'38 won't rev

[briankearney]

Hope someone can help. Have a '38 Special with straight 8 and can't get to rev up. runs at about 650 and revs up to about 900 but won't go any hire. All new ignition parts and a carb kit are installed. Timing advanced a little. Have better than 75 lbs. in 7 cyls. but the #1 cylinder is dead. Tried a comp. test with oil in the cylinder but still dead. Thinking it's a valve but the crankcase seems to pressurized because oil is coming out of the dipstick hole and fumes out of the breather tube. So could it be rings also? Runs smooth at idle and up to 900 rpm's but that's it. Want to make a determination as to how to proceed before I go into the engine. Any help will be appreciated. No knocking or noise out of the engine but does pop back in the carburetor(not misfiring poping) so I'm pretty sure it's an intake valve. thanks in advance

captbrian38

[Guest simplyconnected]

Brian, welcome to AACA. Many of our members are familiar with your situation. They have extensive resources and many years of experience.

You don't really want to run like that, do you? If you don't have knock yet, you certainly will if you continue.

Pull the engine out and take the head off. Inspect all the valves and cylinder bores. If you don't want to do the work, I can steer you towards a good engine rebuilder who gurantees his engines for two years. D&S Engine is in Clawson, Michigan. He has a machine shop capable and well-suited for your straight eight. If you need further info, let me know.

Hope this helps. - Dave Dare

[Mark Shaw]

Brian,

I suggest you first remove the valve cover and have someone crank the engine to see if the valves are moving on the dead cylinder. If they are not stuck, adjust all the valves correctly and try again.

[briankearney]

to all, Have head the valve cover off and have freed any valves that were stuck. also had a bent pushrod and straightened that out. All of the valves are adjusted properly and working. by that i mean up and down not necessarily seating although. I would think with 7 cyls. having compression I should be able to get the engine to run fairly well. I'm still wondering why the oil is spilling out of the dipstick hole.

Brian

[Guest simplyconnected]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: briankearney</div><div class="ubbcode-body">...the crankcase seems to pressurized because oil is coming out of the dipstick hole and fumes out of the breather tube.</div></div>

Go through this engine before any more damage is done. At least, clean up all the parts and set them to spec's. Look inside the oil pump and be sure the rotors are good, etc. Last week we had a member who was missing the top of his valve in a flathead. Anything is possible with an old engine. That's why I suggest you tear it down, clean the crud out, inspect EVERYTHING, and assemble using proper parts and tolerances. Turn the crankshaft by hand to feel any obstructions BEFORE using the starter motor.

Bent pushrods should tell you that your valves can't open enough, or lash is grossly mal-adjusted. Oil shooting out the dipstick comes from pressure created on top the pistons and blowing by. I hope your casting is still ok.

[Gene Brink]

Positive pressure (lots of it) in the crankcase is why the oil is coming out the dipstick tube hole in your block. I'm betting you have a hole in the #1 piston. Time to pull the head for a better look. If you're lucky you may get by with a single piston replacement but will only know after checking everything out. Good luck.

P.S. You might be lucky enough to pull the plug and see something through the hole while shining a flashlight on the piston top. Probably will need the piston 3/4 of the way up the cylinder so you can see most of the top by viewing at different angles.

[briankearney]

pulled the head and what I don't see is now more confusing than ever but I'm committed so I'll go ahead and pull the pistons. Thinking it might be just as easy to pull the engine and work like a gentleman instead of on a creeper for the duration. Can also clean the engine and engine comparment much easier like that. thanks for the help everyone i'll keep you informed.

thanks Brian

[Guest simplyconnected]

If you pull the engine, you can get all water jackets clean, and you can change all the freeze plugs to brass.

Take digital pictures and POST THEM. Can you see cross-hatch in the cylinder walls?

