2838 type 4 buildup

Clatter · Post by **Clatter** » Thu Sep 03, 2009 11:58 am

Bam Bam, the Int's are installed, then Bam Bam the Exh are done,

WhooHoo! Nice!

User Name · Post by **User Name** » Thu Sep 03, 2009 12:01 pm

looking good

can you do mine

Getbackontrack · Post by **Getbackontrack** » Thu Sep 03, 2009 12:07 pm

If you ship them to Denmark I can yes.

Drop me a mail if you need any work done.. [email protected]

Regards, Jakob

bj · Post by bj » Thu Sep 03, 2009 12:13 pm

watch what you say....otherwise you'll have a bunch of heads showing up at your door step

.

what do you estimate your cost so far since you're doing the work yourself?...which most folks can't do anyhow.

bj.

Post by **Type 4 Unleashed** » Thu Sep 03, 2009 12:45 pm

Clatter wrote:
Bam Bam, the Int's are installed, then Bam Bam the Exh are done,
WhooHoo! Nice!

HEY, your not Clowning me are you...

As funny as that seems, it's exactly how I have seen it done, and the guy I have watched, has done it for over 20 years, and never had a seat come out.

Clatter · Post by **Clatter** » Thu Sep 03, 2009 12:53 pm

HEY, your not Clowning me are you...

Not at ALL!

That was exactly how the move goes,
And you could have just saved several people dropped seats...
(Including our friend here)
How many 'windowed cases' will be prevented over the course of this posting's life?

It's really cool to see the DIY head thing coming around.
After spending $2K on heads for my bus,
I'm ready to start doing a set myself.

While you hear that you can get really good power from 'proper porting' and 42 x 36....
I can't help but wonder if the really big valves help make up for the fact that it's 'home porting' not 'proper porting'.

Post by **Type 4 Unleashed** » Thu Sep 03, 2009 2:00 pm

Hi Jakob

It doesn't look like you changed the guides ? The exh still to look like the stock 9mm ones ?

Getbackontrack wrote:

Getbackontrack · Post by **Getbackontrack** » Fri Sep 04, 2009 6:00 am

Havnt changed them yet Richard.. But im going to... I will first "push" them out then port the head and then install new guides.

Jakob

Post by **Piledriver** » Fri Sep 04, 2009 11:39 am

What material did you use for the seats, and are you planning to run Ti valves?

Saw some trick keepers the other day, combination keeper and lash cap (one piece), can't recall who makes them...

Getbackontrack · Post by **Getbackontrack** » Fri Sep 04, 2009 2:45 pm

Im using alubronze JM7 for the seats... Have bought stainless steal valves, maybe titanium next time

Post by **Type 4 Unleashed** » Fri Sep 04, 2009 4:51 pm

Getbackontrack wrote:Havnt changed them yet Richard.. But im going to... I will first "push" them out then port the head and then install new guides.

Jakob

First I want to say excellent work.

Usually what is done, about 3/4 of the inside of the guide is reamed out, leaving a thin shell around the reamed area, and this collapse's as the guide is pushed out, and greatly reduces the stress on the guide hole as the guide is push out.

As for the used guides, you will see when you put in the new guides, will the valves still be concentric with the seats ?

"Edit"
For those that would attempt this: The guides are the pilots to find the center to machine the heads for the seats, then are the pilots used to install the seats, and then are the pilots used to cut the seats. But if you were to use the old guides to find the center to cut the heads for the seats, then use the old guides for the center to install the seats, then replace the used guides for new ones, then use the new guides as the pilots to cut the new seats, you will have found their are too many variables for the new guides, did you have to use over sized guides to replace the old ones ? On 914 2.0 ltr heads, your changing guides for a 9mm stemmed exh valve to a 8mm stemmed valve.

To make a long story short, you need the same pilot for all the procedures, you can't change the pilot 2/3's of the way into the procedure and expect the outcome to come out the same.

Your initial pilot for the center is from used guides.

Post by **Piledriver** » Sat Sep 05, 2009 9:34 am

Heat the heads and hit the guides with CO2, they will almost fall out. (work quickly)

LN2 works much better...

Twystd1 · Post by **Twystd1** » Sat Sep 05, 2009 12:12 pm

Richard,
Your post about the guide centering the seats and the valves was brilliant. and absolutely correct. That would of taken me 2 hours to write and I would of complicated the sheeit out of it .

Cheers,
Clayton

Getbackontrack · Post by **Getbackontrack** » Sat Sep 05, 2009 2:46 pm

Today I got the old guides out and cut the chamber to accept 105 mm pistons and barrels. I have only cut down 0,2 mm in the surface. The whole idea with the welding of the chamber was to be able to get the compression I needed without cutting down in the chamber. Now I need to grind the chambers to the desired cc.

Hey Richard, I really cant see your point. You cant deside the position of the seat weather you use an old guide or new guide for "centering" What desides the position of the seat is how the hole in the head is cut (and of which variables the hole is centered from).

If you want to be sure you would have to put in new guides before you cut the hole for the new seat. But who wants to put in new guides to cut a seat hole for thereafter pushing them out again for proper porting and be in the same position again?

Actually im thinkin about pushing in homemade guides "with no hole for the valve stem" and then put the head up in the same jig that I used for cutting the holes for the seat, center the inside seat area and cut the holes for the valve stems. That way im absolutely sure that the valve head is concentric with the seat.

Like you mention yourself there are to many variables. This way is (the way I see it) the only way to be sure its done right.

Regards, Jakob