Questions on lifter bore correction
 

I'm trying to justify the cost to have this done on my block. 383 big block mopar, stocker.. I've heard costs are $500-700. If correcting the angle and location is worth 20 hp, then fine, if it's getting 3 hp, I'll spend the money somewhere else. Also, when this is done, is the oem angle kept....?

I'm on a budget and want to qualify with a little headroom, not kill it. thanks.

Re: Questions on lifter bore correction
 

$ amount sounds about right.
I have done BBC and SBC,using BHJ fixtures, didn't have mopar fixtures,BBC and SBC you would really be surprised most of the time how far out they are,first tried taking them to .875 and would have 1/3 to half that wouldn't clean up going from .842 to .875 so after a few times of that just went ahead and bored for bushings.
You can install fixture on block and check lifter bore location,with go-no go gauge.
you can also degree cam on every lobe and check for cam timing variances,if shows differences though are lifter bores or cam if off????, but will not show if correct angle and squareness to cam.
Usually lifter bores are corrected to where they were supposed to be from factory.
Have never done a Mopar or done A-B testing on lifter bores, however one time dynoed BBC a guy had had machined elsewhere and assembled himself,wanted dynoed because didn't run right, ended up completely re machining all of it,had to square deck up,rehone,redo lifter bores that had been done, went from .842 to .904 to correct them,rebalance rotating assembly, gained 50HP first pull when went back on dyno.
Mike Taylor 3601

Re: Questions on lifter bore correction
 

It depends on how far they are off and how many rpm you plan on turning.
Overall valve train geometry is everything at extreme rpm. Lifter bushings also allow you to control or adjust the oiling to the top end.

If the angle is not what the cam was ground for the cam timing is not correct nor is the valve seeing the proper lift either.

This is not to big an issue on inline valve heads but on canted heads it's very important as it will increase power and rpm substantualy.

Re: Questions on lifter bore correction
 

For a stocker application can I change lifter diameter? I plan on correcting lifter bore and bush but having a hard time finding quality lifter in my diameter. .921

Re: Questions on lifter bore correction
 

Some Oldsmobile engines using .921 lifters 307 394 look into it

Re: Questions on lifter bore correction
 

Last I looked, Stock Eliminator rules require the stock OE lifter diameter.

Re: Questions on lifter bore correction
 

Alan is correct and it is often but not always checked.
Pete

Re: Questions on lifter bore correction
 

Mike, thanks for the info. sounds like a good thing that guy brought his motor to you.
Bill, thanks. about 6500-6700 rpm. I'll look close at valve-train geometry for rocker arm location and push rod length. Just trying to plan for how much bang for the buck. I understand that it all really depends on the lifter bore location error though.

Re: Questions on lifter bore correction
 

I have always had the lifter bores corrected in my engines. You can use a lifter tru and install bushings with the stock lifter diameter. Then you hone them to fit the lifters perfectly. You can also replace the bushings if you need to down the road.

Re: Questions on lifter bore correction
 

Jeff, if your Olds 307 block has the .921 lifter, the block is for a hydraulic roller lifter, not a conventional hydraulic/flat tappet lifter.

According to the NHRA engine specs, the legal block for your HP rating, has the standard .875 hydraulic/flat tappet lifter and not the .921 hydraulic roller.

Also, the .875 Chevy lifter is not the same as the Olds/Pontiac lifter. They have different oil band locations.

Re: Questions on lifter bore correction
 

Caution on using anyone's fixtures. I bought a BHJ for a BBC years ago and after getting blueprints from Chev, found that the BHJ was out as much as most blocks. Then you have to wrestle with the assumption that the factory design and specs are the most optimum for valve train geometry. At least you will get them consistent.

Re: Questions on lifter bore correction
 

This is a good point, In most cases the factory design is not even close to optimum, as I said earlier specifically with canted valve heads

This was not brought up in the roller cam thread but it is a big reason why some guys are chewing thru lots of valvetrain parts..... did somebody mention.... "lifters"

Re: Questions on lifter bore correction
 

Thank you for the info. I swore they were .921. Just finishing painting 1 car and next is 307 olds motor for wagon.

