I am getting my 1835 heads rebuilt. I spoke to couple of people about the advantages of having bigger valves put in. As you expect, nearly everyone had a different opinion. One said its not recommended because most likely they don't get the seats right. One said there is no point unless you go with a mild/wild cam. One said no point at all, he is running 2.1 stroker using standard valves and he loves it. But he also mentioned something quite interesting. He reckons that the drag guys are now experementing with smaller valves not bigger ones. Apparentley smaller ones create better airflow (kind of a compressed airflow aka turbo) and create more power. I thought that is quite a different view from the norm
Raf
BizarreModeratorThe artist formerly known as blue74l
this is what you put down as experience and what seperates the great from the dog engine builders.
An example is the 1300 twin port motor that came out in later years.
It had small valve heads and yes they flow really sweet. I had a drive of one the other day and you wouldnt pick it as a 1300!
As for your motor - what cam, carbs and exhaust are you running.
My opinion ( :o ) is if you are running heater boxes stay with stock valve heads
You can get 40/35 put in an 040 head and that will flow better but you have to be able to pull the gas with a bigger cam and you have to feed it with carbs ( Webers - not the kads ) and you have to be able to exhaust properly ( not heater boxes and pea shooters )
What sort of heads are you looking at?? and what size valves are you thinking of???
Yes you can run a stroker with stock heads BUT you could make HEAPS more top end power with an expensive set of decent heads. You can still have HEAPS of torque and FUN with the stockers though
Its the standard cam. I do have a mild one but don't want to split the case at this stage. I will be running 40IDFs or 40DRLAs. And I will be running heater boxes. How does heater boxes affect it compared to J pipes?
Raf
BizarreModeratorThe artist formerly known as blue74l
First they are stock diameter and "can" be restrictive in flow.
Some people (Berg for example) make a larger dia heater box. They are expensive though.
Secondly the heater box retains heat and can lead to cracked heads by not being able to disapate the heat.
This is why J tubes were invented.
Nice cheap solution to the problem of bib motors and exhausts
Larger valves in a stock head won't give you much without extensive welding and porting. with stock cam you'll still end up with less power throughout the rev range. Having the valve guides topped, running heavy-duty or dual springs and fitting high-lift rockers would be a far better proposition at this stage. When you're ready for the larger valves, ie; when you're running more than 1900cc and/or your cam produces peak power above 5000rpm, you really should consider the 044s as a starting point.
You might also find the carbs mentioned won't work too well with your combo.
Craig Torrens6 times Australian, 7 times State Hillclimb Class Champion
Well I have got to admit I am new to vw motors but have built many drag V8s and it was more important to get everything to match. Basically what craig was getting at I think. Bigger is not always better.
Yep - NOT that i know but from the info i have scavenged that would be my guess.
You "might" consider 40/35's instead of 35/32's (stock) in some 040 (stock) heads but i dunno if i would. Extra money and stuff.
You said you dont want to split the case as it is a standard cam there.
A stock cam will accept 1.4 ratios and this is good. Dunno if i would waste the money on 1.25's. Ratios are not cheap.
The cheapest i have seen is like $400 a set.
By the way - what sort of crank have you got in there. If it is a standard cam is it a stock crank.
Dont want to wake the engine up too much if it isnt a counter weighted one.
Depends what you're using the motor really. If it's going to be a daily driver, you don't want everything dig. Particularly on a street engine where figures really mean nothing. Ultimately, it's important to match it with everything your motor currently has, to compliment the other parts and therefore make the best sort of power for the job. With what you mention you already have, I'd say stick with stock valves. They'll do the job beautifully and you'll have nice smooth power, which is most important for daily use. Perhaps some 1:1 ratio rockers?!?!
Yep, it will be a daily driver. It has stock crank as far as I know. I know nothing about ratio rockers, why is 1:25 bad or not worth it? Being that it will be an 1835 daily driver (city mainly not even highways) with twin 40 DRLAs and stock everything, what ratios would work with it?
BizarreModeratorThe artist formerly known as blue74l
You are not wrong Barry, I have a big hole in my back pocket which is bound to get bigger, bought the engine for $1k to discover it was stuffed. New P&Cs cost me $600, 6v 200mm flywheel and clutch $450, reco. heads $300, dual 40 DRLAs $600. So nearly $3k so far and still have to sort out ratios & exhaust :jesus
BizarreModeratorThe artist formerly known as blue74l
karmannghia60 wrote:You are not wrong Barry, I have a big hole in my back pocket which is bound to get bigger, bought the engine for $1k to discover it was stuffed. New P&Cs cost me $600, 6v 200mm flywheel and clutch $450, reco. heads $300, dual 40 DRLAs $600. So nearly $3k so far and still have to sort out ratios & exhaust :jesus
What a bummer 🙁 That's why 10 years ago I decided to always by new.
With valve lift, it is proportionate to valve size. Lift should be a % of the valve diameter. If you go over this % then you are openning the valve to far and you are gaining no benefit. With standard 040 valves 1.4 ratio rockers will open the valve more than what is needed. The problem you will then have is that you are putting additional strain on your pushrods! Then you will spend money on Chrom Moly pushrods all to fix a problem that should not of occured !
One more question, if I decide to go the full hog (mild cam, balanced crank, ratio rockers, twin 40DRLAs or 40IDFs, 009 dizzy), what valve size would be better in this case? 40x32 or 40x35.5?
