Whew... getting hot in here!!!

Seriously Bence...

Plastigauge isn't the most accurate way to do it but you already knew that. I would trust a cheap set of Tiawanese mic's a lot better. And I speak from experience also. It's just tough to get good numbers with the stuff. But you can get close. The usual numbers you shoot for are around .001 per inch of bearing diameter. So that means .0027-.0028 for mains and .0022 or so for rods. My current 540 is set at .0032 on mains and .003 on rods. I've experienced some minor scuffing in the past with tighter clearances at these HP levels. My 427 was in the .002-0025 range on all bearings and lived fine. Of course lots less power going on. A little loose is better than a little tight. Use a HV oil pump and you will be fine. In fact a stock pump with the HP pressure spring will hold 70+ psi at high rpm and 30-40 at idle with .003+ clearances. The HV will do a little more a the low end. If you use the HV pump make sure you have at least a 6 qt pan. It is perfect that #5 is looser than the rest.

On the line hone issue... well it definitely falls into the "can't hurt" area. The line bore has to be accurate or bearings will be destroyed. If you tore down the motor originally then you know what the bearings looked like. If there was a problem it would show up on them. If the main studs are installed properly , meaning no force was used putting them in they shouldn't cause any problems. There will be less bore distortion with them than with bolts. You can get an idea of line bore with a straightedge and some feeler gauges (you're gonna have to get some!). lacking that on a homebuilt engine I would definitely disassemble it at least once through the building process to look for bearing issues. After everything on the mains was done and the rear main seated properly I would remove the crank and look at bearings closely for any signs of trouble. On an engine you've dealt with for a long time this becomes much easier. Anything out of the ordinary stands out quickly.

You need to check end play. It's going to need to be right for the std. trans you are running. Everytime you push the clutch, you are shoving that crank forward. Too much and you will hammer it out. That's why extra attention is payed to lubrication of the thrust when a car that launches at high rpm, whether it is a 4 speed or auto. Lots of force on that bearing when you are sitting there at 5000 rpm and the pedal on the floor!

Make sure the thrust bearing is seated squarely. You will need to "bump" or pry the crank forward and backwards several times with the rear cap only snugged down to make sure it is seated properly with the upper and lower halves ending up with the thrust surfaces properly aligned. If the cap is slightly moved either way the load will only be borne by only half the bearing. Not good. Using some prussian blue marking compound ( or a nice magic marker) to color the thrust area and the recheck it after prying the crank forward and backwards while turning it to make sure you are getting full contact.

Make sure you get the rear main seal installed facing the right way. The groove on the seal faces the inside of the motor. I also always offset the two halves by turning the seal in the bore so that the parting lines don't align with the cap parting line. Helps make an extra oil boundary.

You need to make sure rod side clearance is correct. Feeler gauges again if you don't have dial indicators or mics. There isn't much you can do about it except juggle rods around to get the best combined clearances on all 4 sets.

Pay attention to ring placement on the piston. The manufacturers or ring makers have it right. It is important to assemble them with the gaps placed properly with respect to the major and minor thrust surfaces of the bores. Just look at the pictures and follow them exactly.

I personally don't do a lot of oiling mods to relatively mild big blocks. The stock system is very good. You can do some polishing of the hole through the main cap and the block. One thing I always do is I drill a 1/8" or so hole through the surface that the cam gear presses against. You can eyeball it and drill it straight through into the oil gallery that feeds the number one main. This provides pressurized oil to the back of the cam gear and eliminates the issue of destroyed thrust surfaces on the front of the block. No massive oil leak internally because cam gear is up against it and it provides extra oil to chain.

Don't install any oil restrictors in the rear of the block. I think the epoxy'd screens are a good idea in the lifter valley, just in case anything bad ever happens.

Good luck and keep buiding on that dude and take your time. If your uncle has built lots of motors keep him handy. The comments about cleanliness are absolutely vital. Watch out for lint from red rags!


Jim

 

Hey Jim, did the normal pre-made big block lifter valley screens work in your Merlin block, or did you have to make them yourself?

-Joe

 

Jim:
Thanks for the response. I knew plastigauge wasn't the most accurate method but it's all I had at my disposal. I figured plastigauging was better than just slapping the crank and rods in and hoping for the best :). Norval seemed to think the .0030" clearance with the main bearings was ok. The rods turned out to be .0020" so they were a bit tighter. My uncle came over and helped me work the crank back and forth to align the thrust bearing (I was unable to align it myself). I made sure the seal was facing the correct way, with the lip of the seal facing the inside of the engine.

I liked your idea of not lining the cracks of the seal up with the cracks of the main cap...I wish I would have done that before I assembled it. Thanks for the idea!

I plan on getting a Moroso oil pan with scraper and windage trey (6qt + 1 in filter). I also have a Melling high volume oil pump.

One question though. Which mains do the windage trey studs go on? I put the windage trey studs on mains #3 & #4...did I make a boo-boo? :(

 

mountainmotor...

