Technical 4 cylinder mercruiser-engined cars

When I took this engine apart, the head bolts were really really tight. Friend Ernie said "get new headbolts" but considering the dilemma about headbolt thread sealing and retightening headbolts ( you can't retighten a bolt retained with a thread locking compound) I decided the best thing would be to use studs instead.
I could not find 1/2" x 4" studs at what I thought was a reasonable price so I bought 4" long 1/2" grade 5 bolts and made a set of proper studs in my lathe.
The center of my studs is reduced in diameter to the minor diameter of the 1/2" national coarse end 0.410". It looks much smaller than the nominal 1/2" shank but it actually is stronger as all of the stress is otherwise concentrated on the first thread or two of the coarse threaded end. (That is where an unmodified bolt normally breaks at the end of its fatigue life.) "Waisted" bolts and studs not only hold better, they also last longer than straight sided fasteners.

Carried to the extreme, this concept gives us to the single use bolt. I would not suggest making single use studs as too much labor is involved. $12 per stud does not seem so much after spending a day making studs.

 

With only 10 suds I can see an advantage but on a 24 stud flathead V8 it can be a pain to get the head on and off.

 

I have found a possible design weakness in the oil pump pickup tube support bracket on the center sump Mercruiser 120 engines. Vibration fatigues the bracket supporting the center of the tube. Both tube brackets I have are cracked or broken loose there (one had been welded after cracking and broke next to the weld).

 

Here are my two cranks... Forged and Cast. Which would you use, and why?

The counterweights on the cast crank appear larger than the forged crank. This won't be a high HP build.

 

Just out of principal if both cranks are sound I would go with the forged one. It probably will not be an issue. How can you tell if they are cast or forged? I assume the one with the studs is a Mercruiser.

 

They're both Merc cranks. The cast one has a small casting line, rough surface and larger counterweights. It's a later model engine. The forged crank has smaller counterweights, machined finish, wide die line. The crank with the orange timing cover is the forged one in this case.

 

Dennis, I built a Mercruiser 181 for my Model A sedan. One of the best conversions I ever did! In the photos you will see it had two Escort progressive two-barrel carburetors on a home-made water-heated intake. I built my headers from scrap exhaust pipe I had laying around the shop. 2 1/2" pipe was perfect. With a single glass-pack muffler, it sounded like an Offenhauser!

I knew better than keep the Mercruiser cam; they're for boat use and not good for the road. I had the cam re-ground by a cam grinder in Georgia (Steve Demos, of Demos Cams) and it was perfect for my driving.

I used a bellhousing and four speed transmission from V8 Chevelle, with a Ford 8" read end.

As others have said, you can find 181s in forklifts, boats, generators, water pumps, etc, etc. I think the engines that had the easiest life, would be those from a boat. In cold country, you should be careful about cracks caused by the coolant freezing, though. Good luck!

 

That is EXCELLENT!

 

If you happen to win the lottery.

http://www.nickariasjr.com/engine-blocks-gm-pontiac4.asp

 

CNC Dude, what have you done with these products?

 

I also have been working on completing some more universally friendly OEM style head configuration intake manifold patterns for the 153(Chevy II 4 cylinder) and the 194-292 Chevy 6 cylinder engines. I'm having to do a complete make over on the 12 Port head patterns for the 6 cylinder, but I have started more needed(requested) intake manifold patterns for the 153 and 194-292 engines as well. There is also a 4 cylinder head in the works too. Thanks for your interest!

 

I am in

 

hang it up and tap it with a head bolt, if it rings like a tuning fork -its forged, if its a dull clank, its cast.

 

There is a newly available cast valve cover for these engines listed on eBay. There seem to be some options. I want one!
http://www.ebay.com/itm/282120340260?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649&rmvSB=true

 

anyone have an opinion whether a fiero 151 header would work with the appropriate flange? it's already got a the siamesed tubes in the center (one large tube). i wonder what the port spacing and outer tube diameter is...

eh. closer inspection shows the ports appear MUCH closer than the 153/181. No room for the intake ports between

 

CNC-Dude, have you had any luck casting any parts?

