Inliners International Forums General Discussion Engines My new 277

I previously posted about the art deco styled roadster I am building:



The T56 I had originally bought is gone and a T5 with a warranty has replaced it. The T5 is from a V8 car so it should handle the engine with no problem.

I FINALLY got the engine here. I had bought it from a man on Craigs list and a buddy picked it up and brought it to me. The story on the motor is that the man wanted a hot six for his 16 year old son's Nova. A engine builder in VA named Gilbert McDonald built a 250 truck engine with a steel crank for him. McDonald built a bunch of circle track versions of this engine and they dynoed at 325hp with a 2bbl carb. This engine has a LOT more head work than was allowed for the race engines and McDonald estimated 350-375hp.

It was bored to 277 CI, has forged TRW flat top pistons from a 307, was decked .100, has V8 valves, bored .125. It has a 600 lift cam and 11:1 compression, a Clifford aluminum 4bbl intake and Cliffort exhaust headers. Electronic ignition. All new parts in the engine. The engine was built in 84, run for two hours to break in and driven down the driveway and back. The kid said "But it's not a V8!" so the Dad parked the Nova (wonder what the kid drove...if he'd been mine he'd been on a bicycle)

The motor was filled with Marvel Mystery oil and left in the garage. Here it is:



We removed the water pump and alternator just to get them out of the way. As expected, the T5 bolted right up but I was surprised to learn that it is twisted to one side...



Once we pulled the manifolds we could see the extent of the head work. Here is the intake:



And exhaust:



The casting number on the head is 3824437 which should be a 230 head with 72.8ccs

I pulled the valve cover today and everything looks spic and span with not a spec of rust.

Btw, here is a photo of the motor mounts we fabbed up last weekend:



Obviously, I'm going to tear the engine down and look it over. While I'm in there I want to deal with the compression and cam lift. I've been told that the TRW pistons have LOTS of metal at the top and that I should have them relieved .100 (or ????) and rebalanced to get my compression back to pump gas....something around 9-9.5:1. Also planning on replacing the cam while I have the engine down. I think 600 lift in a 2000 lb car with a stick will make for a car that would be a real handful to drive without slipping the clutch a lot and probably not something my wife would be able to handle.

Thoughts, comments, suggestions?

Kerry
Your photos didn't show up double check your links to them.?

The photo's came up for me yesterday and this morning. Hmmmmmmm

thats cool, hey you said that he used 4' pistons in that things, I thought that was not a good idea and that motors dont hold together if going that big, did he sleeve the motors? how was this accomplished?

Looks good.
Yeah, the tranny in Camaros/Firebirds is rolled over about 30 degrees towards the driver. The engineers compensated for that so now the shifter is leaning towards the passenger. That's part of the reason I went with the S-10 tailshaft housing.

Humm, they show up for me.

http://imperialwheelingmachines.com/roadster/Side8.jpg

http://imperialwheelingmachines.com/roadster/Engine1.jpg

http://imperialwheelingmachines.com/roadster/T5.jpg

http://imperialwheelingmachines.com/roadster/Lump1.jpg

http://imperialwheelingmachines.com/roadster/Exhaust.jpg

http://imperialwheelingmachines.com/roadster/Motormount2.jpg

Don't know yet. I'll probably pull the head and drop the pan in a week or so. He told the owner that it would run at 6000 rpm all day and built it for a daily driver so I can only assume he knew what he was doing???? Mainly I bought the motor for the head, manifolds, crank work, etc. Changing the block would be no big deal if it doesn't hold up. I drive like a little old lady so I doubt the motor ever gets much stress although I'm sure I'll smoke them once in a while.

well I had the idea of using like 4' pistons in a 292 to yield more cubes and be able to get like 312 CID or whatever it makes out to be, and be able to buy pistons for much cheaper, this is not to say that I ever want to turn more than 5000RPM but cubes is cubes and free power is awesome, can you imagine haveing a 312 cubic inch six, what a torque monster that would be, but I am very interested on if the guy that built this motor sleeved the block to do this or if he just bored the heck out of it to get a 4 inch piston in it, this sounds like a very interesting prospect, keep us posted

OK, a few questions for the engine wizards. I'm getting ready to tear this engine down. As I stated earlier, it supposedly has 11:1 compression, a .125 bore, 307 TRW flattop pistons, a 600 lift cam with hydraulic lifters, the block was shaved .100, Clifford 4bbl manifold and tube headers, and electronic ignition.

A HOT combination to be sure but not what I want for a street engine in a 2000 lb car. I'm looking for smooth performance on pump gas and want some low end torque. I'm thinking 9.5:1 compression and another cam. The head has had extensive work by a builder who knew what he was doing (see photos above) and I don't want to mess with it.

To lower the compression, I've been told the TRW pistons have LOTS of meat on them that could be taken off the top to get the compression in line then have them rebalanced. Is there a better way? Thick copper head gasket? How do I calculate the actual current compression and determine how much to remove from the pistons? I assume I need to 'cc' the heads. I've heard of this but have no idea how to do it???? Is there a way to determine compression ratio from a compression reading on the engine?? Help.

