# JH Head......



## vwcarnut (Mar 28, 2003)

Man do I feel like a newbie, but what are the easiest ways to tell a JH head from the rest of the batch if it is off the engine & sitting by itself?What are the 83-84 casting #s? I have the opportunity to buy a head for a good price,however I would like to be sure I am getting what the individual claims it is.........







& thanks


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## deer_eggs (Oct 4, 2006)

*Re: JH Head...... (vwcarnut)*

The JH heads have a coolant flange between the #3 and #4 cylinders (approx), while the older ones have a coolant flange closer to the #1 and #2 cylinders - i think it's also on an angle.


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## MkIIRoc (Feb 20, 2005)

^QFT The JH water outlet on the front is also a 2 bolt, the older style is a 3(?) bolt, but def. not a 2 bolt.
Between a JH and a newer one, the JH will have 5 bearing caps, and flat headed valves.


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## ABA Scirocco (May 30, 2001)

*Re: JH Head...... (deer_eggs)*


_Quote, originally posted by *deer_eggs* »_The JH heads have a coolant flange between the #3 and #4 cylinders (approx), while the older ones have a coolant flange closer to the #1 and #2 cylinders - i think it's also on an angle.

This is a feature common to all 1.8L, not just JH heads. What distinguishes the JH head from all other 1.8L head is that it has solid lifters and a distinguishing feature of solid lifter heads is that they have 5 bearing caps, all other 1.8L heads have 4 caps.


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## FissionMailed (May 26, 2006)

*Re: JH Head...... (ABA Scirocco)*

The JH is a hydraulic lifter head, isn't it? Or, at least, some of them were hydraulic...


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## ABA Scirocco (May 30, 2001)

*Re: JH Head...... (FissionMailed)*


_Quote, originally posted by *FissionMailed* »_The JH is a hydraulic lifter head, isn't it? Or, at least, some of them were hydraulic...

Right sort of. Technically, JH refers to the block not the head and during it's production run from 83-87, it has been topped with at least 4 different heads, one of which had hydraulic lifters. From 83-86, when the VAST majority of these blocks were produced, they were topped with a solid lifter head, these heads (3 variants) are what's commonly refered to as "the JH head". Only in 87 did the JH block get a hydraulic lifter head, relatively few of these engines were produced and these heads are generally ignored as they are identical to the other hydraulic lifter big valve heads produced up to that date.
EDIT: I'm not 100% sure I got the dates right, I think the JH may have been produced up to 88, I'll have double check my Bentley. In any event, it's only the final year of production that got the hydraulic lifters.




_Modified by ABA Scirocco at 7:38 AM 5-19-2007_


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## Campbell (Nov 9, 2004)

another key feature of the "JH" head besides the solid lifters is the large intake valve. They have the 40 mm intake versus the standard head 38 mm intake. This is what made a "GTI" head. There are a lot of 38 mm heads out there - all hydraulic. Problem is the Golf GTI, Jetta GLI large intake heads were hydraulic also, the large intake is what you want whether solid or hydraulic so measure that. Each type of head used a different oil pump. good luck


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## ABA Scirocco (May 30, 2001)

*Re: (Campbell)*


_Quote, originally posted by *Campbell* »_Each type of head used a different oil pump. good luck 

True but with a solid lifter head, you can use either type but with a hydraulic lifter head, the higher capacity pump is recommended.


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## deer_eggs (Oct 4, 2006)

*Re: (ABA Scirocco)*


_Quote, originally posted by *ABA Scirocco* »_
True but with a solid lifter head, you can use either type but with a hydraulic lifter head, the higher capacity pump is recommended.

I was told by Techtonics Tuning that the bigger oil pump (36mm) was not reccomended for solid lifter heads... only the smaller (30mm) pump should be used - I'm not sure exactly why. 
There's some very good info in this thread, I'm learning a lot! http://****************.com/smile/emthup.gif


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## ABA Scirocco (May 30, 2001)

*Re: (deer_eggs)*

I've heard that too, it never made any sense to me as all of the oil pumps have pressure relief valves so any excess capacity is released through that meaning exactly the same amount of oil is going to be delivered to the head regardless of which pump is used.
FWIW, I put well over 100,000 kms on my ABA/JH with the 36mm oil pump and not even a hint of any oil pump related problems.


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## vwcarnut (Mar 28, 2003)

*Re: JH Head...... (vwcarnut)*

Great info! It appears that the head is in fact a GTI solid lifter so I bought it for my 1.8/2.0l aba engine....Keep the info coming tho as I am going to be asking a bunch of more dumb questions as I go thru this.







Any way to easily lower the compression on this swap as the stock compression is around 10.3 to 1? I would like to get around 9 or 9.5 to 1............


_Modified by vwcarnut at 1:15 PM 5-19-2007_


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## vwcarnut (Mar 28, 2003)

*Re: JH Head...... (vwcarnut)*

Either a way to lower the compression easily or an easy way to wire a knock box in a car that never had one............ I think that the knock box would be a better idea after reading, only because when cash flow is good .......... more fun . LMK what you guys think either way & thanks again.


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## snowfox (Apr 4, 2002)

*Re: JH Head...... (vwcarnut)*

I have 160k+ miles on a c-flow/ABA (hydraulic head, though) with the compression at 10.3:1 and no knock box pushing my Fox wagon around. Run 91 octane and call it good. No way would I consider taking the compression down to 9 or 9.5...


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## kamzcab86 (Feb 14, 2002)

*Re: JH Head...... (ABA Scirocco)*

JH with solid lifters: up to '87.
JH with hydraulic lifters: '88-'89.


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## switch1685 (Jun 2, 2004)

*Re: JH Head...... (kamzcab86)*

Sorry if this is a dumb question, but do you need to make any modifications to run a JH head instead of a hydraulic one? Also, how much HP do you really gain, and how much do they go for?


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## ABA Scirocco (May 30, 2001)

*Re: JH Head...... (switch1685)*

No modifications needed. There's no HP gain, not at a stock level of perfomance anyways. What you gain are options. There are many more cam options available for the solid lifters, the JH head can be ported more aggressively, the valve train can sustain higher rpm than a hydro valve train.


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## switch1685 (Jun 2, 2004)

*Re: JH Head...... (ABA Scirocco)*

Interesting... I've heard you can run more aggressive cams with the JH head and still have them be fairly streetable. Is that true? I have also noticed that cams for the solid lifters are more expensive than hydraulic ones, why is that? If I were just planning on doing an ABA block swap, bigger cam, new exhaust and intake, rebuilt valve train, and maybe a port and polish of the head, would a JH head make any difference? Thanks for the help!


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