Building a 7 bolt... What clutch? - Page 2

slowbubblecar · 08-30-2005

I "think" barton had a 2600 but I know it was defenitly crankwalked. I thought I heard it was at like .030 whick is huge.

**Shane@DBPerformance** · 08-30-2005

I have stuck with the 7-bolt because I know I won't be putting many miles on the motor. Even a shitty 7-bolt can handle a few thousand miles without crankwalking enough to cause too many problems, and I am cheap.

**Goat Blower** · 08-30-2005

It's not just from a heavy clutch, 1/3 of the CW cases have been automatics. And the engine mount theory, no dice. I came up with that 4-5 years ago, no response from anyone in the know.

Just make sure you have someone build the engine that knows what they're doing, use the correct size main bearings(there are three different sizes if I remember right) and if you are using ARP's on the mains, make damn sure you had the mains line bored and are using the dowel pins.

Any engine can walk, the 7-bolts just seem to have the problem more often than most motors.

Pimpin Dsmstyle · 08-30-2005

Mike sure as hell knows how to build a motor, but Careys walked last year?

Matt D. · 08-31-2005

Quote:

Originally Posted by Pimpin Dsmstyle

Mike sure as hell knows how to build a motor, but Careys walked last year?

And it was determined to be caused by a soft crankshaft. The new crank he has now has been re-nitrided.

Pimpin Dsmstyle · 08-31-2005

Quote:

Originally Posted by Matt D.

And it was determined to be caused by a soft crankshaft. The new crank he has now has been re-nitrided.

I'll quote mike. " Un even wear on the bearings". He said nothing about a soft crank to me. I'm not saying that was the problem, but he didn't mention that to me.

Point is even if you only spend 400 dollars to build this, that is 400 dollars you could have put into a good engine.

**Goat Blower** · 08-30-2005

Shindley has probably built the most 7 bolts around here.

Pimpin Dsmstyle · 08-31-2005

Quote:

Originally Posted by Goat Blower

Shindley has probably built the most 7 bolts around here.

Most people are smart enough not to build 7 bolts. Jakes case is a rareity, more ppl dont basically get given a "built" 7 bolt.

CDeutsch · 08-31-2005

I have a built 2.4 seven bolt with Eagle rods and Ross pistons and I still wish I just would have gone with the 6. The damn thing makes me nervous everytime I hear any odd noise. It's just not worth the risk. Mine is still running but so far it's only seen a stock clutch (12.5 quater mile with it) and an HKS twin disk. My HKS gave me problems. Besides being a bitch to install, I was never able to get it adjusted between not disengaging enough and having pedal pump up. Eventually some how I managed to snap 3 of the 6 flywheel studs.

I'm now in the process of intalling a Horse Power freaks feramic disk with an ACT 2100.

My HKS clutch may still be usable if you buy some replacement studs and/or a rebuild kit. The disks didn't seem to have any problems before the studs broke but I'm no expert just looking at it. If you want to take a risk I'll sell what I have for $100. I'm to fed up with it to give it another try.

CDeutsch · 08-31-2005

Oh and I still remember the advise someone gave me before I started my build. "When you're adding up all the money you're saving don't forget to add in the price of a new moter after yours walks."

When it comes down to it, it's a gamble. And currently the odds are much better if you just do a 6 bolt.

**JET** · 08-31-2005

Mike didn't mention anything about a soft crank to me either. He showed me a 7 bolt block and told me to look at the webbing in it. It is much thinner than a 6 bolt. The thinks it is allowing the crank to move around some. It seemed pretty viable to me. It definately is thinner than a 6 bolt.

cudvig · 08-31-2005

I say go for it jake! its cheap to do it and you got the parts at a killer price. If it walks...oh well. If it doesnt you will have a faster car for cheap. Plus how many motors actually walk anyway? not more than 50% do, and I hear if its less than a 50% chance, go for it. DO IT JAKE, YOU KNOW YOU WANNA!

PS if you need any help in your decision, give me a call!

-Colin

Matt D. · 08-31-2005

*shrug*
I know when I saw the crank and the thrust bearing side by side Mike pointed out that the crank's thrust surface was severly worn, but aside from the metal deposits from the crank on the bearing, the bearing itself was fine.

Alpine TSi · 08-31-2005

I too specifically remember Mike talking about the softer crank issue on the 2G 7 bolt. He had said that he was going to get it nitrided in an effort to prevent that damage again.

**Goat Blower** · 08-31-2005

Quote:

Originally Posted by Alpine TSi

I too specifically remember Mike talking about the softer crank issue on the 2G 7 bolt. He had said that he was going to get it nitrided in an effort to prevent that damage again.

You can polish a turd all you want, nitriding isn't going to solve the problem. If you lose the oil film between the crank and the bearing, nothing will save it.

**JET** · 08-31-2005

Yeah, but the crank isn't even supposed to touch the bearing! As far as the bearings are concerned, the crank could be aluminum and be fine.

So how is the crank touching the bearing? There could be a lack of oil (or too much pressure breaking through the oil layer) or either the crank or bearing are getting out of position.

niterydr · 08-31-2005

Quote:

Originally Posted by JET

Yeah, but the crank isn't even supposed to touch the bearing! As far as the bearings are concerned, the crank could be aluminum and be fine.

So how is the crank touching the bearing? There could be a lack of oil (or too much pressure breaking through the oil layer) or either the crank or bearing are getting out of position.

I would bet the 2900lb pressure plate pressing against the crank doesn't help. The oil layer in there is very thin, and can be seperated very easily. The point of nitrating the crank was to help prevent further wear once contact is made, but then the bearings die...
I say nerts to 7 bolts entirely, its like trying to make a ford fiesta fast, sure it can be done, sure it can be done for cheap, but why bother when there are better options?

Chris C's motor had alot $$ into the machine work (I won't disclose the amount, thats his decision). Everything was done to the block except maybe machine the block to retrofit thrust washers like the 6g72 and most honda motors... There was nothing conceiveable left to try to make it 'crankwalk proof' except switch the clutch out and give the crank a fighting chance.
I am sure it will still walk, its a 7 bolt, just hopefully at a slower pace. But thats just my $.02.

**Shane@DBPerformance** · 08-31-2005

Quote:

Originally Posted by niterydr

I say nerts to 7 bolts entirely, its like trying to make a ford fiesta fast, sure it can be done, sure it can be done for cheap, but why bother when there are better options?

$200 block, $150 in machine work including balancing, keep old front cover and oil pan, 700whp...

niterydr · 08-31-2005

Quote:

Originally Posted by ecoli

$200 block, $150 in machine work including balancing, keep old front cover and oil pan, 700whp...

Oh yeah, very budget setup indeed.
I could also put a 300shot on the stealth when its back together and make a billion hp, but whats the point? Your motor is holding very well all things consitered. How many miles do you have on it? Well since its a drag car, how many passes/dyno pulls?

**Shane@DBPerformance** · 08-31-2005

Quote:

Originally Posted by niterydr

Oh yeah, very budget setup indeed.
I could also put a 300shot on the stealth when its back together and make a billion hp, but whats the point? Your motor is holding very well all things consitered. How many miles do you have on it? Well since its a drag car, how many passes/dyno pulls?

Yea, they make a good disposable race motor. I only have a couple hundred miles on it, I have driven it on the street and even to midway this year. I wouldn't recommend anyone else to build up a 2G 7-bolt, especially on a car that sees a lot of miles. I might do a 1G 7-bolt, they don't seem to have too many problems.