Replacements ?: Cylinder Heads and Pistons/Cylinders

[abl1111]

Going to be installing new cylinder heads in my stock, '79 FI. I have had issues with Brazilian heads and do not want an issue again. What heads do you recommend ?

Pistons and cylinders - stock 85.5. I was thinking Mahle. They make a few different types within the 85.5 model. Any opinions on which are better ?

Thanks

[abl1111]

?

[helowrench]

Location?

[helowrench]

Also,
Do you intend to keep this engine stock?

[Marc]

Why new heads? Are the existing ones beyond repair? L-Jet heads have smaller valves than carb'ed or D-Jet heads (33x30 vs 35.5x32) with 9mm exhaust valve stems (most other heads have 8mm). The LH head needs to have a threaded boss for the head temp sending unit - also found on D-Jet heads but not on the carb'ed ones. So, it's rather difficult to find exact replacement heads - the D-jet (Type III) are often substituted.

With a stock stroke the shorter skirts of the "forged" pistons aren't needed for clearance, and the standard "cast" pistons are of adequate strength. 211 198 069 are dished and yield a C.R. of ~7.4:1; 311 198 069 flat-tops yield ~7.64:1 (with typical chamber CCs and piston deck height).

[abl1111]

Thank you for the responses.

Stock - Yes
Located - New York

The 'old' cylinder heads, Brazilian, with less than 3500 miles had two valve guides, both intakes, that came undone, banging around. It was recommended that I do not re-use them. I have not heard anything great about any FI, 1600 DP heads. Trying to source the best manufacturer. Or, I might be able to buy rebuildable OE German heads.

As for the pistons and cylinders, I think Mahle is the best bet. I'd rather go for over kill, so correct me if I'm wrong, would forged be better or completely unnecessary. Do both cast and forged come flat or dished ?

[helowrench]

AA pistons/cylinders have been proven for Stock to Mid level performance over and over.
As long as you are not adding boost or nitrous, the AA will be perfectly fine.
Mahle/Cima is technically a better item, but if you are staying with the FI system, they would be an unnecessary $150 which would allow you to change cam/lifters while the engine is out and apart.
End result would be a cooler running, more efficient engine, that yields both more hp and more MPG.
As far as the heads go, you have many many choices.

Probably the first thing you should do is head on over to aircooled.net and read through the technical articles.
John does a good job of breaking the knowledge down into chunks by topic.
John covers what minor upgrades can be done with the stock FI system, allowing you to have a bit more engine, all while retaining what you already have.

[sideshow]

A cast piston for your application is better in 99% of the time.

[abl1111]

Can you elaborate as to why cast vs forged would be better ?

[sideshow]

It is all about application; and that a cast piston require less clearances, makes less noise, and will likely last longer.

[crvc]

The AA pistons/cylinders worked for me. But the pins were severely tight. I was trying to put one in, tapped too hard with a hammer and busted the piston, then let the cylinder fall on the concrete floor where it broke. I called the company and they were willing to send me one piston/cylinder and even suggested I put the pin in the freezer for a while before trying to insert it into the piston. This was over a year ago and still running okay.

kevin