Deck Height?

Pritchard · 02-19-2002, 05:37 PM

I am just about to ready to tear the engine down and replace the P's and C's with 96mm.

I have been playing with a compression ratio calculator and was wondering what the STOCK deck height is on an unmodified 2.0L. I will find out for myself in a couple of days, but am anxious to know before then. A measurement from y'all would sure make me happy.

By the way, I have read in a couple of places about an arrow on the piston pointing towards the flywheel. I just received my 96mm KB pistons and can't seem to find an arrow anywhere. ??? Am I missing something?

Thanks for any input.

Pritchard
'74 914 2.0L

Dave at Pelican Parts · Dave at Pelican Parts's Garage

The spreadsheet on our site has some numbers "pre-installed" in it. If I recall correctly, those seemed like pretty reasonable numbers all in all. So the deck height is probably close. Still, there is no substitute for measuring your own motor--tolerance stack-up can really mess with you on this!! Little differences in measurement can result in pretty healthy effects on compression ratio.

The stock pistons have offset wrist pins to reduce piston slap. They have to be installed in a particular orientation for the offset to work correctly, hence the arrows. I don't think the KB ones have offset wrist pins, so they don't have any arrows. Talk to your supplier to make sure.

--DD

Special K · 02-20-2002, 10:24 AM

I don't know about the KB pc's, but my new Mahles didn't have arrows either. There was a funny joggle "T" looking thing that I later realized the top part of the "T" was actually representing the flywheel, and the joggled lower part represented the crank.

yoh!!! · yoh!!!'s Garage

IIRC I measured 0.01 inch after my test installation of my KolbenSchmidt 8.0:1 (alternative to Mahle euro spec). 0.01 sounds not enough, but keep in mind the original setup was designed to use a head gasket (IIRC the head gasket alone is 0.028 inch) My KolbenSchmidt P/C's had also have a miniatur dish of 2ccm volume... hope that helped.

Patrick Koch

Pritchard · 02-21-2002, 04:25 AM

Thanks for the input. I removed all the FI hardware last night and plan to drop the engine this PM. Finally I'll get to measure and see what's up with my Deck Height. I looked again at the KB pistons and still can't find any arrow. I'll ask an expert when I get ready to ship out my cyls. to be rebored.

Pritchard

SteveStromberg · 02-21-2002, 05:31 AM

You need at least .045 deck height to alow for clearanes at running tempor the pistons will hit the head. Steve

yoh!!! · yoh!!!'s Garage

Hi,
I'm not running 0.01 DH, this was just the measurment that was taken without any shims or other modification. At this point my DH is 0.051...
I'm not sure if recomendations like " you should run at least 0.045" can stand by them self. Many other factors play a important role - a head gasket, combustion chamber volume, piston dish ... . The CR calculator is very helpful here!!!
What I'm trying to say is, I think that the original DH of a 2.0l is less than 0.045. At the same time there are other things that will have a DH "increasing" factor for a 2.0l ...
Let us know what you find in your engine!

Patrick Koch

SteveStromberg · 02-21-2002, 07:04 AM

.045 is the minmum you shuold have. Steve

Zeke · 02-21-2002, 07:13 AM

There is already a lot of infor of this subject, Use serch word "quench" here and over at STF. Steve is right, .040 is min according to engine builders that care to post. Also, bigger in the area of .065 will bring about detonation. This according to posts, not my personal info.

yoh!!! · yoh!!!'s Garage

Quote:

Originally posted by Pritchard
I have been playing with a compression ratio calculator and was wondering what the STOCK deck height is on an unmodified 2.0L. I will find out for myself in a couple of days, but am anxious to know before then. A measurement from y'all would sure make me happy.

I guess the initial question was "What is the deck height on a 2.0l Type IV" ...
According to my personal experience and measurements on my 2.0l engine (wich I have to admit is not 100% stock since I decided not to use Mahle P/C's) the DH is 0.01 without any shims. The basic shim included in a gasket kit is 0.01, which would establish a DH of 0.02. And there is also the head gasket thickness that I have mentioned before...
I completly agree with everyone, Steve S. and my Mama that 0.045 to 0.055 is a healthy range for setting the DH depending on application...
Pritchard... I'm courious to find out what you measure after taking the heads off...

Patrick Koch

Pritchard · 02-21-2002, 11:46 AM

Hey! Great info. I might not get the engine dropped tonite. I have a workshop that I must attend 'til 6PM. Then it depends on how much help I get from my 6 year old. HA!HA!

I'm glad that the topic of minimum deck height was brought up. Is this correct: DH < .045" will allow the valves to hit the piston?

I will post actual measurements when I can.

Pritchard · 02-22-2002, 06:51 PM

Got some info. The deck height on my unmodified stock 2.0 without shims is .02". With the head gasket, the deck height would be .047".

Pritchard

Ron Meier · 02-23-2002, 06:02 AM

Deck Height is the piston to head clearance. On our race engines we ran 0.032 - theory was that the piston would just touch the head at high rpm and knock any accumulated carbon from the quench area.

Piston to valve is another matter. It is generally measured by putting some clay on the piston, installing the head and rolling the engine over by hand. You then remove the head and measure the thickness of the valve impression in the clay. Isky used to recommend 0.125 @TDC. We have run as close as 0.60 on the intake and 0.80 on exhaust on race motors. Sometimes, there were slight "impressions" of the valves on the piston.

Generally, piston to valve interference is a consideration when you are cutting the head to increase CR and/or installing a high lift camshaft.

MASSIVE TYPE IV · 02-23-2002, 10:05 AM

I sometimes run .040 or less deck, I have not seen interferance problems till .030 or less were ran..My norm is .040

Tod How · 04-16-2013, 02:29 PM

I just measured the deck height on my 2.0L type IV (without any shims). I measure with a dial indicator and using feeler gauges under my straight edge. Both times I got .05 The heads have been fly-cut and I will not be using a head gasket. Anyone hear of not having to use a shim on the type IV? The pistons and cylinders are new AA.