The elusive 224/3.7 MerCruiser banger

https://www.jegs.com/i/B&B/128/6393...MI7c6w2bbc_gIVBCizAB3LHwLzEAQYAiABEgIcovD_BwE

 

I have a left over valve cover spacer somewhere around here. How tall of a spacer do you need if you could use it?

 

He needs inches to cover those locking things and the stud girdles. It will help that the rockers are away from the top.

 

He is using a stud gridle. The spacer I have is .510 thick. Probably not tall enough. Its mate went on a 470 using a stock valve cover with roller rockers.

 

If your flywheel ring gear has bad teeth on it, the fix is easy. There were directions on a marine parts website, but here is my simple version.
1. Knock off the damaged ring gear with a punch and 2lb mallet
2. sand the rust off of the rim of your flywheel.
3. place an undamaged ring gear in your kitchen oven for 20 minutes at 400 degrees. My oven thermostat reads low as the gear came out violet.
4. place the hot ring gear onto the flywheel. You may need to jiggle it but it drops right on.
5 after it cools you are done.
discussion :
check the thermostat for your oven. I did not allow for mine running hot.
Napa wanted $110 for a new ring gear. I had a perfect ring gear on a non-automotive Mercruiser flywheel so I knocked the gear off and used it. Mercruiser used two kinds of flywheels: one is a sharp edged ford flywheel that a ford pressure plate will bolt onto, the other is a non automotive flywheel that is 8 lbs heavier and it has a rounded outer edge. The ring gears interchange.

The time the gear is heated makes a difference with the color. The color comes from light interference in a thin surface layer formed on hot clean steel.

My wife may make cupcakes today, they may taste of ring gear fumes but I'm not a complaining type.

 

Nice looking valve train.

Brazing up one with that thin steel bolted onto a spare head is easier than welding it unless the extra section is clecoed in place and you have a nice welder. My results would need Bondo not to look odd. Aluminum is expensive unless it is scrap. Wood is cheap and the right size but can crack where it the spacer is end grain.

 

the spacer I referenced is 1.4" thick plus a gasket height

 

Temperature control was a problem until I was able to use a vacuum advance distributor and a lower compression ratio.
My first 3.7 once ran at 260F and survived. I immediately changed to a larger radiator. I expected it to have killed the headgasket but it continued running another year until it hydrolocked and split its block. Maby the heat did it in, it usually stayed under 230 . The next 3.7 did not exceed 180F. I credit the vacuum distributor and lower compression ratio for that as otherwise the engines were the same. However the electric pump is simply a better option than the mechanical one.
The electronic control the pump is good but it is something that can be replaced with an inexpensive temperature operated switch. Without knowing the failure rates of both I can say nothing about their relative reliability. In general, simple things have less to fail in them than complex ones, but they fail also. I always have an emergency bypass switch on the temperature switch circuit for a radiator fan.

 

I was able to take my car out today, it's first drive. I got out on the road, stabbed it and went up in smoke! Tire smoke! It shot off like a rocket! I was not anywhere I could get on it more, just in my housing area. I was pushing a A/F ratio of 11.8 to 12 to 1 so I knew I have more tuning to do but have my biggest pill in, so either drill or buy some more. Temp stayed at 145 and no signs of a ping with my 11 to 1 compression. I am happy with it!

 

91 octane I assume?

 

Nope pump gas. My cam grinder gave me options on where to degree the cam for what fuel I was going to use. Here for pump 81, here for supreme 87, which is all we have, and here for race gas. All where 4 degrees apart. I set it in the middle. I just have not put in supreme yet. It has 175 pounds cranking compression.

 

Excellent!

 

Beck still around? Anyone know if he got his up and running right?

 

Bruce, How is your project coming along?

 

Flatrod congratulations!!

Your 175 psi cranking pressure is spot on. It is what my first engine was. My engines run well with a mixture about like yours, but I adjusted it up to around 14:1 for just chugging along . To keep mine from running hot I 1. used a larger radiator and a better fan. It helped but was not enough. On my next 3.7, I added vacuum advance to the distributor and I lowered its compression ratio to about 8:1 (cranking pressure 135)and its temperature stayed right at 180. As I changed two things I can not say which helped, but it worked and it felt about like the higher compression engine. Fuel consumption is said to be less with higher compression. It looks as if you have it dialed in from the beginning. Congratulations

 

Thanks Dennis, I would like to get my A/F in about mid to upper 12's. Remember it mechanically injected. I am sure I will probably not get it right at all driving conditions, just something I can live with.

