1st Time Overhaul / Performance questions?? - 1275

[NardisCNC]

I'm finally about tackle my first engine overhaul. An A-1275 in particular. Is there any recommended general reading on the subject? I'd like to use the best quality parts I can afford. Who's makes the best bearings? What are some other quality names I should look for?

While I'm in there's I'd also like to upgrade the performance a bit. I'm not even sure what a complete overhaul (stock) is going cost yet, and I know there is almost no limit to what you can spend when it comes to performance. Lets say had a $1,000-$1,500 budget. Could I completely overhaul the engine, and add some HP with those figures? What performance mods would be the best bang for the buck?

Thanks for any help!! - Nardis

 

[DrEntropy]

Head work: Cleaning up the casting, profiling the chambers and CC'ing them, matching ports to the intake and exhaust pipes.

Balancing all the spinny bits (rods/pistons, crank 'n flywheel). Vandervell for bearings, Deves (shameless sponsor plug) piston rings...

With proper attention to detail, doing the above will make noticeable improvement. Going higher compression, camming and all the "boy racer" stuff brings in a whole different level of dollars. If it's to be a reliable driver the speed bits carry a "reliability/longevity price".

Clive Trickey and David Vizard are the authors to look for.

 

[lbc_newbie]

My experience is one you can learn from. Throw your budget out the door and do it right. I'm still paying for trying to do mine on a budget. The $1500 was for machine shop alone. I have a Kent 256 equivalent cam in it that was re-ground by Delta Camshafts in Tacoma, WA. It's a very affordable alternative to purchasing a new performance cam. Only $80 to do it. I had it bored .030 over. I bought all the parts from Import Parts NW, but found that there are better sources with quality parts elsewhere. Make sure you get a quality gasket kit (oil pan and head gaskets especially). I cannot say how important it is to find a machine shop that really knows these engines. Do NOT take it to some machinist who builds big ol' V8's for racing. They will have no clue (ask me how I know). Now that I have it all together and all the problems resolved with the motor, I'm very pleased. Total cost, including complete rebuild of the carbs was around $2800. It would have been much more, but a lot of the "rework" was done by a very qualified mechanic at a reasonable price.

Get the David Vizard book.
Tuning the A-Series Engine: The Definitive Manual on Tuning for Performance or Economy by David Vizard

 

[NardisCNC]

If it's to be a reliable driver the speed bits carry a "reliability/longevity price".

Clive Trickey and David Vizard are the authors to look for.

I would like it to be a reliable driver. Are there any mods that don't compromise that aspect?

Already have Vizard's book. Which of Trickey's books are the best? I see he has a "Tuning the Mini" book and "Modifying Production Cylinder Heads" book... at least according to Amazon.

 

[drooartz]

You might also want to give Hap at ACME speed shop a call. He rebuilt my 1275 with a street performance build (this is not a race motor by any means):

https://www.drooartz.com/index.php?page=44.3
https://www.acmespeedshop.com/

I expect this will still be a reliable street engine.

This was not the cheapest route, but I'm not an engine builder so having someone else do it was the answer for me. Hap's very knowledgeable and can help you. APT Fast is another group of folks who know these engines inside and out:

https://www.aptfast.com/

 

[nomad]

Buy a good used engine if on a budget and just thrash it!!
If you attack the job make sure your machinist takes a surface cut on the head and on the block to make them flat. Very important. Also avoid the temptation to go with too big an overbore. No more than 30 IMHO if you can. Avoid the copper sandwich head gaskets but spring for a name brand gasket kit. If your engine has a lot of wear you will have to budget a cam and lifters. There has been some problems with the lifters on the market so get professional advice on sourcing them.
KA.

 

[DrEntropy]

If it's to be a reliable driver the speed bits carry a "reliability/longevity price".

Clive Trickey and David Vizard are the authors to look for.

I would like it to be a reliable driver. Are there any mods that don't compromise that aspect?

Already have Vizard's book. Which of Trickey's books are the best? I see he has a "Tuning the Mini" book and "Modifying Production Cylinder Heads" book... at least according to Amazon.

The Trickey one on head mods is good.

The things suggested in my first response are all great for making the thing run smoothly and long when done correctly.

 

[GeeBee1]

For $1,500, you can concentrate on a solid rebuild as Doc (whats with Sig)has said.

For this price, assuming that the crank doesn't need turned down and the bores are good etc. I would recommend better breathing for the biggest bang for the buck while retaining reliability.

Some key little hits on the head ports and intake with a die grinder would go a long way, also I would make it an unleaded head while I was at it. Assuming that it is 8.8 and not a 8.3, skimming down the head a little bite to 9.0+ compression would also help. Opening up the chambers where the valves are tight aganist the wall is another option. If you play with the chambers, definatley get the head milled down a little bit.

