The elusive 224/3.7 MerCruiser banger

A geared starter arrived today. (photo on previous page) It fits perfectly and is 13 lbs lighter than a Mercruiser starter. The rotation (clockwise) is correct but I've not tried running it

 

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I haven't been on here for a while, but my project is starting to progress. The chassis is a late 60's Edmunds sprint car chassis, and will be used in vintage racing. Intake manifold is fabricated, and uses the Superflow throttle plates- that are used on VW midgets. I will try.to update as work continues

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That's some coolness right there. What head are you using?

 

It's a closed chamber piece that I bought thru eBay couple years ago. Machine work was all complete but head was empty. Had anlocal shop supply all the guts. Engine will run on methanol.

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I would like to purchase a stock cast aluminum valve cover out of someone's spares pile. Thanks!

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Bunch on ebay <$25. Earlier ones had Mercruiser script

 

Edit of previous post here. I deleted the original.

I'm having a bit of confusion here. I ordered a BBF timing set (C-3079X) but received a similar SBF set(C-3054X). I didn't realize the shipment error and was trying to use the sbf parts.
The crank sprocket did fit. Both of these sets have the 3 keyed crank sprocket.
The SBF crank sprocket in this set was a 21 tooth and the cam sprocket was a 42 tooth. The 3.7 motors are 22 tooth crank and 44 tooth cam sprockets. So neither of the sprockets in this set will work on our motors.
The chain was the correct pitch but way too short.
In summery - make sure you get what you ordered and SBF timing parts won't work on the 3.7 motor.

I will update when I get the correct parts.

Gearheads QCE responded to my original post below. His post doesn't make sense because of the deletion of my previous post.

 

Beck,
Could you post pics of the pieces you're trying to fit together? I'm wondering why a sleeve spacer wouldn't get you mated up.
Does the Cloyes crank gear fit the Mercuiser crank?

 

If the crank to cam centerline is the same as the 429/460 engines, then this would help justify the need to have some billet cam blanks made and use the BBF timing sets. Then the snout on the cams can be made to accept the better timing sets.
Anyone have a non-useable block with main caps they would sell cheap?

 

The BBF cam snout would prohibit the use of the stock water pump. A lot of non-marine users are doing that anyway. I believe the BBF snout would be the best alternative if the roller cams were made.
There has been an attempt in the past to have a run of 6 roller cams made. That was the minimum that mfg would make. We couldn't get 6 guys that were willing to spend that much.

 

Have we got any cam experts here?
I installed a stock cam with a good timing set. I got the cam in right, dot to dot on the sprockets.
#1 intake center is at 116 deg. That doesn't seem right to me.
On the cam I had reground, I was told to install it at 109 deg.
I have a cam doctor sheet for the stock and reground cam if it helps.
With 44 teeth on the cam sprocket, if I move it one tooth that's 8 deg, right?
(360 deg / 44 = 8.18 deg)
The 3 key crank sprockets move the timing 2 deg., right? If you move the chain 1 tooth and then use the 2 deg. retard key it would change 6 deg.?

 

For cams, I have mercruiser cams reground. Their lobes are large so they make good blanks.
I arrange to have a local boat shop call when they pull a Mercruiser engine out. Most boat places don't even try to repair these engines so you get them for scrap prices and they come with lots of parts. Exhaust manifolds I can't use so I give them to the shop and they are happy to get the money selling them ( the exhaust manifold is several times the price of a junk engine).

 

Good hearing that the sbFord crank sprocket fits our cranks. Their smaller diameter might prevent a Mercruiser chain tensioner from working properly. The center of a Merc cam sprocket could replace the center of another sprocket if you are up against the wall.

Chain tools, available in motorcycle shops, work on length changes for single row chains. Tools for double row chains should exist. If you found double row master links you would not have to go through riveting the chain Try a chain dealer. A cam chain break can destroy the housing around it.

