The elusive 224/3.7 MerCruiser banger

great idea, I will

 

update on making grinder holding fixture:
I have the holding fixture in rough form and have suggestions. I had some rusty folded channel about 135 thousandth thick. So I cut it down to the size as it was about 2 foot across. I'm glad it was not thicker as it cut so easily with a 4.5" angle grinder. I cut away one side and then drilled and welded on a little piece to support the other side of the grinder as I was going from a two feet wide channel down to a 100 mm wide(interior) channel. It seems rigid. It looks ugly.
I put the little side on by pinch welding it as I did not want to fight a warped fixture. Easy to break off but it isn't going to withstand much force. I needed slots in it for the bolts to the flywheel. and milling was not working out as I could not clamp it well. I solved yhat by drilling a 5/16" hole at the end of each slot and cutting between them with a cutoff wheel that was now smaller. It was way faster, quite easy and more accurate than milling wobbling steel. but crude in appearance. The slots are slightly wider than necessary but I will put washers under the bolt heads.
The grinder sits flat in the fixture by itself. It was not much cut and try as the measurements I gave worked out.
The cutoff wheel is deeper than it needs to be, so I will elevate it with a 3" x 3" shim x (looks like 0.225" thick is needed). A very shallow test cut will be needed to see if the measurement is ok.
I'm really glad I scribed a line where the cut is to be as it makes checking the cut height possible as you go along.

 

I've been doing chevy pickup bellhousing + saganaw 3 spd transmission mercruiser engines this is #3. Nothing original on my part, I copied Randy Dupree.
I envy those of you running transmissions that don't need an external linkage. My linkage was troublefree in a Camaro but it jams enough that I made a wrench to free the levers and bolted it to the floor between my feet. The wrench is to free it if it binds up on a slight incline.
A different transmission would be nice. Most are somewhat heavy.
Thanks for the suggestion about measuring again. I'd not thought of that. There are several ways of doing this.

 

It looks lovely. Nicely done. Is the little linkage to a brake booster? And is that a car bellhousing? It looks like one.

 

The linkage bolted to the head? That is throttle linkage running over to the injector. I am using a 621 bellhousing,(3899621), yes I believe it is a car bellhousing. It is for a 168 tooth chevy flywheel. As a side note chevy 153 tooth bellhousing will not work unless a lot is trimmed off the bottom. numbers 421, and 403 don't work well. I have the 621 and a 444 that do work.

 

Thanks for the information. After "trimming"
a car bellhousing for the mercruiser flywheel, there was so little of it left that I considered it to have no use except as a wind chime. It was the second bellhousing I destroyed. The first one succumbed to a brush hog. It was over quickly. It is heartening to know that some car bellhousings work with Mercruiser engines.
(I deleted the number)

 

A quick look at bellhousing will tell you which one you need. See the starter pocket on the left one? That is the one that works. The one on the right is for the 153 tooth chevy and you will need to cut most of the bottom off to make it work. Both are car bellhousings.

 

Dennis, are you saying the Mercriuser is a 168 tooth flywheel? All of mine are the Ford 157 tooth. In my picture above the left is for the chevy 168 tooth and the right for the 153 tooth. As far as I know all the 168 tooth chevy's will work on the mercruiser, truck or car. I have no cast iron ones, so I can't speak for those.

 

Same. The flywheel is noticeably smaller than the 168t truck stuff I have kicking around.

 

I'd better not claim any particular tooth number. It just popped into my mind and I entered it. I stand corrected and have deleted the erronious number. Yes, the earlier Mercruiser flywheels are ford flywheels.

 

I compared the length of 3 chevrolet bellhousings I have here. Their height laying flat is the same. The truck bellhousing has the same bolt pattern but is larger around its bottom. I was itching to cut my block and did it outside finishing the cut just before dark.
The cutoff disk did not load up with aluminum. The grinder gearbox became too hot to hold. The cutoff wheel became hot also so I stopped every few minutes for cooling. The heat vaporised the wd40. This block has starter mounting studs and I cut through the ends of them. The pretty sparks ignited the WD40 so I blew the small flames out.
A 7 inch disk with a nut and dished center worked very well except that there was a metal stiffiner on its back side which interfered cutting the extension which is around the starter nose. I just pushed it through and it distorted the cut width a little so Tomorow I will remove enough to have the flange an even height( It took 98 th.) There were a few spots where I needed to cut slightly deeper more than the abrasive disk would do without lengthening the slots in my grinder fixture so I used a hacksaw (it looks like a keyhole saw)to finish 3/16" of the cut in the few places the disk could not reach.
The cut surface is smooth, much better than I expected. Hearing protection is highly advised. It was wonderful fun doing this.
Yes, it was easy to make a consistent cut often within a very few thousandths of my scribed line. Problems began with deep cuts which interfered with metal onthe back of the abrasive disk.. the grinder mount is quite stiff as it must be. I even chained the grinder handle down to the flywheel. The disadvantage of my fixture is that it must come apart for any adjustment by shims. The cut would take about 20 minutes for 2 complete passes. Cutting is slow in the very thick places but the rest is reasonably fast. It is necessary to tilt the engine at each end of the cut to make room for the abrasive disk and whatever the engine is resting on at both ends of the cut. The cut must begin on the distributor side of the block and go to the starter side of the block.