What would be an appropriate cam for this engine?

Thanks in advance.

Well first off the 307 piston is not a 4in bore It is the same as our L6 3.875 bore But yes they could very well be .125 over.
Unless they were a custom order they should have a 4 valve releaf
in the tops. Now depending on the piston head thickness, You could mill the 4 releafs into one dish. As to the CCs on the
your right about that.ONLY if the head hasn't been mill.So depending on if it was milled and as to how much was milled off
the CCs may very well be less.
Now for what I see in the photos All that was done to that head is the Boss was removed that was it. No Porting was done
The Valve area wasn't even blended in.
Reason I say this is because you can see the cut line from the
valve job and you can still see the ruff casting in the port.
so from that if i had to take a guess i would say the Valve guide
bosses were not touched either.

So now my 2cent input is this. Pull the head check the CCs
finish the port work. Unshroud the valves Espcaily if it has
a 1.94 intake this will help gain a few CCs back in the head
and also help the air flow. You could also add the bolt-in lump
Which again will Increase the over all CFMs of the head.Then I'd
take a close look at the pistons and see if they could be dished
That way you can still keep the Zero deck,If that is what it is at. And cam wise look for something in the 450-550 range,
and a small 4b carb.
And if it was estimated 350-375hp why did they stay with a
stock dampener??? even though you are plaining a cam change
I would change the valve springs. Because if the valve train
loaded that whole time the springs could very well be weak now
from sitting under a load.
(meaning rockers holding any valves open)

hope my 2cents helps

Thanks for your insight Larry. I was hoping you'd chime in. Good thought on the valve springs...I wouldn't have thought of that.

Kerry, if I were in your place, I'd think about using a Coolingmist water injection setup to tame the 11:1 compession ratio, and I'd use an RV type cam. Comp Cams 260H would be a good street cam, lots of low and midrange torque. In the late 70's and early 80's I had an El Camino with a big block V8 in it with 11:1 compression, and it preignited like crazy until I hooked up a Holley water injection system to it. It was happy as a clam after that, no more knock or ping. Holley doesn't make that any more, ditto Edelbrock (they made one too), but both systems were a bit primitive compared to what's available now. And at $300 for a Coolingmist system, it's a heck of a lot less expensive and time consuming than replacing the pistons, and you still have the 11:1 that will run on pump gas. The only minor drawback is that you have to fill up the water injection tank when you fill the gas tank, and you'll need to use distilled water or windshield washer fluid for the water injection.

Well i hope i wasn't to hard on you ,about that head.

Kerry, you may have Chevrolet 327 pistons, with either the stock 5.7" connecting rods or 6.0" rods. The 327 pistons are available in two compression heights.

Nah Larry I asked and expected the answer. Good news is it wasn't an expensive engine. Supposedly it has V8 valves. I'll know more after I tear it down and measure everything. I have mills and lathes and measuring tools. I've never CCed anything but after reading the internet think I can do it. I just need to get a big syringe that has CC measurements.

I'll probably be talking to you about the lumps. Are they hard to put in?

Man this site is S.L.O.W. these days!

Also going to look into water injection. Carrying a little water wouldn't be a big deal. I'm not going to be driving this across the country.

No not really if you have the tools/cutters but i can help you with that as well. As to what you will need for the job.
now as for a big syringe that has CC measurements.try any vets or doctors office.or med supply place. you should be able to find/ get one with the needle.

Finally got an email from the previous owner of my engine with all the details he could remember of what was done to the engine. He had all the receipts but they were in a folder that went with the car the engine had been in and got trashed...

Anyway, this is what he remembers:

250 truck block
steel crank (think it was turned 10/10
283 connecting rods (peened)
307 trw pistons
federal mogul bearings
roller timing chain of some version of H/d chain
high volume oil pump
250 cylinder head w/ 194 v-8 valves (small head 350
valves
screw in studs
4130 moly push rods (custom made for .100 milled head.
chevy hei ignition
crank was the only thing balanced.
the head work was Gilbert (the machinist) all the way! The head bolt
under the rubber freeze plugs in the head are allen
bolt because the head passage for intake was blocked
by the reinforcement where the original head bolts
went through the head. That is why you can litterly
stick 3 fingers in the head intake port and touch the
valves.Also I was told we could eventially use the
hole where the freeze plug was to injet NOS into the
intake port

Good news. I pulled the head off today and the bore is 3.935 which is 60 over so it should be much more reliable than the 125 bore.

The pistons are flat top with 4 recesses for the valves. There is a number on top of the pistons 2255P4. Supposedly TRW pistons but I can't find any info on them. The intake valves are 1.94 which jives with what the guy told me about them being V8 valves.

I'm going to try and calculate the compression ratio and measure the cam lift tomorrow.





supposedly has v8 valve springs also.



The motor looks very clean.

Thoughts, comments

It should be right around 9-1---9.5-1 at the very least. Not knowing if it was decked or not and what May have been taken off the head.??