I bought a used Merc. timing set from a man who parts out boat engines. Paid him $100 for it so if you find a cam sprocket that fits, let us know.

 

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couldn't a metal spray process be used to build up a "thick" steel layer on a cast iron cam? the cam grinder I know builds up metal onto worn cams needing more material

 

I have been slowly assembling 2 motors.

I was short a rear main side seal set (straight rubbers and stakes) so I thought I had to purchase a complete bottom end/timing gasket set, CS4909VM, to get it. That set is about $95 plus shipping.

I just realized that a rear seal set, JV1613, available which includes the side seal set,. That set is about $30 plus shipping.

It was too late for me but I thought someone else may benefit.

I don’t know where some of the gaskets/seals in the CS4909VM set fit. I expect they are boat fitment parts.

 

Timing chain set update.
EDIT: After degreeing the cam I find this chain is looser than it should be. I believe the chain should be ordered undersize. (available in -5 and -10 thousands for line bored blocks) This will change the numbers of the chain and timing set listed below. It will also make the parts harder to locate. I would have liked to run the timing set without the tensioner. That will not be possible with this length chain.

I received and installed the Cloyes C-3079X timing set. This is a BBF timing set. It includes the C168 timing chain that anothercarguy reported fitting. It includes a 3 key crank sprocket which allows timing adjustments. The cam timing sprocket included does NOT fit our camshafts. It is for the BBF.

I reused a 3.7 cam sprocket. That wasn’t a great idea, but the only one I could think of. I was too cheap to purchase a new 3.7 timing set to just take the cam sprocket from it. The new chain was not a perfect fit on the used sprocket, but I could tell it was supposed to. The wear in the sprocket was the issue. I had 3 complete used timing sets. One was very nice. I used that complete set on my #2 motor which is going together with a stock cam. Both of the others were worn somewhat.

The reason I went with the C-3079X timing set was to gain some adjustability when degreeing my cam. I am using a reground cam. The grinder was specific as to where it should be dialed in at. I was hoping that sets 3 keyed crank sprocket would handle that. There is also an option of using offset crank keys. There are 2 offsets available.


CNC-Dude commented about using the BBF cam sprocket on billet roller cams. From my “not perfectly accurate” measurements it appears the BBF cam sprocket is .030” taller than the 3.7’s. This could be accommodated for in the cam blank or by machining the sprocket. The cam blank would be the preferred place, so out of the box timing sets could be used. Cam end play may need to be changed for the roller setup anyway. Someone much smarter than me would need to figure that out. IF roller cams were made I believe the Cloyes Hex-A-Just 9-3122A timing set would be perfect.

 

Beck,
You are the man! I'm thinking that there must be a way to get just the 3.7 cam sprocket. Do you think Cloyes makes the 3.7 timing set? I doubt that Mercruiser makes or made them in house. Now, how you get to the guy that can build a special part number set by specing the correct chain and sprockets is another story.

When I worked for Snap-on, I was one of the few guys that could get something like that done without an act of congress. The cool thing is that I met a lot of guys in similar positions at other companies. Many an unobtainium part was back doored to me and by me. Unfortunately, Cloyes wasn't one of the companies I dealt with at that time.

 

If I recall when I spoke with Cloyes back in 2015 I was told they do not make the 3.7 set.
If we knew who was making it, they may also make the performance BBF set.

 

I think I remember it being said previously that the snout on the Merc cam was larger diameter than the BBC by only about .030 or so. You could also just turn the snout down to fit the BBC gear, or open up the hole in the BBC gear to fit the cam snout of the Merc. Both are completely orthodox methods to accomplish this. Anyone know the exact differences in the sizes?

 

Has anyone looked into using a gear drive setup with the idler gears? You keep the standard rotation cam and the centerline spacing could compensated for by adjusting the distance between the idler gears. I have no idea if this would work at all. Not a fan of gear drives due to the noise.