[briankearney]

thanks for all the info, could use some specs on my engine if possible. will try to take pics along the way and would appreciate info on posting them. The cyl. walls are completely smooth with no scoring or any kind of lines in them. three of the pistons, 1,2, and 7 seem to have small pieces missing of the edges and I can see the comp. ring where these pieces are missing. wonder where the pieces went as they weren't in the cyl. I guess they were blown out through the exhaust valve. I will try putting some

30 wgt. oil on the #1 cyl and see how fast it drains out as that may tell me why I had no comp. when I tried this performing a comp. test. the engine only has 38,000 on it but I understand that may have only been the usable life of engines of that era. Very little ridge to deal with so I guess that indicates very little wear. I guess this is a 248 ci engine but don't know for sure. It is a '38 Special with no adornments so I would like to know all I can about it.

thanks Brian

[Guest simplyconnected]

A smooth bore is an oil burner, and NOT what you want. The broken piston pieces are probably the reason for your bent push rods. Smooth bores also show, the engine was probably never rebuilt, and either had very little maintenance or it went much farther than you indicated.

I strongly urge you to pull this engine. Bore the cylinders .010" to .020", buy matching piston and rings. Check/restore the bearings and oil pump; do it right, and this engine will last a very long time. With proper maintenance, I would expect 100k miles.

[briankearney]

I hope I have enough time left to put a 100,000 on a seventy year old car. Anyway I need some specs on this engine if possible, as I'm committed to a full rebuild at this point. What are the cu.in. on this engine, 248? Any other info on this engine that is pertinent and this model car, Special 4 doors, trunkback would be appreciated. I'm in NC and have already used Cars Inc. in NJ for some engine related stuff, starter, carb kit and Kanter for igition parts. Went to Hershey this month and saw two beautiful '38 Buicks, so I know the car has great potential as it is a complete and solid with no rust. At this point just want to get it on the road and drive it and then decide how far I want to proceed with a restoration or keep it HPOF. I have a '41 Plymouth TPC , P11 that is a #'s matching original car and I show that HPOF locally. Agai thanks for any info you can give me through this forum.

Brian K.

[MCHinson]

Brian, Where in NC are you located? Here in Wilmington, we have a member who knows quite a bit about 36-38 Buicks and Packards. He can help you quite a bit on engine questions for your car. I am sure that there are others in other NC areas if you are not close to me. There are lots of AACA folks in NC who would love to help you.

[briankearney]

Matthew, I'm in Arapahoe on the coast near New bern, so I guess I'm about 2 hrs. from you. I'll be using Mike Kutkuhn at CAMS in New Bern for my engine. He is an AACA member and a member of my local club, First Capital. He does excellent work and is familiar with vintage engines. Like I've asked I would need some specs for this engine if anyone can help. tanks for your response,Brian

[Bill Stoneberg]

Buy a shop manual and it will tell you eveything you need to know. No sense guessing. Cars or Bobs Automobilia http://www.bobsautomobilia.com should have a reprint.

[MCHinson]

Go to the following link for contact information for Jeff Oaks:

http://local.aaca.org/northcarolina/capefear/Officers_2008.htm

Call or email Jeff. He is the President of the Cape Fear Chapter and the Secretary of the NC Region. Jeff should have the information that you seek about your 1938 Buick engine.

[eric_b_1937]

Sounds like my 248 straight 8 that I rebuilt two years ago.

It had the same missing material from the edge of the pistons on 4 out of 8. The Odometer showed about 90,000 miles but looking at the wear from other parts in the car like rear end and wheel bearings it is most likely a 190,000 mile car or more. So check out other area's of your car. You probably have 138,000 miles on it. Remember that most these un-restored car's were used for everyday transportation for at least 8 years over the war and on into the 50's.

You will be better off rebuilding and knowing it will last a while.

[Guest simplyconnected]

That sounds more like it, Eric. Pistons don't just give up at 38k, and for the cross-hatch to be gone takes well over 50K miles.