Make sure the cam lobes look good, if not a low performance street cam would be the way to go (check out APT, and their lifters), if they are good, some offset rockers might be the way to go (but they will put you over $1,500 budget.

Also make sure you change the oil pump. Good gaskets like Payen are a must. Lightening the flywheel a little bit is cheap and will give it a better response.

For the carbs, I would make sure that the throttle shafts are good, butterfly's are solid, not with the hicup spring and file down the shafts a little bit for better flow.

This can all be done for $1,500 and would give you a reliable little lump with a little more response.

First concentrate on reliability, then breathing (and for the buck I would lighten the flywheel by a couple of pounds.

If you go for a full blown engine, it will be triple this amount when you get done. Alot of zoom, bet it doesn't seem to me, what you are looking for.

Pat

 

[NardisCNC]

Reliability is of paramount concern, as well as quality workmanship & parts. $1,500 is not a price carved in stone, just a hypothetical "ballpark". I may be willing to go $2,000 or even a little more. After all, this is my first overhaul so I need to try to be modest and not get out of control on my first project.

For the most part, I will be doing the complete overhaul myself. That is, with the exception of the critical machining that I need to leave to more qualified hands. One reason I even got this car, is that I wanted to learn how to do this stuff myself. I've always loved mechanics, but have never done any engine work. I built a CNC Router from salvaged parts that I made a living off of for the last 3 years, but have never worked on any vintage autos. I have some basic machining experience, a Bridgeport Mill, small Atlas metal lathe, and quite a few misc hand tools, die grinders, etc. I'm also an obsessive compulsive perfectionist.

I'm buying Trickey's book right now and am about to get my hands dirty.

 

[nomad]

Yes, Pat said budget new oil pump, one of many sugestion's I'm sure I forgot. When you go to do initial startup be sure to first prime the pump then crank engine till you have pressure at the guage with the plugs out. Use a good cam lube during assembly and plenty of oil on the bearings or STP. Just mentioning these things cause I have known first timers to overlook them. Most guys have learned the easy or the HARD way that have done it.
Have fun, KA.

 

[NardisCNC]

I know this would immediately put me over my spending limit at the moment, but... how are the aluminum performance heads that you can buy "off the shelf"?

What about the cross-flow type in which 2 DCOE's will bolt directly up to??

 

[Hap Waldrop]

Nardis, I build these engines for a living and would be glad to share any tech info I have with you, I also offer a service of putting engine rebuild kits together for my customers who want to do it themselves, I get you parts I know, use and trust, work with you on budget, and get these parts at the best prices, and for free you get pick my brain thru the entire rebuilding process, I even interface with machine shop you are using if needed.

Ok with that being said I think the aluminum head is waste of money, their port design is worse than stock, so save your money and get your cast iron head rebuilt, you already got a better head casting than the aluminum head. For a couple hundred bucks over what the aluminum head cost you can get a fully ported and polished head and for less than half what the aluminum head cost you can get your cast iron head fully rebuild, your cast iron head should be a 12G1316 head.

As for carbs, a nicely rebuilt set of HS2 will handle the ful demand of almost any 1275 street engine, the Weber DCOE for most is nightmare to tune and get right, and at the end of the day, the HS2s kill the DCOE in throttle repsone and mid range. You can have your HS2 carb assembly rebuilt to better than new condition for less than the DCOE and intake would cost, I just finished a set of HS2s for Bugeye last night.

 

[DrEntropy]

YES!! Yes, yesyes!

Hap has made it easy. :thumbsup:

IOW: Don't fight city hall. The info Hap posted is gospel for what you're aiming to do. You'll come away with a rock-solid better'n new mill.

 

[Morris]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]I also offer a service of putting engine rebuild kits together for my customers who want to do it themselves,[/QUOTE]

What a genius idea! I wish I had the opportunity to go that route when I rebuilt my 1500. Hap does it again!

 

[Spridget64SC]

Best advice - Take Hap up on his offer. You have to buy the parts anyway. If you don't know your way around an A-Series engine like the back of your hand, finding someone to coach/mentor is invaluable.

Simplest advice: Patience, cleanliness, attention to detail and the proper tools.

