Big Valves in a waterboxer head

[Dougs Auto]

Has anyone installed larger valves in a waterboxer head> Not just thought about or think it can be done but really have done it?
also what is the correct installed valve height in a wbx head everything I have found says 1.500 Mine are 1.400 bone stock heads what is correct./

Thanks Doug

[34plus2]

Has anyone installed larger valves in a waterboxer head> Not just thought about or think it can be done but really have done it?
also what is the correct installed valve height in a wbx head everything I have found says 1.500 Mine are 1.400 bone stock heads what is correct./

Thanks Doug

Yes, i did it!

Citroen CX 2.5 Diesel Valves (42.7 x 37.5) on stock valve seats. About the same Lengh.
I got them from an aftermarket distributor (TRW)

[fastback]

i have also installed 43/38 titanium in my heads .new seats though

34+2 do you have a part number on these valves?

[buildabiggerboxer]

Wassers are tight on spring deck, as you say 1.4", you need more if you require high lift cams and ratio rockers, you can sink either the valve into the stock seats or use narrower seats if going turbo, increasing the chamber volume obviously, to keep the compression up you will need longer valves to gain installed height. also a god time to loose the 9mm exhaust valve stems with new 8mm ex' guides.
be carefull with retainers, T1 aftermarket ones loose to much installed height, but i use the stock AMC ones at over 7000 rpm just fine.

[Dougs Auto]

I am using chevrolet 5.3 v8 intake valves cut down to 42mm 8mm stem. they are about 1mm longer length than stock that along with sinking the new valve seats sunk down another 1mm should help with the installed spring height. how much meat is there under the valve spring pockets 1-2mm?? exhaust are cut down chevrolet 350 1.50 diameter to 37mm installed height is about the same as the intake stems. above the keepers will need to be trimmed down some.stem size is .356 that comes from a stock size of .341 and .015 oversize stems I am going to reamed the valve guides ou tfrom the stock vw.354 to the chevrolet size.356 the cam lift is .327 with 1.25 rockers should be .408 valve lift.

Doug

[34plus2]

i have also installed 43/38 titanium in my heads .new seats though

34+2 do you have a part number on these valves?

i did`t find the trw part list.

i found these

http://fautoparts.com/parts-valves-part ... auto-parts

Intake valves from Mahle are 42.5 and Exhaust Valves 35mm.

I am pretty sure i had 37.5 mm Exhaust Valves from a Citroen on my WBX. Maybe you have to look at a different Citroen Diesel.

[pocketrocket]

Here are a couple of pics of the cut away OEM VW head. I have reworked the port runner some, then cut the junk head up so I can see wall thickness and the amount I can take off the spring pocket for k-800 springs. With stock springs 1mm is about the limit if the bump is removed maybe 2mm if the bump is left in. The other pic. is of the valve seat cut away. I also have a pic. of a head I have worked on for a aircooled 4"cylinders with water cooled heads, with ti 42 x 38 mm valves.

DSC08567 (Small).JPG

Rocky

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DSC08570 (Small).JPG

[fastback]

good info here.
keep the tips on other valve alternatives coming

[buildabiggerboxer]

good to have rocky working with water at last.

[tencentlife]

good to have rocky working with water at last.

At last? You must have been living under a rock, the dude's been peggin' the wbx meter for years.

[buildabiggerboxer]

I know that, dont you guys ever joke about?

[tencentlife]

No. Never. This hobby is deadly serious, joking around can get someone a broken fingernail or something.

[Piledriver]

No. Never. This hobby is deadly serious, joking around can get someone a broken fingernail or something.

...The Horror....

[Dougs Auto]

HI All

Got the bigger valve seats and valves installed in the heads. removed the excess material below the seats blended in the ports just below the valves. left the intake and exhaust valve port size alone. also swapped oput the cam from 2252 to a 2254 went from 100 HP to 120 @4200 rpm. That was not good enough. Calculating in the intake valve timing with the new cam dropped my dynamic compression ratio down to 8.2 my static calculated ratio is 9.5 pulled the cylinders out an turned off .040 off the top my compression ratio now should be 10.5 static and 9.5 dynamic along with an exhaust change from 1.5 pipes to a 1.625 now I am at 142 HP@4200 and 150 @5000 since I am using 101.6 inch chevrolet pistons my deck height was .165 I was able to machine off the .040 off the top of the cylinders. doing so I was not able to use the stock rubber perimeter head gaskets since my clearance went down from .125 to .085 For a temporrary solution I used a bead of silicone since the engine is just in the testing stages I did not want to mill off the top of the block just yet. Some may be thinking what no quench of squish aera. there a re a lot of engines that were built without a quench aera that run just fine. for example 426 Chrysler hemi, no quench.
A gain of 20 HP over the stock heads and with a cam change.and another 22 with a compression ratio change. was also Running dual webber idf 44s switched over to a single 44 with a custom intake plenum with the stock boxer intake pipes and lost no HP. did gain driveability the engine ran much better a low rpms,also got rid of the intake reversion no more fuel spraying out the carbs a high rpm. AFR was a little rich a part throttle and lean a high rpm new emulsion tubes and jets arrived yesterday will be doing more dyno testing tomorrow. why only 4200 rpm's. this engine is being built for continuous medium rpm High load operation.

Just my uneducated findings

Dougs Auto

[busboy1303]

Some impressive figures! What is the engine in?