Ok, I've finally cut the p-rods and am loading them in and adjusting the valves. Right now it's on TDC for #1. I notice that when I turn the flywheel, at some point in the rotation there is a little tightness for a few degrees, maybe a 1/4 turn or so. My jugs were opened to 96mm with new KB's and hastings rings. Could this be just the rings on one of the pistons when down low in the cylinder? I don't know how free a new motor is to turn. The crank turned smooth as silk before connecting the rods, p&c's etc.

My hands hurt from the teeth on the flywheel so any thoughts would be great.

is it called compression?

PS- next sat fun run. youre invited. no isnt an answer

uh-huh. No plugs in. Not compression. Next?

You'll have to take a no...this time. I'm on a mission to get this motor running an on the road by Xmas. baby steps...baby steps...

uh oh- i think somethings wrong then. jake says these motors hsould turn by hand...

Yeah, they should.... I know you have adjusted your own valves... and you know how that works..

=|


M

Did you notice it before tightening the valves? Did you have the rods off the crank?

(edit) never mind the second question. Did you fit the rods on the crank before installing them in the case, to check your clearances?

Yipper. This is a complete rebuild. When I closed up the case, with rods attached to the crank, with the case sideways I could freely turn the crank by the rods. The tightness I'm referring to happens without the valve train installed. It is now though...

I think there is something going on with either the pistons (they had enough skirt clearance when loaded) or the flywheel? I'm not sure what that would be. I did have the flywheel machined and I have the three shims in. and the little felt piece too.

Yes, that's looking more like what you first suspected with the rings on one of the pistons. But why I don't know. Don't see why the flywheel would cause this.

There is a point when all 4 pistons are in mid stroke twice in each revolution. The drag of the new rings on the freshly honed cyls creates a pretty good resistance.

If it is doing this right after TDC and BDC on no. 1, it's normal. Did you assemble the P/C's dry like a lot of engine builders say to do? Aids in breaking in the rings.

(of course, you shouldn't take advice from a guy who broke 2 motors in less than 5 laps at Willow Springs)

Yeah Milt, that's how it feels. My instinct tells me to just fire the puppy up and get the rings broke in. I might want to start it up prior to installing it in the car. Just to save me a few steps if it fails at that point. I don't have to worry about the cam break in since I have the ceramic cam followers.

I've just been concerned that's all.

Did you measure and set the crank endplay with the appropriate flywheel shims? Could be to little thickness in those shims causing the endplay to be near-zero, which could cause the tightness you are feeling.

Demick

Too little or too much thickness? Not sure what you mean.

Hey! Maybe it just needs to be revved to 10 grand once!



I imagine I would be to paranoid to EVER crank an engine I built.


M

Well then, where is the fun in finding out if you really can't rebuild an engine after all!!

Nothing like a 5k firecracker.

Thank you for your support. WOuld you like to buy some meat over the phone?

Would it stand to reason that if this is the problem, removal of the flywheel and shims would release any binding?

Yeah, sorry - I meant too much thickness would cause binding. And yes, if you remove the flywheel, the binding would go away - if that is the problem.

Demick

Also, what are you using for an oil pump and what are you using for a cam gear? Tolerances can be close between these and using the wrong combination can cause interference.

Demick

i also suspect too thick shim washer between crank and flywheel
the most common mistake is to just reuse the same shims
you must check your end play between the case and the flywheel
i cant tell you how many times someone has brought me a type one after an owner rebuild with the statement, "just rebuilt it ,ran well for about 5 minutes and seized up."
pull the engine , pull the flywheel , insert proper thickness washers ,instant fix.
in any case do not install this engine until you find the problem
type fours without the plugs installed should turn without a lot of effort and NO binding

good luck

jt

posting as my kid again

T1 oil pump (clearanced) Shaedek.. Web cam 73 grind and new Web cam gear.

Jake does say that clearance is very close when the T1 oil pump is used.

Still - if this was the problem, I think you would have caught it earlier. I'm sure that you probably rotated the engine by hand after the oil pump was installed and before the P&C's were installed.

Demick

Not to beat a dead horse, but if the case, crank and rods are the same as what was used before, the flywheel resurfaced and the same 3 shims and only the cam, cam gear, oil pump, cam followers and pistons/rings are new, would the crank end play even change?

A couple of things to check:

First - Crank Endplay as pointed out. Not only will too tight cause problems, but too loose can also.

Second - If the problem is only with the valve train hooked up, investigate there.

Third - Do you have sufficient deck height? Are the valves hitting the pistons?

Fourth - Is their coil bind in any of the valve springs? Watch this with dual springs.

Fifth - Is there a rocker issue? Do they rotate freely?

Sixth - Were the heads completely prepped? Enough Assembly lube?

Hope this helps.

Matt

I don't think this is anything serious [imho]. I had a change once the pistons were loaded and the heads/rockers assembled but only at certain points which leads me to beleive it is just the riesistance of the pistons. I also notice a "puffing" sound with this and I am pretty sure it's the pistons forcing air.

Jake's video only says the engine should turn easily prior to installing the pistons. This is to be sure the bearings are set correctly. Any resistance and it's time to go back in and check. I know this because it happened to me. I almost killed one of the bearings!

