New 1904 - Guidance please

[Danwvw]

As far as the valve springs. You should check to see what the spring pressure is. Good to install new ones. Stock Spring pressures will be in the 115-120-even 130 Lbs range seated. Note: Should read 1.220" not seated, thanks for catching that "modok". It's not un common to find them gone bad with lower pressures though. You may be able to tell something using a removal tool like this: Bench Mount Head Assembly tool. Bug Pack HD springs are about 130 lbs seated and go as high as 250 lbs at lift. http://bobhooversblog.blogspot.com/2007/05/valve-spring-tester.html


Inserts are good to install if the case does not already have them.
10mm stud cases like AE cases need to have 14mm inserts installed to handle 10mm studs and #3 top stud next to the flywheel needs to be deep inserted and a lower stud used to replace the shorter stud. Best to only use 10mm studs and 14mm inserts on a stock bore opening though! Later 8mm stud cases already have inserts and #3 is deep inserted and are better for opening up.
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[modok]

[Dan Ruddock]

Do not insall 14mm inserts. Use the smaller ones 1/2 inch or 12mm ones and convert to 8mm oem head studs. This is by far the best system.

Dan

[modok]

Yep, the 12mm OD vw type case savers and 8mm studs is probably best. Also ok is to use 12mm OD inserts for 10mm studs, called "timeserts"
Also good is coarse thread 1/2" case savers.
14MM is TOO BIG for anything but stock size cylinders if you ask me.

[Hustlers67]

Cool. I will measure the head studs, as I am not sure what I have in there currently, then I can better digest the posts on these points.

Just so I can get it in my head. A stroker crank ( say 76 or 78 ) will be wider than stock with anything other than the 5.325 rods. Correct? . . and being wider than stock creates the issues of:

1. making it difficult to fit the beast in the engine bay; and

2. limit my choice of exhaust? (as they are generally made at certain widths, or with only limited adjustment ability).

So, how wide is too wide when considering these two points?

I will look up some threads on rod size and pros v cons of length. But basically (as I understand it) shorter rod = more torque down low, longer rod = power band higher up the rpm range. Hopefully I havent incorrectly oversimplified that?

[modok]

IMO, if it is within .060" per side of stock width then it is close enough for all purposes. The tin will fit OK, and a good header will stretch that much no problem. Done it many a time.

In my experience cheap exhaust systems are always crooked anyhow,
Only ones that fit right are built on an engine, or cost over 400$

[GTV]

Ok, pretend a stock engine width is "zero". Using a 74mm crank in place of the stock 69mm will make each side of the engine 2.5mm (.100") wider (5mm means the piston goes up an extra 2.5mm and down an extra 2.5mm). Using 5.325 rods in place of the stock 5.394 rods will take that down to about .030" per side (very minimal, you may only need a very thin spacer for proper deck height). A 76mm crank will ad another 1mm (.040") per side, for a total of .070", and so on and so forth. Short rods, a stroker crank, and non stroker A pistons may require some piston clearancing at BDC. The longer the stroke, the more this becomes an issue.
_________________
EMPI Power Rules!

[deadkombi]

I run a 1904, engle 120, CB 1.25 rockers, 044 heads ported and polished, double valve springs, 44 idf's with 32mm vents, 9.75:1 compression, 12 pound flywheel and it goes great. It's easy to get carried away and go off on a different tangent, but if you have the parts go for it. I previously had 2276 with IDA's, definitely not the same grunt, but still fun.

[Hustlers67]

Couple of edits on the OP: "...2nd hand heads...(EDIT 37 intake and 32 exhaust ), obviously already cut for 90.5 pistons, also have the step cut out of the chamber, I assume they also have heavy single springs? EDIT CC of 51 at first measure;"

So with a 74mm crank and .05 deck - compression is bang on 9.0, and with a 78mm crank and .05 deck compression is up at 9.5

[[email protected]]

All this is correct, just pointing out that many stock engines have "excessive" deck height. So while on paper you increase the width by using the 74mm crank, the reality is it's not as much as you'd think, because you will normally be trying to achieve "optimal" deck height of .040-.070".

So for example, you tear your engine down and find it has .100" DH. On "paper" the 74mm crank and 5.325" rods increase things .030". BUT, you want to decrease deck to up compression for that cam you are putting in, and so you tighten deck to .070" instead of .100", and all of a sudden the engine is only .010" wider than stock total, .005"/side.