Re: Questions on lifter bore correction
 

Listen to Dwight's advice, the bhj fixtures are about as bad as just leaving the block alone, we have a CNC mill at my shop that we do this job on, can't beat a CNC machine when it comes to exacting tolerances. We only charge $450 though and seeing that others are charging $500-700 to do it on a manual mill I might need to go up on pricing...lol

Re: Questions on lifter bore correction
 

BHJ fixtures were like hooked on phonics,worked for me.LOL
Allen,
Ten years ago when I did lifter bores w/BHJ we got $375.00 SBC $425.00 BBC including bushings, by time took and bushings was how we come up with those numbers,CNC you can walk away some,manual machine pretty much stuck there.
Mike Taylor 3601

Re: Questions on lifter bore correction
 

Allen, Without the fixture, what do you use for a reference, and how do you choose the angle ? thanks

Re: Questions on lifter bore correction
 

Factory blueprints and a CNC is the best.

Re: Questions on lifter bore correction
 

Sorry I'm slow responding, I don't usually get on here while I'm at the shop, but Dwight answered the question already, we have factory blueprint locations programmed into the CNC, and if needed we just make program changes if an angle or location change is required...

Re: Questions on lifter bore correction
 

Thanks guys. Looking at some dated drawings, w/o dimensions no less, The BBM lifter looks to be 90 degrees to the deck, so at least for this block using the crank and cam centerline to swing the angle, then line up with cam centerline should work. I do dimensional inspection work for a living, so I enjoy understanding how this stuff is done.

Re: Questions on lifter bore correction
 

I do all my blocks in a HAAS CNC machine and we only charge 275.00 for machining lifter bores LOL. I guess I will have to go up.

Re: Questions on lifter bore correction
 

I'm $450 to bore block, install bushings and bore and hone bushings to size

Re: Questions on lifter bore correction
 

Thats a good deal!!

Re: Questions on lifter bore correction
 

How close are Dart's blocks lifter bore locations when you check or machine them on CNC's. I will replace my 3 boring machines with CNC eventually, not sure what brand yet.
Mike Taylor 3601

Re: Questions on lifter bore correction
 

Most blocks I machine lifter bores in I spot face the lifter bores and so far the Dart blocks seem to be spot on, That being said last weekend I machined a World Merlin 3 block going from .842 to .904 and the exhaust lifter bores on the drivers side all needed bushings. Even when I spot faced the to off the lifter bores they were of by quite a bit.

I have 2 HAAS CNC machines I work with both are great machines and if they are good enough for Hendricks Motorsports they should be fine for me.

If I was going to buy a new CNC for machining blocks I would go with the Centroid machine. http://centroidperformanceracing.com..._cnc-video.php

What ever you get for a CNC it a must to get it with a Probe system !!!!!

Re: Questions on lifter bore correction
 

Thank's Carl
The Dart blocks I have checked with BHJ matched lifter bores great,had some merlins not so great.
Only CNC's I have any info on is I had friend who had a Rottler F-65 could have bought 3 or 4 years ago for 55K wasn't right time for me though and subject came up while talking to Tim at T&S machines, one plus for his machine is all parts are generally available and they have great customer service,I really like my upgrade I got from them for my CWT 3000 balancer.
This is a purchase that will be few years down the road at least if even then.

Mike Taylor 3601

Re: Questions on lifter bore correction
 

Stay away from the knee mills its nothing but a glorified Bridgeport there not that rigid.

World blocks have a lot of lifter bore issues as I just machine one from .842 to .904 and 4 exhaust bores on the odd side would not clean up. I had to go to 1 inch and install bushings. When the other lifter bores were spot faced they showed they were off.

One World block that came in a few years ago all lifter bores would not clean up from .842 to .904 had to bush them all and just made it a 1 inch on some of them. Customer said the engine never made any power as I can see why. When dealing with roller lifters you dealing with direct center lines If the lifter bores are of any it will change the seat timing events.

http://i7.photobucket.com/albums/y27...ps7b17d0ea.jpg

Then on some of there blocks they counter bore the lifter bores so deep the lifter bore height is only 1.250 and you have to machine the lifter galley from the deck down to the lifter bore on the exhaust bores.

http://i7.photobucket.com/albums/y27...psdbc8d825.jpg

Re: Questions on lifter bore correction
 

Thanks Carl.
I had about same experience with world block,sold one wollered(KY word?)a lifter bore out in about ten runs, when put fixture on the rest of those bore were way of,in or ex,cant remember had to bush them to fix, which ever it was in. or ex. the other was fine,but bushed them anyway,figured the bronze would be better than the iron.

If I get to the point of CNC,I will being doing a lot of research.

Mike Taylor 3601

Re: Questions on lifter bore correction
 

You might look at the RMC machine as they have some nice units as well. Its best to go to the PRI Trade show in Dec.