The elusive 224/3.7 MerCruiser banger

Okay, next total guess, probably even less likely to work: low strength studs? Ones that stretch/ hold properly at half the foot-pounds?
I'm not at all sure how you might achieve this, other than $$$$ or luck buying & testing cheap import "butter steel" studs in the right size.

My dad was a mechanical engineer & I know that anything you spec can be made if you want to pay for it.

If I had a spare junk block it would be fun to see if the insert idea might work. An aluminum one might be shop- made with a threading lathe, theaded outside & inside, with provision for a larger locating collar to locate the head on the block correctly. (Use a good aluminum alloy)

The head would be fastened with a bolt from the top that goes through the head, the collar, and threads into the insert. I can picture this sort of in my mind's eye but I'm not confident it would work, too many things I don't know about motors, metals, etc.

 

Dick, it is a corolla pump.
Sounds like guys are started building again, good.

 

I liked your idea and turned down an old set of bolts to .5" it was easy.

 

For simplicity, the clutch disk should be one for your T5 transmission.
I used a chevy tranny & bellhousing so I used a chevy disk. to go to the ford flywheel.
Chevrolet also used the T5 you will need one of those bellhousings but the length is critical, simpler tho to buy an aftermarket bellhousing which fits a t5 to a chevy block bolt pattern.
The crankshaft has to be machined for the pilot bearing.

T5 input shafts are 7.18", 7.41" , and 7.85" long and they have ten splines

There is a great chart for the T5 so you can choose one which will work for you. Be cautious as those for the 2300cc engine were weaker. http://www.allfordmustangs.com/Detailed/349.shtml

 

Which T5 and bell housing did you end up using?

So if I understand correctly, you used a Ford flywheel with a 10.5" Mustang pressure plate with a Chevy Clutch disc for your T5?

 

I did not use a T5.

I used a plain old 3 speed Saginaw transmission.
It bolts right to a standard Chevrolet bellhousing
which bolts right to the block which must be milled because the input shaft is 5/8" short.
All this milling stuff depends solely on input shaft length and bellhousing thickness.

With a light car and abundant torque I decided that more speeds would be wasted. Besides mine is supposed to be an old car, you don't row those along with the shift lever. If you want more speeds I'd choose a 4 speed over a 5 speed. They both are abundant, strong and inexpensive. The 3 speeds are cheap (my transmission cost $65 on craigslist). Saginaws weigh 90 lbs, I do wish they were lighter.

I had already replaced the 3 speed Ford transmission in my 65 mustang 289 with a T5. It made no real improvement I just had more shifting to do. The Mercruiser in an 1800 lb car compares favorably with the mildly tuned small ford v8 in a 2800 lb car.

If the engine will be cammed to be peaky, then more speeds are of use. It depends on how you use it. I'd ask Randy what transmission he likes.

Don't forget to get a good chunk of driveshaft that will plug into the transmission, you will need it to make up your driveshaft. They usually come free with a transmission from a wrecking yard.

 

A hydraulic clutch is worth considering as there is no linkage to invent.

I still made one. I knew no better. Mine uses misc. chevrolet parts which go all the way into a chevrolet throwout bearing.

edit: That linkage was difficult to move so replaced it with a cable linkage I made from a parking brake cable. It works easily, both ends adjust and I'm happy with it and have done two cars that way.

 

I posted the part numbers when I made it. I read the first 600 posts yesterday and saw them again then.

 

This will tell you from markings what gear ratios come in a particular Saginaw transmission:

http://www.gitdirt.com/gm3speedsaginawratios.htm

http://www.gitdirt.com/gm4speedsaginawratios.htm

 

I actually like the idea of a 3 speed a lot.

 

Saginaws are both cheap and strong.
Avoid buying those from pickups as low gear was lower.
They are easily identified by a much larger bellhousing pilot.
The same applies to the bellhousing, stay with car parts.
Knowing no better, I bought a pickup transmission and had to replace it with a car transmission.