Sorry if I ruffled your feathers... not intended. I took it offline... you have mail.

Tom

Edit:
PS.. The Dude...

"I will say this about professional engine builders. When they're on their game they're worth the money. When they're not--or when they're hurried--you don't necessarily know what you're getting.."

Absolutely agree.... and that is what got me stared in the business... poor workmanship handed to me by a machine shop.... and I was dumb enough to pay for it. If you can, follow The Dudes advice and check everything you get back from a machine shop... his experience/advice is right on the money.


[Modified by Tom454, 10:26 AM 2/18/2002]

 

Tom,
Thanks for the email.All is well between us.You are a Gentleman!

You other guys/friends that have mailed thanks as well.I hope the info I sent about the "Moraine /block saddles" helped you to understand or rather see where I was coming from or getting at.There are a surprising number of machine shops that still have not had this info passed along to them.Feel free to pass it along.

ddn,
At age 18,you have what it takes .Hang tough with the seemingly endless attention to detail! Soon you will have scary ride that will live :cheers:

 

You can make your own assy lube....STP mixed w/motor oil

or you can use STP by itself

 

Flareside...

Yes the pre-made screens fit fine. I used a Moroso kit.


Bence....

You did fine on the windage tray studs. They are in the right place. I also like using an oil pump stud rather than a bolt to cut stress on the rear main cap.

You can always remove the cap and reposition the seal, it's not too late.

Plan on lots of time fitting the pan scraper if you get one. Best way I know is to do it as you install rods and pistons during assembly. Install one rod/piston and grind scraper to fit. Then install the next one, etc. It's tough to do it when they are all trying to hit it everytime you turn the motor. It's easy to go too far and lose some of the effectiveness. Plus it's easier if you use studs to mount the pan. That way scraper is always in the same place. If you don't want to buy high $$ ones you can get various length carb studs and nuts at parts stores. They sell them in bulk in the Dorman line. But ARP's are prettier!!

Did you end up putting 2.19 valves in it? If you did, you might look into using offset head dowels to position the head where intake valve is a little further from the wall. It can really help on a 4.250 or so bore. They make some.030 ones that would work great. Just watch PV clearance in the corners of the pocket when you move the head.

These are all the little things that make one motor outpull another one with similar parts.

Keep working on it.


Jim

 

Jim:
I think I'm going to pull the rear main seal and try the staggered approach. As a matter of fact I do have an oil pump stud. I purchased an ARP oil pump stud. Yes, the heads that I have currently are equipped with 2.19/1.88 valves. I am interested in hearing more about this off-set head dowel thing :) (if you care to elaborate please). Thanks!

 

I'm not an expert engine builder but i noticed you said you installed the studs by bottoming them out. I also have just completed a crank installation with studs and made sure the studs were not bottomed out on the advise of an expert engine rebuilder. Supposedly if the studs are bottomed ,they can cause cracking of the main webs. I installed mine with full thread engagement but no further. Would appreciate further comments if this is wrong. I too want to make sure i get it right. LOL on your rebuild. Thanks
Bob

 

Offsetting the head helps unshroud the valves. On a big block every cylinder has the intake and exhaust valves in the same position. This is different than say a small block, where the positions swap from cylinder to cylinder. On them the center two cylinders have the ex. next to each other in the center and then the outside ones have the ex. on the outside. The intakes of 1&3 and 5&7 next to each other.

So on a big block we can use offset dowells in the cylinder deck surface to replace the stock ones (that the 2 head bolts go through). This way we "scoot" the head forward on one side and backwards on the other side to physically move the intake valve away from the block bore.

They make .030 and .060 ones commonly. The .030 ones are the easiest because the head bolt holes still line up pretty well. The .060 ones sometimes require you to drill the headbolt holes slightly oversize to get them in without dragging the inside of the headbolt hole.

The only thing you need to watch is to make sure that you really have good piston to valve clearance in the edges of the pockets. Stock replacement TRW type forged pistons get pretty tight with 2.19 valves in the bottom edge of the pockets. You need to check it REAL close. Also make sure that the dome clears the chamber. Just lay the playdoh or modeling clay over the whole piston and then install the head. Rotate it several times and check the thickness around the edges and in the valve pockets ( assumes valvetrain installed). DON'T just check one cylinder and assume. When you start building stuff using aftermarket parts you have to check EVERY cylinder. Don't make any assumptions or you're just taking chances!

This all accomplishes and expands the same type of things that Chevy did in the first place by making a polyangle head. They tilted the intake valve and exhaust valves to move them further from the wall and to make them get further from it as they opened. Exactly what a Hemi does and exactly what the whole 18* and 14* small block heads do. Plus the port angle gets better too!

Now if you really get serious, let's talk about the process of boring the cylinders off center to move the cylinder away from the valve!!

Hope all of this helps. Just look in Jegs catalog. They're cheap!


JIm