The reliability and performance you want is in a simple straight forward rebuild with a judicious selection of a couple of items. 50% of the time, I've found the cam has a bum lobe. So replace it/regrind it with a street performance cam. APT/Kent/Piper/ISKY/Delta and others have what you are looking for. Cam lift not over 0.305 and duration less than 270 will give you a nice idle and plenty of get up and go to 6,000 rpm. Use a new shaft. Make sure the cam is timed properly into the engine. Check your rocker ratio's. My experience shows every thing from 1.24 to 1.34 in the stamped varieties. Getting the valve lift within 5 thousandths is a low cost performance trick. At least 1 lifter is bad 90% of the time, so they have to be replaced. A little pocket porting and some manifold matching gets some more performance. The port shapes don't need to change drastically. Just take out the lumps and bumps. If the head is a later emissions head, the big boss around the exhaust port guide needs to come out. Same in the combustion chamber. Just unshroud the valves on the close side in about a 60 degree arc. Use the head gasket to mark where not to cut. Shaped bronze alloy guides, multi-angle seats, lead free inserts, and properly set valve springs go along with the porting. While the pistons are off the rods, replace rod bolts, resize and balance. Balance crank, flywheel and all rotating stuff. The smoother running engine will be a pleasure worth the expense. Surface the head and block as required for a target compression of 9 - 9.25. The cam will work fine with that. New oil pump. Pick the right pistons. AE21250 will work just fine. These are good to 6-6.5K rpm. Not on a regular basis, but for occassional spirited drives due to the oil drain slot design. I like +40. +30 is just too "odd" for me. The condition of the bores will dictate minimum bore. AE21253 are a more performance piston. But, they are +.020 in compression height and will bump the compression up. Clean everything, Hot tank if you can. Otherwise, use plenty of oven cleaner, degreaser and hot water and brushes. Don't forget Safety Glasses and nitril gloves and maybe a filter mask when using the oven cleaner. It doesn't breath well and turns skin to soap. Clean out all the oil passages with bristle brushes. Replace freeze/frost plugs. With this kind of a rebuild and the re-built SU's you'll quickly be wanting a better handling and stopping chassis.

$2K is probably a more accurate figure. But you can save $'s if you need something that is a good used stock item, like a single rocker, a head stud or a valve spring by getting it from a real A-Series addict like Hap, myself or others. Addicts have 5 gallon buckets of take off engine stuff saved just for that purpose. I know, I've been an addict since 1973!!!!

There are plenty of good basic rebuild books out there. I personally like reading Rich Vogelin stuff and Peterson published stuff. While not A-Series, they are good reading to get concepts and theory down.

Good luck and if you run into any quandaries, use this forum. Plenty of great A-Series minds and experiences available.

HTH,
Mike Miller

 

[lbc_newbie]

I cannot agree more with Mike... take it from me. I brought my A series engine to a machinist who swore he knew how to work on these engines. As it turned out, I ended up spending an additional $500 to fix his blunders. It's hard for me to have confidence in my car knowing that the work that was done was no where near as good as what Hap could have done. You will have to pay for the experience of your machinist, but it's money well spent. Find someone local, or go to Hap, but make sure they have experience in these engines.

 

[NardisCNC]

Thanks SO MUCH Doc, Edward, Hap, Drew, Pat, Mike and everyone else who has shared their valuable knowledge so far!! I'm learning a TON and am very excited about my first build. I will be posting pictures and updates (along with many more questions) as soon as this project starts.

Actually, here's a question.... I do already have a complete 1275 for my overhaul. I got it out of a car that was supposedly running when it was parked several years ago. I have no idea of its actual condition though. Once I get it disassembled, should I have the Head and block magnafluxed or tested in some other way before I begin, or just do a thorough cleaning, bead-blasting, etc and visual inspection??

 

[Spridget64SC]

I spent two years chasing a center main bearing wear problem and it turned out to be a hair line freeze crack in the top of the center cam bearing bore. The block had also cracked through the #2 intake and exhaust lifter bores and the #3 exhaust. Found it through inspection with a spark plug magnifyer after finding yet another worn center main on a high dollar nitrided crank. So yes, inspect and crack check. Most good engine shops will include a magnetic powder inspection of the block as part of the inspection process after hot-tanking. They might need some coaching on places to look for with the A-series. Usually on a head, it can be cleaned up with cleaners and hand tools. A good wire brushing of the valve seats and a magnifying glass of 3-10x will show any bad seat cracks. A good head shop will/should pressure check a head as part of their clean up and definitely after seat installation. Magnetic inspection is a plus. It will find cracks that are not easily seen with the naked eye. Pressure checking will find cracks in the ports where visual inspection is hard to do. If you have some history on the engine and can feel good that it had no hard freezes with water in the block, then a visual could suffice. Conservative approach is to magnetic inspect.

One thing to note on blocks. Factory dry sleeved blocks cannot be bored for normal oversizes (20/40/60)(You might sneak by with a 20, but it would be dicey with a 40 thou walled sleeve). The sleeves just get too thin. Sleeved blocks can however be bored for 73.5mm 1380cc overbores. Sleeve OD = 2.875" and 73.5mm = 2.894". So know what kind of block you have before you buy pistons. You can pull the distributor, retainer hub and the drive spindle and do a "finger exam" of the block. You will feel the curve of the sleeve walls from both #3 & #4 cylinders at the edge of the little recess for the distributor drive. If a piston is down, then you will only feel one of the piston skirts. So without tearing the engine down, you will know whether the block can go standard overbores, 1380 or it is sleeve replacement and stock bore pistons.

HTH,
Mike Miller