BizarreModeratorThe artist formerly known as blue74l
"Install Ratio Rocker Arms: 1-2 hour installation time. If you can adjust valves, you can install these. They MUST be used with shorter pushrods. We recommend 1.4 rockers (which DO work on stock engines). 1.25 rockers give you almost no gain for your work; waste of effort. 1.25's work well with some high performance cam shafts but you have to know what you're doing! 1.4's will really wake up a stock engine, especially if it's a dual port, and if you have additional carburetion. Replace your valve cover gaskets at the same time. If you have problems with leaky valve covers, make sure that you use genuine VW valve covers and bails." - from John C at AC.net
Craig - why do people (not just ACnet) recomend putting 1.4's on a stocker as a hot up??
It certainly be recommended to me with my cam and my stock heads????
Raf
There is no simple answer. You will get many. Hot Rod Matt has 40/35 040's in his 1776 and i think you will find 2 Guns will as well. Both these were CBB based motors.
I have 35/32.
I think Jak was/is 040 and 40/35
Jak was definitely running J pipes and i dont
Dont know about matt???
On the last dyno day we were all in the mid 60's.
Matt runs Kads.
I run IDF's
IF you have money then i think i would go for 040 and 40/35
Last question, promise. I can get the heads I have now reco (ie replace guides) for between $200 & $240. While I can get full reco ones from the US (I will be there next week) including new 40x32 valves, new 3 angle seats and new silicon bronze valve guides for about $300. The later option looks better value, what do you think?
Thanks a lot
There is no simple answer. You will get many. Hot Rod Matt has 40/35 040's in his 1776 and i think you will find 2 Guns will as well. Both these were CBB based motors.
My heads were done for the bigger valves by someone else some time ago.
2guns uses standard valve sizes but they have been reshaped and swirl finished around the stem and the back surface. The porting job on his heads is awesome and flows beautifully.
BizarreModeratorThe artist formerly known as blue74l
They also sound like 041's which were big inlet and stock exhaust.
The head casting was different and didnt cool as well.
Cant get the 35 exhaust in these???
Either way that is an awsome price.
Can hardly buy new stock heads in US $ for $300
If they were 040 castings i would buy them
Futue te ipsum!!!
Craig Torrens6 times Australian, 7 times State Hillclimb Class Champion
blue74l wrote:"Install Ratio Rocker Arms: 1-2 hour installation time. If you can adjust valves, you can install these. They MUST be used with shorter pushrods. We recommend 1.4 rockers (which DO work on stock engines). 1.25 rockers give you almost no gain for your work; waste of effort. 1.25's work well with some high performance cam shafts but you have to know what you're doing! 1.4's will really wake up a stock engine, especially if it's a dual port, and if you have additional carburetion. Replace your valve cover gaskets at the same time. If you have problems with leaky valve covers, make sure that you use genuine VW valve covers and bails." - from John C at AC.net
Craig - why do people (not just ACnet) recomend putting 1.4's on a stocker as a hot up??
It certainly be recommended to me with my cam and my stock heads????
Do it and have an experienced answer 😉
I guess you will read so many varied opinions, and each to their own in which ones you want to beleive .:thumb
I remember reading about a fantastic "black box" , that would do wonders to my holden, written by Peter Brock, it was called a "polariser" !!😀😀
Barry I guess we can agree to disagree about using 1.4 ratio's on a stock cam/stock head combo.
I would ask, for my learning benefit 😀 what do you think/read should be the overall lift for a standard size valve. What lift would be to much ???
Also what is the increased valve spring load ?
Do you loose HP with this added load ?
How much shorter do the Pushrods need to be ?
Do you need to fit chromoly pushrods?
what will this cost ?
What is the added HP to the stock motor ?
I have read that the ratio rockers will increase a standard 1600 tp motor's Hp by 2-3hp, this same book also said you can get over 100hp from a 1600 ??!!
Not saying your wrong Barry, I just dont' see the benefit on this combo, but maybe you can clarify for me the above points.
:thumb
Blab as much as you like Barry, I am getting a lot out of it. Looks like I will go for the US heads. I just have to struggle with airport security & customs
BizarreModeratorThe artist formerly known as blue74l
That's cool Barry, I was not looking for and arguement, just some info I may not have been exposed too.:thumb
Piston size will always be a debate because it is influenced by crank stroke.
But the opening of a valve will always reach a point where it is no use opening it any more. If you want more benefits you then need to go a larger valve, you can then increase the lift to the max advantage of this valve and so on, you then move onto multivalve heads etc.
karmannghia60 wrote:Last question, promise. I can get the heads I have now reco (ie replace guides) for between $200 & $240. While I can get full reco ones from the US (I will be there next week) including new 40x32 valves, new 3 angle seats and new silicon bronze valve guides for about $300. The later option looks better value, what do you think?
Thanks a lot
This price is of each bare head (no springs, no valves, no guides nor seats) + delivery. I am getting the PAIR complete ready to bolt one for $300 delivered
"Proper length ensures that at "half lift" the rocker arm is pushing the valve straight in. If "rocker geometry" is off, the valve will be pushed up or down, and this results in valve guide wear. Get it right! This is one of the most intricate parts of engine building. Cutting and assembling your pushrods is a real pain (I hate it). For assembly purposes, you need an adjustable pushrod to have any hope of achieving optimal rocker geometry. You use the adjustable pushrod to cut your chromoly pushrods to the desired length then tap the ends in using a hammer and two old lifters (to keep from screwing up the ends of the pushrods). Sometimes, depending on the pushrod brand, they have to be drilled out to match the pushrod ends! Sound arduous? Well it is, but guess what!? Aircooled.Net offers the service of cutting and assembling your pushrods, saving you the do-it-yourself grief!" - from ACnet
Futue te ipsum!!!
Craig Torrens6 times Australian, 7 times State Hillclimb Class Champion
