Inliners International Forums General Discussion Engines GM 4 cylinders 151 153 181

I drove into Carson City today to get the rear sump pan, oil pump, and pickup for the 153 from the guy I bought it from (chevy2inreno). I also stopped by Auto Machine Marine to see what my choices are for head and crank work. The main thing I learned is that the difference in the rod journal size of .100" between the 153 & 181 will most likely yield only about +.080 in stroke. It depends on the condition of the 181 crank and availability of undersize 153 rod bearings. I need to take in the crank, talk to Ernie, and contact the actual grinder in SOCAL to see for sure. I'll take the head in to get 1.95 intakes, 1.60 exhausts valves, screw in rocker studs and guides. I'll do the HAMMER removal of intake bosses and installation of my PES lumps. (Sorry Tom, I've had the lumps and hammer for a long time. ) I got 1.70 BBC roller rockers and will deal with Erson for a cam, lifters, and springs. Beater

This sounds like its going to be a fun one. How many cubes as a stroker?
What pistons will you use?

As for the lumps, you know me, a sawszall will do. My install video will work for the PES also. Tom

Well, with the 181 crank and +.080 stroke and the .040 over bore it's not quite 179 ci. If you started with a 181 + .060 bore and .080 stroke you'd have about 190.5 ci. So far I'm looking at some KB 307 pistons. I've got the .050 down the whole # to play with. It's in the planning stage. Tom

It's great to see all the interest in the the 153/181 L4 engine. I may as well throw in my two cents. I am currently building a 153 for a front engine dragster. It has been an education, and I'm willing to share what I have learned, and will learn. I had the head modified by Mike Kirby at Sissel's Automotive. He did all the good stuff: Lump ports, port and chamber work, 1.94/1.60 stainless valves, screw in studs, guide plates, springs, retainers, etc. Mike's work is top shelf, and he is one heck of a nice guy. He is the final word when it comes to head work on the L4/L6 engine series. I highly recommend him. I am working on the short block now. We'll end up with around 12.5/1 compression, and have a custom cam ground to match what we're doing. The object of this whole exercise is to run at our local 1/8 mile strip in brackets, and make some nostalgia and inline events as well. Of course, the main objective is to have fun. I'll post some pics of the head, and give more details later.

That sounds great. I'd like to see pics especially of the head work. That sounds a lot like what I plan for my head.

Another quick note. A good distributer is readily available for the 153/181. The big cap HEI from the 77-78 151 is a direct bolt-in. These were in 77-78 Chev Monza, Pontiac Sunbird, etc. A-1 Cardone part # is 301490. Hope this helps those having problems finding a decent ignition system.

I stopped by Erson Cams today and sat down with Steve Tanzi for about an hour. We discussed the 153 project and he came up with 3 different profiles. Now it's up to me to honestly look at what the car will really be doing. I need to weigh my pile of componants and seriously look a wheel choice and tire size. Whatever Erson will be grinding the cam locally. Beater

Will try and stop by there next week and see you and Steve,if everything works right

I got digging around in the Brazilian web sites and my Portuguese is not as good/bad as my spanish? but after searching Opalla 4 cilindros drag race I found what is supposed to be 2 turbocharged 153's, I think? http://wn.com/Role_de_opala!# then choose Borrachao de Opala

The cast valve covers and side covers show up occassionally on EBay and look pretty good if you sandblast them and then polish them with a buffer. http://cgi.ebay.com/ebaymotors/Mercruise...essoriesQ5fGear

General Motors Brazil makes a 153 with a 16 valve head they used in rally racing that is a crossflow design. It was a 240 HP twin carb engine. I'm trying to find more references to it. ,

That is 1.5 hp per cubic inch from a naturally aspirated engine! We should vacation in Brazil.

With 16 valves in a pushrod engine it has to have an inticate rocker arm system and they moved the water neck to the side.

Yah, unless there was room (and money) to put more lobes on, the usual method is forked rockers. This does bad things to the tappet face vs. cam lobe loading, but it must work or it wouldn't be so common.
The rockers are really no more complicated than they look, and not much harder to design and make than common; they just have more bending moment in the cross plane, but IMHO this is intuitive and easily compensated for (FEA not necessary except for minimum weight) - you'll know it when you see it.
This is also sometimes used to adapt a DOHC head to a pushrod block, losing the benefit of the cam but keeping the 4 valves.

Are these cool Brazilian GM engines actually designed in Brazil or for Brazil? What about the Cosworth? Don't we have engineers here or is it just more green political correctness?
Beater

Using a Google translator line by line it seems that these were developed in the late 80's in Brazil to compete with the Cosworth Fords and Porsches, etc. on the rally circuit. I'm not sure hfow many were made, I wonder if Douglas Carbonna knows anything about them? Portugese is close to spanish but there are a lot of differences. I found it searching for "4 cilindros Opala"

Don't even worry about getting the best cylinder head possible,,just turbo it & run a lot of boost!

Even w/the lousy siamesed port designed 6 cyl head,they can make a lot of power. Your stock siamesed head is the same port layout.

Unless you just want that something different than most have,go for your search.

MBHD

I am using the stock head on my engine. It will get the same treatment as the 6s lumps, 1.94s, & 1.60s. Also screw in posts & roller rockers. Just a fun driver no boost at this time. But you are right that would be the easy and cheap way to speed.