Even if you hire a mechanic to do your engine, you still need a shop manual. For $40, here's the link:

http://www.bobsautomobilia.com/cgi-bin/shop.pl/SID=1225131404.8532/page=product.html/product=2127

Professional engine builders will already have sources for your replacement parts. Identification by cubic inch, etc. is good for you, but engine builders take precision measurements that will change your numbers once your cylinders are bored. If you want tolerances, visit piston ring company sites like Hastings. Here are some basic Hastings stock numbers for your engine:

1938-39 Series 40, 60, 80, 90, Buick

Bore: 3 3/32

#cyl's: 8

Ring Set #: 426

Quantity and width, Compression: 8 - 1/8

Quantity and width, Compression: 8 - 3/32

Quantity and width, OIL: 16 - 3/16

Of course, they offer 'plus' sizes for oversized pistons. Here's the link to the Tech Tips:

http://www.hastingsmfg.com/ContentData.aspx?Contentid=82

You have a great classic engine. I urge you to pick a good engine builder AND a good machine shop that is capable of rebuilding a straight eight (most can only do up to straight six cylinder engines). Check out the Duesenberg's my builder does:

[Steve_bigD]

When I rebuild my engine 20 years ago 6 out of 8 pistons had those nibbled edges and broken or pulverized compression rings as well. There were burned marks about 1-1.5" long and .030 deep on the cylinder walls where the nibbled areas were.

The engine still ran OK but smoked like a locomotive. Here are some photos:

http://demandred.dyndns.org/540i/gallery/album01

Although my odometer was broken at 42K miles, I believe that my car might have turned the clock more than once. My engine needed a total rebuild including boring/honing, new pistons/rings and bearings. After the rebuild and break in it ran great.

Steve D

1938 40-41

[Guest simplyconnected]

What a GREAT restoration, Steve. Why do you think piston holes developed (pre-ignition or detonation?), and how does it run now? I never saw bearings chip off like those. I am amazed your engine even ran before you tore it down. Forgive my 20/20 hindsight, but perhaps if you "caught it" before the burned cylinders, you might have taken only .020" off instead of .030". Running an engine into the ground can easily destroy beyond repair. I'm glad your is still ok. What did you do for your cracked head? Braze and mill it?

[Guest Grant Magrath]

Steve, your engine looked exactly like our '39 when we tore it down. And ours was a fuming, smoking runner as well! It had the original pistons in it, but it was so worn, we had to go .030 oversize. We're almost ready to put the new pistons and rings in!

Cheers

Grant

[Guest ewing]

Steve, I know we are talking engines on this thread, but your pictures show an excellent restoration of the dash. Sounds like you did it. What did you use to restore the wood grain? or did you just apply multi coats of varnish to a reasonably nice original dash?

Thanks,

John

[Steve_bigD]

Hope this is not too long winded:

I bought my Buick from a collector car dealer in Woodmere LI in 1978. It had just been painted and chromed and had new WW tires. The brakes had also just been gone through. However mechanically it was not touched. I knew that the engine/train/suspension, etc would need rebuilding but I was not aware of the extent of the wear and neglect. I only was able to drive the car a few months before I began mechanical restoration.

Given the condition the car ran reasonably well except for the smoking and overheating. On the drive home from the dealer, about 30 miles, after 20 minutes on the highway the oil pressure barely registered and it began to overheat. At the same time heavy rain moved in and the cowl seal began leaking on to my right foot and the wipers barely moved. Getting off the highway I was able to stop on the local roads every 4-5 miles to add water. At one point I stopped under an overpass on the LIE and scooped up water from the rain run off to fill it. I finally managed to make it home and later found the reason for the overheating.

The block was so full of caked rust and sludge that it had completely filled the rear two cylinder water jacket in the block. This must have been like this for years but the car was probably only driven locally. The longer highway run loosened some of this crud and deposited it in the radiator clogging it up. Also I found later (after rebuilding the engine) that the head had a crack on the#7 exhaust valve seat allowing some compression into the cooling system. BTW, I measured the compression and it was not that bad considering the engine condition; 75-90 lbs in all cylinders except the one with the cracked valve seat where it was 60 lbs.

Anyhoo, I rebuild the engine myself and the machine shop that did the head didn’t find the crack which lead to coolant being pushed out of the radiator after a long high speed run. So I switched to water (antifreeze foams) with a makeshift overflow tank for a year or so and then decided to pull the head again. Well I found a used head for sale but that one was also cracked. The seller had a third head which he gave me and I had the shop build one good head from the parts of all three. I have a lot of valves, springs etc left over if anyone needs replacements.