 

I wrote Beck last fall. He was not working on it at that time.

 

Drive it more at this point , it seems to be running cold. That could be the temperature gauge .I run a thermocouple in the hottest cylinder It warns me when things are way wrong. (And they were at 1700F that is why I changed things for it to run cooler and it really did run cooler but I ran leaner (usually 13:1 to 14:1)than you do.

 

Temperature comparisons don't mean much if you're not running your sending units in the same spot....

 

I agree, it is all relative. I measure in the top hose. Good point, I do not know where flatrod is measuring temperatures, or how long he ran his engine and the outside air temperature as he is in colder Alaska.

 

I used a heat gun and read the front of the head. I have a mechanical gage at the front of the intake, said the same. I have a fan controller at the back of the head, intake side. The radiator is 4 inches thick. It cooled the 327 in AZ where the car came from. I was worried a little about heat, and the Toyota water pump doing its job, so put a 165 thermostat in, and will up that if needed after I get some more miles on it. And yes if was probably about 45 degrees out when I took it for its first drive.
I use the heat gun on everything. Intake temp at the butterflies is 45 ish degrees, and builds moisture, headers run real hot on the back two at idle, they were much closer when I got back from going around the block, about 1200 degrees by the time I got out and checked.

 

You must have removed the thermostat. Your control would do all of what the thermostat does and of course much more. So the thermostat would only be an unnecssary restriction to coolant flow

 

A 4 inch thick radiator? at the core? That would explain a lot. The small car body I have limits radiator size . I use Volvo radiators rotated 90 degrees. They do not have much area and are thin. They are light.

 

Well I didn't measure it, but I will says its in the 4" ball park.

 

You could probably free up a few ponies if you swapped to a less restrictive exhaust manifold.

 

Yeah, and it would probably help to bolt it down! But this way I didn't have to worry about the up and down jump these things have!

 

Your radiator is twice as thick as mine is!

 

My front (antifreeze side) seal wore the camshaft but the wear at the rear seal (oil side) was negligible. The grooves are shallow and can be removed with an abrasive roll. It is best (but not essential) to do this with the camshaft rotating between centers in a lathe.

Since the front groove was deeper I put one speedi sleeve over it and as the rear groove was gone that was it. I pushed the cam chain cover in place. and the seals were in place. As it was to test the fit. I tried to remove the cover and found that it is very difficult to slide a seal over a speedi sleeve the "wrong" way. It was like brushing a cat's fur the wrong way. Another problem was that the spring of the rear seal popped off and I could not reach in to put it back in place.

To remove the speedi sleeve I placed a wood chisel against the edge of the sleeve, gave the chisel a "pop" with a hammer and it was off. The chisel split the sleeve nicely. The nicest thing about the sleeve was its easy removal.

If the wear is not deep, just "polish" it away. The seals lip will adjust down the few thousandths that you have sanded away.

Another possibility is to locate the seal so it does not run in the old wear groove from the previous seal. This is the probable result if you change to a different type of seal from the original double sided brass seals.

 

This is a simple little thing that I want to pass on to you operators of the 3.7 mercruiser.
The mounting flange of the oilpan is thin and easily dimpled by over tightening the bolts. There may be imperfect sealing around the mounting bolts and oil will seep out. A way to stop the leaking is to use flange bolts to mount the oil pan. Don't use the ones with serrated heads as the serrations are leak paths. Make simple little paper gaskets to fit under the heads of the flange bolts. Leather is even better as it is softer and is a better match for a cork pan gasket.

If you want to save the cost of flange bolts, you can solder a washer under the head of common bolts to provide a sealing surface.

Real flange bolts, as opposed to soldered washer bolts, have a nice appearance worth having on the visible parts of your engines. Appearance, out of sight, on the bottom of the engine will not matter.

Real flange bolts, without gaskets, have a locking action.

Some types of lockwashers provide another leak path

 

Makes sense, but since that is a pretty rare event without rebuilding the rest of the engine, for me, glue it shut it is. Making a cover or sealing the bolt holes then using a bead of good urethane (a relative of windshield adhesive) to glue it on. One could stand it out on the bead with enough room to pull a cutting wire though, that would make it removable in the worst case and a lot easier than making new holes etc. Unconventional for sure, but simple... yeah I have done windshields and more exotic adhesives. very handy when done right.