Really you never know until you tear it down and see what you are dealing with, because there are so many variables ie: pin heights, do you deck the case?, flycut heads? cylinder length, etc etc.

[Hustlers67]

[Danwvw]

The piston clearance is at the skirts as they will hit a stroked crank. The larger the piston bore though the less clearance is needed if any! With the 74mm crank and the short rods I had to shave about a 1/4" inch off of each side of the skirts using the 88mm bore. If I had used the 90.5 bore I may have needed very little clearance. What happens with the short rods, is the stroke of the crank pulls the piston down into the crankshaft a little.
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[modok]

92 A mahle pistons will clear a DPR raceweight 78 stroke crank with 5.3 length rods. I checked that last time the question came up.

90.5 will be slightly less room, but even so you won't have a problem with 76 stroke.

Fancy rods greatly reduce the amount of case clearancing needed. Going from stock rods to CB h-beams will allow a 74 or 76 crank to fit with almost no clearance work needed. You still must check always as crank-cases vary due to core shift. For instance you may have to clearance for #3,4 but 1,2 will clear, ect.

[stan_tichomirov]

My 1835 is narrower than stock, and that's a VW crank with counterweights, stock rods and A pistons. Using a 74mm crank in it with same rods would not make it much wider than stock.

I have a 76x94 sitting on the stand that fits together and turns with no case clearancing at all, though few spots are very close. I'm using B pistons though. With the 5.5" rods it is also very close to stock width.

Stan
_________________
Aircooled.net
Jansen Enterprise
My 1835cc build
My budget 2276 build

[Hustlers67]

Update here is the wild cam (web 163 +6) has been sold. What would be a good replacement? I am thinking either webcam 118 or 163.

I'll likely get a good set of heads and bigger carbs in the future (likely after it has been running for a while).

I think I will go with the short rods, likely H beams as it sounds these will give me the least hassle with clearance issues (or are these just better for case clearance issues not piston skirt clearance issues?). I won't go bigger than 76 crank. Would Chevy journals help with piston clearance? (I'm still trying to figure out the difference, having not physically compared the two)

Hus

[[email protected]]

You need to decide what crank and bore size, then you can pick the rods that work best. It has to match or you'll have headaches.

I prefer 5.5" rods and B pistons with 76+ cranks. This presents a problem if you want to run 88mm pistons though, because nobody makes an 88mm B piston other than Berg. You will not have this restriction for 90.5-94mm bore, because they are all available in A and B versions.

If it's 74mm stroke, use a 5.4 or 5.325" rod. But know that if you run 5.325 and 85.5 or 88mm pistons, you may have piston skirt/crank counterweight clearancing to do.
_________________
It's just advice, do whatever you want with it!

Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net

"Like" our Facebook page at
http://www.facebook.com/vwpartsaircoolednet
and get a 5% off code for use on one order for VW Parts ON OUR PARTS STORE WEBSITE, vwparts.aircooled.net

[Hustlers67]

Thanks John. It will definitely by my 90.5 (a) pistons and barrels.

I had always planned on the 74mm crank. But if the 76mm crank will present the same headaches for clearancing then I might as well go bigger. (price difference is nil or negligible).

I will get whatever rods make install easiest.

[[email protected]]

Overall the 76 is the same work as the 74. With the 76 you have a little more case work, but do not have to deal with clearancing the piston skirts like you do with the 74mm.
_________________
It's just advice, do whatever you want with it!

Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net

"Like" our Facebook page at
http://www.facebook.com/vwpartsaircoolednet
and get a 5% off code for use on one order for VW Parts ON OUR PARTS STORE WEBSITE, vwparts.aircooled.net

[Danwvw]

I am in the process of building a spare engine for my bus now. It's going to have the Web-Cam 118, Dual Dellorto 36mm Drla carbs and a 74mm crank with the I beam rods (H beam are nice but expensive!) and the 88mm thick wall slip in bottom cylinders. I wish it was going to have the 90.5's but I did not want to open up the case. The webcam 163 or the webcam 86A with 1.4 or 1.5 ratio rockers would make more power than the simple 118 with stock 1.1:1 ratio rockers but I am wanting to improve gas milage and dependability!
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[stan_tichomirov]

Depending on rods, the 76mm may not need much clearancing of the case at all -- mine spun fine but I'm grinding some spots for more clearance anyway, easy to do with a Dremel. You have to clean up the case, anyway.

Stan
_________________
Aircooled.net
Jansen Enterprise
My 1835cc build
My budget 2276 build