Turbo's do make power at a reasonable cost but you loose the audible attraction of the split exhaust, Rappin at Minden would become Rumblin at Minden

how's this for a 2cent why not use two small turbos run of one of each set of 3 pipes and then this way you keep your dual exhaust.??

That'll work, here's a couple of youtubes 153's from Brazil with some noice induction systems, first one has Beaters intake he's looking for, http://www.youtube.com/watch?v=GO74D_Kp0n4 , and one to keep mbhd happy , http://www.youtube.com/watch?v=yg9Y6H8zt3A

Found the intake, now to translate and find out where to get some. also the 6 cylinder weber intakes could also be used, made by ,Engine Racing http://www.engineracing.com.br/pecasnacionais.html ,

That first one is just where I'm headed only it will be in an open wheeled '26 Chevy roadster with a 4 speed OD. What fun!

Does any one know for sure if all the 153 heads have the same chamber volume? Are they the same as the 6s, which ones? My head appears to have chambers slightly smaller than a 6 head that is supposed to have 74 cc chambers. Is there a ratio for reduction in chamber volume per .001" removed from the head? The 153 rods big end is for the 2.00 crank pin. The 181 uses the 2.10 crank pin. Both rods are 5.7. Are they the same forging? Can the 153 be bored to take the larger bearing? How much wider are the 4 & 6 cyl rods than the V8 rods?

SBC rods are .940" and the inlines are 1.030" at the big end.

You can still find some Iron Dukes in the wrecking yards, found this one in Riverside CA with a price tag of $325. including the TH350 out of a postal Jeep.,

There was, two weeks ago, a FWD in an '88 Citation for $255at Pick & Pull. It may still be there

Ok,
Closer to using a 153 or 181 in the farm buggy. Picked up a nice 4 bbl LPgas conversion at a swapmeet this weekend. Complete and working. Going to put this on the buggy.

Need help with distributors. The industrial 181 and merc 120/ 140 hp engines used no vacum advance and maybe not even mechanical advance.

Like to run a HEI with vac advance. What application from the 70's/ 80's car will fit and have both advance options? I think 151 dist will fit if they were from the front dist location, like the inline 6 big brothers. Tom

Also need a Clifford intake for the 153 4 cyl engine.

The 151 front mount distributers should work. I'll try to get some info at work tomorrow. I'd look at some late 70s S10s & maybe the Jeeps that used the GM 151. I've seen some Distributers on eBay. Mallory made a duel point and I think an HEI but I don't know if the had advances. Beater

I found some crank casting numbers today.
153 '62-'02 (must include marine engines) These all have 2 piece rear seals, 2.0" rod pins, and 3.25" stroke. # 3788522, #3793082, #5743014
181 '60-'99 2 piece rear seal, 2.1" rod pin, and 3.60" stroke. #N393775N, #N9341352
181 '60-'99 1 piece rear seal, 2.1" rod pin, 3.60" stroke, uses 1"wide rod. #140966
181 "00-'08 1 piece rear seal, 2.1" rod pin, 3.60" stroke, uses .940 wide rod has a torque converter hole. (?) #93436083
181 "00-"08 1 piece rear seal, 2.1" rod pin, 3.60" stroke, uses .940 wide rod has no torque converter hole. (?) #93436083

The .940 rod width of the last two cranks seems the mean that they could be used with SBC rods that has the 2.1 bore. The ones with 1 piece rear seal could be used in a 151. That would add .60" to stroke. Which makes the Iron Duke a 181.

tlowe: scroll up a few posts, I listed the HEI's that are a direct, perfect fit. Jim

Here's Jim's post. And here's a Mallory on eBay.

Thanks for that , guy's.
Ebay does not have any. Where to get one? Those cars are long gone from the boneyards here.

That's cool to hear. I have a 2004 181 from a forklift. SBC rods will interchange? WOW, maybe this one will get built up for alittle 4 cyl power. The 4" bore allows the use of common SBC pistons too. Already did that on another. Tom

Tom, it looks like the .094 rods would be the same as a 350. Those would be for the ones with the 1 piece rear main seal. I'm just learning about these and am not sure. I wish I had parts to compare but the auto parts business is not what it used to be. I'm still looking for a set of 181 rods, the wide ones. Beater

If you want it's fairly easy to convert a 6 cyl. Unilite to 4 cyl by just changing the cap and rotor to get the vacum advance or I can send you the drawing for a collar to fit over the 8 cylinder distributor to fit the block and you just have to attach a 6 or 4 cyl. drive gear. ,

Does anyone know if the 153 & 181 rods are the same forging #? 153 -250 rods are plentiful and cheap, 181s are not. They are the some except for the big end bore. Can the 153-250 rods stand the over bore? Beater

You'll bore into the bolts, there too close to the edge of the inside bore of the cap and rod.

I think I found a source in Reno. If not I'll spend a day driving around Tahoe and visiting boat shops. Tough duty, I may have to spend a night or two. Beater

I got 3 181 rods today at AIMS machine shop in Reno. Casting # 7755. These are the forged rods for the cranks that use a 2 piece rear seal. I'l get pictures soon and compare them to the 153 rods. I bet something else uses this rod. Now I have a number.