M70 Rebuild Thread.

**dragon850** · 09-10-2015, 12:34 PM

Originally Posted by NevadaMike

Have you considered CO2 (Dry Ice) blasting? You should be able to find a place in the Bay Area. I've also found that regular old paint thinner (not lacquer thinner) does a pretty good job dissolving that carbon. Be sure to get the deodorized kind, you'll thank me.

Ordered gasket remover, alot of guys use it to melt off carbon...

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Originally Posted by fursideup

That will be fun! I better clean off the pool table so you have a place to lay all those pistons, caps and bearings out.

Thinking about it.. Don't want to go overboard with this rebuild, probably would make sense to open one up and take a look at the main bearings...
Wolf has a point on taking the pistons out to soak them outside the block.

**fursideup** · 09-10-2015, 12:35 PM

Originally Posted by bmw528e11

When you planning to do that? I might swing by on Saturday morning?

It wont be this Saturday - I will let you know Dimitri

**dragon850** · 09-10-2015, 12:41 PM

Originally Posted by bmw528e11

When you planning to do that? I might swing by on Saturday morning?

I think myself and Jon are busy this weekend, I will text you when we get ready to do it.
Time is always the big issue...

**Timm** · 09-10-2015, 03:36 PM

Originally Posted by wokke

And yes Tim, the bolts are stretch bolts and I highly recommend to use quality bolts and not some super cheap "on sale" crap.

Thanks Wolf, the reason I asked was due to the discussion on using studs - where stretch bolts are used you can't just swap over to studs as the correct compression of the head gasket relies on the stretch of the head bolts.......

**garylafortuna** · 09-10-2015, 03:42 PM

Originally Posted by B10 BITURBO

I really recommend using studs,, thats my opinion,, it is an aluminum block,, i think can get studs that are almost the same dimension,, 10x110 is oem bolts

here is a comparison,,,

http://www.summitracing.com/int/part...0-1b/overview/

The use of studs is a very wise suggestion. In racing where engines are taken down more frequently, studs are used almost exclusively. A much safer and more secure way to attach cylinder heads, and will prevent metal fatigue in the aluminum block. If you are a strong believer in overkill, then ARPs chrome moly connecting rod bolts are worth considering as well. Don't you think Timm, if you torque the head bolts (or studs) by slow degrees in correct sequence,
the gaskets will be compressed correctly? What do you think Wolf?

**dragon850** · 09-10-2015, 04:43 PM

Originally Posted by garylafortuna

The use of studs is a very wise suggestion. In racing where engines are taken down more frequently, studs are used almost exclusively. A much safer and more secure way to attach cylinder heads, and will prevent metal fatigue in the aluminum block. If you are a strong believer in overkill, then ARPs chrome moly connecting rod bolts are worth considering as well. Don't you think Timm, if you torque the head bolts (or studs) by slow degrees in correct sequence,
the gaskets will be compressed correctly? What do you think Wolf?

Why fix something that's not broken, this is the first time I heard someone saying the threads gave up on an M70 block, actually it was M73. Wolf did say he did 10 engines and NONE had a problem with threads giving up, several had broken head bolts, but those were original bolts I believe. Plus ARP studs are $10 bucks EA. That's $280 just for the bolts. My Victor Reinz head bolts were only $48.

**cartoonz** · 09-10-2015, 05:05 PM

Do what Wolf says above and pull the pistons. At this point, you ought to pull everything and have the block hot tanked - that's the best way to clean everything off.
Also make damned sure you keep track of exactly where everything came from and in which direction

Forget about head studs, make sure your threads are clean and there is nothing in the holes - then use quality bolts.

**dragon850** · 09-10-2015, 10:01 PM

Head gaskets and head bolts just arrived.

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**Mikekugel** · 09-10-2015, 10:23 PM

Originally Posted by dragon850

Head gaskets and head bolts just arrived.

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Great, Now just don't get in a hurry, and as Cartoonz said keep meticulous track of everything, especially cam followers.

**dragon850** · 09-10-2015, 10:34 PM

Originally Posted by Mikekugel

Great, Now just don't get in a hurry, and as Cartoonz said keep meticulous track of everything, especially cam followers.

Will do... I thought rocker arms are interchangeable, same design?

**wokke** · 09-11-2015, 01:42 AM

Originally Posted by dragon850

....
I will remove Cylinders for soaking and look at the bearings.

Better remove the pistons. If you remove the cylinders the block is destroyed.

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BTW, have you ever considered taking the chance for a M73 upgrade? Used M73 should be dirt cheap in the US and it's really worth it.
All you actually need is the M73 block incl. it's internals. You can even keep your M70 heads and probably end up at about 340HP due to the slightly hooter cam shafts of the M70.
And if you go for Schrick cams and a customized engine mapping CSi power is possible.

**bmw528e11** · 09-11-2015, 01:57 AM

Unfortunately Dragon850 already bought an M70 (i think)..
$700 in LA and $660 in Texas..

Wokke, just M73 block with internals, but keeping the exterior parts from M70? what about pcv system, valve covers, and intakes? and what you meant about 'slightly hooter cams'?

**wokke** · 09-11-2015, 02:07 AM

everything from the headgasket upwards can be used from the M70. And some bits and pieces HAVE to be used from the M70 like timing chain cover and flywheel.

M70B54 picture thread (lots of pictures)

Cam data comparison

**Fatandre** · 09-11-2015, 03:26 AM

Originally Posted by wokke

everything from the headgasket upwards can be used from the M70. And some bits and pieces HAVE to be used from the M70 like timing chain cover and flywheel. M70B54 picture thread (lots of pictures)

Cam data comparison

Wolf. Dragon has a supercharger so I guess a m70 is better

**wokke** · 09-11-2015, 04:01 AM

Originally Posted by Fatandre

Wolf. Dragon has a supercharger so I guess a m70 is better

Oops, I didn't realitze that. I fully agree, M70 is the way to go for FI.

**cartoonz** · 09-11-2015, 10:59 AM

I'm all for anything "slightly hooter"....

**dragon850** · 09-17-2015, 11:04 PM

Got almost everything parts wise, now where do I find time to install all of this?!

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**dragon850** · 09-20-2015, 03:37 PM

Heads are off to the local machine shop for cleaning, resurfacing, valve job, new valve guides and seals.

**adamnur** · 09-20-2015, 05:29 PM

Subscribed.

**thelongeride** · 09-21-2015, 08:35 PM

I am planning to tackle the same project. Should be good experience. I will also be ready if my supercharger stresses my motor. I will follow your thread.

**dragon850** · 09-27-2015, 10:45 PM

Rockers, basis and hydraulic lifters after ultrasonic cleaning. The lifters will not be reused, I purchased a whole new set. One of the rockers has a wavy pattern on it and will be replaced.

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Heads are still in the shop.