2838 type 4 buildup

[Wally]

It all depends what you regard as quality.

I beleive that if the chinese crank measures up to spec (by itself or by correction), the forged billet material used is of very good quality and maybe just as good or better than the original cranks.
The final heat treatment that is given to the crank gives the crank its final strength imo and determines the resulting quality of the crank.

Imo, the final heat treatment that DPR gives its welded cranks, is where their high quality (which is strength or 'bending resistance' imo) comes from mainly (apart from the whole 'dimensional specs' - chapter).

So, if you would check out a chinese forged 4340 billet for dimensional specs and have it heat treated done properly (carbonisation is what I'am talking about, not nitrating), you should have the best of both worlds.

Just my 0.02 cents

[Clatter]

Mr. Moderator,
Can we make this thread a 'Sticky'?

it's really the best one so far about setting up heads DIY style.

I searched and searched and searched for this thread one time doing a set of heads....

[Type 4 Unleashed]

Mr. Moderator,
Can we make this thread a 'Sticky'?

it's really the best one so far about setting up heads DIY style.

I searched and searched and searched for this thread one time doing a set of heads....

I have no problem with it. And will do it for as long as there are no objections. Actually I have a better Idea, I will make a sticky for Interesting Type lV Engine Builds, and a list could be made of ones people find interesting.

But for an up date, Ebjørkli a Forum member here, has purchased the heads from Getbackontrack and intends to use them on his Type lV Rallycross Engine Build So maybe Ebjørkli will update his thread with pictures of the completed heads with the 50mm Int valves and drilled and tapped for plugs, and his design for the int ports ?

[Getbackontrack]

Clatter and others: I have a homepage where there is lots of pics of type 4 stuff and machine work an so fourth.. Feel free to check it out:

The address is: GBOTaircooledperformance.dk
Regards, Jakob

P.s. Here is a few more pictures of the heads.. all tha is needed now is porting.

[Getbackontrack]

[Getbackontrack]

Some other heads I have done..

[Wally]

Very nice! I see you have no fear of berillium?
I like the first set of heads, with the smaller and angled plug location best tbh
Well done!

[Frallan]

Why do you say berillium?
There are a lot of copper bronze seats like the Johnson JM-7 that has no dangereous characteristics when machining.
Not expensive either.
Best is that it expands at almost same rate as aluminium too.

[Type 4 Unleashed]

He didn't use Berillium, he used the JM7 Bronze to make his seats.

[Wally]

Whenever I see gold coloured seats, I think they can only be berrilium-copper, but good to learn other alloys work as well

[Frallan]

Not my text. Stolen from a publication. I hope I am not being sued for this?


"The most common materials used for making valve seats for bespoke race engines are copper alloys, as mentioned in an earlier articles about copper alloys. They have excellent thermal conductivity, good wear characteristics and reasonably high strength. Copper beryllium alloys that contain small additions of beryllium are commonly chosen for race engines, with those who specialise in seats offering them as ‘A3 alloy’ or ‘A25 alloy’ seats, although beryllium-free alternatives such as Moldstar 90 and Moldstar 22 are gaining in popularity in racing. As you might conclude from the name Moldstar, such alloys (and also beryllium copper alloys) are commonly used for manufacturing mould tooling, where conductivity is also a highly desirable property."

[joosep]

any updates?
what is the hp goal for such a nice build like this?