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Piston protrusion


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My machinist/engine builder is asking me about the piston protrusion for my WD9. He has everything ready, sleeves and crank installed and pistons are ready too. I could not find any numbers on the protrusion of the piston above the block deck in the manuals. Does anyone know this or is it not that relevant?

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it is relevant, I don't know the numbers for a w9 but whoever you got your parts from should, here's a clip on a diesel but it gives you idea what is going on, people wonder why this work cost as much and takes awhile to do, this is a good example of why just a lot of attention to detail

 

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Are you sure you're not talking about the sleeve protrusion? At least on the MD's / WD-6's, there are 2 types of sleeves available, one that is almost flush (about .004" standout), and one with a standout in the .020's. The configuration of the fire ring on the head gasket depends on which sleeve you're using, either seating on top of the sleeve or just outside it.

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That was my first thought too, but than he said again he needs piston protrusion. I know about the sleeve protrusion, mine are totally flush, like flat with the block deck. But, as it is not mentioned, am I safe to assume that the pistons can just be put in without issues?

1 hour ago, Farmall pete said:

Are you sure you're not talking about the sleeve protrusion? At least on the MD's / WD-6's, there are 2 types of sleeves available, one that is almost flush (about .004" standout), and one with a standout in the .020's. The configuration of the fire ring on the head gasket depends on which sleeve you're using, either seating on top of the sleeve or just outside it.

 

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The protrusion will not change unless the counterbore was re-cut or the block decked. If the numbers cannot be found, he can mike the thickness of the head gasket and subtract whatever the piston protruding right now and find the clearance that way. Once the clearance is known, then the decision can be made whether to modify the reciprocating assembly. As an example, Ford 201 piston crown to block face is .011-.023 above the block. 

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I have a Starrett 'multi-anvil micrometer' that is really handy for measuring sleeve protrusion. Remove the anvil and it becomes a handy dandy little step mic.

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IMG_1441.JPG

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2 hours ago, Binderoid said:

The protrusion will not change unless the counterbore was re-cut or the block decked. If the numbers cannot be found, he can mike the thickness of the head gasket and subtract whatever the piston protruding right now and find the clearance that way. Once the clearance is known, then the decision can be made whether to modify the reciprocating assembly. As an example, Ford 201 piston crown to block face is .011-.023 above the block. 

Yeah thats the thing. Block is decked. The book mentions the spec of head gasket thickness when torqued down, but my guy said it wasnt what he was looking for

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58 minutes ago, Farmall Doctor said:

My big book on IH engines makes no mention of piston protrusion on any engine of that era. Only sleeves. It has every spec that you could ever ask for. 

The book has literally every spec you can ask for, but not the one my machinist wants 🤣

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Just now, Farmall 1466 said:

The book has literally every spec you can ask for, but not the one my machinist wants 🤣

Piston protrusion is a mute point as long as its not higher than the sleeve I'd be more worried about sleeve stand out 

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41 minutes ago, ksfarmdude said:

Piston protrusion is a mute point as long as its not higher than the sleeve I'd be more worried about sleeve stand out 

not finding any different # s here either.

? machinist may have a point but could be overthinking for the PARTICULAR engine ?

if block is decked then sleeve installed to spec is now x closer to the crank ,thus piston will be the same x closer to the head.

critical today and on modified/high rpm engines,maybe some extra space on the d350   ?

it will not make for hard starting on gas.

indeed both /All parts would require 5x checking on a 188/282 etc.thats why, 6 here are in line $$$$.

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2 hours ago, ksfarmdude said:

Piston protrusion is a mute point as long as its not higher than the sleeve I'd be more worried about sleeve stand out 

Its flush and since the machinist is talking about piston protrusion, I guess the piston comes out higher than sleeve

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1 hour ago, mmi said:

not finding any different # s here either.

? machinist may have a point but could be overthinking for the PARTICULAR engine ?

if block is decked then sleeve installed to spec is now x closer to the crank ,thus piston will be the same x closer to the head.

critical today and on modified/high rpm engines,maybe some extra space on the d350   ?

it will not make for hard starting on gas.

indeed both /All parts would require 5x checking on a 188/282 etc.thats why, 6 here are in line $$$$.

I don't know how much the block is decked. I certainly dont want a marriage between head and piston

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Factory specs are for "fresh" blocks, sooo if he's any kind of machinist, he can do the math, if your sleeves are flush, then, with pistons installed, he can measure the protrusion, and measure relief in the heads, by now, both heads, and blocks have been machined a cple times, if too tight, something needs machined. Or replaced.  I would say he is covering his behind if anything goes wrong, or he's way to anal. How many priors throw these things together and have no problems?  Best of what I ever found was sleeve protrusion, I don't think those pistons are domed,. I have a set in the shop, sleeves and pistons, I could look if needed

Mark

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If you are worried if the pistons will hit the head or valves, put some dum dum (silly putty) on each piston. Install head less the gasket and roll the engine over one revolution, pull head and measure thickness of each dum dum mound. Measure the thickness of the head gasket and add to your other measurement. Should give you a pretty close figure as to the clearance you have. 

What my machinist does if that spec is not listed and he has cut the deck or head is to rework the rods to drop the piston down towards the crank equal to what he removed.  His theory is it ran with that clearance before with no issues so if I give it the same clearance again it should be fine. 

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