 

I think you are talking about the Ford (BBF) cam? The Chevy (BBC) cam snout is flat with an offset pin and 3 tapped holes. Those holes are not the same pattern as the 3.7.

The snout on the 3.7 is slightly smaller than the bore of the BBF cam. It is a small amount, but enough that it won't work without some modification. For those that are not familiar, the BBF cam mounts with a center bolt and is located by a pin coming out of the cam face. The Ford cam sprockets also have an eccentric in the center.

 

I typed in BBF, but for some reason my phone is starting to auto-correct everything incorrectly!

 

Head stud update.

Buying head studs for the 3.7 is frustrating. When you go to ARP or other suppliers the studs are listed in sets for a V8 so you wind up with twice what you need. If you call ARP they will sell ½ sets, but it is over ½ price.

When I called ARP and Trick Flow for my application I found that the block end of the stud was threaded for 1.25”. My block has over 1.75” of threads. For the best clamping power I wanted studs with that end threaded further.

In post 1775, iadr recommended C&C Motorsports , Manassas, VA, for studs. They are into the Boss heads and aluminum BBF blocks. I gave them a call and talked to Carrol Carter. I found their studs have about 2.25” of course thread for block engagement. My fitment wasn’t perfect, but better than the others for my application. These are not “budget” studs, but I am happy with what I got. There studs are available in 4 lengths. You may want to check these out. These can be cut slightly if needed to make them work for different applications. A 12 pt nut and washer are about .800" tall so the nut location can vary slightly. My block is threaded to nearly the bottoms of the stud holes. These studs course threaded end has a .26” reduced size extension. This could be removed to make more thread engagement. For my head I will need to hold the stud slightly off the bottom of the hole to have complete nut engagement on the top.

 

I just did an edit of post 1847 (above) concerning the timing chain set.

 

Thanx, Beck!

 

Dennis G came up with a Toyota Corolla water pump conversion back in 2011. Post # 630 has 4 photos.

I had not payed much attention to it thinking my competition motor would be run with a dry block. I’m putting a 2nd motor together that I want to set up for coolant.

I see a common question throughout the thread. What Corolla pump? Dennis posted it was a ’71 to ’74. When I do a search for those water pumps it shows 2 motor sizes, which apparently take different pumps. All of the photos I have seen show a bypass tube. The 1.2 motor selection looks the closest. All I see look like the GMB 170-1090 pump, with bypass.

Does anyone have a part # or know how to find this elusive pump?

 

Could I suggest the possibility of using an electric pump in the lower hose, as it would simplify the adaption/plumbing issues? Some of the FAST club members have had good results going that route, & are considering it a viable option in the future.

 

Johnson has a raw water pump that fits Chevy or Ford pulley pattern. Rubber impeller but most have 2 yr warranty so may last. 1-1/4" outlets.

 

Speedway also offers an electric stand-alone 12v waterpump. The major advantage of the electric pumps is that they may be located beside the motor to reduce overall length. (& do not require pulley alignment like a mechanical pump) I know that some of you may feel that an electric water pump is somewhat "O.T.", but they are just another way of solving length & function problems(the "Nay-sayers" are probably upset that they didn't come up with it!! LOL!!)

 

The Speedway pump I see (# 911880) is made to use with the modular, bolt on, ends that adapt them to common motors. They cannot be hooked to hose. You may have seen a different one?

drtrcrV-8, I am not opposed to the electric pumps. In post 1763 I put a link to one I saw that was an OEM replacement. I am just exploring the possibilities.

The land speed car I crew for had an issue with an aftermarket, top dollar, electric pump. We lost a days racing due to the pump. (granted, it's a salt flats car and salt seems to get where it shouldn't) The company stood behind it but the day lost was more valuable than the pump repair. It is hard to tell when an electric pump quits. I would think typical electric water pump failure would be the motor, resulting in no flow. Typical mechanical pump failure would be seals or bearings, resulting in a leak, but still flowing water.