 

724wd, are you referring to the Mercruiser style engine this thread is regarding, I hate to go off topic but, I most recently got my new true EFI intake finished and cast for the Chevy 250/292 engines. But I would like to do some Mercruiser stuff, these are awesome engines and have huge potential. So if anyone has some ideas on what they would like to have for them, let's start a list.

Also, just had another one of my inline products I designed and manufacture featured in a Hot Rod magazine article. It seems hardly worth mentioning, but to those interested in reading it, here's the link to it.
http://www.hotrod.com/articles/slant-sickness-add-77-hp-mopar-slant-six/

 

Ref: Chevy II 153/181 C.I. I-L 4 Cylinder I'd like to see Reproduced

1. (Mallory Distributor) use to make Mechanical tach drive distributor for the Chevy II 153/181 Engines. They no longer manufacture them. If someone just cast an aluminum Tach drive Body, & use a Stock Chevy V/8 Tach Drive mechanical Components to build a Chevy lI tach Drive distributor. Maybe get the In-Line club to be invoked to get a better demand for this item.

2. Aluminum Cross-Flow I-L 4 Cylinder Head but, I'd like to be able to use my Clifford Weber Side Draft aluminum Manifold.

3. A mid-Slump Aluminum Finned oil pan for the Chevy II 153/181 Engine

4. Someone on eBay is suppose to reproduce Aluminum Finned Side Cover. He already makes a beautiful Finned Valve cover.

As, I'm wanting these items for my 1932 Ford Roadster Pickup, W/Chevy II engine & F170 3-Spd+overdrive Trans., Closed drive to H-101a Quick change rear end.
BigDTexasKd

 

DigDTexasKid : if you go back & do the research you'll find information about how, from the '70s on into the '90s(or later) the Midget Racers adapted the V8 Chevrolet head to these engines, so, for your #2, if you were to use Brodix (or similar), at least a part of your wishes would be answered.......

 

I have a finned side cover already 3D modeled and am ready to make the pattern for that. The problem with a crossflow head is the ports will not be siamesed like your Clifford intake, so a crossflow intake will also have to be made to fit this new port layout.

 

Scott, What about your Duggan/Deppe stuff?

 

Most of that stuff has ended up being a case of Joe cleaning out his garage and getting rid of things that were needing a complete redo. The head patterns for instance ended having cores mismatched from previous head patterns he had years earlier or cores missing completely. So I am gradually moving towards more and more complex patternmaking projects with my intakes and then move toward a completely new updated head pattern. I think i'll start with a 4 cylinder version first.

 

Buy a Fontana....

 

Fontana will work with several different makes of cylinder heads.

 

That's a bummer Scott! OhWell it'll all look good in your "Man Cave." At the rate I'm going you'll have a new crossflow head ready before I get the one Tom built for me on a running engine.
As for parts I'd like to see a timing cover that could run a mechanical tach drive off the cam.

 

One surprise I did get was a 1960's blueprint of a 6 cylinder Crossflow head that Frank Duggan designed, but never made. I think trying to capture a vintage look on the exterior, while implementing 21st upgrades internally(ports, combustion chamber, etc...) would be a cool concept. Making a 4 cylinder head from this design would be easy also. I don't think Joe ever realized he had these blueprints or he had forgotten.

 

Several years ago John Erb started on a Studebaker V8 head. Heads were the limiting component for Studes. The last prototype I saw was Studebaker on the outside and LS Chevy on the inside. I hope he keeps going.

 

There is a new dual side draft intake for these engines. It fits the early style 153 head.
http://marshallsince62.com/index.html

 

This is my pile MerCruiser 4cyl. 700R4 gets down the road pretty good!

 

Would love to see an individual runner intake for dual Webers and a 181 head.