard to differentiate now with Holley owning Accel, MSD, etc. I'm going to try something first and see if I can roll my own with some parts. With the motor on the stand it'll be way easier to mock something up, so may as well try that first.

I do think with the headers I'll probably have to go over the valve covers and down to the plugs.

I used the MSD wires on my 454. The bendable plug ends are nice. You can always put boots on the wire ends. I think the wires will fit best if you go over the valve covers. I did the wiring on the engine stand, and it was a lot easier that way. The reason they used the OEM wire routing is to allow for the OEM exhaust manifolds. You can not successfully run the wires any other way with the OEM manifolds. The wires are shorter too, so the bean counters are happy. Be careful, on my 92 OCC, with an LO5, I have a problem with tightening the #8 cylinder plug. With the headers installed, I had to remove the starter to tighten the plug. My headers may be for an angle plug head. I bought them used, so I do not know the specific use directions. LT1 headers may or may not have similar issues.

Fred, in looking at this - well long story short- probably requires a different strategy for wiring. I'm also not sure it's possible to change #5 and #7 plug with the headers on. I'll be a lot easier to figure these things out with the motor sitting on a cart, anyway.

A real genius designed that. My tight header blocks my #8 plug, and I must remove the starter to tighten the plug. It looks like #7 is going to be the issue. The 4 into one header is less problematic.

FWIW, I used these header bolts on my 454, and they do not loosen when properly torqued.  https://www.ebay.com/itm/Proform-66751-Locking-Header-Bolts-Set-of-12-750-L-3-8-16-GM-Ford-Mopar/224050946789?epid=1139739086&hash=item342a7a22e5:g:tkgAAOSwVSte7OzD

Actually, it's not as bad as it looks. #5 is accessible and #7 can be removed from above. Thanks for the tip on the header bolts, those look like a good choice.

Now I'm trying to wrap my head around making the spark plug wires. The wire is 8mm diameter and the holes in the boots are about 6mm and they don't really stretch. It says they fit wire up to 10mm.

Are you referring to the looms that hold the wires in position? If so, you could run a drill through them.

Fred Kiehl wrote:

Are you referring to the looms that hold the wires in position? If so, you could run a drill through them.

I think he is talking about making custom length plug wires and having a hard time getting the wire through the plug boot.

Some spray lube on the wire or in the end of the boot should help the wire slide through...

You should be able to get boots that fit the wires.

Yeah, sorry, should have been more clear. I've got the Taylor boots and 8mm wire. They say the boots fit their wire up to 10mm. Now I haven't tried lubing the wire up with silicone grease yet, I did try soap as it's less messy and I can't get the wire through the boot. Also their boots have a white plastic doofus inside them which I'm not sure is for a reason other than to keep the boots round when they card and shrink-wrap them. Anyway it's not a problem yet as I'm just learning about the process here and I can go with the MSD set anytime I get tired/annoyed of messing with these.

Chalk it up to being a noob. I did try a few different things, but silicone spray was the winner. Wire goes right in to the boot when sprayed with silicone. The Taylor wire I got actually was wrong and I didn't even notice, my friend did. I got the solid core stuff by mistake instead of the suppression core. I'll use the MSD set on the motor and have the Taylor stuff to practice with.

I've been laid up for a while after surgery but I'm making final progress here. Motor mounts are installed, and I mocked up the headers to make the wire set. Looks like the headers have to come off to change the plugs, which kinda sucks. Otherwise it seems fine. Only thing left to do is change the front trans seal and drop it in.

I must drop the starter to remove and replace the #8 plug on my 92 OCC with headers.

The tri Y headers might be the problem. They look like they are really tight.

Well Fred, I doubt many people install headers to improve ease of maintenance, so I'm not entirely surprised. I'm glad that at least I know this now so I can prepare for it. Good thing those platinum plugs last a pretty long time I guess.

Since I haven't put a SBC back into a car before, let me share my thoughts here and see if the crowd thinks this makes sense:

First I would jack up the trans as high as it'll go to angle it upwards. Then bring the motor in at the same-ish angle, line up the dowel pins and push the two together. Install the side bellhousing bolts, then remove the trans jack and lower the combination to line up the motor mounts. Install the motor mount bolts, then the rest of the bellhousing bolts. Anything missing there?

Once that's done I'm inclined to install the headers since getting them installed is going to be a pain and I may as well get that out of the way sooner than later.

You can loosen the trans mount bolt to allow for more freedom of movement.