Building a bottom end

by **Matt1975** » Sat May 05, 2012 11:44 am

Hi Guys,

I am starting to build the bottom end for my MK II and what a few pointers.

The car is being built as a weekend warrior so I'm not out for all out power but want to build a tough bottom end that could cope with up to 7500rpm occasionally at track days.

I have tracked down a set of datsun L16 rods for $60 and want to know what machining needs to be done to have them suit the standard crank.

Also I am thinking forged pistons. As the L16 rods are 133mm long I think I need a piston with a CH of 35mm.

I have heard that VW pistons are popular and good value but would love some ideas of where to start looking at suitable pistons.

Cheers,

Matt

by **SportsSedanSteve** » Sat May 05, 2012 1:21 pm

If your block is completely apart. get some verniers and measure your deck height, from the part line of the casting adjacent the front seal area to the top of the block face. Standard is 207.5mm. The rod/CH combo you mentioned should give you 206.435mm.
You need to know this before you make any decisions on rod length and compression height.

Ill assume this is a pinto build, so any nice forged flat top piston that matches your datsun rods should be fine. Try JE, Woessner, Mahle on Ebay or Burtons.

If you haven't already, get a copy of Des Hammill's" How to powertune Ford SOHC engines" his tips on short block building are worth the expense.

by **Matt1975** » Sat May 05, 2012 2:22 pm

The plan is to buy another engine and build that so i can drive the car rather than take mine out.

So I should look for a block with a minimum thickness of around 207mm or higher?

Thanks,

Matt

by **SportsSedanSteve** » Sat May 05, 2012 4:14 pm

From my recent experience, take your time and find the best block you can. Most pinto blocks will have been bored once or twice but not necessarily decked. Anyone who offers a "mint block" should be prepared to back up the claim. I wouldn't part with any cash unless the engine is disassembled and you can check the dimensions first.

by **Matt1975** » Sat May 05, 2012 4:17 pm

Thanks Steve,

What should an unmolested block go for these days?

Cheers,

Matt

by **Warren Heath** » Sat May 05, 2012 4:33 pm

Replied to your post over here Matt

http://www.classic-ford.org/cfp/tm.aspx?m=52390

Cheers
Warren

by **SportsSedanSteve** » Sat May 05, 2012 5:05 pm

I've had all my block work done by Milton's here in Adelaide, so Sam Milton knew i had a block that was on .020" oversize, full deck height and standard crank journals. To cut a long story short, i was offered $1000 sight unseen for it as the guy was desperate to get one in a hurry.

I said no deal. true story....

And Wozza has given you good advice there regarding the rods. That CP rod piston package would be great if the money is right.

by **Matt1975** » Sat May 05, 2012 5:36 pm

Crap,

I hope mine is near standard then!

Cheers

Matt

by **G Dub** » Sat May 05, 2012 5:57 pm

Matt

I have a tired Pinto here that i would part with that i am pretty sure is a standard bore. We can whip the head off and measure if you are interested

G

by **Matt1975** » Sat May 05, 2012 6:05 pm

Sounds good Gareth,

When do you have some time?

Matt

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