Perhaps you should crank the engine with the coil wire removed and check your compression before you do the start up. I plan on attaching a pressure gauge in the engine bay on start up day.

I hope this doesn't get deleted..



No thanks buddy, not gay.

If the engine doesn't spin freely- It will die a painful, short lived death!

When did you note the engine starting to get difficult to turn?? What is the end play set to??

Let me help you through this because otherwise you can become a statistic very quickly..

did you set the skirt clearance on those cylinders and pistons? Where did they come from? All are NOT created equal and some are screwed up right out of the box!

Now this is getting scary

Mine turns freely with what feels like a suction resitance at certain points. I had flywheel endplay set at the Porsche shop when we did the case and crank. I installed the flywheel before the pistons and it was very smooth.

I assumed once the pistons, cylinders and heads were installed there would be some resitance.

BTW Jake...welcome back. I hope you had a great week

It was a good trip.... Relaxing and now I'm ready to kick some serious ass and get moved into the new shop!

You will encounter some resistance, but it will not be drastic.

It is imperative when assembling an engine that between assemblies being installed to rotate the engine and get a good "feel" for what the assembly did to the way the engine turns.

Doing things this way ensures that drastic differences are caught and the finger can be pointed to the problematic area easily.

Yet again I ask about piston/skirt clearance and what pistons and cylinders you used....

If you have to be scared- do it, you only have one chance!

Hey Jake, Welcome back. I used the stock jugs overbored to 96mm with KB pistons, hastings rings. I checked the skirt clearance and it was within tolerance. I don't have my notes with me now.


As I recall the pistons went into the jugs with no resistance. I just think that it's the rings dragging in the cylinder. ??

Try it without the rockers on.

It was without the rockers on. THose move smoothly by the way.

Rings have a fair bit of drag, but it shouldn't tear your hands up. Time to tear it down and find out what's up.

Spin it as you take each part off till it spins free again.

What tolerance did you use??

As soon as you go to the Hypereuctectic pistons the stock tolerances are thrown away due to a different expansion rate.

If those pistons are too tight they will smoke skirts in 10 minutes... Been there, done that.

Who bored the cylinders for you?

They stock jugs were machined at European motorworks in Hawthorne.
KBs came from him to and were machined/balanced.

What should the clearance be on this set up?

I just finished pulling my rockers, checking the studs. and re installing them with new nuts to the proper 10 ft lbs.

When the rocker assemblies were off I checked the rotation and it was a little easier to turn [at the fan]. I think all is well. I am using hevy duty springs and they are most likely tightening things a bit.

The skirt clearance was .002". I believe this is what it should be.

Measured where on the pistons?? The KB pistons are measured differently than all others due to their skirt design..

I have seen many sets of cylinders too tight from European.. Those are not rebored German/ OEM cylinders- They are from a third world country...they are cast as 96s

I think it was 1/2" or so up from the bottom of the loaded piston. Again, these are my overbored stock cylinders.

Thats the wrong place to meadsure a KB!

The largest part of that piston is at the very bottom of the skirt. I found this out after 3 engines set at .002 1/2" up on the skirt smoked on the dyno.....

The pistons vary by batch...

So Euro Motorworks bored yours for you=- I see..

So pray tell, where do you measure the skirt clearance on KB's??

At their biggest point, which varys..
Grab a mike and start measuring.

Biggest point...meaning...the widest part of the skirt? compared to what, the ID of the top or bottom of the cylinder?
And what should the clearance be at one or both of those locations?

Aren't we talking about the clearance between the widest point on the piston to the narrowest point on the cylinder?

If the cylinder is honed correctly it will have no taper and will be round no matter where it is measured. Junk cylinders are not..

The widest point on the skirt is where to measure. Normally found toward the bottom of the skirt on a KB, but they vary.. The measurement you will see should be around 3.7785

Want you guys be glad when you can buy these parts with no guesswork and just drop them right in?????

3.778 - That is exactly what the skirts were. I even mic'd them myself when I got them back.

So if the cylinder ID is 96mm...that should give .002" right?

But you measured them at the wrong place!

Trust me, the bottom corners of those skirts are wider than the area you measured.

You cannot go on the spec from the machine shop on the cylinders! You must either use a big snap gauge, or a bore gauge to measure the ID of the cylinder....

Alright...got the P&C's off again.

Good news is that I put the flywheel on and some paper towels under the ends of the rods and the crank ass'y spins nice and smooth. I took out the 3 spacers under the flywheel and I've got .040" or so play. I'll re measure with the 2 spacers to see what I got.

Going to Rimco tomorrow to recheck and have them check the boring of the cylinders and the skirt clearance on the KB 96mm's. I'm not sure what it should be or where to check it but I"m sure they can figure it out.

What should the gap be on the piston rings?

Ok. Got them mic'd and the skirt clearance is uniform for all 4 jup&c's a little over .003". So the skirt wasn't too tight, I think it was just the rings.

Anyone know what the gap should be so I can double check that when I re-re-assemble tonight? They're Hastings. I'm thinking it's .0035" per inch of bore. Measured loaded at the bottom end of the jug. Sound right?

Oh yeah, does anyone know where to get the flywheel shims in different sizes? I'm not sure I've got enough play with the three stock ones.

What's the limit on how many times you can respond to your own thread continuously?? Is there a record?