 

I made finishing cuts today as the first cut was off in some places. I drilled 5/8" center holes in washers of the following thickness: 54 thousandths, 73 thousandths, 98 thousandths. the washer fitted between the abrasive disk and the grinder. The cuts were made with single washers as spacers to cut deeper. I was suprised at how quickly and easily the aluminum ground down. A whole flange grind took only a few seconds for a 20 to 30 thousandths cut. I cut 98 thousandths off in steps and it looks good so far. I will fit a bell housing to it as a check.
The pilot bushing will need to be pushed in 98 thousandths deeper to maintain the Dupree depth setup dimensions.

If you need to remove material I suggest that
7/16" be the first cut with a cutoff wheel.
Then go to the final dimension in a series of 50 thousandth steps stopping at the 5/8" scribed line. These removals are with the face of an abrasive disk. I used my cutoff wheel for this and it worked well even dry.
but after 3 cuts aluminum bits began sticking so WD40 helps if you don't have a disk designed for aluminum grinding.
A surface grinding abrasive disk is thicker and probably stiffer but I did not try one.

 

This shows the grinder with its handle reversed bolted into its fixture. Normally, a chain holds its handle to the flywheel but there was so little force on the grinder in light cuts that bolts were enough for the rigidity needed for a very light removal (30 th).

 

Nice job!! Very clever way to get the job done! But I have to say, to me that looks so wrong. I believe you said you are using a Saginaw 3 speed? I didn't know the input length would be so different between it and a Muncie 4 speed. If I cut my block like that I would be shortening the input shift, trimming the front bearing retainer just to get it all to fit.
It is as Gearheads said mock it up as many times as it takes to get the job done. I know I have lost count on how many times I put mine together and back apart. It fact mine is running now and I still took it apart!

 

Nice job @dennis g . The pictures made it very clear as to your set up and procedure. I had envisioned it with the block standing on it's nose. I'm surprised that the disc didn't load up even with WD40.

My next step is drilling for the pilot bushing. Then I can mock up the clutch & transmission to see if I need to trim the block. I actually would like to cut it down to shorten up the total assembly and I am adding an engine plate mid mount.

@Flatrod17,
You had it running? How did the injectors work out. Did you happen to take any video of it running?

 

I have about a haft hour on it. It does jump up and down and as Beck found, intake pulses. You can feel it with your hand about 6 inch out. Right out the gate it would not idle down, Air fuel gage said fat but ran like a vacuum leak. Air bleeds at the nozzles are to big. I taped them closed, then would not idle, air fuel gage said it was fat but I knew it was not at first. Then when taped it is way fat. So more smaller nozzles and nozzle bodies on there way here. No video's not till I at least get it to run right, plus I have never made one and will have to figure out how to and how to put it on here. But so far I like the injectors!!

 

Bruce, when I cut my crank for a pilot bearing I found one with the same OD but one with Chevy ID and the other a Ford ID, that way I could use either trans, just change the bearing. Depths for me were the same, about 7/16 to 1/2 inch in the bearing.
I thought I had a picture of it installed but this all I could find right now. Just a machined hole.

 

That's so cool. Thanx for the info on the pilot bearing.

 

yes , I accumulated Saganaw 3 spds (all syncro, cheap ($65), strong and 95 lbs) As I set the engines up for torque in 1800lb cars 3 speeds are ample, I never had a Muncie so I don't know about them . It seems stupid that they would have different length input shafts. When I mate the transmission to the engine It does not feel like the Saganaw input shaft goes into the pilot bushing very far. I would like a big tapered hole in the bushing to make it easier to get the shaft in but if it feels like it only goes in a little (like 1/2 inch) so I'm afraid to do that.

 

The advantage of a car bellhousing over a truck bellhousing is that you don't need to have a truck bearing retainer.

 

As I used a Mustang T5 and then put its guts into a Camaro case, I could of used the Mustang bearing retainer but decided to use the Chevy retainer. So I had no special machine work to do other then machine the crank for a polit bearing.

 

I'm impressed as I never imagined that even being possible. It does make sense though. You are immensely clever.

 

There are spacers available to put into the GM truck bellhousing that adapt it to car transmission bearing retainer size.

 

I heard of them and imagined that they were simple disks of approprite I.D and O.D. There must be something more to them than that. Good suggestion, certainly better than driving to a transmission shop 70 miles away for a retainer. Thanks especially for your idea about how to do this aluminum removal, it worked very well and was immense fun. I checked the cut against a bellhousing and without proper bolts it was 6 thousandths off at its worst.

 

The threaded holes in the block that secure the bellhousing to it now have about half an inch less engagement. So I'm going to drill and tap them more. On earlier engines, I ignored that.

 

In a effort to make everything fit on the dyno where I worked, the dyno was Chevy, so I made rings to fit everything else. Just od and id to fit with a step in whatever bellhousing that was being used. Some were pretty thin rings! Most bellhousings were scatter shields with Chevy Trans patterns drilled into them. Could easily be done to make the smaller bearing retainer work.

 

This tells about the rings http://www.toolcraftllc.com/muncie-bell-housing-adapter.php
This guy uses locktite and set screws to secure them , can you tell us more about the step you use?

 

My rings were much like those in your link. All the dyno's I have used are all chevy trans patterns at the pump end. So to adapt other engines to it, I made rings to fit the chevy side (i.d.) or (o.d.) on the pump side, then bored whatever bellhousing to fit a stepped ring. The step kept it in place. It went in from the trans side. Worked well for the 20 years I ran that dyno.

 

It makes perfect sense. In your case, you would not want the ring in forever.