Sending the 360 to the machinist and need advice

[ClovisMan]

Okay, so I am definately going to be sending my crank, block, and heads to the machine shop. I'm pretty sure the block will need to go .30 over and the crank a .10/.10. One main question I have is pistons. Since I am spending the dough on a rebuild, I might as well get a little more ummmphf for my money. I've read on the AMCForum that you can put 343 pistons in the 360 block for more compression. I want more compression, but would also like to be able to use pump gas. I already have a Edelbrock Performer intake, a Holley 670 Truck Avenger and the Melling MTA-1 Cam. I have the 58 cc heads, so those are what I will be using. They will get freshened up with the basics, 3-angle, new seals, springs, and whatever other components end up broken.

So I guess my question is, what will my compression be with the 343 pistons and has anyone on here successfully used them?

[ClovisMan]

Also, is it necessary to use the torque plates when having the block bored over? I'm having a hard time finding a machine shop with the plates.

[bigun]

Also, is it necessary to use the torque plates when having the block bored over? I'm having a hard time finding a machine shop with the plates.

as an old drag racer I would say yes I know that the old days they did them with out them. By using torque plate it you stress the block just as if the heads were on it.

[REDONE]

Your block can be bored just fine without the torque plates. If you were boring big for sleeves or crazy pistons with a filled racing block you would want them, but if you've got your heads off you can see there's a LOT of meat in these blocks and they are good iron.

Summit racing has a compression ratio calculator on there site. I wouldn't be a fan of cast 343 pistons in a 360, although I'm sure it's been done plenty of times before. Cast pistons really don't like detonation, and detonation gets more likely at higher compression. Even if you always use high octane gas and never advance your timing, after a few years of regular use a little bit of carbon can build up and either A: effectively increase your CR into the dangerous zone, or B: glow hot and pre-detonate the air/fuel charge.

However, I do think you should bring your static compression ratio up to at least 9:1 if you're still going to run regular but closer to 10:1 if you're willing to spend for premium over regular or midgrade.

Bulltear has a screaming deal on forged 360 pistons in any compression ratio you want. They cost a few hundred more than cast, but you know you're getting the most bang for your buck. They're on my wish list for my build I'm hoping to knock out around Christmas time.

I know that everything you need for engine rebuilding can be crazy exprensive and everyone recommends the most expensive option, but if you're gonna save money anywhere, look at what the part does. If a gasket sucks the worst that will happen is you leak oil or you leak vacuum. If your rockers suck, the worst that will happen is you loose power. If a piston or timing set sucks, you get to rebuild the engine all over again...if you're lucky.

[bigun]

Or you can go true low dollar like I did on my 440. I had the block cleaned, new freeze plugs and cam bearing put in and the crank turned. I then bought a hone and did the cylinders bought oversize rings and file fit them to the cylinders.

[lindel]

Personally, I wouldn't mess with raising the compression ratio much more than 9.5:1. Put your money where it will do more good and get a cam, intake and exhaust system. Those will go further to making useable, driveable horsepower.

[Knucklehead]

Or you can go true low dollar like I did on my 440. I had the block cleaned, new freeze plugs and cam bearing put in and the crank turned. I then bought a hone and did the cylinders bought oversize rings and file fit them to the cylinders.

Give me some schoolin on this please. Do you just buy rings for 30over pistons then file fit them? This sounds like something I might be interested in doing for the 360 that is gonna go into Grants Wagoneer.

[Stuka]

Or you can go true low dollar like I did on my 440. I had the block cleaned, new freeze plugs and cam bearing put in and the crank turned. I then bought a hone and did the cylinders bought oversize rings and file fit them to the cylinders.

File fit?!

[lindel]

Yup, slide em into a piston hole to get a measurement on the gap, then file by hand til you get it where you want it. Old hot-rodder's trick, very old school.

[Knucklehead]

But do you start out with 20 or 30 over rings?

[lindel]

Depends on what you did to the block. If you had it bored, then go with the overbore size. It's really a good idea to check the rings and adjust them all for the same gap anyway.

They should sell oversize rings in every bore size for custom engine builders, but you'll probably need to ask for them.

[Stuka]

Oooo, ok. I have done that before. Its pretty common for new rings to not all be the same. For some reason I had it in my mind he was filing the outside. Gapping them is only going to work if they are very close already. A 30 over ring is not going to fit right in a stock sized bore that only has a basic hone job. You can file them to make them fit, but they will no longer be a perfect circle.

[lindel]

Yup, you have to match the bore size. The oversize ring is basically a little wider than the standard size ring and will fill the gap if you're using older pistons. Sink the ring in the hole (using the piston to make sure it's square in the bore), then measure the ring gap. Make them all the same size to keep the compression equal across the engine and then you'll stagger the ring gaps to keep the compression at a constant.

A bit of work, but well worth the effort. Every little bit helps.

[bigun]

Yup, slide em into a piston hole to get a measurement on the gap, then file by hand til you get it where you want it. Old hot-rodder's trick, very old school.

LOL I got a million of them. Here is another if you want to keep your bearing from spinning, go to your local drug store and get some pure lanolin. Now everybody knows lanolin is slick, Untill it has been heated then it turns into a very hard glue. Spread it on the out side of the bearing shells and break in your engine normally by the time it has goes through break in the lanolin will have set and lock your bearing into place. I should also add I check ring gaps even when I have new piston and ring sized to the over bore and I use plasti-guage on bearing to make sure they are correct. Someday I hope to have a complete set of inside and outside micrometers so I can do it right

[fulsizjeep]

plastic gauge is also doing it right B-)

[lindel]

Hadn't heard the lanolin trick, but yeah, the plasti-guage is the right way to do it. Good stuff, that!

[bigun]

I picked the lanolin trick from a paperback book written in the late 60s early 70s published by one of the car magizines. They detailed how to build every domestic engine at that time. I wish I could find another copy it was darn near 6 inches thick and destroyed itself years ago. I also use the cylinder that the rings are going to be use in to check the gap. I know some guys who just use the same cylinder for all of them. Smokey Yunic'ks book is another I wish I had bought back when it was still being published.
http://www.ebay.com/ctg/?_pid=1467509&_ ... m570.l1428

[jaber]

Great info.

I have been told that racers use regular spray paint on their head gaskets, but dont know why.

I have also done the Singh grooves. http://somender-singh.com/content/view/7/31/

[whsii]

Never heard of spray paint on the head gaskets, or the lanolin trick, but...

Back in the early 70's running a Dodge Dart Swinger with a 340 with 12.5 to 1 pistons, I had to use a product called "Copper Coat" which is still available today. I was blowing a head gasket a month, with the block decked and the heads shaved, until I started using it. Never blew a head gasket again.

It looks like a can of spray paint, it sprays a copper colored coat onto the head gaskets. It actually is mostly copper dust with a medium to flow it onto the head gasket. You are suppose to put it on thick, so that it runs then put it in place and torque as required. Supposedly, the copper particles fill the micro groves from the machining and make a great head gasket seal.

Most people will agree, not to put anything on a head gasket, but I will not build a Briggs and Straten engine without it. I used it on the I 6 in my project.

Clovis, I would inquire to balancing the engine. My I 6 cost less than $100 while they had it in the shop, it makes everything work more smoothly together. In my opinion, it is well worth the cost for the long run.

Just my thoughts...

[lindel]

Copper Coat is good stuff, I've used it several times before.