Have 73 1.7 bought in pieces. Engine has been rebuilt and ‘souped up’ however I don’t know what internals were installed. New crank, cam, pistons, rods and heads. but I don’t know which ones. Weber 44 idf carbs. Never had oil in it and been stored unstarted for 10 yrs in climate control. I’ve added oil by slow dripping 2 quarts through the oil pressure sensor hole. Oil dripped out of the rockers so I’m pretty sure it got some oil as pre lube. It’s on a home built test stand with the transmission mounted with the starter.

I’m trying to turn the engine over by hand with the plugs out. Have squirted oil in each plug hole. I’m able to turn the engine by hand about 45 degrees and it gets harder to spin so can’t go any further. Would it be a good idea to pull the rocker arms to see if the builder installed some wild cam without checking valve/piston clearance? It doesn’t feel like internals are hitting each other but who knows? Would hate to pull the heads if I don’t have to. Any thoughts before I break something?

Rob Roe
Newbie

Cheap Amazon emdoscope connected to you phone should allow you to see what is happening in the chaber via the spark plug hole I would think. Mine has a 45 degree mirror attachment to view on the side.

With what you just described, I can’t see any scenario where I wouldn’t be taking it apart.

When you say 'by hand', what do you mean? A breaker bar or pulling on the fan?

If you are unable to get a full rotation of the crank somewhat easily, start dis assembling her. Or try the starter to spin it over. If you are able to get her to spin, connect an oil pressure gauge and see if she will pump up some oil pressure.

Might get lucky

Yup. At leat pull the heads and check piston to valve clearance.

I would strongly advise against this. You will not get lucky. The starter exerts a lot of torque on the crankshaft. The starter is fully capable of bending valves. I don’t know the gear ratio between starter and ring gear off the top of my head but it’s probably about a 10:1 mechanical advantage.

If you already have an interference that isn’t allowing you to rotate the crank - more mechanical advantage will only serve to break or bend things.

Without spark plugs the crank should rotate freely by hand, no exceptions.

Oil pressure has nothing to do with not being able to freely rotate the crank at this stage in the game. If the original builder didn’t apply assembly lube to the main bearings and the cam lobes, the damage would be done before the engine ever builds oil pressure by rotating it. And if that sort of negligence was causing a lack of hand rotation (I’ll guarantee it isn’t), that would be all the more reason to tear it down, find out what was done, and reassemble it correctly.

[edit] - I guess the exception would be if the transmission is in gear. Make sure the trans is in neutral and that you’re not trying to rotate the whole gear cluster and differential as you’re rotating the engine by hand

You could remove the rockers and give it a go, if it turns freely you know that either your hitting or you have some crazy powerful springs ...

Removed the rockers and push rods. Could turn the engine by hand by gripping the fan. I’m considering cranking the starter with the rockers and push rods removed to see if it builds enough oil pressure to turn off the oil warning light. If I get that far, then was considering reinstalling the push rods and rockers and adjust the valve clearance very loose and try to turn it over again by hand. With luck, there will be no valve/piston interference and I can turn the crank by hand. Not sure what valve springs I have. They are doubles but that’s all I know. I assume the springs can be heavy enough to make it harder to turn by hand. But sounds like it should be turntable by hand unless there is clearance issue. Going very slow and cautious. Thanks for your thoughts. Please keep your suggestions coming! I might just get an endoscope camera to look inside. I can see numbers on the pistons through the spark plug holes but can’t read the numbers.

I wouldn't worry about oil pressure yet but it couldn't hurt with the rockers off.

The springs are a little worrisome to me. I know they are used but I wonder if that means there is some radical cam in there. Do you have a micrometer? Measuring the lift on the cam might be interesting. You should be able to ballpark it with the pushrod travel.

To determine if it's the valve springs you could put them back on one intake valve and try turning it by hand. If that works add another and keep going. If it gets progressively more difficult but the engine keeps turning...

And it just occurred to me... Check top dead center on 1 and verify the correct timing of the valve events. If they did just 'throw it back together' the cam might be off. I doubt that's the case, but it would be good to know.

It's already OUT!

With the plugs and the rockers off it should spin completely free.

You should be able to turn the flywheel/front pully with a single finger and no effort.
"Gripping" should not be required.

You should tear down.

IMO doing anything else is a waste of time. you should be able to get that down to a "short block" with the rods hanging out of the case fairly quickly.

The most likely culprit IMO is a ring that got damaged during installation.

Using a friend supporting the rods that should "free wheel" with zero drag.

During the tear down you should verify both bore and stroke. The 44s it came with should be on a BIG motor, not a small one.

Ordered borescope today to look inside cylinders through spark plug holes. Hope to learn more about which pistons were installed (part numbers from tops) and better idea of valves and heads. From there I hope to decide whether to pull the heads for a better look. I”ll probably try to measure piston travel and valve lift too. Would be nice to know a bit more about what I’ve got before trying to start.