Only three con rod bearings were chipped but all were worn. The oil pump was also shot and now with 20W-50 Mobil 1 it runs 30PSI hot. Along with the rebuilt head I had the radiator re-cored and a pressure inlet installed. I run antifreeze with 7lb pressure and it never gets hotter than 180 deg up to 100 deg ambient. (boiling is about 245 deg with antifreeze and 7lb pressure).

When I rebuilt the engine I went with original style pistons but in retrospect I would go with the higher compression later domed pistons if I were doing it again. Also don’t overlook the rear engine mounts as mine were virtually melted and allowed the engine to vibrate against the frame. They can be re-vulcanized.

The suspension was another experience. Before I could even get to the bolts I had to remove 40 years of an accumulated grease/mud caking. This had to be scrapped and chipped off and filled two grocery bags! The front wheels had over 2” of vertical play and the upper outer threaded pins were so worn that they came apart without unscrewing them. The shocks were completely filled with a similar mud as was in the engine cooling system but harder. Also the left steering arm was bent so bad you could hear the tires slightly squealing while driving straight forward (toe-in was over 2”).

Over the years I finished all the mechanicals and completely restored the interior, teaching myself how to sew along the way. The dash, I pulled from the car, stripped it (along with the window moldings) , primed and painted a beige base coat. Then after a lot of trial and error I woodgrained it using crumpled rags and newspaper. The finish was 15 coats of polyurethane varnish, wet sanding between every three coats.

My car runs good now but I do need to rebuild the steering box and would love to convert it to 3.6 rear gears. Keeping up with highway traffic these days with the 4.44 gears is not possible.

Steve D

[eric_b_1937]

Steve

I could copy your story and apply to my Buick but in 2005. Same problems even down to cleaning the frame. The guy I bought my Buick from had put a bottle of RESTORE in the engine just before I bought it to disguise how bad the blow by was and it worked for a few days. Later I found the RESTORE listed on a recipt of parts bought for the car.

I hope I don't fall for that trick again.

[Guest OLBUICKS]

Just a reminder to all of the older Buicks that has used non detergent oil over the years. If you have never had your oil pan off to see how much sludge is in the bottom of the pan, it might be a good idea. There was a article in one of the 37/38 Buick Club mags. that one of the owners was driving his and lost oil pressure. Come to find out the oil pick up got clogged with this sludge and cut the oil pressure off.. I pulled my pan after reading this and I was in bad shape in there.. After cleaning the oil pan my oil pressure went up 5 psi at idle...

[Guest simplyconnected]

Great experience, Steve. The part about your machine shop missing the cracked #7 exhaust makes me cringe. A good engine-machine shop should have caught the crack. After all, look at the length of the casting! A magnaflux machine would show the crack like a witch's wart. He could have stopped right then. Magnaflux pays for itself, if you consider the cost of tearing down and rebuilding the head.

How did you get all the rust off the cylinders inside your block? Did you have it acid dipped? (pay attention, Brian)

You mentioned higher compression ratio. What ratio did it come with and what would you go to?

With your present rear-end gear, do you have lots of throttle left, or is your engine rpm'ed out? You could use taller tires, maybe.

[briankearney]

simplyconnected, I am paying attention and I'm to the point where I pull the block which is all I have left or as Steve said bore or hone in place. I just finished cleaning and degreasing the block and now would like to know if there is a boring machine or honing tool that is mobile so as to use in the garage. I will do the head at the local machine shop but my real problem is in the pistons and cylinder walls. The one problem I see with doing it in place is cleaning the water jacket now and I don't think I want to take a chance and try to boil it later with some sort of cleaner, so I guess I answered my own question. I will continue on and pull the block. Am I better off trying to pull the tranny with the engine in one piece, seems the way to do it. BTW what does it weigh?

Brian

[Matt Harwood]

If you're this far into it with the damage you've described, I agree that pulling the engine is the right thing to do. It isn't very hard to get it out of the car. But be aware: that sucker is HEAVY--probably on the order of 700+ pounds (the 320 in my Century weighs 862 pounds without accessories). Finding a machine shop that can handle the long straight-8 might be a challenge, but you'll get better results with the engine out. Good decision.

I had my Century's engine rebuilt and they found several cracks in the block and head during magnafluxing. Here's a very common one in the head:

Also note the amount of gunk in the coolant passage. This was AFTER hot-tanking but before they went after it with brushes and wires. The block was 10x worse. Cleaning it in a hot tank really helped.