 

A 3-on-the-tree would rock.

 

Studs from an automotive application?

I have found an ARP retailer who had large qty's of 9/16" studs made by them, to the point that he can re-sell them to me for $19.50. They are quite a bit long and have a "bullet nose" which adds to the length, but that could be removed. The nuts are also quite expensive- $7.36ea, so I suspect they must be the rarer 12 point nuts- which I probably don't need, as there is lots of room. I have 1 stud with nut and washer being mailed to me today. I'll post photos to the board. I guess I haven't posted up pics of my parts collection yet, either. I'm in Canada, so don't expect an update for around 10-12 days.

 

Those I turned down were from a Mercruiser 470. They machine nicely.

I agree on the nuts being overkill.
And the expense is even worse when the studs are one use studs.

 

It is up to you. I've fought those long sloppy linkages and have no love for them.

I drove a Pontiac with linkage problem into a service bay one afternoon. "You'll have to leave, we are closed" said the manager. "I can't back it out, its stuck in low gear". He freed up the linkage to get rid of me. It never shifted well.

I do prefer transmissions with internal linkages.

 

I was not aware Mercrusier used studs on these motors? Certainly my engine and photos I saved off Ebay for reference showed bolts in use...?

As former warehouse supervisor for an ARP distributor, I can say overall, excluding special orders, 99% of ARP's studs are fully reusable. No torque to yield and few torque-angle.
The ones they make for Porsche engines may not be, because they have a specfic alloy and/or stretch design that allows them to track the growth of the all aluminum "case"/block (air cooled to boot in many cases). One of the really cool demos they did was take a long carb stud, 5/16", and bend it into a loop around a ~7/16 bar. No sign of breakage, yet the tensile strength of that stud was ~15-20% greater than the rock hard grade 8 bolts sold in implement stores.
I know some reading these are thinking I am making way too much fuss about the headstuds, but you see a few real life examples of those studs solving problems, and you hardly want to take chances.
I had no idea they were this tough to source for this motor. Heck for 62-74 Volvo, and 75-93 Volvo, they had them on the shelf for around $120 for everything, and there is not really strong aftermarket support for those.

 

I don't know.... A LOT of cars came with them over the years. Must work.

 

they do work, but they felt less positive than the floor shifting ones. Go ahead and try it, you are not stuck with the decision if you are not satisfied because the same transmission takes the shorter linked easier to manage floor shift linkage.
I suggest factory linkages, no easy thing nowadays, but they are out there.

I bought a cheap aftermarket linkage and could not get it to shift well. I replaced it with a factory linkage which looked about the same but worked better.

 

They are bolts. Total memory screwup on my part.
Yes, I turned down the bolt set.

Studs, especially into aluminum are a worthy improvement.

I've a number of BMW one use bolts in my scrap box. Things too good to throw away but not good enough to keep. Pretty 12 point heads, so I kept them for a "soap box derby car" or somesuch non critical thing.
Yes, I angle torque them to spec.

We know fasteners fail if undertorqued or if overtorqued. I heartily approve you rewriting the chapter on Mercruiser headbolts as you are backed by current established practice.

It will result in more effective clamping force. The thread engagement etc set a tensile limit which we can not exceed but stressing the fasteners more fully will, from what I have heard, improve their clamping. So necking them down, angle torquing and discarding after one use is most probably the thing to do.

 

What you are doing is important. Don't be deterred in your quest. Without some luck, it will be difficult and expensive. I believe it will be worthwhile.

How much excess length is there in the 9/16" studs you found? I'm impressed with the alloy. [ See, you've already had some luck.]

 

This is probably the coolest Mercruiser build I have seen. This is Clint Neff and he is the current NHRA comp eliminator record holder. He is running the new NHRA Ford pro stock head.

 

Dennis- the studs are supposed to be 6.4". When I talked to the engine builder he found some about .400 shorter, but the orderdesk clerk lady said she wasn't aware of any such thing....? If the bullet nose is 3/8", then we are matching for the Boss9 head. The other .400 shorter one might be better for other heads. Like I say nothing as good as having it in my hand to mock up...so I'll stay short of offering much more until then.