The fan is very close to the case. Seems like it might be touching a little as I spin the motor by hand. It’s so pretty with the tin and case powder coated. Hope I don’t have to tear it down too far if at all.

Will post what I find with the scope. Might even figure out how to take pictures.

Are you able to get her to spin reasonably easy? if so, you might be on your way. Fan will be close to the housing, perhaps a special washer was not installed.

Yes it spins fairly easy by pushing the fan by hand. Just remembered Jake Raby advice on loosening the oil filter when cranking the engine to purge air out of the oil passages so oil pressure can be established. Might give that a try while waiting for the boroscope to arrive. If valve/piston clearance looks ok with boroscope I will likely put the push rods and rockers back on. And check with boroscope with valves opening. Then loosen tappets to reset valve clearance and measure cam lobe height by measuring push rod travel from valve closed to valve open. Will also measure piston travel to learn what crank I have. And check compression. Anything questionable and I’ll tear it down to inspect. The motor was built over 10 yrs ago by a supposed “race engine guy” but no records. It looks nice and turns over well by hand and with starter without the rockers installed.

All good news, you may have a winner. Always good to check things out, but it's possible to assemble the beast and she will run. FI or carbs?

Weber 44s. I have all the FI stuff from 73 and a complete 74 1.8 parts car. Will see if the webers are fun and tunable.

Hopefully it was just crazy compression and stiff springs....

44's might be a bit big, depending on cc's, CR, cam, .... I tried 44's on a 2056 build and I was unable to get a good vacuum signal. Wound up with 40's and couldn't be happier

Just measured stroke by inserting a rubber hose in the plug hole and turning engine by hand from bottom of piston stroke to top. It measured 3.95 inches stroke. That seems big compared to stock published stroke at 2.66 inches stroke. Is 3.95” stroke possible with a non stock crank? This is supposed to be a hot engine but adding 1.3” to stroke seems like a lot.

Turns easy by hand now so loosening up.

Wow, if that is right it is a monster. If you have 96mm pistons and your number is correct for stroke you would have a 2.8 liter. I suspect it would eat itself. With 93s it's still a 2.7

And those 44s make sense with that.

Could be a beast

Assuming the heads are still bolted in place and spinning freely, is it an option to put fire in those combustion chambers?

Just remeasured stroke using plastic straw. 3.8” which is 96mm. Haven’t seen cranks for sale bigger than 86mm stroke. So not sure what I’ve got. Looking forward to boroscope viewing to see if I can read part numbers on to of pistons. Might be able to tell if the are 96mm or 94 mm and even see the valves without dismantling it. The heads are supposed to be special, but we shall see.

Boroscope just showed up. Pistons are marked 95.95 on top. They are flat with valve relief cuts. Any idea what pistons these are?

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They look like my 96mm pistons. If that thing is as big as it seems I hope they are forged....

With respect to stroke - you’re neglecting that the spark plug isn’t perpendicular to the piston. What you’re measuring isn’t 1:1

Given that none of this is stock 1.7L I’d be taking that apart to figure out exactly what is in there and how it was built.

There are plenty of stroker cranks that require clearance work be done to the case.

Likewise those relief cuts in pistons may not be clearing valves properly.

As long as the tip of the probe isn't sliding the distance will not be altered if it isn't perfectly perpendicular.

I think it's worth pulling the heads at this point just to figure out what the compression is. If this is a 2.7 you are going to have to be careful. If the bottom end is rotating freely I wouldn't go deeper. But that's me.

Dude not even close to perpendicular to the dome of the piston. Especially on 1.7L heads. I don’t have a set of heads in front of me to measure but probably almost 45 degrees on 1.7L heads.

Geometry matters.
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Ok. Pulling the heads is recommended. What am I looking for/measuring when I pull them? Should I install any new gaskets? It never run so all new inside but been sitting for 10 years without oil in climate control. Anything I need to do when pulling heads?

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And this DVD available from LNengineering.com

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You need to know the stroke, then you can determine displacement.

You need to know the compression ratio.

You need to know the deck height.

Since it won’t turn over by hand with the rockers on it you need to determine what valve lifts you’re dealing with and whether you have adequate valve clearance to the piston. The pocketed pistons are a whole other story. Who’s pistons? How much material is left in the piston dome?

You need to figure out if it was put together with head gaskets and get rid of them if it was. Pay particular attention to Jake Raby’s posts to this link. I know this link refers to 2.0L but it pertains to all displacements.
http://www.914world.com/bbs2/index.php?sho...70781&st=40

Be aware that rubber ages and hardens regardless of whether it was in climate control or not.

You should be checking crank end play.

There are literally dozens of things that should be verified rather than just hoping it was put together properly and won’t grenade when you run it.

There are literally dozens of things that should be verified rather than just hoping it was put together properly and won’t grenade when you run it.



probably best to open her up all the way and confirm exactly what you have instead of risking damage of new parts

Or you could continue to determine if in fact you do have contact (I am personally doubting it) first. Send us pics of the heads, I doubt they are 1.7 heads, but they could be. Do the plugs come in from the top of the motor? Are there 3 or four bolts holding the intakes on?