I'd pull the engine and transmission as a unit. I believe there are six bolts holding the torque tube to the transmission flange, not five. My car was similarly gunky and five of the bolts are arrayed symmetrically like wheel studs. The sixth is at the 12 o'clock position and completely out of the pattern. Don't miss it like I did!

Hope this helps.

[Steve_bigD]

Well you live and learn. I did the block in the car but in retrospect would never recommend that and would never do it again. Hours of wire brush and scraping of the water jackets through the core plug and deck holes. Flushed with muriatic acid followed by baking soda. Each cylinder took over 8 hours of honing with an adjustable hone and a 3/4" drill.

When I did my Mustang engine the machine shop boiled it out and brought all the machined surfaces and cylinders up to new spec. So mush easier.

I believe that the original compression ratio was 6.15:1 and the later domes pistons could raise that to near 8:1. The engine was designed to run on 70 octane gas.

The 40 series turns about 3400 RPM at 60MPH which is still not fast enough to keep up with today's traffic. Even the 60 series 3.9 ratio might not be high enough. Post war cars had a 3.6 ratio. Although there is plenty of power left at 60MPH, a constant 3400 RPM is really buzzing.

I can remember very vividly using a round file on all those holes like the ones in the photo Matt posted only mine were almost fully closed with gunk.

Do yourself a favor and pull the engine and have the block done by a machine shop. You can remove the head and all the accessories to make the block lighter and easier to lift out.

Steve D

[Guest simplyconnected]

Yep! I agree. There is no way to match the precision of a good machine shop mill or boring machine.

Brian, I didn't intend to dis you but please understand, these other guys have had similar situations, like packed-rust around the cylinders, etc.

Boring must be done in a good machine shop, to get a true and straight cylinder. It is impossible to bore in the car. Honing is not meant to take much iron off, because it could ruin the contour of a perfectly straight bore. Honing is done to produce cross-hatch at a 45* angle, both up and down. This is a scuffing process that stops piston rings from hydroplaning (like grooves in the road on a wet day). If you would like to hear how the engine plant matches blocks with pistons, I'd be glad to explain it.

Pulling your engine and working on it outside the car makes everything accessible, and it makes all phases of engine restoration much easier. You can weigh your own pistons, CC the head, and balance your crank/flywheel/damper pulley together. Or, you can slap all those parts together as is, and be done with it. The materials cost the same but the outcome is dramatically different.

I would raise the compression ratio to 8:1. That is not radical. Your engine will produce a little more horsepower and run nicely on regular gas.

Engine building is very precision. You should look for quality parts, a skilled machine shop, and an experienced engine builder. You can do most or all of the build if you have these resources available. Take your time, don't over work or you will start making mistakes, and enjoy this challange. The reward is tremendous. - Dave Dare

[briankearney]

Hi Dave, never thought you were dissing me and how dopey would I be if I didn't take all this well founded advice and information to heart. Brought the head to my machine shop guy yesterday and discussed the project with him. He was telling me about a diesel block that he bored in place, took about 5 hrs a cyl and trying to clean up the mess was staggering. I'm not in a big rush here so why would I not try to do it the best way possible. Will continue on and get the block out, clean it a little more, break it down further and then deliver it to him. Then the fun part ordering the parts. Any help there would be appreciated. Cars Inc. has everything and I think reasonabley priced also. Piston sets @ $290 and rings @ $145. I guess they have them matched for oversized if I need them for eg: 10,20,or 30 over. In fact everything they have seems reasonably priced. Looks like about $1200 for the parts and then labor on top of that. That's if nothing bad shows up in the breakdown. Thanks for all your help.

Brian

[Bill Stoneberg]

Bobs at http://www.bobsautomobilia.com has the parts too, they come from Egge machine and are good quality. Plus they are much nicer to deal with and they know their cars.