Supposedly they took .100 off the block. I don't know how to check easily

Ok, the saga continues. This is an engine I bought sight unseen from Craigs list in another state (750 miles away) Supposedly had a bunch of engine work done on it and was probably going to be too hot for a light street rod.



TURRRRRNS out it wasn't what the seller was sold. The block was 60 over not 125. (GOOD for me!) I did the CC bit on the head and block and cranked the compression...it's 8:1 (a bit lower than I'd like but I'm OK with it). The block was NOT decked. It has the stock 9.15 deck height. (Solves a big compression problem) The crank was not forged but rather the 12 counterweight version. Supposedly balanced but can't tell. I'm OK with it. Pistons are forged flattop (OK as expected) The cam measures .317 lift on the lobe. With the 1:6 big block rockers that comes to a .500 lift at the valve. (A little hotter than I'd like but I'll probably live with it for a while.)

Obvious rebuild. Spotless internals...(good). The head has 1.94" intake valves, with smallblock springs and bigblock rockers. Screw in studs in the head for the rockers. However the head is the issue. I can't believe I didn't see it but it was only this week that I noticed one of the rocker arm bosses cast with the head was broken off.



HUMMM The stud is TIGHT and obviously goes into the block. I didn't force it although the stud next to it came out with an impact wrench.

I'm obviously concerned about this repair.

The good news is the seller is a stand up guy and is sending me a refund... basically given me the motor for the cost of the Clifford tube headers and 4bbl intake. So if nothing else I get a good short block with forged aluminum pistons and I have to find myself a new head.

The question is...is this a viable repair or is the whole thing junk? My thinking is that if it fails, it probably won't hurt anything other than the head because the valve spring will keep the valve off the piston...right?

As Larry posted back on the Inliners board, the valve springs which sat for 10 years will need to be replaced...smallblock chebby shouldn't be a problem to find.

Another issue I notice is the rockers (Big block chevy??)



Notice the larger size of the pushrod dimple on the right? About 4 of the rockers are larger but all are different sizes. Any thoughts on this?

Personaly I think the rocker are wore OUT streched Out in the push rod tip area. Trash them. Yes the L6 can run the BB
rockers. But The L6 rocker is really a 1.75 Not a 1.7 like the BB rockers. Now as to the Stud fix?????? No dout they used the
Extra Long ARP studs and That is Only a spacer From the Looks
of it. and There is VERY little holding in the Head itself.I would personaly Pull that stud and check,To see if it is only a spacer. If So then Yes i would have to say the head is Trash with in reason.Becuase it would NEVER handle and Type of cam Of a Good Size/Lift.
Now as a side note YES any BB or Sb springs do work.

also, notice the allignment of that rocker arm. it appears to not line up with valve. heads are easy to find. tom

The head is off the block...rockers are loose. They line up OK.

Thanks for the reply Larry. I put the big impact on the stud and screwed it out. The aluminum is just a spacer. There are about 5/16" of threads before it gets into the water jacket chamber...not good.

Man, I hate to loose this head. Is there any way to repair it. Brazing or TIGing a new boss? Or machining a new spacer that is tapped for the stud but has 1" male threads that would screw into a new, larger tapped hole in the head...LOTS more thread surface.

I guess I'd risk a repair & failure IF it wouldn't trash the block if it broke. Will it?

I think the longgest stud ARP makes is 1 1/4 on the bottom side.
My only thought is If you really need to save that head and was not going with a High Lift or High rpm cam. To me about the only way to fix that stud mount would be Make the spacer out of steel
Get the Longgest Stud(bottom), And have the spacer tig weld.But
the other problem I see that would come into Play is You would
NEVER match the treads already in the head.(if you was able to Tap the new spacer).Another Idea/way would be to maybe??BIG??
would be to make the steel spacer a Short Grade 8 bolt Match the treads to the rocker stud. Now make a short stud that would go deeper into the head Treads wise ,Screw the spacer onto that.
Tig weld it to the head. Then use a short bottom rocker stud.

Mind you still this could still end up being only a temporary
fix.But i would think it would have to be better then the alum spacer. Now if it broke What i see happening is Trash into the block ,Now you have trashed bearings,Scored who knows what along the way. AND no dout a Over Heated motor Now whats else Cracked Block from over heating????
So I'd say go with what you gut tells you. BUT personaly I'd just find another head and just play with that one.

I agree with Larry on this. Sometimes you just can't get there from here, and I think this is one of those times. I don't think I'd trust that head to hold up, no matter what you did to it in the way of repairs. Just bite the bullet and get another head, and since you need to replace the rockers anyway, you might consider using the Crower SS roller rockers, which are available in the correct 1.75:1 ratio and use the 3/8 rocker arm stud that the new head will have.

how about this.
machine the alum spacer down .1 inch. do the same to the adjoining two rocker stands. make a plate .1 thick that will bridge all of them together( like a stud girdle). this would take much of the flex out of the weak stand. tom

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