If it is not valve contact but instead spring strength, it's your call. I would pull a head to determine compression and measure valve diameter. If they were building a beast I would hope they put big valves in it.

As superhawk mentioned, no gaskets to worry about, however there may be shims under the jug. Nice thing is you will be able to verify how much distance you have between the piston and valves and set your own compression.

That book is a good one and worth having on the shelf. And raby is raby of course.

I DON"T like the raised 95.95.

I want the tops of my pistons smooth as a "baby's ass"

The valve reliefs look rough too.

Look like inexpensive forged to me.

I'd fully tear down.

Remove heads, lock jugs in case with crossbars (you can use wood here, just trying to lock jugs to case) check deck heights and stroke.

Now you know how big it is...

If it's a stroker (more than 71) I'd fully tear down because of it.

Strokers REQUIRE special tricks for clearance of the crank/rods/camshaft and are a significant increase in complexity for the builder.

If it comes out stock 2.0l (71) I might check "feel" of the assembly and re-assemble.

If you have a stroker there you hit the jackpot!

I'd LOVE to "find" a 78mm stroke with flat tops at 96mm bore. That is a 2255 and is a VERY GOOD combo to have.

Take pictures and post on here. You will get opinions, lots of opinions...

Tear down tip!

Keep everything in its originally installed position.

I even watch the hardware for placement and direction/clocking.

All the crap should be "indexed".

If the lifters have ever run, they HAVE to stay on their respective cam lobes!

When you're taking the dash out of a Prius (I know you're not doing this) the placement of every single screw is important. Put a long one where a short one should have gone and you can pierce an ECU.

I once saw a 300ZX twin turbo PCM destroyed by a screw the owner put in the wrong place. $1800 mistake in 1998!

Fastner placement can be CRITICAL

I'll often use egg containers, biscuit pans to keep track of hardware.

U can tell it's a stroker if you can see spacers under the cylinders. Maybe take a look with that scope/camera through the sparkplug hole in the tin? My guess is that you're looking at a 2056 (possibly a 1911).

Yes, check everything. Although not likely, make sure the valve reliefs on the pistons (probably cast) aren't upside-down, because that would be a bummer. Measure and write down all the speciations because you will not remember. Things like bore, stroke, valve sizes, intake and exhaust lift or cam number if there is one, blueprint the oil pump, plug the oil gallerys with tapered threaded plugs, etc., etc.

While you have it apart, lubricate it properly and get ready for startup, especiallythe special lube on the cam lobes. We also had a 2056 project motor that was stalled and sat for over 10 years. When we got back to the project, the molly-lube turned into a grey stiff gunk. Cleaned things up and started again with new bearings, etc.

BTW you can turn the motor over with a 23mm(?) wrench on the alternator pulley fastener if the alternator belt isn't too loose (you can squeeze the belt with your hand while turning the bolt to help stop any slipping). Just don't force anything if you feel resistance.

Best wishes for a successful startup!

Thanks! Have ordered book and Jake’s DVD.

If I’m going to tear this engine down to inspect, a proper engine stand would probably easier than the home made test start stand it’s on now. What engine stands do y’all prefer?

HF will have something decent for not alot of $$, but you will need a yoke, can't remember where I found mine?

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Sorry about the multiple posts of the same photo. Learning how to use the site.

THAT LOOKS PROMISING!

You might have hit a home run...

Fancy retainers/springs, RAT etched in.

Show MORE!

For OP

RAT = Raby Aircooled Technology
HAM = Hoffman Automotive Machine

Those are nice heads - this is why it’s important to disassemble & understand if anything is not clearanced properly.

Those are expensive heads - you don’t want to damage them

You couldn't have any better markings than that!!!!!

The 44s are probably correct.

If it's what I think it is it's MORE than 30K today.

You should ALSO have a "Billy Bad Ass" exhaust with it.

If it measures anything over 71 on stroke you NEED one!

There's a pretty good one in the classifieds right now that might pair well with that motor.

http://www.914world.com/bbs2/index.php?showtopic=370909

Looks like it's pending right now.

It's the nicest 4-cylinder exhaust that has been in the classifieds in 18months...

You have what I WANT to find. A hidden Raby motor (maybe)!

You might have hit a "Grand Slam!"

Be STUPID careful with the lifters. There is a chance they are ceramic or roller...

Pull the tins FIRST!!!!

You want to look at the jugs. If they are "Nickies" you hit the home run.

They will look 911 "like". not VW finned. Aluminum with denser machined fins.

Can see the cylinders without pulling the tin but as stated previously I’d be going through the whole engine anyway.

Raby serializes his engines so unless case has RAT serial number it’s probably not a whole Raby built engine . . . But you never know. If I recall Raby / HAM developed heads were sold on Type 4 Store years ago. Not exactly sure how those were stamped.

For OP - Nickies cyclinders are billet aluminum - very distinctive. Here’s a set of 100mm cylinders I have slated for a build as example of what they look like Click to view attachment