JMayabb As you likely know- bit for others- that's called JC51 head -for Jim Cunningham, a racer who provided much of the impetus (read:$$'s) for Ford to get back into Prostock.

What's interesting is with the old E460-headed build, Clint and Mr From, from whom he bought the car, are already equaling the (halved) output of Prostock cars while running 400-800 fewer RPM. Mainly it would seem that they have extra displacement (500cid limit in P/S, so they have about 25 more CID, which is ~50hp per 4 cyl's at this level). Still a very very impressive engine program...
Don't happen to have a bigger photo, do you??

 

What about these.. AND you can have 2-sets, or split cost with another 470 builder, I might be interested.. Prob find them even cheaper if you look around...

http://www.summitracing.com/parts/ARP-155-3603/

http://www.summitracing.com/parts/ARP-255-3701/

http://www.summitracing.com/parts/ARP-155-4003/

 

FYI, BTW, looks like ARP still recommends Mercs torque spec of "three equal steps to 140 ft lbs"... 200,000 PSI 9/16 inch Diameter

http://arp-bolts.com/instructions/155-4003.pdf

 

Any cataloged ARP sets are for an iron block and will not have enough block length thread.

The quoted ARP torque guide is for use with their super slippy moly lube.
Actually interesting because elsewhere in their catalog a chart suggest they want you to use far more than that.
They will say that if you "must" use motor oil (which I do, having read too much about problems with that lube) you should increase the figures around 12-15%.

Did Mercrusier actually recommend 140 ft lbs? I thought it was like 128...?

The true tightening force with studs is greater for a given ft-lb rating. It comes from bolts having more of a torsion bar effect when they absorb part of the twist, it comes from the finer thread, etc. I'm aiming for less than 130 with oil

Also, I have basically given up on ARP. I have what appears to be an excellent hook up on A1 studs, and the sample has arrived. Updates to follow.

Some links:
http://www.a1technologies.com/documentLibrary/downloadFile.php?id=4
http://www.a1technologies.com/documentLibrary/downloadFile.php?id=5

 

I found a couple of photos of the Kaase Shotgun MC engine in the dragster. This was about '84, I think. I hope to find more.

 

I was curious and contacted ARP regarding bolt/thread length, here's their reply

MercruiserOEM
4-3/8 bolt 10-67503
5-1/8 bolt 10-72769

http://bpi.ebasicpower.com/p/QSTHB370N
4 1/4" bolt
5" bolt
** not sure why they say 1/2" thread, thinking 9/16-12, and 1/2 length would def be too short..

SO, it looks like they are long enough, need to measure the thread length on the OEM bolts..

 

The threads are 1.5" long.

The Mercruiser head bolts are tapered down about 1.25" from the head and do indeed have 1/2" threads making the threads 3 timed as deep as their diameter.

As I have said before I believe that the Mercrury Marine Engineers probably know what they are doing in that they have engineered some of the best and most powerful outboard boat engines in the world.

They have also converted many automobile engines to work in the marine environment which demands much more out of any engine than that required in a car.

I believe that we have a tendency to think about improving on some very sound engineering.

I doubt that unless someone is trying to make a competition engine they will have to use anything other than the original head bolts.

Dick
.

 

I used a set of bolts from a big block ford. $15 for the used set. They look identical to the mercruiser bolts the overall length is 4.875" (4.375 under the head) for each of the 3 sets that I have. One bolt is considerably longer than the rest. thread is 9/16 " x 12 and is 1.625"long

 

Are you saying threads measure 1/2" OD?

double checked mine, 5 1/8 and 4 3/8" long, indeed it does taper down to 1/2" OD, but threads measure 9/16" OD x ~1.5" length

9/16" x 1.5" ~2.6 times dia
9/16" x 1.25" ~2.2 times dia