[Matt Harwood]

I'm always a victim of the "as long as I'm in there" syndrome. So as long as you're in there, make some upgrades. Here are some of the things I did to my 320 when I had it rebuilt:

<ul style="list-style-type: disc">[*]3-angle valve job

[*]Stainless swirl-polished valves

[*]Upgraded modern valve stem seals and springs

[*]Hardened valve seats

[*]Domed pistons (I think I have about 8.1:1 compression)

[*]3/4 race camshaft (I can't wait to hear this thing idle)

[*].040 overbore (it was rebuilt once already and received a .010 overbore at that time)

[*]Decked the head and block to raise compression

[*]Insert bearings

[*]Later straight-8 front cover to have a neoprene seal instead of a rope seal

As long as you're in there...

[Mark Shaw]

Matt,

Where did you get the insert bearings?

Mark Shaw

durcodude@comcast.net

[Matt Harwood]

I actually ended up using a set of later factory rods rather than having my babbit rods machined for inserts. That was the way my machine shop preferred to go and I trusted their expertise. No need to mess with a recipe that has worked for them dozens of times, right?

[Steve_bigD]

Hey Matt, you are tempting me to do a another engine rebuild.

Please let us know how the engine performs with all those mods. I didn't even know that the cam could be reground for better performance.

With those mods and a 3.6 rear end the car should be more than capable of sustaining today's highway speeds.

Steve D

[briankearney]

hey guys

something I just thought of when looking through Bob's Catalog and that is engine size. He has 248 and 263 listed under my year for a 38 Special. Am I missing something here and do I have a 248 in my car. What other designations am I going to need to know to get the right parts. Where would I look on the car for series #'s or engine size or anything else I might need to know. Is theresomething like a build card that I have for my Plymouth that came from the W. P. Chrysler museum. Gave me all the info about the car.

[Matt Harwood]

You definitely have a 248. The 263 was its replacement, though it was very different in many ways. Some of the parts are interchangeable, hence the multi-listing in the catalogs. Just to be safe, always order parts for a 248.

[Guest simplyconnected]

I would never attempt boring a block in the car. Even production block machining is difficult. Navistar ran diesel Power Stroke engines and sent them to Ford with crankshafts offset from the bores. That was a mess.

Machine shops use your main crank journals to locate the horizontal, so they can bore perpendicular to that. They don't use the old bore to locate a new one, they measure center lines, sometimes from the crank rod pins. You need a good, experienced, engine rebuild machine shop.

I like Matt's use of insert bearings. It's easily done and shouldn't cost much. While you're at it, line bore the crank journals and use insert-bearings there, too. That will eliminate the whole Babbitt process of pouring and wiping. Because it is a low compression engine, I don't think Stainless valves or seats will be necessary, but nyril valve seals are. I certainly would NOT grind the cam to anything but a repeat of what you already have. (We've been re-grinding stock cams for decades.) This is not a high-rpm engine. Good torque should be at low end, and you don't want to lose your smooth idle or good gas mileage.

If you can find new valve springs, buy them. They will bring a noticeable, new-engine smoothness. (New roller timing chains restore quick response, on engines that don't use timing gears.)

[briankearney]

Ok two more questions. I'm just about ready to lift the block out. Two things left to take care of. The bell and crank has a bracket, kinda like a knee attached to the Bell housing with a bolt. I removed the bolt but the bracket seems solid I mean really solid like its part of the casting. Any ideas? And the gear shift lever, do I have to take the cover plate off to remove it or is there some clever way to pop it out of the transmission using those spring loaded pins on the side of the housing that it pivots on.I've already removed the cover pan to access the tranny. And I guess I should ask if it's ok to lift the engine on a chain bolted to the block with replacement 7/16, 14TPI bolts in the holes in the block.

thanks, you've all been a big help.

Brian

[Guest simplyconnected]

Use good chain and good bolts, rearward on the block, to compensate for the weight of the transmission.

The more modern clutch bellcranks I worked on, had a ball stud that screwed into the block, and another that was nutted to a "fork" the frame. When you loosten the nut on the frame side, that end would lift off, and the bellcrank would slide right out. (That's how Pontiac did theirs.)

Think in terms of the assembly line. They developed ways of attaching modules relatively easily. Engines were on the frame, then the body was married to the frame. Everything was hooked-up after that. They had repair bays where whole engines were swapped, and the bad one would be shipped back to the engine plant.